EX 500 running like crap....Redux

[vw143]

The more bikes I see on the road , the more I wan to get mine running, today I spent 9 hours trying to figure out my gremlins, I considered everything from carbs,to coils to The cam timing jumping a tooth. By the end of the day we had figured one thing out..... If the fuel petcock was in the off position, the bike would run smooth and fine. if if the fuel was turned on while the bike was runnin, the bile would start to stumble and would begin to recover if the fuel was shut back off, and if the fuel was left on, the bike would die. I believe I am looking at faulty Needle and seat as it can not shut itself off when the lfuel comes rushing in from the tank. Any suggestions?
Thanks, Chris

[mikesf4i]

Hellooooo.... just shut the fuel off when you ride your bike.....duh.
Just kidding. It sounds like you have it narrowed down. All you have to do is figure out why the needle and seat dont seem to be stopping fuel flow. A friend of mine had his floats leak and fill with fuel so the sunk. I would pull the float bowls off your carbs and take a look.

[Mr. Turbo]

Check the vac line from the petcock to the engine. Sounds like you may have a vacuum leak!

[vw143]

Check the vac line from the petcock to the engine. Sounds like you may have a vacuum leak! that could be a very good possibilty, I know it is somehow related to the fuel, I ordered Carb rebuild kits, should I order a petcock rebuild kit as well? I had the float bowls off and everything looked fine My question is though, Why would the needle and seat be screwed up after only 8500 miles? but that seems to be the consensus . Thanks again, Chris

[vw143]

Sorry bout that, I was just saying that is another good suggestion of thins to check

[Jackal]

Does it run bad at idle or all over?

Did you check the float heights when you had it opened up? Closing the petcock would have the effect of gradually lowering your float height. Float height can affect low rpms and idle alot. Maybe they are too high.

[vw143]

Tomorrow I am going to put new needle valves in my carbs to hopefully remedy this problem, any tips on how to do this without fucking up some adjustment . The manual talks of using a float level tool which I don't have, nor do I have the guages to carb sync so I am trying to be as low impact as possible. Any suggestiions y'all have would be greatly appreciated.
Thanks, Chris

[Mr. Turbo]

you're gonna need the vacuum gauge for the carbs to get them synced 100%. You can eyeball it with the carbs pulled from the bike. As for the float level you can set by making your own ghetto float level tool out of clear plastic tubing. Hook the tubing up to the carb drain and flip it upward. You should now see the gas level in the carb carb bowl.

[vw143]

I will give that a try, thanks for the tip