Why o Why

[jonno]

Do I keep believing manuals.Rushed out to buy 81 link chain to fit 15/48 sprocket,as stated it stickys manual ,(not stretched),and on the shop website I got it from....and it doesnt fit nowhere near. Gonna fork out for one of those sprung top guides.

[jonno]

Not a sprung one perhaps a Gran Turismo type one.Suggestions?

[Stevepshipley]

I used a quality pull down one supplied by Corrado on here. Can't remember make but quality kit.

[Digger]

Do I keep believing manuals.Rushed out to buy 81 link chain to fit 15/48 sprocket,as stated it stickys manual ,(not stretched),and on the shop website I got it from....and it doesnt fit nowhere near. Gonna fork out for one of those sprung top guides.

I'd look at your set up - 15/48 is in range for an 81 link chain.

[jonno]

Digger I have an 81 link chain it doesnt fit,the rear sprocket is 5mm off centre,no way will I get the spider in.An 82 is too long,amazing what difference 1 link makes.Ive counted the links to make sure loads of times.Why does it always happen to me?

[hullygully]

get a spring loaded one from chiggy

[jonno]

Even with a push down guide,would the slack in the 82 chain be too much?
With 81 link chain the recommended one

With 82 link chain

The difference between 81 and 82 links,doesnt seem to relate to the difference between them when fitted.

[Wack]

I like the GT one as you can screw the plate to the casing and use the unique adjustment bolts on the slipper whereas some other like LTH the top plates screw can be under the chain.

[Digger]

Digger I have an 81 link chain it doesnt fit,the rear sprocket is 5mm off centre,no way will I get the spider in.An 82 is too long,amazing what difference 1 link makes.Ive counted the links to make sure loads of times.Why does it always happen to me?

Where did you get the chain from Jonno?

[jonno]

Got the chain from camlam genuine iwis i hope.

[Warkton Tornado No.1]

This is why half links exist. Preferably, 'one & a half' links.

The circumferential difference between 81 & 82 is (pitch x 2) = (3/8" x 2) = 3/4" (19.05 mm)

That results in a lot of slack to take up.

[jonno]

Thanks Tornado good info.

[Nelly]

I fitted a GT chain tensioner in my engine, works well in either push up or pull down setting.

[jonno]

Put push down tensioner in place,worried by the angle between sprocket and the tensioner,is it too much,also is it normal to have to undo the nylon block to get to the top fixing bolt? Also bit concerned about having to remove the bottom chain guide to get the tensioner to fit.

[Warkton Tornado No.1]

Personally, I don't use the bottom chain guide, nor have I done so since the advent of chain tensioners made of plastics, rather than rubber. I doubt anybody in competition uses them either, & that's where the loading would show a problem, particuarly down changes.

I've previously commented on this Forum (somewhere!) about using 'one & a half links' as if you don't, what you get is as your image.

However, if all is tight in there as in fasteners, I don't think you need to be concerned.

I hope that helps.

[rossclark]

I suspect that not everyone has the skill or confidence to split a chain and add links, especially one they just spent 30 odd quid on. Maybe it would be worth someone writing a quick 'how to' for JetSet?

To answer the question about having to remove the plastic part I believe that it's not unknown to have to remove it to tighten the screws when using it in pull down configurations.

[Captain Pugwash]

I suspect that not everyone has the skill or confidence to split a chain and add links, especially one they just spent 30 odd quid on. Maybe it would be worth someone writing a quick 'how to' for JetSet?

I could tell you how not to do it, I fitted a half link assembly without any of the correct tools many years ago.

I used a toffee hammer and a steel block and hammered the hell out of the rivets till it looked right (Ish) this was an old Italian stretched 80 pitch chain with a half link added.
It did stay together and it never broke, but all the time I rode it I was never ever 100% confident and the faster I went the less confident I was
It's the only time I've ever riveted a Lambretta chain and I'd never do one again unless I had the correct tools for the job.

[Wack]

I've done the same and never had a problem, the art is to mushroom the pin just enough to prevent the links binding and prevent the pin pulling out. In reality the pin is being pulled in the chains direction of travel, not sideways. Motorcycle chains come with a soft link that allows you to peen it and look at the power put through them.

[Warkton Tornado No.1]

Preferred 0.375 inch cranked Duplex link.JPG

Non-preferred 0.375 inch cranked Duplex link.JPG

As far as any technical writing that helps, I'm happy to oblige. For now, with acknowledgement to Renolds for the images:

Anybody familiar with the late Dave Webster's invaluable manual will be aware that he advocated that connecting any link to a chain should be done with rivetted connectors.

Chains joined by that method are the only type that I've known to fail! To be fair, I have 'inherited' other peoples' attempts @ making chains & often they have been over-zealous in grinding the heads of the rivets & always managed to have ground the link face in the process. On the contrary, I have used the 'spring clip connecting link' type in even number link chains & two in odd number link chains without issue! The springs need to be fitted facing the cover & with their closed end going forward in the direction of the chain travel (ACW)

I hope this helps

[rossclark]

I think this is the sort of spring clip you're referring to (and I know this one is back to front - but it's the only pic I could find) -