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Discussion Starter · #1 ·
Hello. I got a new carb and put it on. The bike ran great, sounded great. So I parked it in the garage and left it for a few days. Well today I go to start it and I get a Huge backfire out of the muffler pipes. I mean huge. I couldnt even hear. Now when I try to start it it just keeps on backfiring and wont start. Every once in awhile it will start run for a minute which seems fine. Sounds fine then it stalls and when I try to start it, it just backfires. I dont know what is wrong. Ca anyone help me? The bike is a 1983 xlh 1000. Thanks alot. If I take off the breather and crank it I can see some gas coming out of the carb. Is this normal?
 

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Adjust the idle mixture screw? Don't know, but that's where I'd start. Try different jets? Just throwing out suggestions. Good luck!
 

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Backfire

I would first check the fuel petcock. Disconnet from carb and open the hose into a soda can or some other non-glass container. If it is the vacuum type, apply vacuum to the port first. Should flow in a steady stream. Next I would check the float in the carb. Make sure it is not sticking and flooding the engine.

Good luck,

SEMJPM
 

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Sounds to me like the needle isn't seating in your carb and it's letting fuel leak down into the cylinder. You may have something keeping the needle from seating in the carb, or the needle seat may be gouged. I'd pull the bowl off and give the seat a little squirt of carb cleaner and just give things a look see. Might be that your float isn't working right either, but you can take a look at that with the bowl off too.

good luck
darrell
 

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I'd take out the plugs and look at them. If all oily and nasty, the bike is getting too much fuel....probably a stuck needle valve.....take a rubber mallet and gently tap on the carburetor float bowl. Dry and clean the plugs before reinstalling them. Then try to restart it and see what happens........
 

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Discussion Starter · #8 ·
The are really black and flakey. I think it might be to rich and to much gas. A combo problem. Dont really know what to do.
 

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The needle valve probably isn't seating right; not uncommon. The fuel leaks through the carb into the cylinder, and eventually flows down into the exhaust. When you try to start the bike, the fuel in the pipe ignites. This can be very noisy; if there is sufficient fuel in the pipe, it can also be very unhealthy for the bike and anyone in the general vicinity.

As the moco says, you should turn the fuel off at the petcock when you park the bike.

Hopefully, you haven't done any serious damage to the machine. Try closing the petcock, pull, clean and regap the plugs, kick the engine through a few revs to dump excess gas from the cylinders, reinstall the plugs, open the fuel petcock, and fire that mother up.

Remember to keep the shiny side up and the rubber side down...
 
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