I had a 86 TRX 250 engine a bunch of years back and looked into this.
At the time I was using DDR to do my RS 125 stuff and he said it would make a great engine……with a bit of updating.
“Updating” is a nice word for “Credit Card number please….” ;)
Needed certain model CR cylinder, aft market ign./head/pipe/reeds/cage….etc., etc…..
It’s a package……it’s always a package!!!!!
Yes, the counter shaft and 6 speeds was nice but the engine was very heavy. For the $$$$ and work, your better off with the CR dude.
Never did the mods but we did run it twice, on a laydown at Grattan and Gingerman. The guy driving it was just 150lbs, it was quite a handful. He never drove it again!!!!! :)
Just put 2 – CR 250’s on that thing man!!!!!!