Looking at a 2002 TTR 125
 

What's the general lifespan of these engines? Anyone know what compression it should show (I have a compression tester)? Anything else I should look for or know about?

The TTR is a play-bike, which means that its lifespan is forever if taken care of.

You going to mini-tard it?

Trail bike for the woman. And, possibly, pit bike for me.

You got to rebuild em just like any other dirt bike. Good news is parts are real cheap if you blow it up on these little bikes.

A quick search says compression should be around 150psi.

BS on the rebuild.

There are plenty of 20 and 30 year old dirt bikes and ATC's running around that have never been rebuilt.

I bought one of these for my wife as a wedding gift. I got her the 2003 version.

My advice, get the electric start version. Had I done that, my wife would likely still be riding it. Those things never started well in the cold.

All in all, I loved this bike for what it was.

Thing is, I want a bike I don't have to rebuild. I spend enough time in the garage with the race car, a 22-year old daily driver and two finicky Sweedes.

How cold? It's pretty warm here.

This bike is owned by a friend who's giving it up for a pretty good price.

All TTRs are electric(to my knowledge)

As long as you don't beat the crap out of it, it should last a few years before the rings need replacing.(ultimately requiring the piston to be replaced also) But it's less than a $200 job that takes 2 or 3 hours depending on your mechanical ability.

The newer ones are electric.

The older models were kick start unless they were the "L" model.