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Little End Bush Fitting

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Just looking for some advice please. Had a quick look on the Internet regarding the fitting of bronze little end bushes and what I thought would be an easy job of drawing in a new bush an sizing it using an adjustable reamer is in-fact not so simple. Concerns are keeping things true, not taking out too much with a reamer and so on.

Any advice would be appreciated.

You don't say which motor, but likely to require some special jigs such as used on the aircraft rods I have done at local specialist machine works.

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The bike is an AJS Stormer, not exactly pre65 but I know the principal in fitting and reaming the bush should be similar for most bikes...I would have thought. The info I have found would suggest you just draw a new one and and ream by an adjustable reamer, but then others say it has to be reamed to within a thou of being true with the crank. Others mention all sorts of horror stories when its not just spot on. Anyway was just looking for a bit of advice on how to get things as near to spot on by doing it myself....take it to an engineering workshop perhaps would be a better answer. By the way the crank is out but still attached to the Conrod.

Sorry b40rt but what is Rupert Ratio page 71 all about?

Shows how to do this in detail, worth having a look.

Rupert Ratio is a B40 book, but check it out if you can borrow one.

An experienced worker at a local engineering firm offered to size the small end bushes on a pair of Guzzi conrods for me using a honing machine. He didn't rate trying to do it with a reamer due to the difficulties in keeping it square without making a Rupert Ratio style tool.

He also said if the fit is right the pin should slowly fall through under its own weight. If it drops through like a stone there's too much clearance.

Edited by craig10

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