Yamaha R6 Forum: YZF-R6 Forums banner
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37 Posts
Discussion Starter · #1 ·
Hi i have a R6 which has just out of the blue decided to give me crap.
Problem is the bike would not idle after its warmed up . I thought it was a carb problem and had it off and cleaned it twice but every time i put it back on the same thing would happen.
If i went into the shed and started it from cold it would run a bit then start cutting out unless i reved it hard.
Anyway after allot of head scratching i could not understand why every time i started it without the air box on it would idle on its own.
After a bit looking on the internet i have found they can suffer with crank breather problems due to poor rings which causes to much pressure to the carb.
If i put my finger over the breather hose there is allot of pressure building up and it pops my finger off and also has vapor.
I have done a compression test and number 1 cylinder is down. I have 90 psi on no1 and 2 3 4 is 160 psi. I messed up and did not do a wet reading.
I have taken the head off to check the valves and done a leak test and they seem spot on with no leaking fluid. I think i am looking at a piston ring needed on cylinder 1 but thought i would ask for advice. Also the engine oil stinks of petrol.
The bike has only got 21,000 miles on the clock.
It looks like there is a canny bit stuff to take off to separate the crank case to get into changing the piston rings.
I will have a go at it on my own if she needs doing but would need to find a little how to guide if anyone has heard of one or if someone on here can give me some advice. I am a car mechanic by trade but bikes are a little more tricky.

"Old Slow Guy"
40 Posts
If in doubt, get a good shop manual, and maybe take some good zoomed in pics with a camera for reference when you begin putting it all back together. Really, other than the extra clutch and trans shaft, shift forks and shift drum, working on a bike engine isn't any different than rebuilding an engine from say an Eagle Talon. If you can set the cam timing on a 4g63 or SR20DET, you should have no problems rebuilding an R6. Good luck.
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