Oil leaks

Classic Norton Commando Motorcycles.

Oil leaks

Postby Paul1972 » Thu Mar 25, 2010 10:02 am

Any sugestions on the best way to seal a primary chain case? Someone told me silicon was a good option?

Also the oil tank return pipe is leaking where it joins the top of the tank even with two union clips on. I don't want to over tighten the clips, what size should the rubber pipe be?

Any help to the above questions is much appreciated :D
User avatar

Paul1972
Posts: 26
Joined: Tue Oct 28, 2008 2:16 am
Location: Bournemouth UK

Re: Oil leaks

Postby pete.v » Thu Mar 25, 2010 10:17 am

Have you had your primary off lately?
I believe the best and only way to seal the primary is to verify that the surfaces (inner and outer) match up proper. Behind the inner at the mounting stud in the center is were shims go to bring it all home (square). " 060399 3/8" Washer Shim, .027" Thick" Otherwise, when securing the outer at the center bolt you will flex at the point were the inner mounts to the crankcase causing warpage at the mating surfaces and therefore areas that will not seal even with a new o-ring . This needs to be done, of course, before final assembly. There will alway be an issue unless done right. I hope this is not too bad news.
Last edited by pete.v on Thu Mar 25, 2010 3:34 pm, edited 3 times in total.
Good judgement comes from experience,
experience come from poor judgement.
User avatar
Access Norton VIP Paying Member
pete.v
VIP MEMBER
Posts: 4361
View Photo Album - Images: 0
Joined: Sat Oct 31, 2009 4:24 pm

Re: Oil leaks

Postby Paul1972 » Thu Mar 25, 2010 10:38 am

Nice one, I will give it a go. Thanks
User avatar

Paul1972
Posts: 26
Joined: Tue Oct 28, 2008 2:16 am
Location: Bournemouth UK

Re: Oil leaks

Postby Baldrick » Thu Mar 25, 2010 10:52 am

Check RGM motors they have a special square section primary chaincase O ring?

Having said that I put it on and 5 minutes later I put a belt drive on and it cured any oil leaks...he he!
"Nothing Suceeds Like Excess"
'52 ES2 Plunger
'73 850 Interstate
'05 GS1200 Adventure

Baldrick
Posts: 82
Joined: Wed Oct 17, 2007 8:09 pm
Location: Mount Maunganui New Zealand

Re: Oil leaks

Postby Danno » Thu Mar 25, 2010 1:37 pm

Before I swapped the '71 750 motor for the '75 850 (with the new style primary case) I used to run a bead of silicone in the groove of the inner half and push the o-ring into it. Then, before it dried, I'd use the outer to press the o-ring into the silicone uniformly, then take the outer back off and let the silicone set up before buttoning it up. I used a similar method with the new-style case's gasket, only with Hylomar or Yamabond between the gasket and the inner half.

Danno
Posts: 447
Joined: Sun Feb 07, 2010 10:42 am
Location: Southwestern Illinois

Re: Oil leaks

Postby maylar » Thu Mar 25, 2010 2:03 pm

I always run a light smear of RTV on the outer cover edge where it butts the o-ring. Never had much trouble with the o-ring in the groove. The only primary leaks I get are around the chromed centre securing nut, but that's just a dribble.

The rubber hoses are 8.7 mm I believe, about 3/8 inch. Look carefully as the leak may be comming from a crack in the tank around where the rear mounting tab is welded to it.
Dave from CT
850 MKII
User avatar

maylar
Posts: 1090
Joined: Sun May 13, 2007 7:19 am
Location: Connecticut

Re: Oil leaks

Postby rvich » Thu Mar 25, 2010 2:08 pm

Danno,
I would say that is a pretty good idea, as in theory if the faces are not mating properly the silicone would fill the void behind the O-ring when you use the outer cover to push it into place. I would just add that you don't want to over tighten the outer case on the first fit-up so that you don't squeeze out all of your goo.

Russ
"Yust vun sheep!"
Follow advice from this poster at your own risk!
User avatar
Access Norton VIP Paying Member
rvich
VIP MEMBER
Posts: 2403
Joined: Sat Jul 25, 2009 8:09 am
Location: Juneau, Alaska

Re: Oil leaks

Postby swooshdave » Thu Mar 25, 2010 3:29 pm

rvich wrote:Danno,
I would say that is a pretty good idea, as in theory if the faces are not mating properly the silicone would fill the void behind the O-ring when you use the outer cover to push it into place. I would just add that you don't want to over tighten the outer case on the first fit-up so that you don't squeeze out all of your goo.

Russ


I think, if like he said, you let it set up a bit it might not squeeze out.
User avatar

swooshdave
Posts: 7899
Joined: Wed Apr 15, 2009 10:53 pm
Location: Portland, Oregon

Re: Oil leaks

Postby illf8ed » Thu Mar 25, 2010 5:03 pm

The biggest leak from my primary case comes from the felt seal around the gearbox out manshaft. How that's supposed to seal eludes me especially if using ATF...too thin. The oil runs down the inner case and drips from the bottom - looks like the rubber seal isn't working.
David
Northern California Norton Owners Club
'72 750 Commando combat roadster
2007 Sportster XL1200R
User avatar

illf8ed
Posts: 1828
Joined: Tue Dec 30, 2003 8:29 am
Location: Brentwood, Ca

Re: Oil leaks

Postby Danno » Thu Mar 25, 2010 9:28 pm

rvich wrote:Danno,
I would say that is a pretty good idea, as in theory if the faces are not mating properly the silicone would fill the void behind the O-ring when you use the outer cover to push it into place. I would just add that you don't want to over tighten the outer case on the first fit-up so that you don't squeeze out all of your goo.

Russ

Yeah, I would just sort of hold it together by hand for a second so the silicone would hold the o ring a uniform distance from the outer half.

Danno
Posts: 447
Joined: Sun Feb 07, 2010 10:42 am
Location: Southwestern Illinois

Re: Oil leaks

Postby ML » Sun Mar 28, 2010 7:04 pm

illf8ed wrote:by illf8ed » Thu Mar 25, 2010 4:03 pm
The biggest leak from my primary case comes


Yep, the factory knew this too, just before they released the Mk3, they brought out this inner case collar version for the Mk2's. Fits all pre-electric Commandos and stops the leak down the back from that poxy felt seal.

Mick


Image

ML
Posts: 851
Joined: Sun Jul 29, 2007 11:58 pm
Location: Melbourne, Australia

Re: Oil leaks

Postby regental » Mon Mar 29, 2010 9:35 am

Out of interest, is the above collar piece still available? If so, any idea of the part number? Thanks Alan

regental
Posts: 16
Joined: Mon Dec 21, 2009 4:20 am
Location: Yorkshire

Re: Oil leaks

Postby pete.v » Mon Mar 29, 2010 9:46 am

I'm not saying they're not available but I could not find it like the one you see. I replace my the plates during a beltdrive conversion and I took one of these off. I could have saved it but cause I am dry now I do not need it.
Good judgement comes from experience,
experience come from poor judgement.
User avatar
Access Norton VIP Paying Member
pete.v
VIP MEMBER
Posts: 4361
View Photo Album - Images: 0
Joined: Sat Oct 31, 2009 4:24 pm

Re: Oil leaks

Postby DogT » Mon Mar 29, 2010 3:52 pm

I have heard of this inner primary case collar, but have never seen one. Cool. If anyone can get a part number or source. I am sure we would all appreciate it. I know I had mucho oil come out of that dumb felt seal, and it gets on the chain and then is all over the bike and it appears as if the primary chaincase is leaking because the oil drips down to the lowest part, the primary chaincase.

Dave
69S
User avatar
Access Norton VIP Paying Member
DogT
VIP MEMBER
Posts: 6112
Joined: Tue Jan 20, 2009 8:03 pm
Location: Hume, VA

Re: Oil leaks

Postby grandpaul » Mon Mar 29, 2010 4:43 pm

That late style mainshaft seal gizmo must have the two halves tack welded together to effect the installation.

... just so's you knows...
GrandPaul
author "Old Bikes"
too many bikes to list, including MkIII Interstate, Dunstallized Combat, and homebuilt Triton
User avatar
Access Norton VIP Paying Member
grandpaul
VIP MEMBER
Posts: 7201
View Photo Album - Images: 30
Joined: Tue Jan 15, 2008 1:11 pm
Location: Laredo (south) Texas

Next

Return to Norton Commando Classic Motorcycles

Who is online

Users browsing this forum: WZ507 and 3 guests