dead cyl when hot...

[MR_NST]

Ive used the search tab to no real success with this issue. so i hope maybe someone can shed some light on my problem.

last Monday i was on a long ride and washed the bike immediately when i got into town... after the wash i noticed a slight miss and a little lack of power. i figured wet spark plugs, so i got it home and left it.

Friday, was the first time on the bike since Monday, fired it up, sounded good, ran fine. about 15 minutes later it developed a slight lack of power again and i noticed the exhaust sounded different at the lights. got the bike home and started pulling wires, the number 1 cyl wouldn't change the sound of the exhaust so i figured the spark plug was cracked from thermal shock when i washed the bike. there is a strong spark, my tester shows over 25000 volts on #1 cyl. i replaced the plug today, fired it up and it idled great, revved great, and rode great.

planned to go on a long ride today, made it 15 minutes away and the same symptoms are happening over again.

HELP i don't know what to look for next. Ive only had the bike for two months and love it, but Ive never had this bike apart to know where to look. I'm extremely automotively inclined so, don't be afraid to get technical.

the bike has 2500 kms on it, and this shouldn't be happening now...

thanks to all in advance,
Evan....

 

[broook]

You could have a tight valve that does not close properly when hot.
Try a comp. test on #1 when hot to check it out.
Just a thought.

 

[one2dmax]

Did you try and actually replace the plug? They can go bad and do that as the center electrode changes shape during the heat cycles. Very cheap to try. Get it from your local auto parts store and not the dealer (will be a hell of a lot cheaper). NGK DPR8ea9 which is also 4929 in most of their parts look up systems.

Sean

 

[MR_NST]

thanks for the reply guys.
im not so sure of a sticking valve, it would backfire if that were the case either out the intake or the exhaust. i haven't done a compression test yet as my tester does not fit the spark plug hole. although i am confident that there is lots of compression.
i did replace the spark plug with the same ngk plug you noted. the problem still occured when warm. i figured it was a faulty plug from the start, but from what im reading the coils are a bit iffy from the get go... im sure ive got a good spark i just cant explain it. i tried insulating the spark plug boot even further with electrical tape to no success. im starting to think a COP swap might help, but then what if it doesnt.

if you guys can think of anything else please let me hear it.

and sean, by the way. the previous owner of my bike bought one of your seats for it. i must say its certainly better than my friends stock seat he has. thumbs up!!!