Tri-z Engine Upgrade Question

[Just-Tri-It]

Sorry if this has been asked.
I’ve seen the Tri-z motor swapped with the 490. Has anyone used the 460 as well with any success? And has a better looking pipe system been made for anyone that would look more like the Tri-z OEM design? Would the OEM popes for the 490 and 460 even mount up to the side of the Z if it would hookup to the exhaust? I understand that the frame is in the way so that the 490 pipe can’t hookup at the exhaust port. But if it could would the rest of the pipe snug up around the Z or is it all out the window?
Thanks.

[El Camexican]

Don’t know about the engine fitment, might want to look Raffa up, he may. What year and model of 460? I thought the YZ jumped from a 400 to a 465 and then the 490 before they gave up.

I doubt any air cooled Yamaha dirt bike pipe would fit a Tri-Z frame without cutting it up and trying to weld it back together.

So just curious, but why the interest in putting a 460 in the trike chassis?

[sledcrazyinCT]

So just curious, but why the interest in putting a 460 in the trike chassis?

I would say his user name is a good explanation :lol:

[El Camexican]

I would say his user name is a good explanation :lol:

Ha! Good one.

I asked because I've pondered the 490 engine in the past, but if you believe what's out there on the Internet it's an evil nasty beast that's stumped a lot of tuners. Seems the big bores are best left to the red and green brands. Then there's the starting issue with stock fenders and the pipe issue. I read somewhere that no one ever made a decent pipe for the big Yamahas.

It would be a cool project, but not any easy one to be sure.

[TrikeKid]

The 490 had detonation issues and was a bear to start if you weren't careful. There are things that can be done to remedy the pinging with some machine work to the combustion chamber. The 465 OP mentioned doesn't have all the issues the later bikes did and is really well regarded by comparison.

None of it is going to be an easy/bolt on deal though. As far as a "better looking" pipe goes, the pipe has to be the size that it is for tuning reasons. It can be moved around but it will more or less always be at least as big as it is.

I'd be looking to see if Klemm Vintage is still building their big bore Tri-Z stuff before I spent the time trying to cram a 465 or 490 engine in it.

[Tri-Z 250]

The 490 had detonation issues and was a bear to start if you weren't careful. There are things that can be done to remedy the pinging with some machine work to the combustion chamber. The 465 OP mentioned doesn't have all the issues the later bikes did and is really well regarded by comparison.

None of it is going to be an easy/bolt on deal though. As far as a "better looking" pipe goes, the pipe has to be the size that it is for tuning reasons. It can be moved around but it will more or less always be at least as big as it is.

I'd be looking to see if Klemm Vintage is still building their big bore Tri-Z stuff before I spent the time trying to cram a 465 or 490 engine in it.

If you keep compression down on a 490 and use a better than stock carb your detonation prob goes away. The hard start is a TDC start only on first kick( gotta roll it over).
I agree with the BigBore route but again do not max compression the head. A good squish on a mild Comp motor will run smoothly. IMO it’s better money spent DynoPort will hand build you a larger bolt on pipe.

[ATC King]

It seems like the large, air cooled, old-school smokers are best for lower RPM torque.

The large two cycles don't necessarily rev any higher than the 250cc ones, or even as high. They appear to be the choice for lower RPM and less stalling, or making more use of each gear.

ATK had a 700cc (single cylinder) two stroke. I don't think it ever won a major off road race, unlike the KX500.

[christph]

Klemm still makes a 350 big bore for the Z. It's around $1200.

[oldskool83]

prob dont want to hear this buy a YZ400F/YZ426F motor will rip you a new one. I'd rather covert to that after owning one. I'd never go back to 2 strokes now. Your other option is doing a tri-z motor up. Its basicly a 86-87 YZ250 which I've also had done up. I did a nice 265 kit with milled and redomed head from eric gorr racing, piped too. It ran good and harder but nothing like one of that YZ426s, nothing like it!

[Dirtcrasher]

Raffa had a YZ490 in his Tri Z back in 2008 at Trikefest. I believe the big end bearing launched pretty early in to the races unfortunately. That's when YAMAHONDAMAN was around and he'd make us just about anything we asked for...