i have a problem with a 2001 yamaha raptor 660r i rebuild the the engine from the crank shaft up new push rod and bearing piston and rings
when the engine is cold and i crank the engine for about 15 minutes and when the exhust pipe on the bike heats up to an untouchable tempurture the bike will start and run perfect but if i let it cool down for about 3 hours same problem again i have cleaned and jetted the carbs changed the egnition coil checked the timing
now i am all out of ideas . any help you have will be greatly appriciated
thanks in advance
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Cranking the engine for 15 minutes? I hope that's not continuously...

Sounds like your valves are way too tight.

 

have you ever thoguht of using the choke?

 

Im amazed the battery would last that long, and the starter too.

What does it sound like once its running? Whats the compression look like?

 

It's your valves. Check the clearance.

 

your right i didnt make my self clear i hook up the battery to my van and then i hit the starter on and off for 15 minutes till the engine cast warms up then it starts and it runs perfect
but starting it is the issue
the valve clerance is fine . i checked that last night
sombody told me it might be the the coil next to the stator
does that make any sence or do you have any sugestions

thanks for the reply
chris

 

Did you check for spark during the "cold period"?

 

thanks for getting back to me so fast

yes the spark is perfect
but in the long cranking phase i was talking about some times a blue flame shouts out of the exhust or light white smoke comes out wich i presume is gas from the comresion crank
thanks

 

I am bored today.

When you checked the spark, was the plug wet with fuel?

Also, how about valve timing? Did you get the marks lined up perfect?

Do you think you have good compression?

 

YES THE PLUG IS WET AND TIMING IS PERFECT THE COMPRESION IS ALSO GOOD
I JUST PUT IN PISTON AND RINGS
DO YOU THINK ITS THE PICK UP COIL AND DO YOU KNOW WHAT THAT PIECE DOES


THANKS AGAIN
ANY ADVICE IS APRICIATED[img]i/expressions/face-icon-small-confused.gif[/img]