MZ fuel problem

[Gazdaman]

Right, fitted the new MZ ignition tried to start it up. Nothing, whipped the plug out, bone dry.

Took carb apart, poked various jets, float bowl was full of fuel so that wasn't the problem. It also flowed fine. Looks like there's a fair bit of rust crap in the bottom of the tank though. Might be blocking jets every time I clear them?

When I put my hand over the inlet stub thing with the carb off it feels like it blows if anything, can't feel it sucking as I expected it should.

Any ideas?

Gaz

[Nath]

Put the carb back on, but leave off the airbox/filter (assuming you were going to use one anyway). Stick your hand over the carb air-inlet as you try to start it, to manually "choke" the engine. Your hand should get wet with petrol (and the bike may try to fire).
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Hard livin', hard luck.

[stinkwheel]

Stick some premixed fuel down the sparkplug hole. It should fire up for a bit. I found that my Jawa wouldn't fire up after being left standing without doing this. Not sure if it helps the rings seal or what.

I work on the principle that they were first designed with a tickler rather than a choke anyway and all you are doing is replicating the effect of tickling the carb.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Gazdaman]

Good idea Stinkwheel, I hadn't thought of that.

Tomorrow I'll clean the tank, clean the carbs, and stick a bit of fuel down the plug hole.

Shall keep you posted.

Gaz

[Gazdaman]

That fired it up Stinkwheel, which at least lets me know the timing is vaguely right and that it's not seized/low compression.

Still no fuel coming through though, cleaned fuel tank today, and checked jets again, nicely clear.

When the bike had an oil pump it was pumped in just below the barrel via a plastic tube, I've only sealed that tube, and there was a little bit of 2t oil left in the tube, which has now disappeared therefore isn't perfectly sealing it.

Is this a huge problem? It's running on premix, so is getting the right amount of 2t oil.

Gaz

[stinkwheel]

I'm not familiar with the MZ autolube system.

If that tube is leaking, depending on where it goes, you could be loosing vacuum on the induction side.

Is the carb filling up with fuel properly? Is there a drain screw in the float bowl to allow you to measure the float height?

Ever thought about putting a mikuni on it?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Gazdaman]

I have a very limited time scale, i.e a trackday on sunday.

The float bowl is filling up fine, when I take it off I get a very cold leg.

There seems to be petroil over the downpipe aswell, yet the plug is still bone dry.

It just doesn't add up.

Gaz

[Gazdaman]

Problem solved.

Turned out pixies had come into my garage and changed the adjusters on my throttle cable so that the slide sat half open when the throttle was closed.

I suspect it was pixies, and not me not checking it...

Anyway, it runs now. Trackday is a go!

Gaz