sosbe
03-23-2009, 07:46 AM
I have a 2005 yfz 450 that I recently decided to do some motor work to. I sent the case off Sparks racing to have the oil mod performed. I put a +3 mm hot rods crank with a CP High Compression full race piston. All new bearings and seals and o-rings along with a new shift drum.
I had it together 2 weeks ago and it ran good - besides the fact I didn't have neutral. So I pulled it back apart and replaced the shift drum and it took care of the problem. I put it in and now when I crank it over it is VERY sluggish. I replaced the battery and it does the same thing. When I pull the spark plug out it snaps it right over with no problem.
I decided to pull start it and it does run, but won't idle, like it wants to seize up. When I pulled the head cover off, there were all kinds of rubber shavings from the timing chain slides, like it had too much tension. So I loosened it up, no change. I am stuck and am on the virge of taking it to the yamaha dealer. Does anyone have any suggestions? Is it just too much compression? Why did it run fine 2 weeks ago, but not now. Everything is done by the book. Please help if u have any suggestions.
I had it together 2 weeks ago and it ran good - besides the fact I didn't have neutral. So I pulled it back apart and replaced the shift drum and it took care of the problem. I put it in and now when I crank it over it is VERY sluggish. I replaced the battery and it does the same thing. When I pull the spark plug out it snaps it right over with no problem.
I decided to pull start it and it does run, but won't idle, like it wants to seize up. When I pulled the head cover off, there were all kinds of rubber shavings from the timing chain slides, like it had too much tension. So I loosened it up, no change. I am stuck and am on the virge of taking it to the yamaha dealer. Does anyone have any suggestions? Is it just too much compression? Why did it run fine 2 weeks ago, but not now. Everything is done by the book. Please help if u have any suggestions.