20mm Or 22mm?
I have a race crank (shimmed big end for cenralising the con rod) so do I need a 20mm or 22mm small end bearing, or doesn't it really matter.
It's got a 20mm in at the moment but as I'm replacing the piston I thought it would be a good idea to see if I had the correct small end bearing.
Cheers
John
Small end bearing
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coaster
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I asked that question back in 2005 when I was building my Muggy 186, Camlam told be it didn't matter and that 20mm small end bearing were fine. I have read that it's best practice to use a wider bearing so that the bearing is always kept completely within the eye of the conrod. However, whenver I've needed a small end bearing since no one has had them in stock 
The Mugello has done around 4.5k miles with no issue and I have logged a around 2k miles on my 225 (1000 with an Avanti kit) and still not experiencing any problems. If it was a high reving TS1 or RB I'd probably serach out a 21 or 22mm bearing.
Just my expererience FWiW
The Mugello has done around 4.5k miles with no issue and I have logged a around 2k miles on my 225 (1000 with an Avanti kit) and still not experiencing any problems. If it was a high reving TS1 or RB I'd probably serach out a 21 or 22mm bearing. Just my expererience FWiW
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Avantone
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Depends on the width between the small end shoulders on whatever piston you're running. Get the size that gives a little side float without the small end eye on the conrod running off the rollers on the small end bearing.
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Terrible Taff
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John,Minority wrote:20mm Or 22mm?
I have a race crank (shimmed big end for cenralising the con rod) so do I need a 20mm or 22mm small end bearing, or doesn't it really matter.
It's got a 20mm in at the moment but as I'm replacing the piston I thought it would be a good idea to see if I had the correct small end bearing.
Cheers
John
Fit one that fits between the piston bosses, 20mm or 22mm, the piston will run central to the bore.
The Conrod as you say has shims fitted so no problem there as it also is running central.
Ian