We have a problem (part 2 Rebuilding The Zundapp)

Throwback to around last May, I had to send my part off to be milled.

[@metalwarrior6683]

You cant Exchange Single case halfes!!!!!!!!!! Because the Final machining is done to two cases clamped togehther! Only the cases with the Same number fit together correclty. Only change both cases at once if Not the Shafts will not sit correctly and it runs rough also the bearings get destroyt

[@michaeltolomei6623]

it already didn't work out, the bearing seat on the main was not the same size diameter because the case was for a different year. I ended up having to re-machine the original case and repair the busted pin, which I think I covered in one of the later videos.

[@metalwarrior6683]

Michael Tolomei Yes I saw that I am from Germany I rebuild a lot of these and I have never seen something like that work Perfectly well 😬 always caused some type of problems

[@michaeltolomei6623]

@@metalwarrior6683 The Trouble's been getting all the parts. The manual is not always correct either, I have run into occasional translation issues. Not all of the tooling is available here either for end play adjustments. The bike was heavily mistreated when I got it. The first years of me working on it were not something I had filmed, but if you had seen the shape it was in, you'd have figured there's no way it was even worth attempting. Several problems I am still to this day having with it, are getting it to run leaner, no matter the jets, no matter the adjustment, she smokes bad. No matter the mix of fuel, it seems to smoke too, I am running at 40:1 and still she spooges out of the exhaust. The cyllinder has a slight head leak at times, despite having it machined, and running a copper crush gasket, I occasionally see bubbles, so I don't really ride it. Just start it for a couple minutes to keep the seals in use. The other major problem is the exhaust pipe, it's so rotten, and I keep having it brazed and welded shut, but pin holes re-appear. And I believe this and the head are the main reasons I can't get the bike to behave much. Also the shifting is very weird, I am not sure that I solved it's problem. It seems that you can shift past each gear into a neutral space. It's like there's a neutral between every gear. I know the bell nut is supposed to dictate the gear's actually grabbing, but no matter the adjustment, it's like I have to play a game of finding the gear. Eventually I can find it, but it's definitely not working correctly. Maybe you have some insight on this issue? my manual is not very helpful, it just explains by turns where the bell should be, but it seems to act no different than any other setting if that makes sense. In order to get it into gear, I have to do half shifts, and listen for the cam to actually send the balls into their locks. And of course it sounds slightly rough when it's running.

[@metalwarrior6683]

Thats normal that you have a neutral between the gearts its an adjustment thing its caused by the geometry of the shifting wedge. On my Hercules bikes with a Sachs Motor its the same. Exaust pipes are rally available here in Germany. And the copper gaskets never workt for me Original the must be something like a carbon fiber one thats quite thick with a Aluminium ring in it. here in germany its no Problem to get these parts but i dont know how available they are where you live

[@gekkehansie]

he yo, did you get it running?

[@michaeltolomei6623]

yes, I got it running, but it's rough. When I had the head milled the shop I hired I found to be lazy. They told me only the head itself needed to be squared, and not the cylinder, which I thought was odd since both are aluminum which warps over time. needless to say, it runs with about 120 lbs of compression, but the head bubbles. and I have tried a few old timer remedy's but to no success. So the power lacks what it should and I am afraid to run down the trail with it doing this because it may blow a hole though the piston. I start it from time to time, to keep seals fresh, but I will likely have to tear down the cylinder and head again, and have someone else mill it as I ask. Copper crush gaskets are premium gaskets and shouldn't be having this issue, so I know the shop I used was mistaken.

[@gekkehansie]

@@michaeltolomei6623 hi, A:normamly the cilinder never warps, I assume milling-shop checked though....flat=flat, then don't touch it i would say. By the way, if cilinder warps at top-end.....then.....at bottem-end it also should be warped...are you gonna mill that too? brr...don't go there. B: You mention copper gaskets.....the copper ones I know are thick or thicker or too thick. You could try using thinest (paper) gaskets available UNDER cilinder & between cilinder/cilinderhead (alu). C: did you check pistonring-gap? If the gap is too big, the pistonring is worn and must be replaced. D: did you hone the cilinder? If so, then maybe compression will increase after run-in..... Hope this helps. Bye!