I have rebuilt my 4 synchro rod change gearbox with new bearings and baulk rings however i am at the stage where the gears are all in and as i put the 3rd motion retainer in and tighten it the gears get very tight.
On inspection the tightness is it seems at the 3rd 4th syncro . Is this due to the syncs being new and needing to be worn in a little bit ? I have read that the baulk rings can cause issues ( these are new )
For reference the third motion bearing retainer when loosened off alleviates the problem.
The gears seem to move back a bit and there is no problem.
Checking the 3rd motion retainer loading seems a bit tricky as well. I have driven the bearing in as far as it goes then prt the retainer on and tightened the 4 bolts lightly and have 4thou which is the shim that was in there originally ( is this the correct procedure ? )
I have tightened the 3rd and first nuts up and the problem still seems to be there.
So I was thinking that the following may exist.
1. Syncro baulks need to wear slightly
2. The retainer needs a little more shimming.
3. The baulks need swapping around or are out of shape.

Any feedback would be appreciated as not many people seem to know much about this and the gearbox was not tight when i pulled it down

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Did i tell you that all my minis are 850's ?

Did you take the 1st/2nd synchro hub apart, if so the inner bit may be in back to front. this displaces the whole shaft assembly a little.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I had the same issue. There are two circlips to choose for the 1st motion bearing retaining and I also lapped the 4th gear baulk ring with valve grinding paste. Also ensure you set the 3rd motion bearing tolerance.
Mine had no shims when dismantling. All info in workshop manual.

It seems the new baulk rings are 6 thou wider ? That is an extra 24 thou ? Could this be giving me trouble ? I think first and second Syncro is ok but 3 and 4 is tight


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Did i tell you that all my minis are 850's ?

I found it was definitely the Baulks causing the problem and have gone back to the ones I pulled out as they have little wear anyway, after doing some research it seems the only ones that would fit properly would be the competition baulk rings you can buy


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Did i tell you that all my minis are 850's ?