Few Quesitions

Hey guys and gals how is it going? I recently purchased a 2001 YFZ 426 has a ton of aftermarket parts on it, except for the 450 mod. I have only ridden the bike once since owning it, a month now. After kicking and kicking the bike I started to research some and noticed the all mighty "450 mod". Seems like from looking around 2003-2005 more bottom end and 2006 up better top end. I plan to go with the 2003-2005 cam. As bike has plenty of top end for me. ;) Now the problem is seems like most post about it are a year old or so and information is kinda of scattered here and there. I plan on doing it myself as seems easy as most folks said. Plus I am mechanically inclinded and like to work on my own toys. Now comes my quesition what cam will work? A stock 2003-2005 YFZ450 cam? Anything else needed other then the cam, feeler gauges, and basic tools to do the job? The bike has 10 hours on it since was rebuild by the guy I bought it from. So do not think, scratch that hope it does not need anything else, LOL. Can some one just confirm what I need and where to find the PDF file or instructions on the install from start to finish?

Thanks! :eek::banana:



With any cam change, there is the need to verify and possibly correct the valve clearances. You also need a reliable torque wrench capable of indicating 75-80 inch pounds.

Look at the Common Threads Sticky for the links to a service manual download and read the piece regarding cam chain replacement for some general cautions.

Meantime, on starting:



Thanks man! I do have a Snap on torque wrench capable of 70-80 inch pounds. Would I need to buy a shim kit for the valves? Also is this the cam I need to buy for it to work? In the link the bottom right I was going to snag that shim kit if need to be.


Going to read the links you posted now! Man he makes it look so easy in the videos, LOL.

Yes, that's the cam.

Save your money and spend a little time on the shims instead. The kits break up into two size ranges right at the size that YZF's commonly use. So you either pick one, pay $90 for it, and hope you don't need one you didn't get, or buy a refill kit in the right range for something like $40.

Either way, at worst, you'll need 5 shims (if you discover that all of your intakes are out of spec). They're about $5-6 apiece over the counter, and every Honda dealer in town will have a good stock of them on hand. They take the same ones as the CRF450. With any luck, you'll only need one or two, anyway, and then what will you do with all those expensive shims?

Ordered it and hoping to have it here next week and riding by the following weekend! Sounds good on the shim kit, I am hoping that the valves do not need them, but if they do I will gladly pay the ~$30 vs the $90 kit and all it will serve is as a paper weight. Thanks a ton man!

Just an update, I installed the cam in the bike today and everything went great. Kicked it over a few times to get fuel to the carb and bam within the second to third kick fired right up. I than killed the bike and did it again to make sure I did not get lucky. Well worth the money and time for this mod. Hardest part is the wait to go riding to break in the cam, LOL. I highly recommened this mod to the bike, as I dreded starting it. Now I am glad to jump on the bike and let her rip. Now to do the BK mod and get a steering stabilizer and have it. Thanks again grayracer513!

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