[Apostle2]

Hey folks,

I've worked on many thumpers in my day but I'm a little confused about my CBR250r. I just checked the valve lash on it at 8000 miles and the exhaust valves measured 0.27mm and the intake valves measured 0.27mm. I had the dealer performed the 600 mile service and they said they did adjust the valves. Now what confuses me is that in my experience the valves on these thumpers always tighten up with wear (less valve lash). Isn't this correct on these engines? All of my other thumpers did not have rocker arms like this CBR does but I wouldn't think that would matter. Either the dealer lied to me or adjusted the intake valves incorrectly or the valves lash increases with wear. Which is it?

 

[Minifur]

Every time I have had to adjust the valves on other bikes the clearances are tighter than they should be. What usually happens is the valve seats deeper and deeper into the cylinder head with use.

 

[sendler]

Mine wore tighter.

 

[Apostle2]

What usually happens is the valve seats deeper and deeper into the cylinder head with use.

Yep, this is how all of my 4-strokes have wore also, I've even had to replace heads before from so much wear. But I don't usually have rocker arms involved. These intake valves were either very loose from the factory or the dealer simply screwed up if they did actually adjusted them. I'll just get the correct shims and get them set properly.

Thanks

 

[jsonder]

Older Honda singles had the intake and exhaust set the same. A hurried tech could have missed that the 250R has different intake and exhaust specs.