I grew up riding the 87 mx lt. The engine was the best part about it. Awesome power absolutly hauled!!! The chasis was hurting tho. Too much of a plow to really stay up in soft snow. More built for trails. The rear suspension got destroyed in ours, don't remember what broke so we put a 121 inch track and skid off a 97 formula 500 and that worked good. Hooked up real good. Just made the back end sit a little higher. Put over 13000 km on the motor without touching it before it finally locked up. Sounded like a crank, but I never looked into it. Sled wasn't worth enough to justify the new motor. But now I'm wanting to tear it down and see what exactly went wrong.

 

They didn't make a 500, it was a 467 in the MX the 500 come the next year in the S chasis. Great handling sled on smooth trails, hard to beat for cornering, ride, well not so much in the rough stuff, but back then thats all we had so we rode em hard for many miles. One day in 1990 rode it 473 miles in 14hrs but the trails were all very good. Desent on fuel good wind protection with the high windshield,lots of moving parts in the rear suspension, bushings have to be changed quite often,and keep an eye on the clutch side jackshaft bearing, had a habbit of going bad because of the locking collar and would chew up the shaft.

 

Yes in 1986 it would have been a type 467, 462cc l/c engine. Unless someone put in a type 503 fanner? I think many called the 462's 500's, but I know later Doo called them 470's.

The S chassis didn't come out until 1996 though and in limited models. I could be incorrect on this, but I am thinking the 670 only in the mxz? 500 l/c in 1997?

If it is a type 467, bulletproof engine. Love them, they are the little engine that can.