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860
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4/1/2008
Location
Ankeny, IA
US
Fantasy
279th
Edited Date/Time
12/25/2012 1:49pm
We just got a new '08 CRF 250 ran it for the first time last night, REALLY, Really hard to start. We put on an R&D float bowl(this made our '06 run better and easier to start) but other wise the motor is stock. Any ideas? My daughter is already saying "I hate that bike" and we are 2 weeks from our Lorettas qualifier. Please I'm not looking for "you should have bought a 250 2 stroke" it's not really an option for my 110# daughter. One thing that was odd, we never touch the throttle when starting but we did once and it popped and flamed out the exhaust but it did start.
Gas on. Choke on. Slowly kick engine over 4-5 cycles without touching throttle.
Three twists of throttle to prime chamber. Hand off throttle.
Kick to start. If it blubbers and runs a couple of seconds and dies, it burned the prime out. Two twists of throttle to prime again. Hand off throttle and kick again. Should stay running this time, although I've had to repeat a third time when it's really cold out.
I'd put the stock bowl back on and try it then. While you have the bowl off check the needle/seat/float to make sure it's working correctly.
The Shop
Not sure if this will help.
My routine was:
Cold--choke. No throttle. Hand on brake reservoir. Bike would light within 4-6 kicks.
Warm--No choke. No throttle. Hand on brake reservoir.
Hot (after fall) -- Hot start on. Hand on brake reservoir.
Let us know. You might have carburation problems, but I'd try staying away from the throttle, just to see if that works. Best of luck.
Cold, drmarkr's method should work but I don't do the 4-5 slow kicks first. Just pull the choke, twist the throttle 2 or 3 times and kick 3 or 4 times fairly quickly. Make sure your kicks are full solid strokes. If it doesn't fire after this, give it two more throttle twists and kick again.
If you have not luck there, pull the hot start and kick until it starts.
Once the jetting is changed, if the bike pops any on decel then turn the fuel screw out in 1/4 turn increments until it doesn't pop any more.
Also, I don't know if this is your first four-stroke, but they really don't like a lot of air filter oil. I'd still go to the 45 pilot but you might also try with the filter out if you think you might have too much oil on it.
What gas you running?
left intake was a little tight also and exaust valves way tight.
Changed needle and leak jet reshimmed and and much easier to start but still have to do a drill similar to what Dr. Mark suggests.
The cam I think is a little agessive, some guys are grinding on decompression duration via thumper talk. I didn't do that , but overall the bike starts way better a runs very well Got jetting specs from everyones favorite mag MXA. Give me a couple of hours and I will post up leak jet and needle I installed or do a search on MXA
p.s. not saying 45 pilot won't work but tried that first and it got worse
Try a 65 leak jet, NMUU needle W/ clip 2nd from top and fuel screw 2 1/2 turns out.
Depending on elevation clip & fuel screw will need tweaking to dial for optimum performance.
The R&D bowl works if you want to invest but I did not think it was needed after I made these changes.
If you have not checked valve clearance, do so as mine were off out of the box, a first for me, as I have owned five new Honda 4 strokes.
45 pilot doesn't work... makes it worse.
try turning up idle a fair amount.
leak jet has nothing to do with starting.
Regards, Jeff
Pit Row
Just take the tappet cover off and check the clearances, its probably easier than getting that damn carb out! Good luck.
It struggles to start in the cold even with the choke
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