Hello,

I have a 2004 Yamaha SR 250. I have recently changed the oil and cleaned tappets and the engine sounds great and has a lot of power. When I start accelerating it is fine but when I accelerate fully the clutch slips and the bike sometimes misfires. Is this serious? Do the clutch plates need changing? Or is it just a matter of adjusting the clutch settings and if so, how do I do this? Any advice would be great as I am new to the bike.

Thanks,

Grant

You did use a bike-specific oil for the change, didn't you? Not some generic car oil that may (or may not - but most likely will) have friction modifiers that play havoc with wet clutches (ask me how I know this!) .... If you did use the bad stuff, you may get away with it by changing it again for a bike-specific type - I've used Halford's own Motorcycle Semi-synth in all my machines for years (ever since I had clutch slip on my NX650 after an oil change, funnily enough!).

As for the misfire .... plug breaking down or fouling, plug cap going bye-bye, loose leads, failing ignition black box .... the possibilities are endless. Of course, if it's only misfiring when the clutch slips, it could be a rev-limiter type thing - just guessing there.

You're welcome

Make sure you have 3-5mm freeplay between the clutch lever and clutch lever holder and as Kirriepete says make sure the oil is suitable for bikes Not for cars.Check the oil container it should have JASO-MA spec which is suitable for bike wet clutches.Tony.

hello,

thanks for your tips. the oil used for the crankcase was 20w/50 multigrade. i phoned the yamaha dealers in my city and they say that this is what they use for sr250s. will adjust the clutch and check the cable to see if i can sort it out. thanks again, grant

Bike specific oil...not from a car shop........?

As to the ignition check all the easy stuff first like spark plug etc.