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hon450

73 Mar 250 gearbox

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Would anyone have bearing numbers for all the needle bearings in the gearbox.  I would like to replace everything while I have it apart.  Would anyone have recommendations on where to order the bearings from.  Thanks in advance.  

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I’d contact Kieth Lynas at OSSA Planet.   

http://www.ossaplanet.com/

Make sure you carefully shim everything when reassembling. They are picky about that.

Edited by lotus54

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In regards to OSSA parts, I have been buying from Alex Snoop in New York.  

Alex has been great to get stuff from.  He recently rebuilt my friends MAR crankshaft, that engine will be going together this fall.

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Sorry for the late response.   I appreciate the help.  I am seeing you can buy the case bearings.  But do you have to source the needle bearings for the gears from a bearing supply company.  Has anyone actually took the time to replace these.  Thanks again. 

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Not sure which needle roller bearings you mean?

The MK1 mainshaft runs on normal roller bearings and the layshaft runs in bushes. On later MAR, TR77 on, maybe MK3, the layshaft runs in needle rollers rather than bushes but they won't work with the earlier gearbox as the shafts are different lengths and diameters on early / late boxes, even though they look identical side by side

In all gearboxes there is a needle roller under the 1st gear cog on the layshaft - I've never had to change one of these as never seen one worn.

There are two that the final drive sleeve gear on the mainshaft runs on. Never had to change these either.

None of them have serial numbers that I've ever seen so you'd need to measure and obtain from a bearing stockist if you want to replace if none of the old Ossa dealers in the US stock them. Not aware of anyone in the UK or Europe that does

 

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