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Wr to Yz cam , starts easier runs worse

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:mad:I have installed the YZ auto decomp cam into my 01 WR250f, now she starts awesome, I was concerned over buying the wr cam or the yz , I picked the yz and now when I accelerate it gurgle rrrrrr and than picks up ,like a two stroke, It ran great b4 , but was horrible to start, . I run a standard pipe and it is all out of wack now . The yz cam must have a direct affect on on one main object ,that should get rid of this borrrrrrrr at low revs .Can some one with the same effect tell me what the first positive fix was after the mod. It starts fantastic, but I just want it to go the same , Ive read and read and read , :cry:

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This is only an educated guess. The YZ intake cam is different than the WR (according to the parts book), just as the two exhausts are different. You would have found some reduction in low speed power, along with a substantial increase in mid-range and top end, if you used a PAIR of YZ cam together, as they were intended to be. You have probably aggravated the drop in bottom end power by mixing the aggressive profile of the YZ exhaust with the milder WR intake, since the engine cannot produce enough power with the WR intake to take advantage of the YZ exhaust. The YZ exhaust, on the other hand will still pull down the bottom end power due to its longer event timing.

The right thing would have been to use the '03 or '04 WR exhaust cam. Or so I thinks.

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The intake cams on the YZF and WRF are the same. Only the exhaust cams are different.

cam_timing.jpg

It is more likely that you need to rejet your carb now that you are running the YZF timing. Try adjusting your needle clip one position richer. You may also need to adjust your fuel screw and or change to a larger pilot jet.

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:cry: I dont know if any one goes this far back but here are the results , I hand built a power now , or james now , fitted it up , did my mixture screw , got my exhaust opened up , wow looks like a staintune, and she was real gurgly still real flat , friday before going riding my mates and I pulled the top of the flat slide carby of by loosening the clamps and spinning carb , pulled out main needle and moved circlip up 2 notches which leened the bike out . we did it one clip at a time , first notch huge difference and than second notch , perfect , did the flat out run and killed it and removed the plug , showing a nice tan colour, bike is heaps snappy ,

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