I'm doing some overhaul on the primary side on my -59 TR6. Upon dismantling I noticed that the primary chain had 72 links(with master link) and that the adjuster/gearbox was way back. Even if the adjuster was all the way back there were still to much play in the chain. Now I have replaced the primary drive sprocket and clutch "basket/housing". I also bought a new 1/2 5/16 chain and cut it to 70 links (with master link) but when I try to install it its waaay to snug at the opposite direction, this time I max out the chain adjuster at the other end. So now I have a old 72 link chain that is too long and a 70 link chain that is to short. Why Im I not able to put the gearbox adjuster in its "middle" position? When I search for the primary chain part number its 70 links Renolds according to google / eBay. What can be wrong?
Will the 70 link chain fit, with the correct play, when the gearbox is in the forward position? If so, I'd think that ok. It will probably need to be tightened a bit more in the 1st few hundred miles anyway. Or it can't be fitted at all?
@koan58, I can get it on but only if I fit the chain on the sprocket and clutch basket when its off the bike and then assemble it as a unit. But then the chain is soo tight that the mainshaft is pushing against primary case (in the hole where the oil seal metal ring is) and there's no room to tight it further to let the mainshaft have some room.
Hmm.. I will try to clean it and see if it does help. But I'm in doubt that there will be enough room given that the gearbox is really forced all the way forward and I haven't even tried to tighten any nuts (to secure the gearbox in place) yet and that will probably tighten the chain even further. I cant understand how it can be so out of spec when Im using the proper parts according to manual.
I've just looked into this a little further. It seems that a 70 link chain is listed for just about all the models, including the 500's when they were still about (pre-unit). It didn't seem to make any difference whether the engine sprocket was 22 or 24 teeth. So that would mean if the 22 allowed a sensible amount of adjustment when new, then a 24 with the same chain must be on the tight side, say approx 5/8ths (one link top and bottom) closer to the engine. I suspect the person who put the 72 link chain on probably had the same problem. It may be that the middle ground is the best compromise, which is to use a cranked link = 71 links.
Thank you very much for looking into it Koan58. I’m new to four strokes and definitely new to old triumphs. What do cranked link means? I also thought that 71 would be a good compromise but since the master links always seem to be the outer link how do I accomplish 71? I did get a chain tool that can rivet but again, I have only seen master links that is the outer one
Not the best of solutions but beggars can't be choosers, other option is a pre-stretched chain, its not actually stretched but ran in so the initial rapid wear is done and the chain is slightly longer but will that be long enough.
Actually Kom's comment made me think, perhaps creatively? Initially, use 2 spring links, the old and the new, with a link from what you say you cut off your new chain, run that gently for ~100 miles, then you will likely find it's as slack as a... Then see if you can take the unnecessary bits out, in the meantime look for a cranked link, easy in my youth, don't know about availability in my dotage! Just try and remember to take the old spring link out, when the opportunity arises. Dave
Thanks a lot guys! I will see what I can accomplish in the garage this evening and try to find a cranked link tomorrow. Have never seen that type of link before, I understand that it won’t be as strong as a regular link but since the whole engine is rebuilt I will take it gently for a long while anyway.
Thanks again and I will report back when I tried this. What would I do without this forum
So why not use your old spring link, a link, your new spring link for a short distance? Most have been saying that the chain will be loose after ~100 miles, then your problem will be history, until you wear that chain out!
It looks like a new chain with 72 links may work. I will be able to get the right chain tension but the gearbox is now pushed all the way back and won’t allow any further tensioning that direction. Unfortunately I realised I bought the wrong type of chain, it’s not strengthened(is that the right word?) and a new chain is on its way. I now ordered a Renolds chain that comes with 78 links but it didn’t say if there were a half link included. Anyway in that case I will do as suggested above and use two master links for a short while.