Need help troubleshooting bike tune 250m drag

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BCjohnny
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Re: Need help troubleshooting bike tune 250m drag

Post by BCjohnny » Tue Apr 21, 2015 4:45 am

I'm guessing most of us had little formal education regarding engine work, so you're not alone. From the above post you need to pull it back apart, check the cam for straightness and bearing clearance (I'm guessing machined directly into the head parent material).

You still answered why you replaced the valves. Bent? Worn? Either way I can't see how the seats can't need truing. If no-one can do any of this locally maybe you have the seeds of a business........
"If an honest man is wrong, after demonstrating that he is wrong, he either stops being wrong or he stops being honest." Anon

bladefrost
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Re: Need help troubleshooting bike tune 250m drag

Post by bladefrost » Tue Apr 21, 2015 7:12 am

BCjohnny wrote:I'm guessing most of us had little formal education regarding engine work, so you're not alone. From the above post you need to pull it back apart, check the cam for straightness and bearing clearance (I'm guessing machined directly into the head parent material).

You still answered why you replaced the valves. Bent? Worn? Either way I can't see how the seats can't need truing. If no-one can do any of this locally maybe you have the seeds of a business........

@bcjohnny

i've already checked the cam bearings & it was good. I replaced the valves because it was leaking maybe slightly bent because grinding doesnt fix the leak. There are machine shops who reconditions valves seats here. I've checked valve lash today at different position on the base circle and on the intake there's a difference of 0.05mm between the smallest & the largest i measured, while on the exhaust side there's a 0.10mm difference. quite big. There is a point where you make the clearance smaller & smaller and bike would not run right or would not rev high & you can hear the valves bouncing or maybe floating & there's alot of vibration & no power on the higher rpm ranges.

madmikeracing
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Re: Need help troubleshooting bike tune 250m drag

Post by madmikeracing » Fri May 08, 2015 7:25 pm

I would Remove the spark plugs, bore scope down the Cylinders concentrate where the wrist pin has perhaps buggered of on you, (I have had this before fro mcrooked cylinder bore work, it runs great for a while suddenly lost power still runs alright but wont go as quickly!! also do leak down compression test check fuel flowe and condition. Just my 2 cents worth Good Luck!!

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Re: Need help troubleshooting bike tune 250m drag

Post by madmikeracing » Tue Jan 12, 2016 5:28 am

WELL did yo usort it?? Mike

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