250-500cc Spark plug issues

More than a few times I have seen guys lean out a bike that probably had low compression. The bike would run pretty good for a ride or two and then blow up. I started doing a compression check as soon as the top end was broken in which gave me the highest possible reading. Then at a later date if I suspected a compression loss I could do another compression check with the same gage and compare. The thing about the WR250-300 is that they can have good compression but wear the intake side of the piston with a deep enough groove to cause the piston to break. After learning this I take the reed block out once a year and have a look. My 2009 WR250 has the original piston and rings and as of last month 205 psi cranking compression so they are pretty tough and dependable but everything has it's breaking point.

compression tests are way overlooked.

Yep, that is why I didn't. I figured the jetting was fine for almost 100 hours at that point so I wasn't going to mess with it.

I did the same thing, tested the compression after break in and have been monitoring it. With the lectron I doubt I would notice the a difference as the compression drops.

My issues were all back in the mikuni days, I don't miss that carb one bit.

Later,