Clutch bush

[gaz_powell]

Got a job to swap out the riveted back sprocket for a solid one so need to ditch the needle bearings for a bush so bronze or brass.

I have always just used bronze but see brass are out there now - any better ???

I have an indian origin bronze one to hand and did a dry build to find its a sh@#e fit on the brand new sprocket and spider - it seems too big to fit in the sprocket and to small to fit on the spider. Tried it in some other sprockets and on spiders and its the same so my assumption is the bush is a poor product.

Gonna measure it accurately(along with the sprocket and spider) with a view to machining it to fit at work next week.

Gaz

[HxPaul]

MB do a bronze clutch bush.
http://www.lambrettaspares.com/search/c ... 0bush.html

[a.lo]

i had to fit one where i usually always use roller bearings because the inner spider(RS) although hardened for rollers(supposedly) did not seem to be finished suitably for a bearing. i tried a couple of the oil drilled bushes (different makes) and they would not go in the sprocket and the only one i could get in was the standard cheap ebay indian one that i slotted with a file. i have since seen that the bushes have to be pressed into sprockets and then reamed,never heard of that before and would make the outer oilways redundant, so that only the spider moves on the bearing any body know better?

[gaz_powell]

I've never pressed one in and reamed it before (??!! ) I've always just dropped them in - just this one seemed a s#*te fit. I dropped a a roller bearing in the sprocket and it was fine.
Will get another and work on it!
Lambretta parts!

[gaz_powell]

finally got round to accurately measuring all the parts and to be frank they were all on the p#ss - not massively but all the factors have caused the problem

the back sprocket aperture for the bush was tapered and the bush was oval............ I believe the sprocket o be the biggest culprit to the issue.

so I have corrected the centre bore on the sprocket, there wasn't enough to take off with a cutter so I used wet and dry while spinning the sprocket on the lathe - this allowed the bush to fit by pressing in (with minimal force just greater than by hand) At this point it had still closed the bore slightly so I then ran an adjustable reamer down the bush to make sure the spider fitted nicely.

Before I go any further whats opinion on how tight the bush should be in the sprocket ? As said currently it wouldn't go in by hand but having accurately checked the measurements now it is what I would class as an interference fit.

Brand new back sprocket (allegedly SIL but know im not sure) and brass bush (not MB but a supposedly good quality with oil ways already machined on inside only).

For what is a relatively straight forward job what a f~@k on, I`m luck to have access to kit to alter stuff.