Excessive oil from crankcase breather pipe.

There has been plenty written on this subject but a newly rebored engine can suffer with blowby till it beds in . If you are going to leave the bike for more than a few Days then wet sumping is likely and you need to deal with it by draining the sump or other means. I deal with it by arranging the breather to run into the Tank tower (on a DL) plus running the bike at least weekly at very low revs for a mile or so to avoid blowing out the mains seal into the primary.I check the oil level and if very low,drain the sump , a later sump filter with magnet plug helps (although the old sump spanner will not fit the new filter unit,thanks AMC!) and none of your dommy spanners will fit the magnet ,thanks again!).They fit on my bike though after heavy file work.I will probably fit a tap at some stage despite all the doom mongers.

Hello Tim - That does sound a bit excessive even for a newly-honed bore. May I ask - how long had it stood since the engine rebuild ? I'm wondering if an oil scraper ring has stuck in......As you have a late wideline frame you would be able to fit the later slimline oil tank with the 'return tower' as per the later 650's and Atlas's. Then connect the breather accordingly with the longer breather pipe. There is also a take off to breathe a mist to the rear chain. A better set-up all round. Of course you then would not know if excessive oil was passing through the crankcase breather so it's better to sort that out first. As Robert suggests a valve/tap to stop the wet-dumping may be the answer if you're not running it weekly. I use the Mick Hemming's valve on mine (so far trouble-free) but I know there are doubters out there and much has been written on that subject should you wish to read it and frighten yourself !! Keep emptying the sump before you run it until you've done around 80 miles or so to bed-in the bores. Good Luck , Howard

The new pump may be bigger than needed and may have 6 start gear set. Could over supply the earlier motor?.

My 99 refused to "run in" untill after many thousands of miles past including some full bore blasts round tracks. The breather into the tank is not a final solution either, Tank breathing becomes an issue and condensation in the tank can rear its head. Engine emissions are acidic and are not the best thing for rear chains. I have a large bore vertical untimed breather on a single and only h20 comes out.

Hello fit an oildump tank you can buy nice ones off eBay and the thing to be worried about this new oil pump it one to fit a commando or not has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears made for higher pressures so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled and large end shells with holes and pressure relief spring or have the original oil pump refurbished at RGM motors

Tim,

Have you checked the compression to get an idea whether the rings are sealing? A leakdown tester is a useful tool to identify where leaks might be occurring.

If new rings were fitted without a rebore and the bores were not de-glazed, the glaze/lacquer could prevent the rings bedding in - does the engine smoke at all?

Not suggesting you try this, but I was told this story by an ex Wellworthy (piston and ring manufacturer) engineer. A new set of rings had been supplied to a haulage company for a large truck engine. After fitting the rings and re-installing the engine, Wellworthy received an irate call from the company, complaining that rings were faulty, as the engine was smoking badly and was down on power. Wellworthy sent a service engineer round and he confirmed the symptoms. When he asked if the bores had been de-glazed before fitting the rings, there answer was no! He removed the engine air filter inlet duct, asked for the engine to be started and got out a tube of Vim, which he then proceeded to lightly dust into the intake duct. Whilst still shaking in the Vim, the smoking began to subside and after about few seconds had ceased altogether. A test run found power restored and no further problems were encountered. Who needs de-glazing tools! Finding Vim, Glitto or similar now might be the tricky part though.

Andy

I saw Ajax powder a while ago, lemon scented, would that be ok?!

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2053587.m570.l1313.TR0.TRC0.H0.Xlemon+ajax.TRS0&_nkw=lemon+ajax&_sacat=0

Sounds ideal -- if you want to turn your bike into a lemon ...

Previously Dan Field wrote:

I saw Ajax powder a while ago, lemon scented, would that be ok?!

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2053587.m570.l1313.TR0.TRC0.H0.Xlemon+ajax.TRS0&_nkw=lemon+ajax&_sacat=0

The Commando oil pump has 30% wider scavenge gears, and perhaps wider pressure gears as well. If you fit such a pump to an early machine, surely this will just mean that it scavenges a bit better, and has a higher oil pressure - something the early bikes seriously lack. It is fitting the 6-start gears which require the plain rocker shafts and other oil system modifications of the late bikes

Paul

Previously anna jeannette Dixon wrote:

Hello fit an oildump tank you can buy nice ones off eBay and the thing to be worried about this new oil pump it one to fit a commando or not has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears made for higher pressures so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled and large end shells with holes and pressure relief spring or have the original oil pump refurbished at RGM motors

I've read of people using jeweller's rouge in a similar way to Vim although I'd hesitate to do it myself......

Previously paul_standeven wrote:

The Commando oil pump has 30% wider scavenge gears, and perhaps wider pressure gears as well. If you fit such a pump to an early machine, surely this will just mean that it scavenges a bit better, and has a higher oil pressure - something the early bikes seriously lack. It is fitting the 6-start gears which require the plain rocker shafts and other oil system modifications of the late bikes

Paul

Previously anna jeannette Dixon wrote:

Hello fit an oildump tank you can buy nice ones off eBay and the thing to be worried about this new oil pump it one to fit a commando or not has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears made for higher pressures so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled and large end shells with holes and pressure relief spring or have the original oil pump refurbished at RGM motors

Hello yes, it's all very well to have more oil going round your engine but with narrow return passages the oil find the weaknesspoint to bleed out of, usually the rocker cover end caps, or valve guides So you not gaining anything, Yours Anna J

Previously tim_harris wrote:

Previously anna jeannette Dixon wrote:

Hello fit an oildump tank you can buy nice ones off eBay and the thing to be worried about this new oil pump it one to fit a commando or not has 3 starts are not the same oil pump the commando one are that bit bigger inside with wider gears made for higher pressures so if this is the case you need to take your engine out for a complete rebuilt and update on rocker shafts plain not scrolled and large end shells with holes and pressure relief spring or have the original oil pump refurbished at RGM motors

Hi Anna, thanks for your comments. I am sure that the oil pump fitted is correct for the model 99, it came from Andover Norton who specialise in these Nortons. I can't seem to find any oil dump tanks on eBay, I don't suppose you have a link do you?

Many thanks

Tim

Hello there are loads of dump tanks On eBay try putting in oil tanks and breathers mods yours anna j

Tim,

I had the same issue as yours with my Norton Slimline 500cc engine.

Oil is leaking out from the crankcase breather like open a water tab. I asked many people around and seems like no one has experienced this kind of issue.

The only similarities between you and me are the engine is newly rebuilt. I keep the engine like 1 year plus after the rebuild before assemble and start the bike. Some people advise checking the piston rings, camshaft breather disc & spring.

Now I assemble back the engine with new spring, disc & piston ring. Haven't started the bike yet. I'll update again if I solve the issue and you please keep updating.

Here is a stupid question (you can consider the source):

Are the oil hoses fitted the wrong way around? i.e. the high volume side of the pump is feeding the engine?

Mike

Previously michael_sullivan wrote:

Here is a stupid question (you can consider the source):

Are the oil hoses fitted the wrong way around? i.e. the high volume side of the pump is feeding the engine?

Mike

Hello Mike,

Do you think it likely that if the delivery pipe were connected to the return side of the pump that it would still pump oil around the engine?

Regards, Ian.

It would until it had used up everything in the return pipe - which isn't a lot.......

Previously tim_harris wrote:

Having recently bought a 1959 Dominator 99, and being new to the model (my other bikes are Commandos) I need some advice on the amount of oil coming out of the crankcase breather pipe. This is routed to the underneath of the crankcase behind the primary chaincase, unlike the Commando, which returns to the oil tank. Is this correct?

When I bought the bike I was told that the engine had been recently rebuilt, although, as it was bought from a deceased persons estate, there was no paperwork with it. It also wet sumped quite frequently, but it helped enormously when I replaced the oil pump with a new one from Andover Norton. When the bike is running, in less than five minutes it has peed about 2-3 eggcups full of oil from the crankcase breather pipe. Is this normal for a Dommie? I don't really think it can be, but you never know with these old bikes.

Can anyone help with the reason for this, and a possible cure?

Many thanks

Tim

hello member now what do you call excessive oil coming from the breather pipe on startup you will get an excessive amount of oil coming out of the breather pipe as all this is oil that'srun back into the crankcase sump area and on startup the crankcase pressure forcesthis oil out , and the only way out is throughthe timed breather witch Norton manufacturer to do just this, so you can say it's only doing its job, and this oil then was supposed to be used for lubricating the rear drive chain, but what I have done with my two Norton twins is divert this breather into a catch tank and halfway up there is an outlet for oil to then run down to lubricate the rear drive chain, in a drip feed more like a scot oiler dose, you can by nice alloy catch tanks from eBay under car performance parts, now I do hope this may shed some light on things yours anna j

Tim,

There are a number of variables to consider when measuring compression, so it would be difficult to give an exact figure that you should expect to see. Gauge accuracy, piston ratio, head skimmed?, compression plate?/gasket thickness, engine temperature, etc all have an effect. As an estimate, 100-120psi would seem about right - the delta between cylinders should hopefully be less than 10psi; much more and I would investigate. A little oil added to the upper cylinder after the first test is always useful to see if the results is higher, indicating ring leakage, and your leakdown tester is handy for checking whether pressure holds and and listening for valve leakage (with ports exposed).

Andy

Previously Andy MacKenzie wrote:

Tim,

There are a number of variables to consider when measuring compression, so it would be difficult to give an exact figure that you should expect to see. Gauge accuracy, piston ratio, head skimmed?, compression plate?/gasket thickness, engine temperature, etc all have an effect. As an estimate, 100-120psi would seem about right - the delta between cylinders should hopefully be less than 10psi; much more and I would investigate. A little oil added to the upper cylinder after the first test is always useful to see if the results is higher, indicating ring leakage, and your leakdown tester is handy for checking whether pressure holds and and listening for valve leakage (with ports exposed).

Andy

Hello To test for any piston ring leakage now you need to remove your cylinder head or best done in your rebuild of your engine, now to test you need your hand over one cylinder and press down on the kick starter so the engine turns over quickly do this a few times and remove your hand and see if you have oil on them or oil coming up the bore, you should not have any oil coming past the piston rings if gaped right, your piston compression rings, end gap should be no more than 8 thou and on more than 10 thou for the oil rings . to test for valve leakage with the cylinder head removed turn the head so the valve are looking skyward, and rest the head so it does not move, and mix up white spirts and a small dab of engineers blue and stir well in untilblue now with this pour this blue mix into the dishedpart of the cylinder head around the valve so it covers them, and leave it to stand and watch for any blue running out of the inlet or exhaust ports this need to be done without valve springs in place if you have nothing running from the ports you have a good valve seal , yours Anna J Dixon

Don't think it would run with only 25 psi, you must be doing it differently to normal.

Previously robert_tuck wrote:

Don't think it would run with only 25 psi, you must be doing it differently to normal.

Hello 25 psi is just ridiculous you will have more than 100 psi each cylinder or you must be using Newton-meters per bar So do a retest before you takethe head off for no reason yours Anna J

For the compression test you need to open the throttle wide to make sure it can breathe in as much air as possible, and kick several times.

If just one cylinder was that low, then it might have a hole in it (been there, sadly), but holes in both seems unlikely. A hole on one piston leads to oil in all sorts of undesirable places, not to mention loss of power and LOTS of smoke, at which point even the most reckless rider will probably stop before even more damage takes place.

could the valve timing be out

Previously Barry Carson wrote:

could the valve timing be out

Or a bent valve in the mix , yours ajd

Under cylinder head on the XS650.de website "breather PCV" (20 euros)

You can fit it in the breather between the engine and the oil tank but that will route any condensation that builds up in your engine back into the oil tank. Consider routing the breather outlet into a small catch tank. I find my pipe, that is routed into a catch tank on my Commando, picks up about an eggcup full of oil in about 1000 miles but also some water. since fitting it, oil leaks are almost non existent and the oil tank doesn't get that mayonnaise build up in the neck. whether you screw it to any part of the frame is up to you, it could just sit in the pipe. I made the plate you can see to fit the back of the early Commando timing chest.

Some quick googling suggests that you might try Heiden Tuning if you can't wait:

http://www.heidentuning.com/p/28/2501/mo74-cg|25=7/%2315-0677-reed-type-pvc-valve

Previously tim_harris wrote:

It appears itâs not in stock at the moment, but Iâll keep my eye on it, expected in a week or so before Christmas, so I may have to treat myself! ð

Previously tim_harris wrote:

Previously david_evans wrote:

You can fit it in the breather between the engine and the oil tank but that will route any condensation that builds up in your engine back into the oil tank. Consider routing the breather outlet into a small catch tank. I find my pipe, that is routed into a catch tank on my Commando, picks up about an eggcup full of oil in about 1000 miles but also some water. since fitting it, oil leaks are almost non existent and the oil tank doesn't get that mayonnaise build up in the neck. whether you screw it to any part of the frame is up to you, it could just sit in the pipe. I made the plate you can see to fit the back of the early Commando timing chest.

Ah, that explains it, it was the plate that confused me as I thought that it came with the kit.

On my early dominator the breather pipe goes straight to the ground, as it doesn't have a later oil tank with the stack fitted to enable it to vent to the oil tank. I think it was originally meant to drip on the chain to lubricate it. Ok, thanks for all your efforts, as I said earlier, the gearbox is coming out next week to be refurbished, so I'll bear it in mind for when it's back on the road. The alternative is to fit a later style oil tank to vent it back to the tower stack, if I can find one!

If the gearbox is coming out you will be removing the oil tank anyway so why not add a tower stack while you are on with it. it cannot be a big job and I'm suresomeone on this site will have already done it or has the necessary dimensions.

A couple of inches of 22mm copper pipe and an end feed cap , some 3/8th copper gas fittings ,a tank cutter and plumbers solder/flux ,not difficult as the tank is of welded construction and won't melt. Oil in at lower level and breather out near the top.

Hi Tim, I tought myself plumbing and electrics by installing my own central heating,electrics and gas in my first house after my 70 year old Retired Bricky Dad said he did not do plumbing or electrics!, We started with an empty 100 year old wrecked shell. We did everything ourselves and learnt on the way. No tradesmen ever came in. Have to have a stubborn can do attitude. Or even just attitude!.

As Robert says - there's nothing magic about plumbing. Although that was then - nowwehave lead-free solder which is not reallysolder at all since it requires more heat than the proper stuff, and then dribblesaway. And has poorer fatigue ----etc etc.

You could buy a 'MAP' torch (try Toolbase in Wickes) and some brazing rods and try that. Gone are the days when doing a bit of brazing required you to own or hire gas bottles. I got some bent Norton footrests up to red head and successfully bent them back to shape with a MAP torch. And successfully brazed one I cracked earlier when Itried to bend it cold. I's buy a scrap tank at a jumble to practice on though! And watch out it is gas free inside anddoes not explode! On that thought, maybe it's best left undone...