ETZ 250 1985

[postie]

Hi All,just rebuilt my etz 250, bike started and ran ok but the clutch lever sprung back to the handle bar and the clutch lost all adjustment. Same thing happened after i reset the clutch and restarted the bike, Any ideas before i take the clutch cover off. Many thanks Andy

[keleto]

The 3 screws on the small round clutch cover /tacho drive cover are probably loose, allowing the coarse adjustment plate to rotate.

[postie]

Thanks for that but they are as tight as i can get them,3 white knuckles. Any other ideas ?

[keleto]

EEEEK, they don't need to be 'as tight as you can get them' you will strip the threads like that !!!! They are only 6mm, in soft alloy too. They should be snug enough to positively retain the adjuster plate. Maybe also check that the plastic grommet which the cable sheath end bears against in the little tube which the cable enters is undamaged ? I presume the clutch is properly mounted on the crankshaft ? (It should be unless it has been messed with, they are usually an insanely tight fit on the taper). What is the mileage on the bike, and had it been stood for long ? perhaps the clutch plates are worn, or delaminating ? Maybe the oil seal on the clutch adjustment cover was replaced with one so big that the cover can't tighten down enough to retain the adjuster plate ? It is hard to tell without knowing the history of the bike. Was it working for you before, then stopped working ? Or was it messed with recently before you got it ? If it is nothing obvious then I guess you will need to remove the clutch cover and check the pushing mechanism. If you feel tempted to remove the whole clutch, be really careful to avoid damaging the crankshaft end with the puller. You must make a cap/sleeve arrangement so that the considerable force of the puller is transmitted into the body of the crankshaft, not the end.

[postie]

Hi all,have reset the coarse adjustment,started the motor,no problems pulled the clutch lever in to select gear and the motor stalled loosing all clutch movement [will now have to reset the coarse adjustment ] This is the 3rd ETZ motor i've done in 20 years and it has all new bearings,seals and clutch plates. On another note does anybody know of another fuel tank that fits as they are in short supply in Australia.

[keleto]

Fair enough, sorry if it sounded like I was talking down to you. The 'white knuckle tight as i can get them' just rang an alarm bell, that is all. I have heard some oils cause the clutch plates to bind and swell, what oil are you using ? Apparently GL4 oils are OK but GL5 oils cause problems......

[Blurredman]

This strikes me as a similar problem as I had first time when I put new oil in my bike.

I used GL5. Make sure your oil bottle says GL3/GL4....... If it is GL5 then it sticks the clutch plates together..

[postie]

Hi All,the clutch problem,reset the coarse adjustment started the bike and held it at 3000 rpm,slowly feeding in the clutch until it almost stalled,pulled clutch lever in increased revs back to 3000 rpm and did the same again quite a few times with the clutch improving all the time.Its now as it should be.The oil i use is Nulon 80/90 and in my last 30 years off MZing i;ve always used Valoline outboard two stroke oil,never had a problem and its cheap,a sad reflection of my personality ? Many thanks Andy

[keleto]

Yay, glad to hear it. The fancy modern GL5 gearbox oil apparently has something in it which causes clutch problems but the cheaper basic stuff is OK. As long as it has GL4 or GL3 written on the label it should be fine. I use this one http://www.wilko.com/car-care-products/ ... vt/0077164 at the princely price of £3.50/liter. Or a lot of people just use bog standard 10w-40 or 20w-50 engine oil which is also fine.

I do use fully synth for the 2-stroke oil but I buy in bulk so the cost is not too horrific. Works out about the same as getting mineral 2T by the litre at a garage.

[Blurredman]

Obviously there must have been some sticking on the clutch plates? Did you re-assemble it or has the clutch not been unused for an extended period of time?? (on or off an engine-doesn't matter)

When I picked up my recent MZ ETZ251 it hadn't been on the road since 2003. The clutch was solid. The only way to break it off without disasembling the clutch was to start myself at a rolling pace and put it into 2nd and pull the throttle and whilst the engine was pulling me along keep on applying the clutch, braking, throttling etc. It freed off after just 2 or 3 quick 100 yard attempts. Each time I came to a stop I would keep the throttle on (put pull the clutch lever) and apply the brakes. This also helped.

Sticky plates are a troublesome thing!

[keleto]

Using a really thin oil like 0w30 as a temporary flush might be a help to unstick a seized clutch, and rinse all the old gunk out of a long-stood engine too. Then change to the recommended hypoid oil after a few miles.

[postie]

THE ANSWER- Talking to the MZ guru here in Australia is that aftermarket clutch plate kits from China have the wrong thickness fibre plates.Hope this might help.Andy PS the carbies are also crap.

[Blurredman]

I've used the new clutch plates in the past and they have waaaay too much material on them. So much so that I staggered old and new plates at the time..

My clutch slips now though, something interesting to look into.

[Guesi]

Meanwhile there are clutch plates on the market that have the right thickness.
They should be about 3,1 mm thick.