Reassembly Of The Transmission (part 4 Rebuilding The Zundapp)

Excluding the clutch, this is my reassembly of the Zundapp 125cc 2 stroke transmission.
Protip: magnets.

[@TheLuckyfreeman]

I wish we had all this information and videos back in 1970 or so it would have really helped all of us struggling with these old bikes and nobody anywhere in the USA that knew how to work on them

[@TheLuckyfreeman]

yes this is the nightmare from hell with all those roller bearings 19 of them in all ok . I wonder if this guy is from upstate new york and had a metice zundapp for sale???

[@michaeltolomei6623]

I'm from Washington, mine was found in a barn, dead. I got it for free, but put more in to it than she's probably worth lol. Yeah my trick was using magnets to get the weird roller pin bearings to stay put, as well as those funky ball locking bearings. Trouble is with those free little pin bearings is they can wear funny, and I found I didn't much like the way mine were wearing last time I looked in there. A regular bearing race would be so much better. if the bike ever has a fail, and survives it, that's what I'd likely put back in their place.

[@zundapp-werk]

The shims on that shiftshaft (that's the wordwise translation) belong always between 1. and 2. gear! And there are always shims! Youre putting that transmission together the wrong way, you put all shafts into the right housing, the left is like a cover. Asap I will give you a link how that really works! Greetings from Zündapp-Land!

[@michaeltolomei6623]

Don't worry, I figured that out, I believe mention it in one of my later videos. The biggest issue with this project is the people before me really messed the bike up bad. I can tell it's been dropped and had the shiftier sent into the case once in it's life. I have it all together now, I posted a small update on it along with some of my other stuff. It runs and shifts, but now I am fighting the carburetor for a smooth run. Right now it runs real rich, and I have jetted it down quite a bit, (too the smallest sizes offered, 2.68, 105, etc, I have really nice plastic float tanks that work way better then the foam ones. I guess Bing made both, and I got lucky and found a set for the 53 carb. My needle is in fairly good shape as well. The main issue now is getting the floats to stop sticking. Occasionally they stick when in the off position. Also my fuel tank may be to blame for some of my carb trouble, it is not the cleanest, (despite sloshing it out a few times). I'm thinking about doing some further treatment on it but I don't want to risk putting holes in the old steel tank. I don't intend on riding this bike too much, I just want to slowly restore it, and preserve it. There are a lot of things I wasn't able to replace so I am leery about it's outlook. Some bearings are original in it unfortunately. I just intend on riding it a few times a month as a trail bike. I have a Yamaha for the harder riding.

[@zundapp-werk]

@@michaeltolomei6623 sorry, the Video for the 288 engine, similar to your 285 is still not ready, meanwhile this one is usable too: kzbin.info/www/bejne/o2a5qmR4esl0f7M. carb problems are not so easy to explain via writing, and even more difficult since my deutsch is way better than my english, if still needed, we can try, let me know

[@febriyogapratama7462]

Its a awesome engine. Can you explain how this transmission gear shift when drive and how it work? Because it wasnt similar in any motorcycle transmission on this day

[@michaeltolomei6623]

Basically, instead of forks moving gears in and out of drive, the gears are all in constant mesh, and the ratio is selected by a cam lobe that slides in and out of that hollow shaft. When the lobe is in line with a gear it forces these ball bearings into the gear and that is how the gear is selected. It's known as an Expanding Ball, or Ball-lock, transmission. They aren't common, but in the early days of motocross, the smaller cc engines could get away with a design like this, bigger cc engines would devastate the ball locks.

[@febriyogapratama7462]

@@michaeltolomei6623 thank you bro. You exlpain it well. I always searching entire in internet but didnt get the sarisfying answer.. This transmission is awesome. A hightech from past time that give little cc engine run like a jetplane.

[@TheLuckyfreeman]

is that the shaht with all the holes in it that has those 50 little roller bearings around a race that all fall out when you pull the shaft out My 1965 KS-100 had the same set up not sure if somebody did not upgrade that and remove and replace that lousy design with a solid 1 piece roller bearing for that shaft if anybody knows that would be appreciated they never should have used that 50 separate rollers that came out of the race

[@michaeltolomei6623]

indeed it was, I used magnets to keep them in place because yeah it's a terrible design. The bike still runs to this day for now. But that transmission is one scary sounding little thing. And I never did get it to shift strong. I can find all the gears but it's a dance cause no matter where I tune the "shift bell" for the drum shaft, it doesn;t seem to limit the kick enough. Bike seems to shift past gears most of the time.

[@luckyfreeman5079]

There is a guy in the Netherlands that builds brand new engines it's on you tube

[@michaeltolomei6623]

@@luckyfreeman5079 Sounds like something mine could use at least the transmission anyway. Compression wise my engine's gained a few pounds. I did a compression test a week or so back and it was hovering just over 140lbs. When I first completed this, it was only 120~.

[@MrGS125]

ks 125

[@williamcox5872]

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[@williamcox5872]

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