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Running T120 with open chain primary

3K views 23 replies 9 participants last post by  graniteshins44 
#1 ·
Aside from keeping the roller bearings greased (still trying to solve that riddle) can anyone tell me any potential issues? I'm not changing over to a belt drive just want to run open chain. Anyone else had luck doing this? Secrets to success?
 
#3 ·
Mine is a 68, so no worries on the 3 vent holes on my application. 2 things I'm trying to achieve...first, no more primary leak. I've tried everything...triple thick gaskets, yamabond, etc, can't get it to seal. Secondly. I think open chain primarys look pretty sweet
 
#6 ·
Well that's good enough for me. If I was going to run it open, I'd go belt. Your going to have to lube the chain some way, and it's going to sling lube on everything. Alternately, if you can't stop the primary leak, just leave the cover on with no oil in it. At least the chain will be protected, and so will your leg.


Bob[/QUOTE]

Wouldn't that cause too much heat build up with the cover on and no fluid to cool the chain?
 
#7 ·
Wouldn't that cause too much heat build up with the cover on and no fluid to cool the chain?
The stator is more of a heat concern than the chain. If you run closed and dry, it would be a good idea to include some ventilation for it. Be ready for accelerated wear on basket sprocket and roller bearings. A BNR belt drive is the best solution, however it is also the most expensive solution :D
 
#10 ·
Did it for about 6 months and in that time I went thru 1 chain and 2 1/2 of the stock tensioners, that rubber/plastic shoe just couldn't hang. I tried all the different lubes with no difference and I had 1 adjuster fail on me out on the road. I wouldn't do it again without going to a belt..... just my 2 pennies
 
#11 · (Edited)
Damn...ok good to know. A $800-$1100, Newby drive or similar ain't in the cards for me. I gotta scratch just to afford dumping ATF in my primary, that quickly leaks and ends up on my back tire...
I may be able to swing one of those $400 belt drives...but I'm still left with the issue of lubing the rollers, thrust washer/basket...
And if the $400 ones are shit, then I'm still in the same dilemma of a non-op primary but $400 poorer for the effort...oh decisions
 
#17 ·
I agree..however my application has nothing to do with aesthetics and all to do with function. A badly leaking primary dumping oil on the back tire...not the safest.
 
#14 ·
I had the same issue with my preunit and even though I prefer ATF ,I ended up using straight 20w engine oil . It doesnt pour out like water and I havent had any clutch problems , But I always keep a bolt in behind my clutch lever to keep the plates seperated when not in use .Also try using valve grease on your primary gasket next time . It is some sticky nasty stuff but if it will stop gas vapors from leaking around a ball or gate valve seat it'll stop some oil
 
#15 ·
Dave....you said you went through multiple tensioners.....anyone thought about fabing a "roller" tensioner? such as the ones most of the ones some of us use on long rear drive chains? Maybe a skate wheel "machined down" to a smaller diameter and width?...
I think that with a good chain wax / o ring / lube would take care of the chain wear... Im still looking for that thread that showed the roller bearings being replaced by a sealed one....I remember the center ring of the clutch basket had to be removed and the sealed bearing fit with minimal machining.....I think it was located at "grainger"....or MC master????
 
#16 ·
That's a he'll of an idea! I wonder if the casting of the aluminum on the cases will be strong enough to weld a little arm to with tensioner wheel? Thanks for looking for that sealed bearing thread! Switching that out would help and I may do the open belt...if the $400 belt drives aren't just total shit and a waste of money
 
#18 ·
Primary chains run at a much higher feet per minute speed than final drive chains. It would take a very big roller diameter to keep from spinning the bearing into a grenade. I didn't bother with the calculations, but I think it's why you rarely see rollers on primary drives.

Bob
 
#19 ·
Truckedup: I agree, I thought I looked kinda cool but in the end my wallet and loss of reliability proved it wasn't worth it.

Graniteshins: have you made sure your surfaces are completely flat or tried a different cover. I took a piece of glass from an old end table, stuck on some adhesive backed sand paper and sanded the primary, then removed my startor/rotor etc and used the same glass/sandpaper like a giant sanding block to flatten out the mating surface of my case. Looked funny doing it and I'm sure someone has a better way but at the time I was really tight on money and it worked. A light smear of yamabond and the cover has never leaked since.
 
#21 ·
....I agree...see about fixing the leak. It would be a whole lot less work and fabrication....
BTW. Im running a belt drive on my shovel....and it has a "bearing" tensioner...Also remember, there are tons of bikes, motors, rotating parts that spin at a high rate....ever looked at the cam belts on a Ducatti?? or other high reving motors... those bearings have to be made tough and would most likely last better than a skate wheel bearing......I was just thinking outside the box....
 
#24 · (Edited)
The leak seems to be coming from the case or the seal between case and cover or through a screw hole. The cover isn't leaking at all
 
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