I've been building an 86 tri-z with the hopes to MX race it here in AZ. I put a carb from a 82 yz250 on it, because it was carb-less when I got it. I had it running on Monday and was going to do a lap around the neighborhood and plug chop on the way back home. Well needless to say I didn't make it back home with a running trike, I had to push it home. I had pulled over to adjust the clutch cable and it started reving really high with out twisting the throttle, it wouldn't shut off with the switch or when I pulled of the plug wire, Then it backfired and shut off. Fuel mix was 50:1
so at this point I think I need to pull the top and apart to examine and see if I did internal damage. I have a 1982 YZ 250 motor that was rebuilt and never made its way back into the bike. It has been sitting for about ten years, so the seals may need to be gone through. This motor has the power valve set up on the jug. I feel if I'm going to have to do any major motor work to the tri-z motor I should upgrade it if I've got the parts available. What are the differences if any between these motors?