Dirtbike hard to start?

[white98]

I just picked up a 1990 Honda cr250r and it is really hard to start cold. It has been bored .030 this spring so the top end is fresh. I installed a new ngk br8eg spark plug and it has 110 sunoco in the tank. What would cause me to have to kick on it for 10 minutes to get it to start? Once it gets warmed up it gets alot easier to start. Any ideas would help save my leg:D

[MIKEtheBIKE]

Low compression?

[rjharris]

plugged choke circuit? Octane way too high??

[justinb417]

plugged choke circuit? Octane way too high??

No need to run that high of octane. Inless you have extensive motor work.

[white98]

I just bought the bike last night and that is what is in the tank. I always run bp93 or 91 in my other bike at 50:1. The choke could be the problem, it wont stay open on its own, you have to hold it open by hand.

[dirtd]

I got a 99 cr that had a small leak so small it was virtually undetectable, that caused it to be real hard to start after sitting three to four days. Check around your carb real close.:)

[rjharris]

I just bought the bike last night and that is what is in the tank. I always run bp93 or 91 in my other bike at 50:1. The choke could be the problem, it wont stay open on its own, you have to hold it open by hand.

If you tear the carb apart, make sure you use some compressed air to blow at all the circuits really well. It may seem like overkill but that usually makes all the difference.

[JOS51700]

Check for vacuum leaks. Install NEW sparkie plug. Drain the 110, run real fuel. Yeah it's been apart, but I doubt they built to make 100 horsepower. Clean idle circuit in carb to perfection. Check compression. Just because its a new top end doesn't mean it wasn't thrashed to death since, especially if the air filter isn't super top-nopch.

[Tom]

+1 on all the above. And finally, just be prepared to accept that some old 2 stroke dirtbikes are just plain difficult. I had a pair of Kawasaki KD100 (small frame) dirtbikes as a kid. Think they were '76 or '77's, one blue, one silver. But each had a VERY specific (and different) starting sequence mostly involving the choke, repeated kicking, special swear words no 9 or 10 year old should practice :cool:

Tom

[white98]

I started looking into the choke and figured out it has been broke off before and glued back together. But it had came unglued and wasnt opening the choke when you pulled it. Anyone know where i can buy a new choke for the carb?

[rjharris]

I've got an address for a place for vintage motorcycle parts at home. If I can find it I'll post it here for you. They've gotten me parts for bikes dated in the 70's.


http://www.temeculamotorsports.com/fiche_section_detail.asp

This might be what you want. Good luck

[R1ray]

+1 on all the above. And finally, just be prepared to accept that some old 2 stroke dirtbikes are just plain difficult. I had a pair of Kawasaki KD100 (small frame) dirtbikes as a kid. Think they were '76 or '77's, one blue, one silver. But each had a VERY specific (and different) starting sequence mostly involving the choke, repeated kicking, special swear words no 9 or 10 year old should practice :cool:

Tom


Tom, you crack me up buddy.


Ray