10 minutes then dies

[MikeGyver]

Greetings all. I have a GT5 on my mountain bike. I have 125 miles on it. At first, I had rubber in between the motor mounts. Well that vibrated the carb so bad that the it broke apart the mounting ring on it. I bought a new speed carb with made it run much better than the High efficient carb it came with. Also, the vibration had busted both of my rear motor mount bolts. I could not get the bolts out, so I drilled and threaded 2 new holes, which also aligns my drive chain better. The ignition wires had touched the muffler and melted some, but the motor was still running good. Now, after running for about 10 minutes, the motor dies as if not getting spark. I have spliced in new wire where it had gotten hot, but my problem still exists. When it starts acting up, it also backfires. I have adjusted the needle valve in both directions with little change. It seems to work best in the leaner position. Can anyone help me with this?

 

["the prussian" Shop Dogs]

Not to prempt lord vador , but have you checked the head bolts ,running cool and not running hot is often a bad gaskett no...or the head is losse from the vibe. Just a thought.

 

[MikeGyver]

Yes sir. All bolts are tight.
Thank you for the reply.

 

["the prussian" Shop Dogs]

No prob ... Still think it's a heat an leak situation , gaskett can be tight to head and still be bad. We'll see what norm thinks good luck

 

[MikeGyver]

Thanks again. I'll look into it.

 

[MikeGyver]

It is now looking like my spark plug boot. My engine came with a spare, but the inner connector popped out of that one too. I've called a couple auto parts stores and they don't carry them. Any suggestions on where I can buy a good one?

 

[Al.Fisherman]

Lawnmower parts store.

 

[2door]

Is you fuel tank cap venting? When after the ten minutes you say it runs, then dies, check to see if you have fuel flow from the tank to the carburetor. Sounds like you're running out of fuel because it isn't able to flow due to the tank not venting.
Try riding with the fuel tank cap loose and see what happens.
Tom

 

[MikeGyver]

Yeap, that was one of the first things I tried. I also have a clear fuel filter, so I can tell when the gas is not flowing.

Thanks for the reply.

 

[2door]

We've seen this problem caused by a faulty CDI. There have been reports of the ignition mudule misfiring after it gets warm. Just as an experiment try changing the CDI with a known good one and see what happens.
Tom

 

[MikeGyver]

Thank you. I just ordered one this morning.

 

["the prussian" Shop Dogs]

You can change the boot and wire on some older cdi' s but newer one aper to have end glued in . Any place that has outboard engine parts will have what you need . So even with new cdi I still recomend changeing boot and wire ,there are a number of good post re: this fix

 

[MikeGyver]

Thank you for this valuable information. I will check into it.