ETZ 250 misfire?

[Ricardo]

Hi
I have an '85 ETZ 250 that I use for long distance trials. I have noticed recently that it is losing power markedly even though I run a 14T gearbox sprocket. Tried fitting a Mikuni from Allens but that seems to be even worse. Ok on small throttle openings but won't clear or rev out and seems to be firing all over the place. Quite noisy on opening the throttle - from the head - like pre-ignition, but I have just decoked. Any ideas? Timing? Points? Are they prone to any particular troubles in this way?
Ricardo

[Skorpion]

The engine shouldn't pink, if spark is all over the place renew plug, check/replace points, condenser, coil, and check ignition timing 2.5-3.0mm btdc, check also for a partially blocked exhaust.

I also found the carburetter that you have in your picture can be a bugger to set right , when worn the C clip that holds the needle, has been known come off and go through the engine with devastating results, the previous carb with the three float bowl screws is far superior, and easier to adjust.

[DAVID THOMPSON]

modern cdi box would help a bunch
if it is allowed in your type of racing

look here
viewtopic.php?f=18&t=3811

[Ricardo]

thanks gents

will implement suggestions and report back. Powerdynamo interesting; they do one for Bantams too.

Should the exhaust be cleaned out with caustic as of old or will it came apart? It does sound like it can't breathe.

Ricardo

[Old Dog]

Sounds like timing to me, I would look at the points and change the condensor as a matter of course.
Airfilter too worth a look. But exhaust and filter will not cause it to fire wrongly
Tell me, what tyres are you running and is that a 21" front? Also how did the fitting kit on the mikuni work and did you keep it?

[Steve1200s]

Thats a very cool bike you have! what a good use for an ETZ.

I've just installed a powerdynamo, it would be a very good bit of kit for your use (the battery isnt even required to run the bike and lights, but if you stall, the lights go out!), so good for low maintenance, very easy to install too.
I have an electonic ignition for sale if you want to get rid of the points?

How have you done your rearsets? Its a job I'm planning to do on mine, but not figured it out yet....... I'm assuming that you need to fold the left peg up to use the kick start?

[Ricardo]

Sounds like timing to me, I would look at the points and change the condensor as a matter of course.
Airfilter too worth a look. But exhaust and filter will not cause it to fire wrongly
Tell me, what tyres are you running and is that a 21" front? Also how did the fitting kit on the mikuni work and did you keep it?

I have a new air filter and points (not yet fitted), and I'll get a new condensor too.

The tyres are Pirelli MT43, 2.75 x 21 front, and 4.00 x 18 rear. The mikuni fits straight on to the original inlet tract, so does the throttle cable, but you need to make up an adapter for the carb to air intake bellows as the Mikuni has a bellmouth. Yes, I've kept it, but too busy to try it really apart from one short ride. Pulls really cleanly up to 1/4 throttle, and started without problems (though to be fair, it did before). Beyond 1/4 throttle it is definitely having a problem (but I think this is points or timing).

Ricardo

[Ricardo]

Thats a very cool bike you have! what a good use for an ETZ.

I've just installed a powerdynamo, it would be a very good bit of kit for your use (the battery isnt even required to run the bike and lights, but if you stall, the lights go out!), so good for low maintenance, very easy to install too.
I have an electonic ignition for sale if you want to get rid of the points?

How have you done your rearsets? Its a job I'm planning to do on mine, but not figured it out yet....... I'm assuming that you need to fold the left peg up to use the kick start?

Thanks for your offer of elec ignition - I may take you up. And thanks for the compliment. To be honest it isn't the ideal bike for 'trials' but it has a certain charm. The rear set footpegs are the original pillion mounts fitted with modified BSA pillion footrests, which fold to clear the kickstart. Not ideal but works for me, and I don't want to modify the bike beyond the point of no return - at the moment I can replace all the triallsy bits and get back to the original bike.

Ricardo

[Ricardo]

I have an electonic ignition for sale if you want to get rid of the points?

Hi Steve can you email me on rick.howell@talktalk.net

Regards
Rick