Hard to start - Yamaha YFZ450 Forum : YFZ450, YFZ450R, YFZ450X Forums
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post #1 of 8 (permalink) Old 05-19-2017, 03:09 PM Thread Starter
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Hard to start

Hey all, I just got done doing a few mods and now my 2007 450 is hard to start, cold/hot, and shoots flames during high rev. The quad has a HMF comp exhaust kit, quickshot3, CFM intake w/ KN filter, JD jetting kit, and stage 1 Hotcams. The new mods are the intake and cams, everything else was on last year. I believe the fix is in the jetting, but wanted to get a second opinion prior to wasting a lot of time. I'd like to start running C12 fuel also so any recommendations would be greatly appreciated.
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Adam
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post #2 of 8 (permalink) Old 05-20-2017, 01:49 AM
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are you 100% sure the cams are in the proper timing??

OI 480


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post #3 of 8 (permalink) Old 05-20-2017, 09:15 AM
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Don't bother with the c12. You're wasting money and probably losing power if you do.
Double check your timing, then go to jetting

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post #4 of 8 (permalink) Old 05-20-2017, 06:54 PM
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What's your valve clearance set at
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2012 YFZ450R
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post #5 of 8 (permalink) Old 05-20-2017, 06:59 PM
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No need for C12, it been proven that using high octane in a low compression motor is useless and will cause power loss. I would check your valve clearance as BadAss stated, although I will tell you that my bike is just a ***** to start no matter what! I have tried ever possible mixture of the screw on my bike and a 42 up to a 52 pilot jet. Listen to Sheerider and Badass.


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post #6 of 8 (permalink) Old 05-22-2017, 09:15 AM Thread Starter
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Thanks I'll open it back up and check both clearance and timing. The clearance didn't change from factory, however, the exhaust was .001 less than the min. Like I said this was factory so I choose to leave it alone. I'll set them to the middle and give it another try.
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post #7 of 8 (permalink) Old 05-26-2017, 09:07 AM Thread Starter
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So after rechecking the cam measurments there was no change, I eneded up increasing the main jet and seems to be running much better. Thanks for the advise. I believe I'll need the quickstart next year
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post #8 of 8 (permalink) Old 05-26-2017, 05:25 PM
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Quote:
Originally Posted by Adam Wells View Post
So after rechecking the cam measurments there was no change, I eneded up increasing the main jet and seems to be running much better. Thanks for the advise. I believe I'll need the quickstart next year


Are you running the hot cam in both intake and exhaust

2012 YFZ450R
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