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Smoke on cold start up

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Hi, a new CRF owner here. Bought an 09 and put about 21 miles on it breaking it in as per the manual. I then installed a JD jet kit, cut the air box, oversize tank and a few other mods. I noticed some smoke out the tailpipe when I goose the throttle after I take the choke off (cold start only-never does it on warm restarts). It will do it a couple of times then it is clear after that. I am not using the choke on warm restarts. The smoke is when the RPM is rising, not falling. I only leave the choke on for between 5 and 20 seconds and the smoke is blue, not black. Coming from an XR400 I am used to oil smoke on start up, but the CRF only has 21 miles on it. Is this normal for this 'hi perf' motor?

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Since its still relatively new, the rings are likely still seating as are the valves. Ride it for about 3 hours, then get the valves checked and change the oil.

BG

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Personally, I don't touch the throttle until the tops of the radiators are hot. I just let it idle. I want nice hot oil and metal everywhere before I 'goose' the throttle.

I think the puff is normal.

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I don't raise the RPM that much, just enogh to keep it idling. I only leave the choke on for about 15 seconds then turn it off. The bike still has trouble idling on its own so I manually raise the RPM (to about 2800) to keep it going until it can idle on its own. It is when I raise the RPM that I notice the smoke. When it can idle on its own there is no smoke. Probably being over concerned (aka anal) and the rings are not seated yet.

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Glad you're not revving a cold motor, ghostbuster2. One of my pet peaves is when guys start a cold 4-stroke and twist the throttle until they hit the limit while the bike is on the stand. That's theeee very best way to ensure short engine life by catastrophic failure. I cringe every time I hear it.

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Glad you're not revving a cold motor, ghostbuster2. One of my pet peaves is when guys start a cold 4-stroke and twist the throttle until they hit the limit while the bike is on the stand. That's theeee very best way to ensure short engine life by catastrophic failure. I cringe every time I hear it.

Me too, why rev a cold motor.

My 450X used to blow a little smoke when it was new. I haven't noticed any at all for quite a while.

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mine does it too. After its fully warmed up it goes away but any throttle application when cold will have a puff of smoke.

I think the X burns oil. Even more important to change the oil regularly and often.

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mine does it too. After its fully warmed up it goes away but any throttle application when cold will have a puff of smoke.

I think the X burns oil. Even more important to change the oil regularly and often.

what he said

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