yz250 and tri-z

[Daltons200x]

hey guys, i have a yz250 dirtbike that i hardley ever ride due to so many injuries on the bike. so i was thinkin. should i look into converting the bike with trike parts, or find a ragged out tri-z and use my yz motor and the inverts and all and make it a nice updated z? or should i just continue hoping that the bike will sell and continue building my 350?

[puggerton03]

I would keep it and ride it more carefully so you dont get hurt.

[factoryX]

bah hum bug, I would put the motor in a Z.

[Mosh]

The 83-86 YZ motor drops right in a Z frame, but you have to make a vacumn line feed for the Z fuel pump or go with a top mount tank. Plus, you either have to trim the rear fenders for the kicker, or swap the Z kicker and sidecover to the 83-86 YZ engine to make it kick forward. Even with the power valve set-up of the YZ engine, I dont think it makes anymore power than a Z engine so the benifits are almost nil, except the YZ engine revs quicker due to the smaller flywheel for the dirtbike with no lights. Plus you lose the lighting system,unless you split the cases and swap the Z crank and stator and flywheel into the YZ engine.

Any newer YZ engine than 83-86, and you are going to have some fab work in front of you. It looks like you want to use a 2001 YZ engine, so here are some of the issues you may encounter.

Some of the bigger obstacles with a newer YZ engine will be.

Chain alignment.
No lighting system.
Kicker set-up that clears the Z frame and rear fenders (since the newer YZ engine kicks backwards)
Intake alignment for the newer YZ engine plus airbox / airfilter issues.
Either, dump the fuel pump system for the Z, and go with a top mount gravity feeding tank, or drill and tap the newer YZ jug for the vacumn line for the fuel pump for the stock Z fuel system.
Pipe Fitment with a newer YZ engine, and last but not least, motor mount issues coupled with radiator/cooling hose issues and fitment.


The pros, of doing that fab work for a newer YZ engine will be:
Less Vibration
More power and,
Better parts availability for the engine, plus whatever you come up with for a invert fork set-up.

If you do this with inverts, you really need to look into a aftermarket Banshee shock, to match the extra front suspension you will gain. You may even want to redesign the hole swingarm set-up out back which will require relocating the upper and lower shock lingake mounts on the Z frame. Maybe with a 450 R swinger which will give you a nice roundhouse carrier set-up with updated rear end parts that are easy to get from the quads.

These are questions I put on myself when I wanted to do a 98 YZ 250 engine to a Z chassis, which I ultimately bailed on, due to the cons out weighing the pros.

I am not trying to deter you from doing this, I am just trying to let you know what is ahead for you in the long run.

[Daltons200x]

The 83-86 YZ motor drops right in a Z frame, but you have to make a vacumn line feed for the Z fuel pump or go with a top mount tank. Plus, you either have to trim the rear fenders for the kicker, or swap the Z kicker and sidecover to the 83-86 YZ engine to make it kick forward. Even with the power valve set-up of the YZ engine, I dont think it makes anymore power than a Z engine so the benifits are almost nil, except the YZ engine revs quicker due to the smaller flywheel for the dirtbike with no lights. Plus you lose the lighting system,unless you split the cases and swap the Z crank and stator and flywheel into the YZ engine.

Any newer YZ engine than 83-86, and you are going to have some fab work in front of you. It looks like you want to use a 2001 YZ engine, so here are some of the issues you may encounter.

Some of the bigger obstacles with a newer YZ engine will be.

Chain alignment.
No lighting system.
Kicker set-up that clears the Z frame and rear fenders (since the newer YZ engine kicks backwards)
Intake alignment for the newer YZ engine plus airbox / airfilter issues.
Either, dump the fuel pump system for the Z, and go with a top mount gravity feeding tank, or drill and tap the newer YZ jug for the vacumn line for the fuel pump for the stock Z fuel system.
Pipe Fitment with a newer YZ engine, and last but not least, motor mount issues coupled with radiator/cooling hose issues and fitment.


The pros, of doing that fab work for a newer YZ engine will be:
Less Vibration
More power and,
Better parts availability for the engine, plus whatever you come up with for a invert fork set-up.

If you do this with inverts, you really need to look into a aftermarket Banshee shock, to match the extra front suspension you will gain. You may even want to redesign the hole swingarm set-up out back which will require relocating the upper and lower shock lingake mounts on the Z frame. Maybe with a 450 R swinger which will give you a nice roundhouse carrier set-up with updated rear end parts that are easy to get from the quads.

These are questions I put on myself when I wanted to do a 98 YZ 250 engine to a Z chassis, which I ultimately bailed on, due to the cons out weighing the pros.

I am not trying to deter you from doing this, I am just trying to let you know what is ahead for you in the long run.

wow youve really done your reasearch lol. i probably wont go through with it due to all the fab work i now see that has to happen. i wasnt sure if the newer yz motor would just drop in or not.

i guess ill just continue trying to sell the yz so it can fund my 350x build. just because i dont feel i have rhe resources or knowledge to get into something like that with all the suspention modification. even tho im probably gonna get into that anyway with the 350 scince im building it for mx lol