2001 YZ engine in Tri Z....check out pics

[Darius1502]

I know you probably thought the motor was in the trike...but look how close the mounting holes appear to be. Can someone measure the mounting holes placement on the respective engines. I may get to do it this week...but if anyone has a Tri Z and a YZ....let me know:

This is a project with serious potental. There are also big bore kits of up to 300 cc 's for the modern YZ that could make it a 50 hp motor.

The only issue I see is with the pipe and maybe the airbox and carb. Obviously you would fabricate some airbox set up and get rid of the Tri Z high breather system.

[Darius1502]

Also since the kickstarter will kick backwards the rear fenders will have to be taken off to start it. A set up where the seat and rear fenders are bolted together (like the ATC 250R) would be best here.

Vibration may be an issue since I think Tri Z motor has a counterbalancer....but I could be wrong.

Also a hole will have to be drilled in the bottom of the cylnder for the fuel pump to create a vacum. But thats not a big deal.

Lastly, if I want lighting I need to get the coil from a WR250.

What else might I be missing?

[CHAINSAW]

they look very close. How does the hole on the bottom of the motor line up?
As for the head stay, I wouldnt really worry about it. My 85 with a YZ doesnt have the headstay bolted, and I think that machine has less vibration then a regular Tri Z.

[Darius1502]

I don't know. If you look at the frames it looks close. The bottom brackets could be re-welded into place.

It looks pretty darn close but someone needs to do some measuring.

[CHAINSAW]

Also since the kickstarter will kick backwards the rear fenders will have to be taken off to start it. A set up where the seat and rear fenders are bolted together (like the ATC 250R) would be best here.

Vibration may be an issue since I think Tri Z motor has a counterbalancer....but I could be wrong.

Also a hole will have to be drilled in the bottom of the cylnder for the fuel pump to create a vacum. But thats not a big deal.

Lastly, if I want lighting I need to get the coil from a WR250.

What else might I be missing?

Zs dont have counterbalancers either.. the only downfall of them I see. If they rode as smooth as a 250R, Im sure we would see double the amount of tri Zs we do.

[XFR_Dozer]

a head stay would be ez to have fabricated. tri-zs do indeed have a counter balancer . they have 1/2 of yz crank and 1/2 all their own. (i learned that today lol) the pipe may be a prob. it has to be mounted correctly for the pipe. the carb and airbox are not a prob. you toss the old airbox and straighten up that carb with a special reed spacer

[smokinp]

That would be sweet if it would fit.

[CHAINSAW]

a head stay would be ez to have fabricated. tri-zs do indeed have a counter balancer . they have 1/2 of yz crank and 1/2 all their own. (i learned that today lol) the pipe may be a prob. it has to be mounted correctly for the pipe. the carb and airbox are not a prob. you toss the old airbox and straighten up that carb with a special reed spacer

Then why do they vibrate so bad? 250Rs dont vibrate at all, but Zs wil knock your fillings loose!

[Darius1502]

hmm...I don't know...mine does not vibrate that much at all.

Anyway it looks like this project has some potential. If anyone has a YZ and a Tri Z shoot me some comparision measurements please!!!

[XFR_Dozer]

ok im not a mechanic either chainsaw but i spent the better part of today researching through yamahas parts files to find interchangeable parts for for the tri and yzs as well as the old 400s and 465s for possible solution to my long rod project. what i found was that 1/2of the tri-z crank is the same,part number and all , to a 84-87 yz 250. the other half is a number only for the z. i assume this is for a counter balancer but the possibility exists that i am wrong.btwthe wrist pins , thier bearings and the con rod for a Z is all the same as the 84-87 yz 250. im still on it and will let ya know if i find anything interesting. ooo darius,you can put the gears in for the Z kicker and leave your fenders on.

[Darius1502]

even with a 2001 or later motor??

How about some research expertise on my new potential project...XFR? Since you are now the official 'Mr. Tri-Z'!! *













NOTE: there was once a guy called Mr. ATC who was very knowledgable but was banned from the board.

[XFR_Dozer]

ill be happy to look at it for you as long as you promise to never ever call me mr.tri-z again. lol it was once said that a little knowledge was a dangerous thing ,and i am a very dangerous man. ive forgotton many of the techincal aspects of Zs over the years and am far behind what is available now. I do have some good notes on old stuff but most of it isnt made anymore . back in the old old days guys did some wild chit to hop up the atc 90s. history is repeating itself as we once again must create our own mods. this was always the trike communitys greatest strength ,and it looks like it hasnt changed.

[Darius1502]

You got it XFR....I am glad you are on this board!

Great point about trikers....its kinda like we are going back to the early days of the ATC 90's and the flat track oval races....

we have to keep our sport alive!

Darius

[TimSr]

In all the Z motors Ive had all the way down to cases in half and gears laying on the bench, I have yet to find a counterbalancer in one. Id never seen one before I got my 250R, so I as of 2000, I do know what they look like and how they work. A TriZ does not have one.

[XFR_Dozer]

do you know why the tri-z has 1 crank part number thats only for a Z and the other is the same as a yz? the conrod and everything is yz until the piston so for what reason did they not use the entire yz crank?

[Beer_Smurf]

While I haven't had any Tri-Z engines apart, I do know what the counterbanancer in a Blaster looks like.

[Groundworx]

I am sure you could get the motor in without that much trouble. I have been wondering the same thing myself. If needed, you could make some motor mounts. It shouldn't take much modification to get the carb and air box hooked up.

I don't know anything about the counter balancers, but I have had 250Rs and I currently have a TRI-Z. I can't tell a lot of difference. I don't think that vibration will really be an issue with the motor swap.

[TimSr]

If you are asking why the YZ and the TriZ do not use the same crank I cant answer, or for that matter why they used a different top end and piston. Its been years since Ive had a YZ, so I dont know a lot of specifics on them. My best guess is that the crank on the TriZ was changed to accomodate some other difference, but without even know what part of the crank is different, and what all the differences are, I cant even guess. Off the top of my head, besides a different top end, the YZ started using a powervalave somewhere in there. You might find simialrities in the IT and TriZ that are not in the YZ.

As far as newer motors fitting, motor mounts are easy to alter, but the back of the motor has to fit IN the swingarm, and that willl be your critical measurement.

[CHAINSAW]

yamaha has always done this. Do weird things in the motors, then at the last minute change them. Looks like they did this with the Tri Z/YZ, they did this with the blaster/DT200, and Im sure some of the newer models have simularities and extra stuff.

[Jeb]

..ooo darius,you can put the gears in for the Z kicker and leave your fenders on.


I don't think its that easy. On the older YZs (84-87), you have to switch the YZ clutch cover for the Tri-Z in order to used the internal reverse kicker gears. I would assume the same on the 01 YZ motor. Now, will a Tri-Z clutch cover go on an 01 YZ motor? Probably not, but who knows???

[Darius1502]

Who says it has to kick forward??

I can bolt the rear fenders to the seat assembly and create some fender braces. Now the whole thing comes off with the flick of a lever.

It can work...and I am really considering it.

[Red Rider]

Or, you could bolt up some Banshee rear fenders and kick through a tunnel. That way, all your friends won't rag on you for taking off your fenders every time you need to start it. As an added bonus, the Banshee units come from the factory in every color imaginable.

[denn]

hey guys whats up, to answer some questions. I have had about 4 yz engines that I have aquired over the years to modify tri-z's they are an 85, 86, 89, 91, Here is what I found: after 87 the cases and cylinder are no longer a direct bolt on. Also the cooling is plumed through the cylinder which also has changed to a bigger base bolt pattern. The head stay is a bit taller. The bottom mount for the cases is a bit shorter which means you would have to raise them on the frame. Also the front brackets are a bit different too. The rear mount is the same. None of the internals are the same. They are of the same design but just enough different to make them not interchangable. I tried to install my 6 speed tri-z shafts in a yz motor and they were a bit big. The side cover was changed and there is no way of getting the tri-z kicker on the yz cases without cutting and welding. The clutch basket is different too. Basically you can only install the yz motor if you fab the mounts and install it like darius said. Taking the fender off it to kick it or cutting it out. I have placed an 89 and 91 yz with kicker and all in my tri-z frame and it looks like the kicker will hit the frame. Maybe you could mod it. The 2001 motor dosen't look like the powervalve assy will clear the front of the frame, it sticks foward a bit far.

Last issue, the tri-z has only half of a yz crankshaft for 2 reasons, due to the fact that you have to run lights on it and weight. You need a external rotor design to run lights and they are much bigger than the yz internal rotor design. Also the bigger heavier rotor also helps for torque and if anyone ever herd of (flywheel effect). Which is common in enduro which is what the tri-z is partly based on. So the crank half has to be beefer. A yz rotor won't fit a tri-z crank. A YZWR has the same principle as a tri-z. It was a yz enduro version and has a bigger flywheel for torque and to run lights. Hope This helps. If anyone wants in a week or so I can take some pics of the yz motor placed in a tri-z frame. Let me know.

Denn

[Jeb]

Good point on the enduro power vs MX power. Like TimSr said, it would be interesting to see if the crank half in question shares the same part number as an IT250 and maybe the open class ITs.