b52 gearbox

brian laud · Post by **brian laud** » Tue Feb 14, 2012 9:04 pm

I am in process of preparing all bits ready for reassembly. However after reference to the exploded drawing from the archives I find I have 2 off of 12-11-3 missing. From the diagram they look like plain washers but where do they fit. It looks like somewhere around sprocket/mainshaft oilseal area but cannot see precisely. I don't see them listed on JSL either. Please can someone enlighten me.

hunter · Post by **hunter** » Tue Feb 14, 2012 10:50 pm

Brian,12-11-3 listed as spacer 1/16 thick x 2 in my old yellow BMS parts book but does not tell or show where they fit,
i can only assume in the final drive sprocket area.
Can find out tomorrow.
cheers

willschub · Post by **willschub** » Wed Feb 15, 2012 12:13 pm

I also wondered about this. Do they both fit between the sleeve the seal runs on and the output sprocket? Could they be there for chain line adjustment?
Regards, Bill

john · Post by **john** » Wed Feb 15, 2012 1:18 pm

There was thread on the topic 6 years ago; see link.

Topic

I still stand by my thought then that they are shims to take up wear in the sleeve gear.

B52 layout

(link to B52 drawing added)Edited by - john on 15 Feb 2012 1:45:50 PM

Rob Harknett · Post by **Rob Harknett** » Wed Feb 15, 2012 4:46 pm

http://archives.jampot.dk/Technical/Tra ... d_view.pdf

Does this show a better picture

hunter · Post by **hunter** » Wed Feb 15, 2012 9:53 pm

Rob,
Thats the one i have but it does not define where they go

john · Post by **john** » Wed Feb 15, 2012 10:01 pm

Click on my "B52 lay out" above and it will show you!

Rob Harknett · Post by **Rob Harknett** » Thu Feb 16, 2012 1:39 am

I think the link I put up is clearer, and it shows them going either side of pt no 27-12-2 On the one you have put up John I can only see one part number 12-11-3 shown, and that appears to go in a different place to 2 off parts on the pic I put up. Could there had been a change or is it just the fact I see the parts quite clear on the pic I put up, but not on Johns pic he put up. If I was working on the gear box I would start reading Burman and AMC manuals to find the answer. Also parts list to put names to the parts. Plus of cause the many articals , gearbox rebuild, tech tips old forum messages Help liner AMC service sheets that give changes made, etc etc, the answer must be agreed out there somewhere. But then John has come up with an answer, that he's proved OK on his bike.

john · Post by **john** » Thu Feb 16, 2012 8:10 am

My theory is that as the splines / dogs wear on the 4 gear (a problem experienced with this box) a shim could be moved from outside of the box (where it has no purpose) to go between the sleeve gear shoulder and the main bearing. Moving the sleeve gear in towards the box and increasing the engagement by 1/16” on fourth gear. This helps to explain the number and name it is given in the parts book “2 off bearing spacer”.

It is all a bit academic as most boxes I have seen these spacers are missing because there is no obvious point to them, so they are normally missed off on reassembly.

brian laud · Post by **brian laud** » Thu Feb 16, 2012 9:35 am

Thankyou everybody for your inputs. I think I will reassemble without then check chain alignment insitu, fitting spacers as required. Can anybody advise what thread size is on clutch end of b52 mainshft.