MZ/MuZ Riders

High folks. My name is mick and I have just re-joined after having password trouble, I used to be here under the name Bullgoose.
After threatening for years to strip down the engine on my TS250 I have finally gotten around to it a few days ago. I was quite surprised to find I could not use the assembly bridge to remove the RH case, so I had to pull the LH case and leave everything in the other half. Luckily the gear cluster came out without any problem.
This bike has been used as a field bike by the look of it and has the clutch welded together for some reason. The engine has been apart before and has quit a bit of carbon clinging to the steel disc in the RH case showing quite a bit of blow by. The piston looks great but there is a wear ridge in the cylinder bore. The clutch taper was a great fit, but the big end and the main bearings are shot. I could not get more than 3 gears before disassembly, but I think the neutral indexing had been lost at some time.
Can anyone recommend someone to rebuild the crank for me and say who makes a good replacement conrod and big end assembly. I have seen some from Japan.
I will clean everything up and have a good look at what's needed.
Ta

Hi,

The usual person most people talk about for crankshaft re-builds and balancing is 'Burwins' in London. The shop itself doesn't actually do it anymore, but the elder owner still does MZ stuff on the side, as he has done since the late 70's/early 80's (??).

His phone number is 07726000075- his name is Martin. I'd call him first and then get his assessment. The price for re-juvination and balance is roughly £70 (but I guess you should also add ontop of that £10 either way carriage fee).


But then- where are you from?/ Where do you live?

The above contact is based in the UK.

Cheers Guys.
I am in Newcastle upon Tyne and I'm sorry I have not made a good job of making myself clear. This is the first MZ I have taken apart and I thought I could use the new made assembly bridge that are available from Germany to separate the RH case and leave the crank and gear cluster in the LH case. Now that I look at things, I see that it might have been possible if I use a G-clamp on the end near the front engine mount.
The engine was started up when I got it and the main bearings sounded terrible, so I had to take a look see and assess the condition. I have not gotten round to washing everything clean yet, but there does not appear to be any bluing of the selector folks.
I will clean everything and offer up the cluster back into the LH case and try and find all 5 gears with the neutral detent spring and ball in the proper position.
I did notice that the small rubber plug that is fitted inside the LH case to separate the oil to the main bearings was missing.
Ta for now.

Armstrong's in Westgate Road will rebuild the crank locally but you might have to source the kit yourself. I cannot advise on that unfortunately.

Wow, fantastic thanks very much. I have now washed the crank cases out and have cleaned all the engine parts with paraffin ready for inspection. There were some chewed up areas where the thin circlips for the main crankcase seals are fitted that will need washing out with a needle file, but otherwise it all looks ok.
The RH crankshaft seal has the Lilypad lip facing board i,e the garter spring facing the crank and the LH was the opposite with the lip facing outboard. Is this correct?
Ta

Hi Mick,

Yes it's true- the oil seals are from the factory installed in different orientations. But there is differening and academic talk regarding this, esspecially on the RHS of the engine. You can see this talk in this thread:

viewtopic.php?f=20&t=12741

Thanks folks. Looks like I will install the seals with the Lilypad lip facing the crank. Can anyone say if the tapered O/S installation tool is available in the Uk or Germany. I know Armstrongs well so I will give them a call and I think I can get the new conrod and big end from The MZ shop here in the UK.
The gearbox cluster looks ok except for bluing showing on selector folk 012, but I will have to wait for the cluster to dry off to give it a good look.
Can anyone say which way the selector folk shaft is orientated as I failed to note it down and I have a bad memory after throwing the Bonnyville up the road once too often.
I intend to refit the gearbox bearings and do a trial run at assembling the gear cluster with the spring detent located in the neutral groove of the selector drum and try and find all 5 gears.
Ta

I'd suggest you watch the MZ service film, as it shows everything much more clearly that those illustrations and b&w photos found in the manual.

Here's the link:

https://youtu.be/e71KJeBD76Y

It is intended for the newer models, but the TS/1 has the exact same bottom end and gearbox. as the ETZ. So you can pretty closely follow the assembly procedure of the ETZ for your TS.
I found it very useful when I was working on my TS.

Thanks folks.

Hi again folks.
I am making progress on the engine and am nearly ready to re-build it. I re-installed the old and now clean gearbox bearings into the crankcases and put the gear cluster back in and had a play until I found what the problem was. The gear change was locking and jamming, and the culprit was the end of the selector drum that has the single screw holding a large washer on.
The screw was not very tight and when I removed it, the side facing inboard was horribly worn or abused with a grinder of some sort but the little selector guide with the free spinning wheel was unworn and looked very good. The star type guide the wheel locates in at every gear change and is located on two pins seems to have been put back on incorrectly.
I could not find a new washer for sale, so I bought a whole new selector barrel. The gearchange is now smashing.
I had the head, barrel and the two-engine covers aqua blasted and the barrel and the crank are now in Armstrongs for boring and a crankshaft rebuild. I supplied the piston and conrod assembly from the MZ shop.
On the point of the re-bore is the book correct as to the 0.04mm clearance as it seems way too tight at 0.001574 " just over one and a half thousandth.
My arse will be twitching like a rabbit's nose at that clearance.