[Grand Designs] project - my ETZ 250

[Andy_C]

As I may have already said in my opinion it works really well - engine just feels a lot more liveley.

It is near to the dimensions in the given in http://www.amrca.com/tech/tuners.pdf which some say is the "bible" to meet the dimensions in the guide it needs to be a few inches longer.

Would be fun to run it against an ETZ fitted with a standard pipe.

[dirtsurfer]

Thanks; 0.06mm might be on the tight side for that piston, be careful the first 1000km & vigilant of any signs of sticking. On the other hand, I don't really know the clearance you can run this particular piston at, so it might well be that 0.06mm is fine. FYI, 0.05mm is what is advised for the original pistons in K20 alloy, 0.06mm for Almot's in K20 (less accurately made, yet from the proper alloy), and 0.07mm is a typical clearance for a €200+ racing piston.

Did the fuel go into the crankcase?

The exhaust says it had been waiting a long time for things to come. Normally they rot on the outside, in a 2T with oil in the fuel.

You jogged my memory, I think the rebore said something like .05 for running around and .06 for racing. So it probably is .05 clearance.
No fuel in the crakcase.

[parrbd]

[quote]A couple more setbacks

For reasons too complicated and not really interesting enough to post here; I was unable to access my bike for about 24 hours after I created that video. In that time the entire litre of premix drained from the leaking fuel tap. When I could access the bike again, I tried to restore the fuel tap with some miscellaneous O rings that I had laying around. This made it leak worse. . I hoped one of my BMW taps might work but they're bigger.
/quote]
I found the O ring used on my DR650 oil filter was the right size for the ETZ fuel tap.

[Andy_C]

Dirtsurfer - you have mail.

[dirtsurfer]

A couple more setbacks

For reasons too complicated and not really interesting enough to post here; I was unable to access my bike for about 24 hours after I created that video. In that time the entire litre of premix drained from the leaking fuel tap. When I could access the bike again, I tried to restore the fuel tap with some miscellaneous O rings that I had laying around. This made it leak worse. . I hoped one of my BMW taps might work but they're bigger.

I found the O ring used on my DR650 oil filter was the right size for the ETZ fuel tap.

I found time to start it up again this week end but the gearbox is not functioning properly. I have started to dismantle it again

[parrbd]

I found these to be helpful. http://www.starfield181.co.uk/MZ%20Supa ... 20Woes.pdf https://www.youtube.com/watch?v=-wSTLNjLeZQ

[Blurredman]

Any news on your gearbox?

[dirtsurfer]

Any news on your gearbox?

I have it apart again, but havent had time to have a good close look at it yet

[dirtsurfer]

Any news on your gearbox?

Well it did not function properly when I assembled it in my jig. After messing around for many hours, I could not see the issue. But I decided to replace 4/5 sliding gear (the one that selector fork 010 mobilises. It was worn but, previously I judged it to be good enough, when I replaced the other two gears which engage with selector forks, why ? I dont know! . It all seem to operate smoothly in my jig now. I have replaced my clutch plates too , just for good measure. I will start reassembly soon

[Puffs]

Good you're making progress!

What is this 'jig'? Can you show a pic?

[dirtsurfer]

Good you're making progress!

What is this 'jig'? Can you show a pic?

Maybe jig the wrong word; just a little cradle to hold the shafts

[Puffs]

Cool, ta. Good way to test.

[Blurredman]

Indeed, I have seen various people on the internet rig up a jig like yours. It's also the prefered mounting method whilst outside the engine too, according to MZ themselves..

[dirtsurfer]

Life has been getting in the way lately however I did get the crankcases together and back in the frame again last week end , also cylinder and head on., Mikuni in place, clutch mounted but not torqued down yet. Maybe I'll make some more progress this week end before another break.

[dirtsurfer]

*Sigh* Got it back together, starts first kick, clutch works fine but it seems I can select only one very high gear and a neutral.
Now it sits parked whilst I regain enthusiasm to split the cases once more