First of all. Please contact us what you need. We need check and make sure everything in stock.
What's the difference between 52 (we mark A in the options) and 331 (we mark B in the options).
See your gearbox reverse lever.
If you see only 1 lever. That is 52 factory (model A).
If you see 2 levers. Looks very close your forward gear levers. That is 331 factory (model B).
ALMOST ALL THE INSIDE PARTS CANNOT EXCHANGE! DON'T CHOOSE THE WRONG ONE!
VERY IMPORTANT: In this page, all parts for 331 gearbox transmission only. And due to some reason, which we also very confused: some parts are missing in this page. So, we will give you the options also （which our customers always asked). But if you cannot find one you need, please check the 52 (model A) gearbox transmission page. Find the number, and 'contact us' before buy. We will let you know if we can find it out.
Again! DON'T take the wrong one! 52 totally different with 331!
Gearbox assembly = 331 gearbox assembly with reverse gear. No polished.
#01 = front cover.
#07 = 4th gear.
#08 = 1st shaft.
#14 = reverse gear on 1st shaft.
#17 = start shaft.
#18 = start gear.
#19 = inner gear.
#20 = gear.
#21 = joint gear.
#22 = gear.
#23 = reversing puller fork.
#25 = joint sleeve.
#26 = start pedal stop spring.
#27 = 2nd gear.
#28 = 2nd shaft.
#29 = joint sleeve.
#30 = joint gear for 2nd shaft.
#31 = joint gear for 1st gear on 2nd shaft.
#34 = forward gear changing plate & shaft assembly.
#38 = reverse pedal.
Following are some usual parts which missing in this page but customers
#B-01 = 3rd gear (yes, this page didn't show you)
#B-02 = 1st - 2nd gear puller fork.
#B-03 = 1st - 2nd joint gear.
#B-04 = 3rd - 4th gear puller fork.
#B-05 = 3rd - 4th joint gear.
#B-06 = a small block with spring and pin on starting shaft.
All options quantity: for 1 bike use.
Some parts can also use on: URAL M72, DNEPR K750, BMW R71 and some similar bikes.
If the selection show 0, you can double check with me. Maybe I can find, maybe I cannot. Thanks for understand.