Author Topic: o-ring primary chain  (Read 936 times)

Offline 427Thunderbolt

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o-ring primary chain
« on: 06.08. 2016 00:57 »
Can a person run an oringed primary chain so you don't have to run oil in the primary case ? If it's good enough to run the wheel why not the primary?   The reason for my thought is I can't get the oil leak from one of the three bigger Allen bolts to quit leaking . I cleaned threads in case really good and dried, put some "right stuff" gasket maker on threads . Thinly coated the two gaskets and spacer up from behind the primary cover backing plate , tightened down then put oil in .  Leaks every time .  That bolt hole in the crank case is suppose to go all the way through to the inner  correct ?

Offline muskrat

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Re: o-ring primary chain
« Reply #1 on: 06.08. 2016 06:24 »
G'day 427.
You could but I wouldn't advise it. The primary runs a lot faster than the rear drive chain to start with. The O ring chain will sap a lot more power to run and the sprockets will wear a lot faster. More costly and harder to get than rear sprockets.
Try fitting fiber washers under the screw heads.
Cheers
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Online bsa-bill

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Re: o-ring primary chain
« Reply #2 on: 06.08. 2016 09:19 »
Quote
Can a person run an oringed primary chain so you don't have to run oil in the primary case ?

Friend of mine tried running without oil in the primary case, everything in there got extremely hot (too hot), racers do it but then they cut holes in the cover to allow cooling air to pass through.
No the oil in there lubricates and cools, both of equal importance
All the best - Bill
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Offline ellis

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Re: o-ring primary chain
« Reply #3 on: 06.08. 2016 09:38 »
Hi 427,

I wouldn't advise running with the chain case dry, because the clutch bearing needs a little bit of oil now and then to stop it seizing up. I used to have oil weeping from that Allen bolt so I fitted a small O ring on it and now its leak free. Just use a little Vaseline or silicone grease to allow it to go in without it snarling up. As regards chain case oil I did a measure of the oil capacity needed to touch the bottom of the primary chain. A after fitting the outer chain case I found I needed 310cc of oil to just touch the bottom of the chain, that's with a totally dry chain case. If you are just doing an oil change it only needs 190cc of oil and do not over fill it as the bearing only needs a splash of oil now and then. I only use motorcycle engine oil 10-40 Castrol as it doesn't contain additives that make the clutch slip. SRM also recommend this and not ATF. Hope this helps, and yes the Allen bolt does go all the way into the crankcase but make sure its not too long as it will foul on the Crank.

ELLIS

Offline 427Thunderbolt

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Re: o-ring primary chain
« Reply #4 on: 06.08. 2016 13:28 »
Thanks !    I'll try again with new gaskets and an oring .    Good idea !
I like the belt drive idea but for $900 .....kinda pricey

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Re: o-ring primary chain
« Reply #5 on: 07.08. 2016 10:52 »
Primary covers take a beating over the years .
Over tightening the screws causes the hole to collapse which makes maters worse.
Then there are the morons who will put allen headed cap screws into the primary that have only 1/2 the surface area under the head and that makes matters even worse.
It does not stop the leak so they do them up till it does or they strip out the thread whichever comes first.
It is worth while to get either a counter bore or end mill and square off the contact face.
Find some washers that are a good close fit to the outer edges of the hole then tighten them finger tight + 1/4 turn, no more.
One of the bolts is the drain and it needs a sealing washer of some kind and O rings do an excellent job, if they have something vaguely flat to seal against.

As for the O ring primary, as already stated, not a good idea.
Bike Beesa
Trevor

Online trevinoz

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Re: o-ring primary chain
« Reply #6 on: 07.08. 2016 22:15 »
I am one of the morons who use socket headed cap screws in the primary case and I am happy to report, that against the odds, I don't have a leak from ANYWHERE in my primary case.
Gearbox mainshaft included.

Offline 427Thunderbolt

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Re: o-ring primary chain
« Reply #7 on: 08.08. 2016 01:31 »
2 days now and no leaks !!!!   

Offline ellis

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Re: o-ring primary chain
« Reply #8 on: 08.08. 2016 04:09 »
Hi 427,

Pleased to hear that it worked for you. *smile*

ELLIS

Offline muskrat

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Re: o-ring primary chain
« Reply #9 on: 08.08. 2016 07:53 »
Me too Trev. Fiber washers are my friend. O rings won't allow you to do the screws up tight.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Online BSA_54A10

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Re: o-ring primary chain
« Reply #10 on: 08.08. 2016 09:54 »
I am one of the morons who use socket headed cap screws in the primary case and I am happy to report, that against the odds, I don't have a leak from ANYWHERE in my primary case.
Gearbox mainshaft included.

But you are technically competant enough not to over tighten them.
Although I am suprised that you do not put washers under them to spread the clamping load
Even then, pounds to a peanut there is a creep step at the bottom of the holes
Bike Beesa
Trevor

Offline duTch

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Re: o-ring primary chain
« Reply #11 on: 08.08. 2016 18:26 »

 My problem is finding fibre washers that size. I ordered some from the DraganFly last order couple of years ago, but received some for a complete other much bigger use.
 I have some the right OD, and others the right ID, but they're quite hard and fiddly to modify. Saw a diesel shop the other day, maybe I'll try them next pass.
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Online RichardL

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Re: o-ring primary chain
« Reply #12 on: 08.08. 2016 18:37 »
Though I'm not using them any more, a while back I set out to reduce steel washers to the correct OD in order to protect the covers against the heads of the Allen screws. I put a bunch of washers on a bolt and let them spin against the grinder. They eventually got down to size but it was a pain, so I'm not bothering with it anymore. Not sure that's the best decision, but that's where I'm at with it. I don't think I have leaks from under the Allen screws.

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Online Greybeard

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Re: o-ring primary chain
« Reply #13 on: 08.08. 2016 19:03 »

 My problem is finding fibre washers that size. I ordered some from the DraganFly last order couple of years ago, but received some for a complete other much bigger use.
 I have some the right OD, and others the right ID, but they're quite hard and fiddly to modify. Saw a diesel shop the other day, maybe I'll try them next pass.
What about copper washers?

Offline muskrat

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Re: o-ring primary chain
« Reply #14 on: 08.08. 2016 20:11 »
I use Richards method for the fiber washers. And every time I do it that way I get bit by the grinder and say "next time I'll use the lathe"  *bash*
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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