Lets clear this up, Z motor swap

[Kintore]

Anyone who has done this, only person I know off its Nathan.

Will a 83 yz 250 motor bolt in no questions asked? Anything needed to make it run?
Can you use stock electrical? Will you have lights?
Did you have to drill a hole for the fuel pump vaccum line?

Will any other years bolt in? Nathan I guess your the only one I know off that has done this. Please reply:lol:

And what kinda power did you see? I saw somewhere you said it stayed with a 310 R down at TF?

Anything else I should know?:welcome:

[MTS]

Direct swap,Yes you need to drill a hole for a vaccume line, no lights if you Use just the YZ motor i belive the cranks are diffrent, you cant run the Z flywheel and Lighting set up....

[Jason Hall]

The reason that Z ran with my 310 at trikefest was because the track was like racing on concrete with a thin coat of sand on It. It was spinnfest until It rained, then It was mega muddy. Nathan Is an excellent rider, but I would put a wager on the 310 to eat the Z for lunch on a hookin track :w00t:

[Derrick Adams]

If the 83 is the same as my 85 YZ was, (and it should be) you'll have to swap out your side cover and kicker assembly, add the vacuum port, swap heads, and rig up an air filter.

[Bryan Raffa]

I passed on a tt 600 today for 900$ brand new motor wonder if that would fit in without too many mods any of you guys ever hear of someone doing that??sorry to get off the subject just wondering??

[Kintore]

Derrick, when you did it you said you didnt notice a HUGE gain right? or am I going crazy.

[MTS]

I passed on a tt 600 today for 900$ brand new motor wonder if that would fit in without too many mods any of you guys ever hear of someone doing that??sorry to get off the subject just wondering??
a TT500 is suposed to fit in the Z frame.

[03 ORANGE SHEE]

Anyone who has done this, only person I know off its Nathan.

Will a 83 yz 250 motor bolt in no questions asked? Anything needed to make it run?
Can you use stock electrical? Will you have lights?
Did you have to drill a hole for the fuel pump vaccum line?

Will any other years bolt in? Nathan I guess your the only one I know off that has done this. Please reply:lol:

And what kinda power did you see? I saw somewhere you said it stayed with a 310 R down at TF?

Anything else I should know?:welcome:
bolts right up, you will need to put the z flywheel and stator it it if you want lights
you have to drill a hole for the pump
83-87 bolt in.. the 83 head is the same as a z so the hoses go right on
they (1983) motors are rated at 40hp, the z motor is 32 hp.

[03 ORANGE SHEE]

its a big power gain on top end, and the low end is much stronger
the exhaust port is ALOT bigger than the z, i have NO elecrical stuff on mine, i run a pvl or motoplat, a baby flywheel and a coil, thats it!

[Kintore]

Thanks nathan, whats the straight intake one? 83?

87 Straight intake too?

[MTS]

Thanks nathan, whats the straight intake one? 83?

87 Straight intake too?
87 is angled, 84 prior is straight i belive, i have that 86 set up for sale....:naughty:

[370banshee]

i did this swap.... mine a 85 tr-z with a 87 YZ250 engine.. i drag cut my rear plastic and mine kcks backward... gotta modify the frame gusset and the kicker itself.... on the later head you gotta watch so that the hose doesn;t hit the rad and pinch shut.... with the striaght intke yz motors you can still use the stock tri-z airbox...

[Kintore]

I thought of a few more questions at school-
Will the Z head fit a 83+ like a 87?

Can I use the yz carb right with it?\

5 or 6 speed box in the yz's?

Any gearing changes, due to the tranny and all that cause of the weight.

What is better, PV stock, or a wrench modded cylinder.

And, 370 you said the rad hoses rub, How did you solve this? New head? Got pics, thanks guys.
And-

Anyone know of a 83 for sale? Just PM me if you do.

[Kintore]

And also, does porting take away from a stock Z longevity? Mines been going 20 years on same piston. IF I port will I still get some reliablity?

What about a mild port job?

[03 ORANGE SHEE]

z head fits the 83
i use a yz carb, 38mm bored to 40.5mm
5 speed gears come in the yz's
well, the pv setup feels so much more powerfull compared to a z motor, i havent ported mine yet, only rechambered and cut the head, i might get it ported before trikefest, but im keeping that a secret til it hits the strip!!:D
portwork makes the engine breath and let the exhaust gases out more effecient, it doesnt make the motor turn up higher, only adds performance, you wont be rebuilding it every year if thats what your looking for:cool:

[Kintore]

If the 83 is the same as my 85 YZ was, (and it should be) you'll have to swap out your side cover and kicker assembly, add the vacuum port, swap heads, and rig up an air filter.

If I bolt in the YZ motor, I use my kicker gears so its forward, drill a hole, and swap heads and im good to go?

and on that note-
Will the Z head fit an 87? so I dont have to mess with rad hoses?

And the exhaust, any special mounting? or like spacers or anything? or just bolt up and go?


Nathan, thanks for the pics. Question- That right sidecase on the motor looks like a Z. IS that stock in the motor? Or is that a Tri-Z one?
And did you just swap in the kicker gears and cover from your Z and wola?

Thanks alot guys, im just trying to find as MUCH info as I can.

[Darius1502]

Kintore,

Before you swap engines....put a new piston in your Z and get the Wrench Report mods done. That should be enough to really surprise you.

[Kintore]

Thanks for all the help guys, Im thinking im going to buy another cylinder and get the mods done to it, or send it to ronnie for some GOOD porting. The PV seems sweet and all, but I like having the stock motor and they are hard as heck to find on around here. I called all around yesterday and nothing, BUT I am contacting a 87 YZ owner tonight. :) So its still up in the air what im going to do.

[03 ORANGE SHEE]

yes you will have to take the kicker gears out of the z bottom end to make it kick forward
z head will fit a 87, but a 87 head is o-ringed
and the side case is a yz one, just like a z

[brapp]

well the way i build the one i did i used the tri-z motor, and swaped the cylender, clutch cover, and clutch cover side crankcase and allthe powervalve stuff with the yz stuff, the only problem i ran into is the intake near the intake, i machined a billet piece, nathan could give better idea what needs to be done.