2 stroke help in Iraq (no fuel in cylinders i think)

Crazee Eyez · Jun 12, 2009

Okay... First post... here's the deal I'm a contractor working in Iraq (retired Marine) and I got my hands on a 350 Jawa made in Checkolsovakia (left side kick start, oil injected, twin cylinder stripped down to bare essentials plus head and tail light by a former owner) to ride around on base and to and from work. The Grey Ghost ran well for about two months but two weeks ago went down hard and I'm spinning my wheels here. As you can guess parts are a bit hard to come by as is expertise... hence the post. Anyway, she started to flood out pretty bad but I was usually able to let it sit and then get it running. However, (flooded so bad the air cleaner was full of fuel) after that failed I pulled the carb and removed the bowl thinking the float was stuck (not the case). Upon reinstallation the bike did start but was getting way to much fuel. If ya kept the throttle open full it would run but if ya let it idle it would flood out again. My limited knowledge led me to believe i had a stuck needle. So... i disassembled the carb and cleaned it as best i could. After re installation I seem to have an entirely new issue.... gas is getting to the carb both plugs are sparking but no fuel seems to be getting in the cylinders so the bike will not fire (tried multiple push starts... no joy) I've tried spraying carb cleaner (no ether) in as i kick it still no fire.

Feel free to break it down barney style for me (my expertise is aircraft) Any help would be greatly appreciated

RM_guy · Jun 12, 2009

I think you were on the right track when you went after the float. You had too much gas and found that the float was stuck open so all of the gas was flowing past the float needle. Now it's not getting any gas. You say the carb is getting gas but I wonder if it really is.

The needle could be stuck again because the float adjustment is off. You said you a crash that started all of this and maybe the tab that sets the float height got bent to the point where it is forcing the needle closed with very little gas in the bowl.

Who knows what the float height should be but you could set it with trial and error. Not fun but possible.

Another way might be easier (or not) is to remove the carb and determine how much gas should be in the bowl when the needle closes. Then put the bowl back on and fill the bowl with that volume of liquid. If you can then blow through the fuel inlet then the needle is not closed so readjust the float height. If you can't blow through the inlet then it's time to adjust the float down. It's still trail an error but you don't have to put the carb back on the bike and try to start it each time. You'll may still have some monkeying around with it on the bike but it should get you in the right ball park.

I may be all wet there but that's my first pass at it. I hope I didn't ramble too much :laugh:

julien_d · Jun 12, 2009

Another way might be easier (or not) is to remove the carb and determine how much gas should be in the bowl when the needle closes. Then put the bowl back on and fill the bowl with that volume of liquid. If you can then blow through the fuel inlet then the needle is not closed so readjust the float height.

This will not be accurate, since the floats will displace some of the fuel causing the level to be higher after re-installing the bowl. Why not do it semi-correctly.

Attach a clear hose to the drain on the bottom of the carb (by whatever means necessary) and run the hose up vertically higher than the carb. Turn the fuel on, and look at the fuel level in the hose. Most carbs want this level just slightly below the mating surface of the float bowl.

RM_guy · Jun 12, 2009

julien_d said:
This will not be accurate, since the floats will displace some of the fuel causing the level to be higher after re-installing the bowl. Why not do it semi-correctly.

Attach a clear hose to the drain on the bottom of the carb (by whatever means necessary) and run the hose up vertically higher than the carb. Turn the fuel on, and look at the fuel level in the hose. Most carbs want this level just slightly below the mating surface of the float bowl.

Thanks for doing a better job explaining how to do that. I didn't quite like the way I did it but it got the idea across.

whenfoxforks-ruled · Jun 13, 2009

What type of carb is it? Just sounds like a bad/dirty float valve. If you clean and inspect it, and it still does it, it needs to be replaced, and the seat if it comes out. The wreck could have moved the float valve/seat orientation to a position it does no longer seal properly. It usually takes extra effort to knock the float tang out of adjustment. But, it could have broke a seal on the floats themselves. Check they have no fuel in them/ they are still air tight.

2 stroke help in Iraq (no fuel in cylinders i think)

Crazee Eyez

RM_guy

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julien_d

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whenfoxforks-ruled

Old MX Racer

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2 stroke help in Iraq (no fuel in cylinders i think)

Crazee Eyez

RM_guy

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whenfoxforks-ruled

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