Hi all

First post, I have just purchased a 1984 Honda TRX200, what a cool machine this is, runs great for a 20 plus year old ATV. Anyhow to the problem, the ATV will not start no way no how unless I remove the gas tank cap, I have turned the vent both ways and it still will not start without removing the cap, once the cap is removed there is a a loud hiss and a gurgling sound, like water running down a sink hole, first press of the starter after removing the gas cap the engine fires up and runs all day, even with the gas cap back on.

The only thing that has I can think of recently that has changed is the gas tank was full of rust and crap so I cleaned it out with a bike chain inside it and some weak acid, this broke the plastic piece of the petcock inside the tank, could this be the problem?

T.I.A.

 

It sounds like a venting problem your cap may not be allowing air to get through.

 

^^^ what he said.

 

The fuel tank must have been upside down resting on the fuel cap .. This bent the " T " that operates the vent ...

 

Thanks for the replies guys, I`ll check the gas cap, and the vent hoses see if I can see anything wrong.

 

Here is a couple of pictures of straighting the " T " that operates the vent ..
If you take the cap apart mark it so you get it back together straight .

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Great

Thanks for the pictures, great help.

 

omg, what a great write up. i can't wait to try this in the morning. my cap is not venting, my 86 trx 125 will run about 300 yrds the stop. i tracked the problem to the cap and thought i needed a new one. i will try this and hopfully i can get it fixed... thanks to this forum and especially hondamechanic! I assume the cap is pressed together?

 

I took my cap apart this morning and the tabs were bent down as described by hondamechanic. I haven't ran the maching yet but i believe it's working correctly now. I took some picture ( I'm sure way to big to upload) and i'll describe what i found.

First, I didn't realise this being new to this machine but the **** that you turn off and on should raise up in the on position, that's how i could have known i had a problem. I'll try to tag some pics of closed, then open position of the vent.

 

When i took it apart it fell apart and there is a small spring that went AWOL for about ten minutes under my workbench so watch for that. A guy really needs a vice to hold the cap. I took a hammer and punch and seperated my cap. I took all the parts apart and inspected for any clogging of air holes. There is a one way rubber piece, and i unsured it was intact and in good condition. I took a few more pictures, i'm sorry about the hair in the one pic. i didn't see it when i took the picture but i wanted to show the small spring. I'm hoping the cap is fixed and later today, I'll try it out. Thanks again to hondamechanic for the insight.

also ensure the cap is tightly together to maximise the lift from turning the vent on.