Yamaha tri z motor swap question

[Yamaha_Rules69]

Still looking to build a motor for my tri Z. Since im fairly new to the yamaha tri z, I was wondering what motors for sure fit into the frame with basically no modifications. I have done some research, and from what I know so far is that the 83-87 yamaha yz 250 should fit, along with the yz 490 or IT 490 earlier years (exhaust coming left from jug) Anyways, is this correct so far? I noticed that the yz motors would be power valved, so you would have to use a yz jug and piston then, because the tri z jug is different and wont bolt up, is this correct? Also, am I able to convert the yz motor to forward kick? I see it uses virtually the same clutch assembly as the Z as well. Would the YZ 250 motor even be good with this early powervalve setup in teh tri z frame? If anyone has any advice or tips, just let me know. It seems like the YZ motors are a little more plentiful than the tri z, but not by much either. Would it be worth it? Thanks again, Jon.

[Dirtcrasher]

I'm sure RAFFA knows what works and whats too much work......

[factoryX]

I would try a it490, so you have lights...

[Bryan Raffa]

the later years for the It490 and yz 490's after 84 with the exhaust port in the center..even then its a reverse kick

yes you can convert a Z motor to a powervalve..and use the Z kickstart gears for a reverse kick..its a PITA.. 03orangeshee and Gdkarma both have them

real sim for a direct bolt in ...cuttin torch anythings possible.. me myself.. would like a 250f with a 290 kit on it in a tri z ..even then you gotta deal with the kickstart

[Yamaha_Rules69]

Thanks for the advice guys, Raffa, your tri z looks like it goes like a bat out of hell!! So I would need a yz 250 bottom end and matching jug, since the Z motor is different, right? You cant swap jugs?

I wish I could drop the IT 490 in it, but then I would have to find a whole bike, because I wouldnt want to buy the motor on ebay then have to buy the electrical,exhaust, so on so fourth..........

[Bryan Raffa]

you can use the tri z bottom end ,, you will need to find a power valve cylinder, the clutch cover, and all the guts for the powervalve..it will work with the Z bottom end.. there the same cases as the powervalve motor.. 370banshee has a complete motor for sale in the classif....

[youngbuckatc]

just got a tri-z last night always wanted one one ? is the sleeve reg or coated can i just bore this old girl out and be on my way its an 86 all stock far as i know has k&N and an after market boost bottle on it traded my 88 lt250r quad for it and that tri ran right with my lt250 that had mods i want to break this old girl down and ground up build it maybe in the next yr or 2 i will be done with it but got to find some things out about it first

[Racerguy381]

I know where there is a complete YZ motor. Im pretty sure its 86 or 87 and completly rebuilt. I know he doesnt want much for it if anyone is interested. The only problem with this is the 84-87 cylinder intake kicks off at an angle. It makes it a pain to run your intake.

[Yamaha_Rules69]

^ Also the exhaust pipe has to be modified from what I understand if you use the YZ motor. No, I personally dont need a motor. I just rebuilt mine, with a 68.75 mm sudco piston, cleaned up the ports, added the extra boost port installed a DG pipe and answer silencer, and shaved the head. I still need to replace the water pump seal (it leaks) and install my carb kit in the old carb, and mess with the jetting. Right now I have the tecate carb on it, it runs okay but it cuts out on the top end in high gear, almost seeming lean. Ill try this carb kit in my original carb, and see what happens. I will try to get some pics up here one of these days.

[03 ORANGE SHEE]

the pipe does not have to be modified . i had a dg hooked to mine and no leaks as long as you use the proper o-ring and metal thing that goes in there, and a tube of permatex, high temp red that is

[Racerguy381]

^ Also the exhaust pipe has to be modified from what I understand if you use the YZ motor. No, I personally dont need a motor. I just rebuilt mine, with a 68.75 mm sudco piston, cleaned up the ports, added the extra boost port installed a DG pipe and answer silencer, and shaved the head. I still need to replace the water pump seal (it leaks) and install my carb kit in the old carb, and mess with the jetting. Right now I have the tecate carb on it, it runs okay but it cuts out on the top end in high gear, almost seeming lean. Ill try this carb kit in my original carb, and see what happens. I will try to get some pics up here one of these days.

Sounds about how mine ran... I was running an older 38mm VM round slide off of a YZ I couldnt get the jetting quite right. The last time I ran it I had a 510 main and 40 pilot. It still had a lean spot right in the middle. So I put a PJ Keihin carb off a CR500 seems to be better I still have to jet it. Cant really do it this time of year here and expect it to run good in the summer. As far as your exhaust goes I just used a small section of exhaust pipe as a spacer on the cylinder. No problems there just a little high temp RTV.