Did Yamaha make a liquid cooled 490?

[Derrick Adams]

Or any Big CC 2-stroke. I'm really looking into building the ATC500R but, if I could find the Yamie, i'd just as soon build a Tri-Z.

[Yamahammer490]

Nope - nothing that ever reached production :( . The YZ/IT 465, YZ/IT 490 and WR 500 were all air cooled.

The YZM 500 you'll see pictured on various Yamaha web sites was a hand-built works racer. Only a handful (5, I think) were ever made.

[TrikeKid]

you may be able to make it fit. i've seen a TT600 engine in a YZ frame

[Yamahammer490]

Derrick,

For what it's worth I've seen some Tri-Z frames with YZ 490 motors. There are a few threads on here about that. From what I understand it is a fairly simple bolt in with the correct year YZ 490.

Obviously the YZ is air cooled so you'll need to remove the radiators and so forth. Yamaha switched the YZ 490 to a center exhaust port in 84, I think, so you'll need an 84 or later engine. The early models of the 490 (and 465) had the right side exhaust port which would probably hit the frame.

[TimSr]

The bottom end motor cases on the 490/465 are the same dimensions as the TriZ, so they fit without altering motor mounts. The top end and exhaust are the biggest considerations as Yamahammer has stated.

[BigGreenMachine]

Thats pretty awsome that the bottom mounts are the same. I bet there were alot of privateer flattrackers running the big 490 in their Z for competition.

[Yamahammer490]

Flat track racing wasn't real big around my neck of the woods so I really wouldn't know. There also wasn't a big open class like with bikes. Probably because the only "big bore" trike was the 350X and it came near the end of 3 wheelers anyway.

I remember the gonzo motors being used more in the "mud runs" and drag races where you need lots of explosive power and they have fewer restrictions on classes.

Kinda sad that both trikes and big two strokes have gone the way of the dinosaur...