TS250 5 SPEED

[Blurredman]

What is your intention with the bike? You say you've had a few before.. Do you just like doing them up and selling them on? Do you have them for any extended periods of years?

I had awful awful problems with my ETZ251 for MONTHS after getting it (and probably will be with my ES250 too that i'm rebuilding), but perseverence got me in the end- and yes.. I seriously SERIOUSLY was thinking about just leaving it in a ditch somewhere I was so frustrated. But after solving the last bigger problem (2k miles after purchasing), I did another 15,000 miles on it since (8k in the year 2017-2018). And yes I still have it and still use it....

All I can say is don't give up- maybe just put it to rest for a little while and come back to it later?

[Puffs]

Removed

[jam23a30]

Andy, I'm no expert on MZ's but have had similar issues with a TS 250 I bought.

On first inspection there didn't seem to be much wrong with my carb but I later noticed the needle was not seating properly in the slide despite having the correct clip in the correct groove. I also took some time to ensure the ignition wiring was in good order throughout and found several dubious connections. The bike now starts easily and is a joy to potter about on so, don't give up take five and as others more skilled than me have said 90% or carb faults are in the ignition system!

I note you are confident the timing is good but do you get a good strong spark without much arcing at the points? may be worth running a different condenser and or coil just to see if it helps the plug keep itself clean

Hope this helps, Andy

[Andy_C]

The ignition system is 100% - I renewed all the connections including adding a blade fuse box, spark is good, unless of course the coil is playing up, but it has never ran long enough for the coil to overheat.

I did wonder about the slide / needle. Both clip and needle are new and the clip sits in the slide as it should do. I do wonder if I have the correct size, hard to know as there are no markings on it apart from a number which I think may be a 5 - anyone know how to identify the slide?

Floats dont leak - I have even imersed them in water looking for bubbles, when I last took the float bowl off the fuel was at the correct level accoring to the manual - 14mm I think it is.

I have never had these problems with any previous MZs, both of which were bought as non runners - I had both up and running in a couple of weeks.

I dont buy these to retore and sell, I buy them to ride, and I regret selling both of them, this one was intended to be a "keeper" but at the moment I have zero confidence in it.

If I do ever get it going I might just sell it if I dont feel confident about it, ideally an ETZ301 would be best, I really do regret getting rid of the one I had.

[Andy_C]

OK so this is it:

Timing: Correct
Carb: Settings as per handbook
Float OK, fuel level in bowl correct
Silencer: No blockages
Choke mechanism: Not sticking / completley closing off
Coil:swopped out with a known working one

Started it tonight ran for a few minutes, then stopped, plug fouled as usual.
Cant be gearbox oil becsue I drained it before starting it.

The only thing I have not changed is the air filter which looks clean, but may be about 19 years old according to what looks like a date stamp, as a last gasp effort I will replace that, and I have checked the air inlet in the frame and that is clear.

If the air filter does not solve the issue, then it will be going on E-Bay, as my patience has run out with this particular one, and I woul rather cut my losses that keep on spending time and effort on what looks to be a lost cause.

[dave47]

As jam23 suggests, its starting to look more like an ignition/electrical problem. The good spark outside the cylinder might be breaking down inside.If the new air filter doesn't work,before giving in you could try swapping the plug cap - one of the few things left. An iridium spark plug would also do no harm.

[Puffs]

Removed

[Andy_C]

Puffs - no need to apologise for being persistent, this is the only way the problem is going to be fixed.

On the carb front al the internals are new, valve suts off / fuel level is correct.

I am going to bypass the points assist ignition, just in case that is at fault, I have tried 3 seperate plugs & 2 plug caps & 2 coils !!

I plan to pull the cylinder off when I get time and see if there is an accumulation of oil in the crankcase, if there is I'll suck it out with a syringe and pipe, and may jst leave it apart for a week to see if any oil seeps into the crankcase.

I really am wondering if the sealant between the crankcase halfs has broken down and is allowing oil in from the gearbox, but having said that it does not smoke that much, although when I first started it after buying it you could not see for smoke for a few minutes, and that is the odd thing I took it out for a short run just after I bought it and it seemed OK.

I may just split the cases for peace of mind - really dont want this thing to beat me........watch this space.....

[Andy_C]

Another update !!

Had a few hours to myself this afternoon so I took a deep breath and started pulling the engine down.

With the head off the piston crown was black but fairly dry.

Pulled the cylinder off and the piston skirt was thick with oil - on the exhaust side of the piston skirt the oil was black and smelly, pulling the cylinder off the bottom of the liner was covered in thick oil.

Piston off - gudgeon pin had a thick layer of black smelly oil on it.

Turning the crank through 180 degrees you could clearly see that the flywheel had been sitting in oil.

I did refill the gearbox after trying it with no oil in it and have had it running a few times since, and noticed that I was about 100ml short when I drained it, it looks like the 100ml must have found it's way into the crankcase.

Undoing the screws that hold the crankcase halfs together, most of them are covered in horrible smelly black looking oil, I also noticed that there was signs of leaking between the crankcase halfs, so I am pretty sure the seal between the crankcases has broken down, of worst case their is a crack somewhere.

I'll be splitting the cases in the comming weeks.

What amazes me is that the bike did not really smoke that much on the rare occassions it actually ran.

[Puffs]

Removed

[Andy_C]

No worries Puffs - guess I have got a "second wind" with this bike, I am determined it will not beat me, I will get it running properly!!

It's a lot of work but hopefully worth it.

Andy C

[Andy_C]

Update.

Engine is now out and the timing side stripped ready to seperate the cases, currently making up a tool to pull the cases apart, based on one I saw somene using on You Tube.

Heat gun at the ready to get the cases nice and hot - something like 150 Deg C I am told - enough to make spit boil.

I hope the cases seperate easier than it was getting the gearbox sprocket nut off, some idiot in the past had used loctite or similar on it and done it up murder tight, in the end I had to dremmel and gently chisel away pieces of the nut until it let go, even applying heat to the nut did not break the stuff used to hold the nut in place !!

Just hope the same idiot did not use the same locking compound on the bearings otherwise this will be scrap.

Plan to get it apart over the weekend.

[Puffs]

Removed

[Andy_C]

It's apart, it suprising just how much force you need to apply to seperate the cases.

The timing side came away with the bearings in the case, the gearbox outsput shaft bearing is going to need replacing as that it pretty rough.

There is no sign of any sealant on the mating faces, just an oily film - the little traiangular depression in the lefthand case (see picture) was full of gearbox oil and that is idealy placed to let oil into the crankcase through lack of any sealant. The little rubber plug was in place but does like it was not fitted properley which could I suppose wedge the cases apart a little which would not help.

Bild 27. Schaltung und Getriebe.gif (32.34 KiB) Viewed 6145 times

Any tips on re assembly?

Do I fit the new gearbox bearing to the case, or fit it to the gearbox shaft first?

I am thinking that I could make up a couple of mandrels that I could use to heat the inner races of the bearings before attempting to re fit the cases - there is one shown in the blue workshop manual for fitting the main bearings to the crank. Doing it this way the bearings would be mounted in the case which is how it is shown in he blue workshop manual

Any help appreciated.

[Puffs]

Removed