07 450 pissen me off

7 replies to this topic
  • DBOBYZ450

Posted August 14, 2011 - 12:24 PM


My bike ran great prior to my last ride, i have a float adjuster/airflow mix screw on the bottom of my carb bowl that fell out and i replaced it, it ran fine after i put it back in and then i stalled my bike really hard after getting cut off by a sandrail. now my bike wont kick over unless you kick it like 40 times!!!

i only have a ride in on my top end since break in ,i cleaned my airfilter, checked my plug(pretty black), and im going to change my oil. i also now have increased compresion when trying to kick over my bike.

whats goin on with my bike ?:eek::smirk:

  • Mr. Neutron

Posted August 14, 2011 - 04:34 PM


Are you by any chance talking about your fuel screw on your carburetor??? :eek: I'm sorry, but I'm having a tough time figuring out what you're attempting to say in your post..... :smirk:

The fuel screw is the one that is just in front of the float bowl, going up into the carb from underneath. Stock, they were a small diameter brass headed affair, usually knurled, and with a slot in the end for a screwdriver to fit in. If you're lucky & have an aftermarket fuel screw, they usually have a big enough knurled head that a person with average sized fingers can twist to make adjustments.

There's a spring, a washer, & an O-ring in there that can all fall out if the screw falls out, although typically the o-ring seldom falls out. You need all of those parts in there, in the correct order..... It will affect starting to a degree....


  • bnichols87ss

Posted August 14, 2011 - 06:19 PM


Had the same problem. Check your timing. Sounds like its time to replace your cam chain... When kicking it over is it really hard when it gets to TDC? And I'm not quite sure what this float adjustment thingy is??

  • DBOBYZ450

Posted August 16, 2011 - 12:00 AM


yea when its at tdc it takes me jumping on in to budge and its a aftermarket fuel screw

id post a picture but i dont have a camera

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  • bnichols87ss

Posted August 16, 2011 - 07:07 AM


gotcha, I'm pretty confident your cam chain is binding. I bet your exhaust cam skipped a tooth. Same exact thing happened to me on my 07 YZ450. You can get a new chain for 20 bucks. However you need a flywheel puller to get the chain off. I got a motion pro puller for $35. The reason it's so hard is that the exhaust valves arent opening at the correct time, resulting in a "hard spot" and has nothing to do with your fuel screw.. Its very easy to replace the chain. Just make sure you clean out the chain guide bolt holes with carb cleaner to remove any oil that has seeped in, and use thread locker just to make sure they don't back out (speaking from experience) lol.. Good luck!

  • crf450319

Posted August 16, 2011 - 07:16 AM


Had the same problem. Check your timing. Sounds like its time to replace your cam chain... When kicking it over is it really hard when it gets to TDC? And I'm not quite sure what this float adjustment thingy is??

X2, I'd check your timing and check the clearance for your auto decompression. Not that it's terribly common to have the auto decomp out of specified clearance (as far as I know anyway), but it's a relatively easy thing to check.

I replace my cam chain every 50 hours, changed my original at 60 hours and had 6 or 7 links that were binding/tight. The OEM cam chains are $20 as bnichols said, ProX cam chains are around $67 but I couldn't find any information as to wether or not they are stronger, wear better, or last longer than the OEM units.

  • WB450

Posted August 16, 2011 - 10:03 AM


This is the answer I received from grayracer when I asked him what cam chain I should use.

"OEM. If you're worried about it, the only aftermarket chain I would use is Pro X, and that's because I know they are made by Borg-Warner Japan."

  • DBOBYZ450

Posted August 17, 2011 - 01:06 AM


Thank you!

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