Hard starting two-stroke

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8/5/2018 4:34 AM

Hey all, looking for some input with my issue here.

Bike is an 03 Cr125, I tore the carb down, rejetted to pro circuit specs 390 main jet, 37.5 pilot, stock needle on 2nd position and screw 2 turns out. With this configuration, my bike is super hard to start. Once running, if I turn it off and then restart it it starts no problem. Does this sound like a float issue or the clip setting too lean? (FL roughly 70-90 degrees).

Also, it is running much better while running and idling, however I still feel like there is a vacuum leak somewhere. I replaced both crank seals, are there any other obvious places for air leaks?

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8/5/2018 4:48 AM

Your base gasket and head gasket, as well as the gaskets for your reeds and boot to the carb can all habe leaks. The bike would rev to the moon if there was a leak.

If your motor is all tight id be willing to bet youre not rich enough on your pilot. What does your plug look like? Can you drop some gas in the spark plug hole and start it easily?

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8/5/2018 5:32 AM

While trying to start it, I pulled the plug and it was solid white. I then turned the air screw in 1/2 turn. However I also failed to turn the fuel on for the first 10 kicks, im used to my efi kx250 lol. I didn't check the plug after I had it running though. It revvs a little high and doesn't come straight back down to normal revs when I give it a higher rev but its not like crazy bad or crazy hanging if that makes sense. I also think it needs a top end, I can kick start it with my hand but im not 100% which size piston to get, I was planning to pull it before making a purchase.

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8/5/2018 8:24 AM

Livinloud11 wrote:

While trying to start it, I pulled the plug and it was solid white. I then turned the air screw in 1/2 turn. However I also ...more

If it needs a top end, you'll never get dialed in right. Got to have a good top end before reading plugs/messing with mixtures/setting idle speed

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Many thanks to everyone helping me out this GNCC season: SRT Offroad, Acerbis, FCR Suspension, O'Neal Racing, Evans Waterless Coolants, Rekluse, Twin Air, Braking Brakes, Carbsport

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8/5/2018 9:13 AM

Yea rebuild your top end first. Hanging idle means your pilot is lean or you got an air leak.

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