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Carb needle for 99

My mixture is very rich so i thought to check the needle in the 11/16 376 carb, No markings other than a C at the top 5 clip positions and 3 and seven eights long . All my other spare needles have 3 clip positions and are an inch shorter ! Can anyone confirm which is right? Also any clue as to the hole size a 106 needle jet should be, And yes i know that 106 is the flow rate.I remember changing these parts before the bike was laid up but its possible i bought dud stuff ,

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I've put the long needle in, on the top notch, I'm running B6ES plugs, perhaps a bit cold?,also running the top grade of fuel with no ethanol,this does run a bit rich in my single so could be the problem.Italian carb jets are denoted with the actual size so its easy to check the wear.

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Assuming that you have an AMAL monobloc 376, you can get the correct needle AM/376/063 by return of post from Hitchcock Motors, Tel. 01564782192. Price £5.50.

Their website is very helpful on all of the AMAL carbs. I found that my 99 was running ultra rich and discovered from their website that the needle furnished by a well known classic supplier was in fact for a GP carb.

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Off the top of my head - 5 needle positions are for monoblocs, 389s being longer than 376s. 3 needle positions are for concentrics. I am sure I will be corrected if I am wrong.

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Thanks for your thoughts guys, Ive measured the needle and there's no wear , I'm reluctant to buy new stuff as i have a garage full of new parts not good enough to use.I'll probably buy a smaller jet and size it myself by trial and error.

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Hello there,

Have you checked the float height and the needle valve.? Too high a float height or a needle valve not closing off properly(due to a bit of dirt) cause a rich mixture even if everything else is right. I assume you have already tried adjusting the air screw and got no improvement.

Sorry for interfering ! Lightweights only have Amal 375s. but they are the same in principle.

Patrick.

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I will be fitting a new viton float valve, i am surprised how much clearance there is between the needle jet and needle, Thought that with the slide down there would be no flow.

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Are you using a new, genuine 106 needle jet? These things wear fairly steadily and yours may well need to be replaced.

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Hi Gordon, Jet and needle were replaced some time ago but bike has had minimal use. The jet has no Amal marking but measures the same as the Amal one that came out , My trust in new parts is nil ,so now i measure and question everything!!.I've put the Amal one back in , getting a set of hotter plugs today.May change to half cheap fuel and half the good stuff .

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Hi, you haven't said what throttle openings you are using - I would only change the main jet if it was running rich at full bore. Most of the time you are on the slide cutaway which you haven't mentioned. I would be inclined to check that it isn't flooding then play with the needle height and slide cutaway as per the Amal leaflet. Does it idle nicely? And is the motor standard or tuned? Cheers, best of luck, you will get it right in the end.

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Robert. I had a similar problem on my 650SS, after fitting new plugs from my local bike shop. They provided B7ES; wrong plugs.They needed to be BP7ES, the ones with extended electrodes. Once thay were fitted, the problem was solved.

I noticed that your plugs are B6ES, which have the standard electrode, and are a bit soft. I don't know if the 99 requires the extended electrodes, but if so, that is likely to be your problem.

Ian

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well guy's for your information The Model 99 the correct Amal carburettor is a 376/67 1.1/16th of a inch .with a 250 main jet a 25 pilot jet cut-way side 3. needle position 3 .needle106. spark plugs Bosch -W 8DTC are the best .tired and tested As these spark plugs are shielded where as NGK B7ES are Not Shielded, And there the same heat range as Champion N5c, you can look this up on www.Green-spark-plugs.co.uk . I have been running my 650 on Bosch W 7DTC these are the same heat range as Champion N4c . for two years now and I not even taken them out yet. and my bike Starts easy and runs very nice, and I had no trouble since fitting Bosch Spark plugs But you can get the same type of plug with other manufactures look on the above website yours anna j

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And most owners are using the old type of spark plugs and running on 5% Ethanol and having trouble , where as Spark plugs have move on . and owners have not move with them. Green spark plugs now recommend that with this type of fuel that you change you spark plug to suet the triple electrode spark plugs handle this ethanol added fuels in a better way giving you a better ignition and fuel savings and better running at all condition and these types of spark plug are Shielded.from fouling and last longer so take a closer look at your spark plugs , yours Anna J

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Its going to be either, too much clearance in the needle jet,but both appear to be as spec, float valve seating u/s ,plugs too hard, indigestion from top grade fuel. I don't get near to full throttle so i won't worry about that. Running a shiney chrome no3 slide which is a good fit in the orriginal carb. I'll take it out after dinner to see if the top notch position helps.Tickover set with a colour tune plug is fine.

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Looking thro my box of bits i have some new Bosch R6 super4plugs FR78 can't find a cross reference to anything bike related ,any ideas?These are extended nose multi electrode,shame to throw them away.

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Bosch R6 super4plugs FR78 is a resistor plug. OK if you are coil ignition, not if you have a magneto. My 99 was always happy with NGK B7ES though I also used BP7ES. Didn't seem to make a difference. I use either type with my Atlas.

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Amal suggest 3 1/2 cutaway and 240 main jet in the 99.

I suggest Champion N5C plugs and Ethanol free petrol.

Bet that will fix it......

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Interesting,,all my references say no3 slide for single carb 99, ,Is that a recent change to suit todays fuel?, Also if i use the top grade (eth free) fuel in my other bike the plug always comes out sooty,and comes clean as soon as i switch to cheaper eth fuel.I have coil ignition 12v.I have a spare slide which i could make into a 3 1/2.

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From memory extended nose plugs were not used in the dommys but came in with the Commando,Has anyone noticed any difference switching from one to the other?.While I'm struggling with mixture problems it would be better to stick to an easy to read standard plug designed for normal (sedate!) classic riding, A B6ES seems about right.I'm also running a 6 start worm set so there is perhaps a bit more oil around than standard.

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The 99 Dominator uses an 1 1/16'' Amal Monobloc with a size 3 cutaway, 106 needle valve, needle position 2, pilot jet 25 and main jet 250. The 1'' version used on the 88 uses a 3 1/2 cutaway,106 needle valve,needle position 2 ,pilot jet 30 and main jet 210.

Reference, Norton Publication P106/P, maintance manual and instruction bok for the unappproachable Noton Motorcycle.

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Robert / Charles: Just looked on the Amal site. My apologies. It does indeed say for this carburetora No 3 cutaway and a 250 main jet. It also says needle in position 3. All there to see for yourself. Just go to the bit where it says make and the drop box below, model. The top reference is 99 1956 - 1961.

The mix up is that as I have a new Mk 1 28mm handy I shall initially be using that and the settings I gave earlier are suggested for that.

Hope to have my restored 99 running by Autumn and I'll let you know what the carburation is like, always an option.

Now as Ethanol is about 35% oxygen it will make the mixture weaker and I'm not sure ifAmal calculated for that. I'll not be using E5 if I can help it.

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Just a point on the high pressure oil pump system, I think you need to be using non scrolled rocker spindles with that to prevent over oiling.

I have a high pressure oil pump, serviced by John Hudson and not used since, came with service notes. This will be going in my 650 when it comes apart, along with plain spindles.

So Robert, if you are using the scrolled spindles with that oil pump then that might be a part of the problem? Others may think different?

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As i have the low pressure return to the head,(which left the rockers dry most of the time) any additional flow should not be a problem, Also i have some well worn big end journals which need plenty of oil to keep up the pressure, I'm probably getting a bit more oil fling from the crank which is also why i have not siezed a drive side piston in a long time.I probably should be running the later (650) type of oil rings to control the cylinder oiling , I'm going to order a smaller needle jet ,I'll let you know how it works out.

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Previously neil_wyatt wrote:

Robert / Charles: Just looked on the Amal site. My apologies. It does indeed say for this carburetora No 3 cutaway and a 250 main jet. It also says needle in position 3. All there to see for yourself. Just go to the bit where it says make and the drop box below, model. The top reference is 99 1956 - 1961.

The mix up is that as I have a new Mk 1 28mm handy I shall initially be using that and the settings I gave earlier are suggested for that.

Hope to have my restored 99 running by Autumn and I'll let you know what the carburation is like, always an option.

Now as Ethanol is about 35% oxygen it will make the mixture weaker and I'm not sure ifAmal calculated for that. I'll not be using E5 if I can help it.

The ideal air/fuel ratio for a gasoline spark ignition engine is about 14 parts by weight of air to 1 part by weight of fuel. For ethanol this ratio is 10:1.Both give or take a bit. E5 would have an ideal fuel/ air ratio of (0.95*14)+(0.05*10) = 13.8. Given that carbs are rather crude devises and that the acceptable air/fuel ratio is pretty wide using E5 will have no noticeable effect on weakness or richness of the mixture so rejetting is not required.

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Thanks for this info Charles. For the benefit of all riders, would you mind recalculating for E10, just in case the day comes when we will have no choice.

E 5 or E0is a bit of a dogs dinner in the UK and you don't always know what you are buying but E10will come with a warning. So E5is like biting on half a cyanide pill.

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Previously neil_wyatt wrote:

Thanks for this info Charles. For the benefit of all riders, would you mind recalculating for E10, just in case the day comes when we will have no choice.

E 5 or E0is a bit of a dogs dinner in the UK and you don't always know what you are buying but E10will come with a warning. So E5is like biting on half a cyanide pill.

E10=13.6:1, again OK for mixture even if not for fuel lines etc.

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The plugs have cleaned themselves up after dropping the needle to the top notch, It may be worth trying a 105 needle jet which could then allow me to use a middle notch and leave me with some room for adjustment ?,

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Previously robert_tuck wrote:

The plugs have cleaned themselves up after dropping the needle to the top notch, It may be worth trying a 105 needle jet which could then allow me to use a middle notch and leave me with some room for adjustment ?,

Well No one is reading my advice and you all have been writing away some of it I have all ready written before hand , you do not need a 105 needle , you need a 106 and second notch from the top so you can adjust the cutaway so you have a nice even tick over , BP7ES and B7ES are not Shielded from debris and can foul up, with E5 ethanol So this better to use Bosch W8 DTC these plug are shielded and will not foul up ,with ethanol , I been using them for two years now its the best move I ever made, my bike runs very nice , and I never had to take out the plugs yet, So try reading what I have put for your benefit. so give Bosch a try out, they cost £1.90 each from Green Spark plug Co.uk Yours Anna J

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Hey Anna, if you have never needed to take the plugs out then how do you know the state of them?

My ES2 runs OK (of a fashion) but I know the plug will be black if I took it out. Just bought the correct No 4 slide for it.

Something else, a strong smell of petrol is always a good indicator of rich running, assuming you don't have a leak.

BTW, Gordon was suggesting a genuine new 106 needle jet.

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Previously neil_wyatt wrote:

Hey Anna, if you have never needed to take the plugs out then how do you know the state of them?

My ES2 runs OK (of a fashion) but I know the plug will be black if I took it out. Just bought the correct No 4 slide for it.

Something else, a strong smell of petrol is always a good indicator of rich running, assuming you don't have a leak.

BTW, Gordon was suggesting a genuine new 106 needle jet.

well I told you earlier that the needle you needed was a 106, second Notch from the top setting, And I do not need too know what the plug are like they will take care of them self's as there Self Shielding and so this mean's they clean them self's there anti-fouling plugs so there is no need to interfere with them as they start the bike within 3 kicks most off the time its first kick, hot or cold, you really should try a set out, and see what you think our Chairman As now going to try a set in his 1960 Dominator model 88 too see if it improves the running , so we get back to you on that one, I am very happy using Bosch W-7DTC in my bike there the same heat range as Champion N4c the C is for copper core , I have a look and see if Champion are doing something smiler too Bosch I get back with some more Info for you all on Spark plugs, yours anna j

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Hi Anna and Gordon, I value your input which i know comes from experience, I have new jets, needles , slides etc, But standard settings can only be a guideline after 50 years wear,650 comp pistons add on air filter,and modern fuel.I expect i will have to go up a grade in hardness on the plug to suit the HC pistons ,Once i have done a few runs on fixed throttle positions to check plug colours and settled on a heat range ,i will look at using some fancy multipoint gizzmos.Getting some Kickback at the moment and pops and bangs, suspect the capacitor in the dissy, and an air leak at the silencer joint,Have got to sort it before the weekend.

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Previously robert_tuck wrote:

Hi Anna and Gordon, I value your input which i know comes from experience, I have new jets, needles , slides etc, But standard settings can only be a guideline after 50 years wear,650 comp pistons add on air filter,and modern fuel.I expect i will have to go up a grade in hardness on the plug to suit the HC pistons ,Once i have done a few runs on fixed throttle positions to check plug colours and settled on a heat range ,i will look at using some fancy multipoint gizzmos.Getting some Kickback at the moment and pops and bangs, suspect the capacitor in the dissy, and an air leak at the silencer joint,Have got to sort it before the weekend.

Hello What model Norton Are we on with hear as you may know where only trying our best to help > Yours Anna J

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Previously anna jeannette Dixon wrote:

Previously robert_tuck wrote:

The plugs have cleaned themselves up after dropping the needle to the top notch, It may be worth trying a 105 needle jet which could then allow me to use a middle notch and leave me with some room for adjustment ?,

Well No one is reading my advice and you all have been writing away some of it I have all ready written before hand , you do not need a 105 needle , you need a 106 and second notch from the top so you can adjust the cutaway so you have a nice even tick over , BP7ES and B7ES are not Shielded from debris and can foul up, with E5 ethanol So this better to use Bosch W8 DTC these plug are shielded and will not foul up ,with ethanol , I been using them for two years now its the best move I ever made, my bike runs very nice , and I never had to take out the plugs yet, So try reading what I have put for your benefit. so give Bosch a try out, they cost £1.90 each from Green Spark plug Co.uk Yours Anna J

Thanks for the tip Anna,

I have been having terrible problem with fouling with local fuel, if the bike runs the tiniest bit rich it just stops and the plug is dead, it has been costing me a fortune in plugs, before anyone says it, I haven't been able to get E-free here for quite some time, even Murco has Ethanol in it.

I shall give the W8 DTYCs a try.

Cheers,

Niall

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Anna, its a 1960 99 with single monoblock, Niall, try dropping the needle in the slide one notch,my plugs went from fouled sooty black to light tan electrode and a fine carbon ring round the mouth ,the earth strap has a heat line slap in the center, All much better. A sooty plug also means your oil will be contaminated with carbon very fast.

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Previously robert_tuck wrote:

Anna, its a 1960 99 with single monoblock, Niall, try dropping the needle in the slide one notch,my plugs went from fouled sooty black to light tan electrode and a fine carbon ring round the mouth ,the earth strap has a heat line slap in the center, All much better. A sooty plug also means your oil will be contaminated with carbon very fast.

Robert,

thanks for the help, but when I said a tiny bit rich, I meant it, the plugs don't come out sooty, they look fine, they just stop sparking, cleaning them will not remove whatever deposit stops them working, new plug(s) and we are away, this is not one bike, but several, (650/99 hybrid, Model 50, Venom, BMW R69S outfit, the only one which I never had this trouble with, strangely, was a 250 MZ trophy, possibly a much hotter plug to begin with). The Bing carbs on the BM are notorious for float problems, if the float in one of the carbs sticks down, the plug on that side will pack up almost immediately. I have tried different makes and grades of plug, without success.

I am buying plugs by the dozen now and spending more on them than oil.

I don't buy my petrol from the same place all the time, I have tried both regular and super grades (at the few places they still sell it). Dropping the needle on the 350 did not help, but increasing the slide cutaway did, althogh I have not got it quite right yet.

The 650/99 hybrid motor overheated in town and spat out a valve guide, I think I went a bit weak with that one, The BMW outfit, I am wondering if I can afford £700 for a new pair of carbs....

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Niall, I assume you either live in SW England or outside the UK.

I run on BP Ultimate and have to travel to get to my nearest station but when I know I will pass one in the car I'm ready with a plastic can. I take it you might be able to do the same when out of the E zone.

That said, while we know Ethanol can destroy fuel system components, including tank sealant, I wouldn't have associated it with rich running. @ 35% Oxygen of the current 5%, pro rata, it is more likely to produce the opposite if anything. Charles previously wrote that there would be no need to change jetting as a result. But Ethanol certainly promotes hot running.

Two of my singles started running hot in 2006/7 and it was only after I found the petsealcoming away and gone soft that eventually I found out why.

If only the stake holder FBHVC had warned us instead of staying silent! Who's side are they on?

Anyway, if your 99 is carboningup, sooty plugs etc then it will make the oil dirty, as said, and rather quickly.

I'll let you know in a month or so how a Mk 1 28mm with 3 1/2 slide and 240 main jet go on my 1960 99.

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Plugs that stop firing are being fouled by something, I wonder if you have a weakness somewhere in the ignition system,or the remains of a tank liner coming through?,You could try cutting a plug open to see whats going on down the bottom of the insulator.It could also be that the hot running is glazing a deposit from the fuel onto the insulator,Even with sooty black plugs my 99 kept firing.Perhaps now i'm running hotter i'll be bulk ordering plugs !!.

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Hi again,

I don't think I've expressed myself well here.

The E-fuel is not causing rich running, but carburation needs to be much more accurately set up throughout the full range of throttle openings, none of my bikes have been sooting up, but unless my carburation is much better set up than it needed to be before, any SLIGHTLY rich period, if I stay in it for more than a short while, and something in the fuel is not being burnt off and is coating the plugs, which look fine, but will not spark. I have tried cleaning them but it is useless and now I just whizz them, some have lasted 3-4 miles only. As I get nearer with the carburation this is much less, but I never leave home without at least two changes.

I don't even know where there is a BP station, I thought they only had them in Scotland now, There are very few branded stations around here any more, they are all car valeting establishments, and all the Supermarket Petrol comes from Ellesmere Port anyway, regardless of whichplaceyou buy it from.

Modern fuel injected vehicles equipped with Lambda sensors have very precisely metered fuel delivery and run much hotter than our old bikes, which used to allways err on the rich side to avoid damage to valves, piston crown etc.perhaps that is why they can run on this stuff.

I am really surprised that other people have not been having similar problems, Incidentally, none of the tanks on these bikes have ever been Petsealed, I keep my filters clean, and the bikes listed have 2 Rita systems, 1 BTH electronic and 1 old but very effective Lucas K1F Magneto.

If this is not a fuel problem then I have learned nothing at all in the last 40 years that I have been messing with bikes.

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BP are nationwide. If you are not in the SW of England then check out your nearest station, please. Only Ultimate 97 RON is E0. But remember, not in South West England.

Fuel or more likely dodgy plus appears to be the issue. Never had a bad Champion yet, although we know about counterfeit N*K's.

If you are getting your plugs from the same supplier, as with fuel, then change.

Since you have the same issue with mag and electronic ignitions I can't think what else if at one stage all was well.

Please let us know how you get on.

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Previously neil_wyatt wrote:

BP are nationwide. If you are not in the SW of England then check out your nearest station, please. Only Ultimate 97 RON is E0. But remember, not in South West England.

Fuel or more likely dodgy plus appears to be the issue. Never had a bad Champion yet, although we know about counterfeit N*K's.

If you are getting your plugs from the same supplier, as with fuel, then change.

Since you have the same issue with mag and electronic ignitions I can't think what else if at one stage all was well.

Please let us know how you get on.

Thanks again Neil,

I have taken your advice and by happy chance it seems that the Shell station near where my Mum lives is now BP, so I shall try the Ultimate and see how I get on.

Once again, I near to clarify myself, the problem I have is imperfect carburation, the Velocette is damn near perfect on the carb, the only time it happened to me on that was when I got stuck behind a JCB 3C on a windy B road, but the result was the same, a dead plug, fit new one, away instantly, with the BMW the problem is worn float needle seats which cause the float bowl fuel level to rise at low speeds, the last time I took it on a long run I used 5 sets of plugs coming back from the Dragon Rally, nearly all on the near (sidecar) side unfortunately with the OE carbs now at £700 a pair I don't know what to do about this, the Model 50 had an engine change but the previous 626 carb was retained and required different settings, the dommy was running OK when I had it on LRP but again fuel changes required carburation changes. My point is that 4star or LRP would tolerate small errors in carburation, and this E-fuel seems not to, it is my belief that something in it requires a very high temperature to burn, and a cooler, very slightly rich engine allows this substance to build up on the plug and foul it, what is frustrating is that whatever it is will not come off and the plugs are scrap.

The plugs themselves have been Champion N5Cs N3Cs, NGK B8ES, Bosch W240T2, W260T2, W7CC, various old KLG FE100s and FE 80s ant the same sort of stuff in the BMW but short-reach ones, (Champion L3, L5, Bosch W240T1, W260T1, NGK B7HS), I tried the old ones (which came from my own personal stock, saved for years and which I now regret using), because I read a piece which said that old glazed nose plugs did not suffer this problem but to no avail, about the best were some old Esso plugs said to be N4 equivalents they did quite well.

It seems that setting up the carburation on a bike if no combustion gas analyser is available will from now on involve the sacrificial offering up of a few new plugs, and how can you set up a rebuilt bike according to the book, which involves full-throttle running, until you have run it in at slow speeds where carburation used to be less critical?

I think I have bought more plugs in the last 3 years than in the previous 25, I am sure that once I get set up bang on I shall be able to forget about plugs again for a while. Unless the fuel changes again.

Incidentally the comment about not how do you know if your plug is OK if you never need to take it out, reminds me of when I was a kid I knew a guy with a CB32 Goldie which he claimed had not had the plug out for 10,000 miles, his girlfriend said 'he must check it when he has the head off every weekend!'. LOL!

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Previously Niall Topping wrote:

Previously neil_wyatt wrote:

BP are nationwide. If you are not in the SW of England then check out your nearest station, please. Only Ultimate 97 RON is E0. But remember, not in South West England.

Fuel or more likely dodgy plus appears to be the issue. Never had a bad Champion yet, although we know about counterfeit N*K's.

If you are getting your plugs from the same supplier, as with fuel, then change.

Since you have the same issue with mag and electronic ignitions I can't think what else if at one stage all was well.

Please let us know how you get on.

Thanks again Neil,

I have taken your advice and by happy chance it seems that the Shell station near where my Mum lives is now BP, so I shall try the Ultimate and see how I get on.

Once again, I near to clarify myself, the problem I have is imperfect carburation, the Velocette is damn near perfect on the carb, the only time it happened to me on that was when I got stuck behind a JCB 3C on a windy B road, but the result was the same, a dead plug, fit new one, away instantly, with the BMW the problem is worn float needle seats which cause the float bowl fuel level to rise at low speeds, the last time I took it on a long run I used 5 sets of plugs coming back from the Dragon Rally, nearly all on the near (sidecar) side unfortunately with the OE carbs now at £700 a pair I don't know what to do about this, the Model 50 had an engine change but the previous 626 carb was retained and required different settings, the dommy was running OK when I had it on LRP but again fuel changes required carburation changes. My point is that 4star or LRP would tolerate small errors in carburation, and this E-fuel seems not to, it is my belief that something in it requires a very high temperature to burn, and a cooler, very slightly rich engine allows this substance to build up on the plug and foul it, what is frustrating is that whatever it is will not come off and the plugs are scrap.

The plugs themselves have been Champion N5Cs N3Cs, NGK B8ES, Bosch W240T2, W260T2, W7CC, various old KLG FE100s and FE 80s ant the same sort of stuff in the BMW but short-reach ones, (Champion L3, L5, Bosch W240T1, W260T1, NGK B7HS), I tried the old ones (which came from my own personal stock, saved for years and which I now regret using), because I read a piece which said that old glazed nose plugs did not suffer this problem but to no avail, about the best were some old Esso plugs said to be N4 equivalents they did quite well.

It seems that setting up the carburation on a bike if no combustion gas analyser is available will from now on involve the sacrificial offering up of a few new plugs, and how can you set up a rebuilt bike according to the book, which involves full-throttle running, until you have run it in at slow speeds where carburation used to be less critical?

I think I have bought more plugs in the last 3 years than in the previous 25, I am sure that once I get set up bang on I shall be able to forget about plugs again for a while. Unless the fuel changes again.

Incidentally the comment about not how do you know if your plug is OK if you never need to take it out, reminds me of when I was a kid I knew a guy with a CB32 Goldie which he claimed had not had the plug out for 10,000 miles, his girlfriend said 'he must check it when he has the head off every weekend!'. LOL!

Thinking of buying some shares in NGK,BOSCH, CHAMPION etc.

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Previously robert_tuck wrote:

Previously Niall Topping wrote:

Previously neil_wyatt wrote:

BP are nationwide. If you are not in the SW of England then check out your nearest station, please. Only Ultimate 97 RON is E0. But remember, not in South West England.

Fuel or more likely dodgy plus appears to be the issue. Never had a bad Champion yet, although we know about counterfeit N*K's.

If you are getting your plugs from the same supplier, as with fuel, then change.

Since you have the same issue with mag and electronic ignitions I can't think what else if at one stage all was well.

Please let us know how you get on.

Thanks again Neil,

I have taken your advice and by happy chance it seems that the Shell station near where my Mum lives is now BP, so I shall try the Ultimate and see how I get on.

Once again, I near to clarify myself, the problem I have is imperfect carburation, the Velocette is damn near perfect on the carb, the only time it happened to me on that was when I got stuck behind a JCB 3C on a windy B road, but the result was the same, a dead plug, fit new one, away instantly, with the BMW the problem is worn float needle seats which cause the float bowl fuel level to rise at low speeds, the last time I took it on a long run I used 5 sets of plugs coming back from the Dragon Rally, nearly all on the near (sidecar) side unfortunately with the OE carbs now at £700 a pair I don't know what to do about this, the Model 50 had an engine change but the previous 626 carb was retained and required different settings, the dommy was running OK when I had it on LRP but again fuel changes required carburation changes. My point is that 4star or LRP would tolerate small errors in carburation, and this E-fuel seems not to, it is my belief that something in it requires a very high temperature to burn, and a cooler, very slightly rich engine allows this substance to build up on the plug and foul it, what is frustrating is that whatever it is will not come off and the plugs are scrap.

The plugs themselves have been Champion N5Cs N3Cs, NGK B8ES, Bosch W240T2, W260T2, W7CC, various old KLG FE100s and FE 80s ant the same sort of stuff in the BMW but short-reach ones, (Champion L3, L5, Bosch W240T1, W260T1, NGK B7HS), I tried the old ones (which came from my own personal stock, saved for years and which I now regret using), because I read a piece which said that old glazed nose plugs did not suffer this problem but to no avail, about the best were some old Esso plugs said to be N4 equivalents they did quite well.

It seems that setting up the carburation on a bike if no combustion gas analyser is available will from now on involve the sacrificial offering up of a few new plugs, and how can you set up a rebuilt bike according to the book, which involves full-throttle running, until you have run it in at slow speeds where carburation used to be less critical?

I think I have bought more plugs in the last 3 years than in the previous 25, I am sure that once I get set up bang on I shall be able to forget about plugs again for a while. Unless the fuel changes again.

Incidentally the comment about not how do you know if your plug is OK if you never need to take it out, reminds me of when I was a kid I knew a guy with a CB32 Goldie which he claimed had not had the plug out for 10,000 miles, his girlfriend said 'he must check it when he has the head off every weekend!'. LOL!

Thinking of buying some shares in NGK,BOSCH, CHAMPION etc.

well you only need to give one set of plugs out and there Bosch W8DTC , there the same heat range as N5c but better as these are self cleaning and there anti fouling as well. when my old Norton manxman 650 as been stud for a mouth and a half . and I fire her up she smokes with the oil weeping in to the crankcases as all Norton's do if there no tap in line, she start and burn that oil of and run real nice a run down the road and back that about 5 miles then there not a puff of smoke from then on its never seams to bother it away so that how good these Bosch plug are as if it had been a Champion the engine would of bean a pig to start , and then it would run lumpy all the way too roundabout and half way back with the odd spit and bag though the carb , then you have too take the plug out and clean them. with the Bosch plugs You do not need to do that now, its even run on half tank of diesel I put in buy mistake think I was in the van , my head was not on this planet that day , any way it run ok on it with no banging or popping , and I am not the only one that's done this our Chairman Harry he did the same with his ES2 , it run ok for some time then he started to have a bit of power lost, and got to the next filling station and filled up with fresh petrol, than it was ok from there on , so our old bike will just about run on anything , yours anna j

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I am at a loss as to why you are eating plugs. I have had no spark plug failures in very many years, well, except last year a Champion in my 1952 Land Rover. My Domi disliked Champions way back in the 1970s - newplugs would fail after 7 miles. Since then I have used NGKs in everything - Norton, Velocette, BSAs except the 1913 Douglas which has Bosch, just to keep Anna happy. Fuel is mostly BP Ultimate but can be supermarket unleaded cheapo. No plug problems, even when the mixture has been a bit out. All I can suggest is BP Ultimate and NGK B7ES or B7HS (depending on the reach) and it should work. Well, it works for me.

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Hmmmmm I'm at a loss too. Talking about a model 50 with a 626 carb. Mine has the most wonderful carburation one could wish for. In the last 5,000 miles I have taken the same Champion N5c out a few times and put it back in again, perfect colour and dry with not even a gap adjustment necessary..

I was running on 4* Leaded until two years ago when Bayford Thrust wouldn't break bulk for Northern Energy. Since then it has been BP Ultimate or E0 Murco super but for that one you need to check where it came from.

The only other thing is that I use Red X Leaded petrol treatment with Ultimate etc but even that is getting hard to find. All they seem to stock now is petrol system and injection cleaner. Can get RedX Lead Treatment at Autojumbles and I'm sure there will be some on remaining country small garage shelves. I wonder if this stuff makes a difference?

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Previously neil_wyatt wrote:

Hmmmmm I'm at a loss too. Talking about a model 50 with a 626 carb. Mine has the most wonderful carburation one could wish for. In the last 5,000 miles I have taken the same Champion N5c out a few times and put it back in again, perfect colour and dry with not even a gap adjustment necessary..

I was running on 4* Leaded until two years ago when Bayford Thrust wouldn't break bulk for Northern Energy. Since then it has been BP Ultimate or E0 Murco super but for that one you need to check where it came from.

The only other thing is that I use Red X Leaded petrol treatment with Ultimate etc but even that is getting hard to find. All they seem to stock now is petrol system and injection cleaner. Can get RedX Lead Treatment at Autojumbles and I'm sure there will be some on remaining country small garage shelves. I wonder if this stuff makes a difference?

See if you can check what the composition of the Red-ex additive is. We had a NGK rep speak at our local club and he advised that lead free replacement additives based on manganese salts tend to foul up plugs very quickly. Potassium based products are trouble free. I use "Valvemaster" in my bikes and tractor. I've used Champion N5's in my 650SS and replace them about every 5 or so years. Never had a problem. Starting always firstor second kick hot or cold. The only plug problem I have had was when I treated the WD Big 4 to a new NGK. It only lasted 5 miles. Put the old Lodge plug back in and a way it went.

regards, Ian

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If the plug is coming out fairly clean then the problem could be glazing of the insulator, Done some research on this ,the gist of it seems to be, clean up the carburation of any richness,go up a grade of hardness, Despite what the fuel suppliers say fuel today is formulated for lean burn watercooled cars. Not the dinosours we ride with crude carbs and hot heads.

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Previously robert_tuck wrote:

If the plug is coming out fairly clean then the problem could be glazing of the insulator, Done some research on this ,the gist of it seems to be, clean up the carburation of any richness,go up a grade of hardness, Despite what the fuel suppliers say fuel today is formulated for lean burn watercooled cars. Not the dinosaurs we ride with crude carbs and hot heads.

Well we all have to convert them too electric , like Harley Davidsons New Electric bike, I fit a alternator and a bank of large Capacitors and two Cadmium battery's that should keep the change up ok so then there be no need for any more fuel stops , free motorcycling , yours anna J

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As with many posts, this one is rambling round in circles, it might be this, it might be that, and repetition of the same statements.

Norton did, and Amal still do, give the correct details of jet, needle, cutaway etc for the 99. It is not outrageously expensive to replace these parts with the correct items. Once the carb has been set up, as described in the manual, if the problem persists the answer lies elsewhere. Start with everything set up as per manual, then check out one thing at a time.

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OK John but most riders following this thread would like to see a successful conclusion before being closed down. That's all.

 

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