03 loses power and dies after 15 minutes

[John Savage]

I just bought an 03 for my son. It started right up at the former owners house and ran great. We went trail riding in NH on Sat and it ran fine for the first 15 to 20 minutes then died. I tried to restart it but it felt like it had no compression. We towed it for the next couple of miles and it restarted right up. He rode it for another 10 minutes and it died again. Anyone have any ideas?

 

[strokeddemon]

Have you plug chopped? Sounds like its to lean. Had the same problem 2 years ago.. Problem was is tbat jt had a 230 main with fmf not to mention a bad header leak

 

[John Savage]

Plug chopped? I pulled the spark plug and it was pretty dark. It has an aftermarket pipe. What did you rejet to.

 

[strokeddemon]

You need to check the main jet in the carb, search for plug chops. There should be plenty of old threads

 

[Awk08]

compression test, throttle held wide open, kick till the needle stops moving, reply with results.

leakdown test:
http://www.blasterforum.com/do-yourself-20/how-perform-leak-down-test-44653/
http://www.blasterforum.com/threads/leakdown-testers.55015/

clean carb: http://www.blasterforum.com/threads/how-to-clean-your-carbureutor.254/
check set float level: http://www.blasterforum.com/threads/float-heights-and-how-to-adjust-them.50565/

check main jet # while your in there, should be at least a 270+ for most aftermarket pipes.
plug chop:http://www.blasterforum.com/threads/how-to-plug-chop.53237/

 

[John Savage]

You need to check the main jet in the carb, search for plug chops. There should be plenty of old threads

Thanks for the help
I'll pick up some new plugs tonight and give it a try

 

[strokeddemon]

Thanks awk, can't share threads with my phone

 

[speedyslyder]

what part of n.h. did you go i may be real close to you lol

 

[John Savage]

I live in
Mass and my friends parents have a house in North Haverhill. We rode down to Lisbon. I did a compression test using a car compression tester and got 90. I think that's real low even if you add 10 to 20 percent more for using a big bore tester. I'll do a leak down test tonight.

 

[Blaaster]

90 is too low.

A compression tester is a compression tester, and will test the psi on any engine.