The impossible dream, a leak free primary

Previously robert_tuck wrote:

for years I have had a leak free primary due to the liberal use of silicone sealer between the rubber and case inner.After some repairs to the drive I found myself really struggling with cleaning off the silicone from the inner case. Without the silicone the case leaks badly. Is there another alternative sealer found to work?. The case is in good nick and has been given the Hudson treatment.

Since mine will be going back together before too long what is the Hudson treatment?

When I removed my primary cover the rubber hung down low... so a new rubber will go on. But it had no silicone or other sealer and didn't leak - odd.

Previously Bruce Mitchell wrote:

Previously robert_tuck wrote:

for years I have had a leak free primary due to the liberal use of silicone sealer between the rubber and case inner.After some repairs to the drive I found myself really struggling with cleaning off the silicone from the inner case. Without the silicone the case leaks badly. Is there another alternative sealer found to work?. The case is in good nick and has been given the Hudson treatment.

Since mine will be going back together before too long what is the Hudson treatment?

When I removed my primary cover the rubber hung down low... so a new rubber will go on. But it had no silicone or other sealer and didn't leak - odd.

The Hudson treatment was that getting the inner case in line and stright and true, and the out one too match, and did you use waterproof Slikalene Grease, or something else, thats top Secret and on a need to know bases that shure got us all thinking now, Happy days yours anna J

Wouldn't know the answer. The chaincase on my '54 88 doesn't, and never has, leaked. I use no sealant at all, just a smear of oil, on the seal when assembling.

My chaincase is once again suffering continence issues. When I take the outer off, I know the rubber seal will dangle. I have a new seal waiting to go on (Norvil or RGM, can't remember). The important thing is to put the seal on the right way round (see the manual for a clear explanation). A well greased seal and not overtightening the centre nut should sort out the current leak for a good few years until the new seal eventually cries enough.

Previously robert_tuck wrote:

for years I have had a leak free primary due to the liberal use of silicone sealer between the rubber and case inner.After some repairs to the drive I found myself really struggling with cleaning off the silicone from the inner case. Without the silicone the case leaks badly. Is there another alternative sealer found to work?. The case is in good nick and has been given the Hudson treatment.

i have tried several ways to stop the leaks...silicone is ok until you have to remove the case then cleaning the sealant of is difficult.

i,ve strieghtend the case used a new rubber seal with some success

but not perfect.then i fitted a belt drive..should have done it years ago.

it now don,t slip or drag..a easy way out that works

I had 4 dommies in the sixties and eventually tried a good amount of ordinary LMP grease in there followed by a short run on the road to distribute the grease then about a half cup of engine oil poured in. A bit messy when you pull it apart for maint but all the grease would be mixed with the oil and right round the chain run top and bottom. No clutch slip and no bearing failures on my longest "onner" Edinburgh to Swanage for 2 weeks camping and back. The things you do in your youth!

Patrick.

I have always used Wellseal, rather messy but it doesn't set hard and has worked for me.

Previously robert_tuck wrote:

for years I have had a leak free primary due to the liberal use of silicone sealer between the rubber and case inner.After some repairs to the drive I found myself really struggling with cleaning off the silicone from the inner case. Without the silicone the case leaks badly. Is there another alternative sealer found to work?. The case is in good nick and has been given the Hudson treatment.

Just to give hope to all those whose chaincases leak,i seem to have the only one in captivity that doesn't leak AT ALL ! The only silicocne on it is a small bead in the corner where the rubber band sits on the inner case,just to make sure it doesn't move when removing the outer.The outer only has a smear of grease between it and the rubber to help it seat properly. I still get a tiny amount of ATF from the back of the sliding seal,which i hope to cure with a fix i've dreamed up.Don't give up hope,it is acheivable!

Be careful with the sealing band. I have bought one, 06267, from Andover Norton. Just for spare.When I compared it with the one which is on the bike I've noticed a major difference: The edge that goes to the inner edge of the outer case wasn't rounded as on the old one to match the chaincase. Therefore I think it would be harder to seal with this.Smear the rubber with grease before you mount it preventing the sheets from sticking on the rubber.

Fritz

Watch out for moths!, sounds like i'm going to have to open my wallet for a new seal. I have an almost pathalogical hatred of new parts (that don't fit). Who stocks a decent seal?. The Hudson treatment is well described in several places and uses simple methods to straighten outer cases that have been distorted by overtightening. Come on Anna,don't be shy, whats your secret?.

information ! and I do Not Use ATF Has This Kills the Rubbers inside the clutch I use H-D V.twin Clutch lubricant, formulated for wet clutchs like the Norton Oil bath

yours Anna J Dixon

Just stop it and put a belt drive on, job sorted.

I tried many times to stop the leaks on my 650ss until just before I sold it. I had to take the outer cover off for a bit of maintainance and just bolted it up and put oil in it. To my suprise it never leaked, luck ,or was it just taking the Micky.

Try the heavy duty one sided adhesive closed cell foam - with grease. The reports are promising.

Previously robert_tuck wrote:

No chance Tony, I've got three vehicles with belts that cost a fortune to change----no more belts.

robert..

i don,t know what you call a fortune ?.i also have three bikes with belt drives.my commando has a rgm belt thay cost about £45.and the other two have bob newby belts you can get them from a general supplier for about £25.i know they can snap but i,ve been lucky so far.i know a friends triplex chain snapped on his commando new chain £50.and a couple of hundred to repair all the other damage..

chains are ok they.ve been used for years.... but engineering and

electrics have moved on so i choose to go with it and spend more time riding than spannering

My brother tends to over engineer needed repairs. What he did to fix his primary leak was the following:

He took a new sealing band and froze it in a glycol/dry ice mixture and then machined off the outer sealing edge back about 1/4". He said that he had to re-freeze the band a number of times to keep it hard as the machining of about 6-8 linear inches at a timetook place. With the band machined he glued on (using CYA) a 5/16" diameter of neoprene tubing into the 1/4" square notch that he had machined. On installation the tube compressed a little into any irregularity there was on the outer case.

He said that the fix worked a champ and he never had another leak all the time he had the bike.

Would it be possible for a company that makes rubber extrusionsto make long lengths of something like this? Having the long length cut to the proper length for fitment, all you would have to do was glue the ends together at the top.

Mike

Previously stuart_munroe wrote:

Try the heavy duty one sided adhesive closed cell foam - with grease. The reports are promising.

Well your nearly there with what you have done, I use a black high temperature silicon sealer, Now for the back of the rubber band for the outside a High temperature water proof Grease , Now take note of this, Not all Grease is water proof, Morris do a water proof Grease its good for wheel bearings as well has this job then add Lucas primary chaincase oil this is no ordanary oil its liquid engineering for less clutch slipping longer life of the chain smoother performance and a quieter clutch and its cools as well , it dose what it say's on the bottle !

Yours Anna J so Have Fun

Previously robert_tuck wrote:

No chance Tony, I've got three vehicles with belts that cost a fortune to change----no more belts.

Hi Robert

I have only broke one belt in 35 years using them. This was overtight and on a 750 Norton race bike. I raced for many years and belts just seem to last forever, these were all 30mm wide. The one on my road 650ss was only 25mm wide and this was on for at least 5 years before I sold it. I also did not treat it to gentle . The trick is to have them so you can twist them 90 deg between clutch and engine pulley.

Also I found as the belts were just std rubber tooth belts any local stockest could supply them much cheaper than a chain. I also made my own engine pulleys from the std cast Iron ones and bored the inside to suit, again, very cheap.

Previously anna jeannette Dixon wrote:

Previously stuart_munroe wrote:

Try the heavy duty one sided adhesive closed cell foam - with grease. The reports are promising.

Well your nearly there with what you have done, I use a black high temperature silicon sealer, Now for the back of the rubber band for the outside a High temperature water proof Grease , Now take note of this, Not all Grease is water proof, Morris do a water proof Grease its good for wheel bearings as well has this job then add Lucas primary chaincase oil this is no ordanary oil its liquid engineering for less clutch slipping longer life of the chain smoother performance and a quieter clutch and its cools as well , it dose what it say's on the bottle !

Yours Anna J so Have Fun

Silicongrease, waterproof and cheap. Asusedbydiversfor their breathing apparatus....

I have just put my 99's chaincase back on. The silicone sealant that I used on the clapped out rubber band 3 years ago was very hard to clean off. I am never using that bodge again. This time, prompted by this thread, I have usedScapa 3259 - 12mm thick, 25mm wide black PVC foam tape. No leaks yet. I think it should be fairly oil resistant but I know petrol will damage it. Time will tell.

Previously jonathan_newton wrote:

Previously anna jeannette Dixon wrote:

Previously stuart_munroe wrote:

Try the heavy duty one sided adhesive closed cell foam - with grease. The reports are promising.

Well your nearly there with what you have done, I use a black high temperature silicon sealer, Now for the back of the rubber band for the outside a High temperature water proof Grease , Now take note of this, Not all Grease is water proof, Morris do a water proof Grease its good for wheel bearings as well has this job then add Lucas primary chaincase oil this is no ordanary oil its liquid engineering for less clutch slipping longer life of the chain smoother performance and a quieter clutch and its cools as well , it dose what it say's on the bottle !

Yours Anna J so Have Fun

Silicongrease, waterproof and cheap. Asusedbydiversfor their breathing apparatus....

Please read again , I did not put down silicon grease,! I us engineers High tempertuer Black Silicon sealer , for the Back of the rubber band , to seal this over night, then Water proof grease for the outer of the bubber band ,this is beween the outer chaincase and the inner chaincase ,the Grease is there so its easy too remove the outer chiancase whithout disturbing the rubber sealing band, and divers use big lead boots too !

yours anna j

Sorry to resuscitate this thread.....

I've bought a new seal from NOC spares and for the life of me can't see how John Hudson managed to describe 4 ways of fitting it. There are only 2 that I can see (unless I turn it "inside out"), and the seal itself is symmetrical being the same thickness inside and outside. Rather than having a rounded corner mentioned above it in fact has what looks like a moulding "flash" on one corner, which I'm positioning to the outside edge of the external chain case. It's also slightly too long.

I'm trial fitting it off the bike and the best result I've managed is a slow weep from the forward lower edge (ie beneath the engine sprocket). I'm clamping the two halves together with a long stud and big washers. That result was after lubricating both chaincase halves with grease - no silicone or anything else. I haven't yet tried Anna's suggestion of silicone grease - is this like this: https://www.wickes.co.uk/Wickes-Clear-Silicone-Lubricant---250ml/p/432013 ?

Is this seal fit for purpose? Should I shorten it (as John suggests) and if so join the ends with superglue?

The outer chaincase is undistorted around the fixing stud and the 2 stiffening ribs are at right angles as John describes.

When I last had a Norton single in the 1970s I had neither the money nor the time to sort this issue out but would like to get it right this time!

If the seal is too long, shorten it. Just keep the join at the top. It certainly is what works with Velocettes which have equally challenging chaincases. Actually, more challenging.

There is or should be a raised lip along only one corner so there are four places to put it. The manual says what they intended. I''ve tried all four but I don't believe it makes much difference. Sometimes I put it together and get no leaks but usually it does! Moulding flash on the new ones doesnt help.I buy cheap puppy training mats from the pound shop. A tin tray always gets kicked eventually. I dont buy posh ones. The absorbent crystals dont absorb oil.

The seal on singles is a bit different. I guess Norton tried new ideas when the knew the old ones didnt really work.

Of course prewar motors (and engines in the '50s) didnt benefit from modern seals so nobody expected dry engines and clean garage floors anyway.

Thanks both. Actually, I was successful with both a Venom and a G80S Matchless which both had those horrible band type chaincases so refuse to be defeated by the Norton!

I'm not sure which manual people suggest - I have a copy of Edgar Franks's red book (inherited from my dad complete with greasy thumb prints) and several pdfs of the Norton manual but none really says anything about sealing the chaincase other than "ensuring the sealing band is in good condition".

I do see that the part number (A2/486) seems to be consistent right from the rigid framed singles through the early featherbed twins, but this isn't shown on the NOC item (13185). Andover Norton quote both A2/486 and 13185 for their item so I suppose it is the same.

I'm working on the Do Not Disturb basis. I had the chaincase sealed with an new band from Andover Norton but had to take the case off to fit a new clutch. If I can get it to seal again, I have now fitted two blanking grommets to let me adjust the clutch and check the ignition timing without removing the chaincase. Obviously, if I have to do major work on the clutch or replace the primary chain, the case will have to come off, but I'm hoping that won't be too regular a need!

There is also the Haynes manual for Dominators etc. (The most recent reprints have poor illustrations - they must be facsimiles and not printed from original plates). And the Neil book ('Pitman Press' I think) but that seems to be out of print.

There are are least two and maybe three bands. The later Dommie one is rectangular with a 'pip' in cross section which extends from one edge. I'd have to look but I think the Haynes manual says to putthe lipped edge against the outer case. Then my late friend's featherbed ES2 had a wedge shaped band which he assured me was original. And my prewar 16H has a slightly shorter plain rectangular band which I think is also slightly smaller section than the Dommie. The earlier bike has thicker tinware I believe.

Silicone grease sounds maybe worth a try since oil shouldn't wash it off. It's about £10+ for 500g in plumbers' merchants.

I've carefully removed about 1" from the band and glued it back together with superglue. Now fitted (off the bike ) after making sure all surfaces were spotless, bare metal on the inner case and a good coat of grease on the outer. Then nipped up with a through bolt and large washers.

And it held oil (ATF) for the hour or so I left it!

I think the excess length was making the band squeeze out at some point. Now to fit it on the bike, where it will no doubt leak as soon as filled with oil.

I may just try the silicone grease rather than the normal HMP stuff I've used. I'm assuming the real sealing effect is against the little step on both the inner and outer rather than on the large flat areas of the band, and the grease is to help the whole lot slide into position rather than act as a sealant itself.

There is quite a gap between the outer case and the outer side of the band but that doesn't seem to matter.

Hi Ian

Do you have a photo from the back with it assembled off the bike? I've never done that! It's hard to know which bits are important.

There are two sources of oil leak from the Dominator Primary Cases. One is the section where the band fits and the other is all the holes drilled in both cases.

The band will not seal very well if either of the cases is distorted or the band itself is defective. ie stretched and too long or hardened with age. Buying a new band ought to be a big help as the modern rubber used in them tends to more flexible and consequently seal better. However, one of the bands that I recently purchased had a nice wedge section, which was good, but the actual band width was about 5mm less than the old band. So when the cases were put together the new band did not get compressed enough to seal well.

Going back to the holes that may cause dripping. If your engine has a worn main crankshaft seal then blowthough from the crankcases into the primary will occur. This then overpressurizes the cases internally and promptly blows oil vapour through the clutch, footrest and alternator cable holes (if you have such).

Hi David.

Sorry, I didn't take any photos as my hands were dripping with ATF..... All I did was to use 2 large diameter (about 3") "washers" - which may even have been isolastic parts - and a 10mm setscrew long enough to go through both sides. The advantage was that I could see what was going on with the band - of course with the chaincase in situ it's hidden.

I've now refitted the inner portion to the bike and am fitting the clutch internals etc. Dare I test the oil tightness? I am waiting for a new primary chain so will wait for that rather than do a trial assembly which will probably be fine only to leak when I do the final job.

I have worked out that the actual sealing effect is from the band being compressed across its width between the small steps on both the inner and outer cases. I had initially been under the impression that it was sealing on the wide faces. I suspect that's why it wasn't sealing when it was too long as it was being squeezed away from the step at some point.

I can cope with a slight weep / leak from the holes when the engine is running but what I can't abide is a chaincase that will empty itself while the bike is standing in the garage.

Hi try an industrial O ring and superglue it at the top. Buy a length from an industrial tool supplier like Cromwell. I used them all the time years AGO, CUT WITH A RAZOR BLADE AND JOIN AT THE TOP. FIT WITH OUTBOARD MOTOR GREASE.

Scapaâ? 3259 Black PVC Foam Tape 25mm X 6 mtrs Thickness 12 mm SEL325925

from Adhesive Supplies Ltd.

Had to trim the leading edge a bit and cut it to length but it is more flexible than the std rubber ring and seems to do the job with the usual provisos of cleaning evreying first and applying grease before the cover goes on.

George

Unfortunately couldn't think of a helpful comment as on my Dominator, still in Yorkshire, not got round to the stage of seeing this problem off!

But to my mind this is a prime example of a Company, Norton, who should have known better, resorting to "Micky mouse" engineering solutions, instead of using a fully cast Primary Drive side cover with inspection hatches, filler and oil level drain screw; like Royal Enfield, BSA and Triumph did, though this development happened in stages!

And we, (perhaps some of us) wonder why, sadly that large sections of British engineering became the laughing stock of the whole World! This is one of the good reasons why, Honda, Suzuki, Yamaha and Kawasaki are still in business of producing two-wheelers! Even my budget model BSA Bantam had a proper fixed and sealing, primary chain-case!

So how could Norton, a premier British company, or even AMC of all people, not re-engineer this negative feature to put things right and level with the other manufacturers. And why aren't there other proper suitable solutions out there, like re-engineered castings for the Primary drive, as opposed to often having to change the entire primary drive side to a belt driven?

The primary reason being to stop oil leaks, no-pun intended!

When I had my bike running in the '80s I greased the rubber band and put it together carefully. Instead of winding it together with the centre nut, I squeezed the outer part back, and then tightened the nut, but only hand tight. It was oil tight.

Now I have rebuilt my bike, and seem to have lost the knack. It leaks.

BTW my new sealing band from RGM is wayyy too long. The old one went back on

Paul

Robert - good luck and please keep us posted.

Looking at John's criticisms - I think they are unfair. Back in the '50s and '60s when Dommies being built, most cars were not oil tight, and every car parking place had a black oil stain under the engine. Nobody cared because there wasn't much point.

Our new Landrover (1957) came with a drain plug fitted to the bell housing. After a few thousand miles, the gathered oil wrecked the clutch. That plug belonged in a screw threaded bracket on the chassis and was only intended to be fitted if you intended to wade through a river!

The singles had stiffer cases than the Dommie and I'm sure are less prone to leak. So perhaps they thought the design was fine but made a mistake when they relaxed the design for the Dommie. And in any case - before lip seals were introduced, felt seals were used and gear boxes and engines leaked more than the primary case.

Other firms made different choices - but firms like BSA and Triumph were ten times bigger and could more easily absorb tooling costs.

The Japanese bikes arrived at the same time as technical advances in material and sealing technology, and a rapidly rising local market that dwarfed the UK market, at the same time as the UK bike manufacturers were hit by the rise of the private car in families who used to rely on motorbikes. So the Japanese caught the wave... as the Chinese look set to do today for much the same reasons.

But my Dommie is brilliant anyway...and the few oil leaks don't worry me in the slightest! And the fact of a dry primary chain case isn't enough to convert me to preferring a Bantam.

Previously robert_tuck wrote:

I think I was hoping for for something like candle wax poured in hot to find the cracks and solidify and not mix with the ATF that i'm thinking of using. Might give it a try, with a new seal.

Having asked a mate who has been riding his â67 Atlas since new about ATF, he said heâd tried it a few years ago, and found it unfriendly to his clutch plates. Heâs back to 30 weight. Just having put ATF into my primary before a test run, Iâll drain and follow his advice.

Having asked a mate who has been riding his â67 Atlas since new about ATF, he said heâd tried it a few years ago, and found it unfriendly to his clutch plates. Heâs back to 30 weight. Just having put ATF into my primary before a test run, Iâll drain and follow his advice.

Previously ian_soady wrote:

Previously ernie_olivo wrote:

Having asked a mate who has been riding his â67 Atlas since new about ATF, he said heâd tried it a few years ago, and found it unfriendly to his clutch plates. Heâs back to 30 weight. Just having put ATF into my primary before a test run, Iâll drain and follow his advice.

I find this odd as ATF is (obviously) designed for automatic gearboxes which are full of clutches with a very similar construction to bike clutches.....

Hello Well there is a right way and a wrong way of sealing the primary chain case first you need to know and check that both inner and outer covers are straight and true and then have a new rubber band and waterproof grease for the outer edge of the rubber band, And for the under-side of the rubber band use engineers black silicon sealer, do this bit first and let it dry then next day put the waterproofgrease on the outer edge of the rubber band and then fit the out cover and do up the center nut, So you have two threads showing, Then take off the filler cover held by the spring chip arm, And undo the nut at the lower half of the outer cover , Next use LUCAS PRIMARY CLUTCH fluid and pour some in to the primary case until it comes out were the nut is in the primary case then refit the nut and filler cover and spring arm in place job done , AND NEVER USE ATF fluids It attack your center rubbers and make then go very soft and mushy, only use the right stuff to get good results below Lucas Primary chaincase oil

I believe the seal is actually on the narrow faces of the band, ie where it contacts the steps in the cases, not the wide faces. I did think I had achieved nirvana when I tested the PCC off the bike with no sealant but of course once fitted I got a slight weep. So after several attempts I was successful with the merest smear of RTV on said narrow faces, fitting the band to the inner PCC then a thin smear of grease on the broad face of the outer to help it slide on and careful fitting without overtightening the centre nut.

However, I haven't yet ventured on the road so we'll see how it behaves then although I have had it running on the stand for several minutes.....

My primary cover is currently fitted using a smear of grease on both sides of the rubber sealing band. It's not bad for leaks. Next time, I intend to try using silicone sealer.

Method - put a bead of silicone on the outer cover where it meets the front face of the rubber sealing band. Let it cure. Then clean the rubber sealing band carefully, smear some silicone on the inner face of the rubber band so it glues to the inner cover, and fit the outer, lightly. When it is cured, fit it properly. This way, the cover is easily removed and re-fitted, but the sealing relies on silicone sealer

Paul

Previously robert_tuck wrote:

I have tried silicone and it was moderately usefull, Must have been good stuff as almost impossible to remove remnants from inner case flange. No thanks.

Hello ,

Patrick Lindsay had written in March 07. 2015. that I tried . So it works well . Since then i have it riding . So the oil stays inside .

Best Regards :

IstvÃ?n

Previously robert_tuck wrote:

I have tried silicone and it was moderately usefull, Must have been good stuff as almost impossible to remove remnants from inner case flange. No thanks.

You can buy silcone remover from the likes of B and Q

dan