Phosphourus Bronze Bush

Justin350 · Post by **Justin350** » Fri Apr 13, 2012 8:45 pm

I've just cracked open the motor to sort out the sezure and found the culprit to be the bronze bush in the timing side crank case, the only reason I can think of would be poor oil circulation as it wasn't great after the last rebuild (big end 25 miles ago).

Can any one give me information as to wether a replacment bush will do the job or is there is a bearing upgrade availible?

I think the oil pump needs attention anyway but, any ... thoughts?

Don Madden · Post by **Don Madden** » Fri Apr 13, 2012 9:13 pm

Are you sure of the bearing material? I have encountered brass bushes, which are not suitable. Itma knows the specification for the proper bush. Cheers, Don.

itma · Post by **itma** » Fri Apr 13, 2012 10:15 pm

go on Don drop me in it.

AMC*** describe the bush as 'bronze' what sort of bronze I don't know,but you are right about the crap brass bushes that were about some years ago; Brass T/S bushes were sold by various parts suppliers for lots of bikes, they were all rubbish.

I would not be surprised if the shaft was also knackered and I would certainly be worried about the big end.
oil pump should not be the problem rather the fit of the shaft in the bush.
sounds like a through strip is called for.

***http://archives.jampot.dk/Editorial/Roa ... 958%29.pdf

Ian5913 · Post by **Ian5913** » Fri Apr 13, 2012 10:20 pm

I am not aware of a bearing conversion and the bush I take it you mean 042239 normally works pretty well. Lack of oil would hinder it though (It would over heat) When it was re built was the oil pump plug 042044 re fitted correctly with the little locating screw (042046) and the seals on this in good condition. This part is easily over looked. Oil should really be filtering back at a good splurt when running at a steady tickover and observed in the two normal places (rocker cover & oil filler cap hole)

Check the oil filter is in the correct position and the right type also and the seal on the big plug the other end of the shaft (in the crank case at the back) 042045

Their was only ever one oil pump shaft listed but I have seen differences (possibly off over models) if the same one went back in then okay but if not it is worth checking against the old one.

OPil supply you will know is key the only other thoughts would be a blockage caused by gasket or gasket seal stopping circulation
Hope this helps

IanEdited by - Dean5913 on 13 Apr 2012 9:22:01 PM

itma · Post by **itma** » Fri Apr 13, 2012 10:27 pm

In regard to lubrication ought I to mention that oil that dare not speak its name.......?Edited by - itma on 13 Apr 2012 9:27:19 PM

Ian5913 · Post by **Ian5913** » Fri Apr 13, 2012 10:32 pm

As ITMA states the bush should have a clearance the new parts supplied and I BELIEVE IT TO BE (iT DOES NOT STATE) phose bronze material.
I quote
Refitting the timing side bush (042239) Carefully line up and press in the bush the fit the locating pin to prevent the bush moving. A New bush is made to spares size, but it should be reamed to .8755 to 8750" in situ. The inner side of the bush should be flush with the crankcase (Quote end)

Ian