Hi, I am about to rebuild a 1982 Montesa Honda 123 which was taken apart years ago and have some questions if anyone can help, such as amount of gear oil it takes, 2 stroke mix ratio and I have a piece that i am sure is from the bike (photo attached) but I cannot figure out what it is.

any help would be greatly appreciated 

Mike

I suspect it fits on the rear wheel spindle, sprocket side, and acts as the mounting for the chain tubes.

It acts as a spacer in the back wheel and a support for the chain tubes - similar to the 348/9 .

 Aye hamish

Thanks Hamish

Mike

Yep I’d agree with previous answers. Points forwards but can’t remember whether it cranks out or in to line up with the chain tube mountings. Should be obvious when you have it in place. Still can’t decide whether they were any use or not those chain tubes. Seemed great when I had a mont 200c, saved all the mud being carried towards the drive sprocket, but still needed to clean the chain just like modern bikes with nothing similar. Maybe just been persuaded over the years that (relatively) open chain is ok.