Question for the KLX
 

How many miles can our KLX go till we have problems. 5k? 10k? 20k? 40k? 70k? 100k?

Not being negative here, but that's really a question that has no definitive answer based on how open ended your questions is stated. One KLX used a certain way under certain circumstances might last 2, 3, 4, or more times longer than another KLX used by a moron who flogs the bike mercilessly without proper maintenance. You need to look at Rickypanecatyl's post on ADV Thumpers to see how even a 351 kitted KLX can run an extreme amount of miles...with proper care of course.

I'm talking about avg lifespan. Change your fluids. Don't go crazy on it. So just kinda looking for an aprox avg.

Really, infinite life then. If you're regular on everything, nothing should fail. There are no common issues I've seen with this bike. But to me, regular maintenance can include a periodic rering and hone. Some people consider head work regular on a dual sport. If you're looking at only changing fluids... ONLY... Don't expect it to last forever. I'd figure you would have valvetrain problems if you're not adjusting the valves on their schedule. Really though, it's so circumstantial. Any bike will run as long as you let it.

Well, taking a very wide, speculative guess, I'm going to say around 50K...with the best care. Now, that's a very wild guess. I'm using 50K because I think many singles probably need a valve service for optimal performance at that point...as well as many multicylinder bikes too. The bore, piston, and rings on most water-cooled motorcycle engines are probably in fine shape with proper care, but valves on most/many motorcycle don't last as well as Gold Wings or Honda Accords. But then there will be exceptions on the high side and low side, and I'll say again...there isn't really a definitive answer.

Alright, for some reason i thought the bikes got like 100k miles with just regular minimal maintenance. I guess the 1k i got already + the 2k im going to put on it this summer means i'll have this bike for awhile.

Well on a single cylinder machine, top end rebuilds will be necessary at some point (head, re-ring, valves) because of how much stress the one cylinder is under.

However, I'm more concerned with how long the transmission will last, that would definitely NOT be as simple as "taking it off and sending to a shop" as redoing a head or cylinder.

I'm thinking riding normal would give that 100,000 miles as a likelihood. My 650 has 45,000 on the general bike with a set of fork seals and regreased headset. I did have a shifter return spring crack and break over those 45,000 miles too. The cam tensioner failed twice and exhaust valves burnt (I'm thinking more likely my fault) within the first 15,000 necessitating the top end be redone.

if the cam drive is kept good and the valves properly adjusted the engine should have done 45,000 miles virtually trouble free. It is still good to go a lot more. I want to take it apart to clean and paint the frame and relube everything on the frame and swingarm.

I think the 250 should do as well too... but I"m thinking big bore before that - just because!