MZ TS250 cylinder head removal in frame

[alexxx]

Hi Folks,

Is it possible to remove the head from a ts250 supa5 while the engine is in the frame?
I have already removed the top mounting and the head bolts but the head won't pass the top mounting.
If I have to remove the engine, do the rear engine mounting bolts go into fixed threads..ie no need for a spanner on the other end?
Or is it side cases off?

Regards

[Andy_C]

Alexx.

When I did mine recently it came off with the engine in the frame - all I did was put a jack under the front of the engine to support the weight and lowered down the engine as far as it would go.

I also managed to get the cylinder off the studs - just as well at the 2 front studs were seized in the case.

The rear bolts go into nuts welded to the engine plates - no need for a spanner both ends.

[alexxx]

Hi Andy,

How the heck did you manage to lift the head beyond the top mounting?
On my bike I can get it halfway up then it contacts the top mounting, I slackened the mounting centre nut and that allowed me to turn the mounting sideways but I can't see any way to remove that mounting until the head is off and I can't get the head off because of the mounting
The motor has dropped as low as it will go, trying to avoid pulling the lump out.

Regards

[Andy_C]

I did remove the top mount from the frame - just a single bolt, but honestly I got the head off.

I am pretty sure that once I removed the 2 nuts from the stud to head I dropped the front of the engine with the jack, once I did that I could remove the bolt holding the mount in place.

I am sure that I did not remove any of the rear mounts - guess if you remove the top one the engine will drop down a bit more.

May be easier just to remove the engine - the 2 rear bolts come out easily and the engine does not have a lot of weight to it.

[jam23a30]

the final drive chain will limit how much the engine tips forward. You may get a little more space if you slacken the chain too.

Andy

[alexxx]

Thanks folks,

I've slackened the rear engine mount bolts and removed the chain.
Will try to get the head off without pulling the motor, find out very soon
I want to see if it is just the rings rusted to the cylinder or has the piston or crank seized before it was laid up.

Cheers

[breakwellmz]

Why not just take the exhaust header pipe off and look up the exhaust port?
Have you put some diesel or penetrating fluid down the plug hole?

[alexxx]

Had to remove the top engine bolt then the head came off followed by the mounting.
The problem is the top mounting bolt, it is welded from inside the frame bracket to prevent it turning, however, I tapped it a few times and found the weld broke easily so the bolt can be pushed back a bit but not enough to remove the head without loosening both bottom mounting bolts.
It will not be possible to tighten the nut that will hold the mounting on unless I re weld that bolt in place otherwise the bolt will just spin within the frame bracket.
Anyway, got the piston and cylinder loosened off, did not remove the cylinder completely, just enough to see the con rod can move around its pin but it looks like seized main bearings as the crank does not want to turn.
Likely water or condensation has got inside and rusted the bearings, I could see the crank rotors looked a bit rusty.
Will strip the motor later for a rebuild.

[Puffs]

Removed