Just wondering what everyone averages before a topend rebuild on a DT? (I know we're not talking about 4 strokes. I've got a Honda XL with 26,000 going strong) But what would be a reasonable expectation with relatively easy miles and regular maintenance? Thanks.

Ive never really seen one with more than 10,000 miles that didnt need a bore job, the cast iron bores wear out more on these old bikes than modern nikasil plated stuff. Youll probably have to replace the rings a few times in the 10,000 miles.

Well I saw 23,637 on an AT2 which did seem to need a 3rd bore but did run on the 1st over; www.yamaha-enduros.com/index.php/forums/...ration-enduro-thread

I think ~5,000 is more realistic for a bore and stepping up in size on an old enduro if doing any kind of off road/trail riding.

New bikes, just like new cars, are different. In both the materials used and tolerances. Sure the WR250R is 26k miles for valve checks. But when she needs a bore or any kind of serious work it's not going to be ~$100-200 for a top end either.

5-6k should be no problem if it not eating dirt or being run ragged.  Mine had a little over 4k on it when I purchased it and it ran very quiet.  No audible piston slap, could have kept going and going without a doubt.