PW80 Motor Swap into YT60 Tri-Zinger

[94_9K2.3T]

New here, anyone ever done this before!? I've tried to use the search function on the site but Google usually works better. I work at a machine shop and have access to CNC machines and can weld, so I'm not too worried about that.
Currently the YT60 motor runs Great! It's got the DG pipe on it and it's been re jetted. Could I use the pipe on the PW80 motor too? Any guidance or suggestions are welcomed, thanks.

[HoldMyBeer]

I’m not 100% sure on this one. In the past I’ve fitting stock head pipes onto different mufflers. I put a XL100 engine on a 300EX frame using the 300EX muffler and XL head pipe. It worked well. The thing it seems you have going is the head pipe route is totally different between the two bikes. Personally I’d try to match up to the stock exhaust route, whatever combo that turns out to be. Good luck

[Shep1970]

Well the zinger is shaft drive and the pw80 is chain driven right? So that'd be your very first hurdle to jump. The exhaust would be the very last thing i'd worry about of your swap issues.

shep

[94_9K2.3T]

Well the zinger is shaft drive and the pw80 is chain driven right? So that'd be your very first hurdle to jump. The exhaust would be the very last thing i'd worry about of your swap issues.

shep

Exactly! I'll be able to change the gearing now. Thanks for the input. I'm planning to use a 1 & 1/4 axle from a race kart, I'm going to machine bearing carriers and have them bolt to the holes on the rear of the frame where the old dif and hub originally bolted up. Thinking to use a brake rotor and caliper off of an older snowmobile, when they were still cable driven. Also going to swap the PW forks in. I don't have a triple clamp so I'll end up making that too.

[ATC King]

You're taking a good running Tri-Zinger, and butchering it?

There's probably someone who'd trade you a roller and some cash so you'd have more of a blank slate and they'd have a good Zinger to enjoy.

[94_9K2.3T]

Woah woah, I never said anything about butchering or cutting a frame or completely junking the motor. All the old parts will go on a shelf in my barn if it is ever to be put back to its original glory. I just want gears. Keeping up with 70 and 80cc 4 strokes is tough in a single speed without sacrificing reliability, no? I'd love to put a Malossi kit on it, port match and polish the thing up, blah blah, but I don't really want to be absolutely screaming in the RPM range. Maybe I'm missing some fantastic, reliable modification info? Fill me in!

[Shep1970]

How about a "sneaky pete" nitrous oxide switch.....

shep


ok, maybe not but it'd be fun.....

[Tri-Z 250]

Nitro has been done don’t recommend it there is video from TF 20?? of it drag racing. I use www.PWOnly.com motors and KX60 18mm carb pod filter and delete the oil pump with the DG pipe.

[ATC King]

Woah woah, I never said anything about butchering or cutting a frame or completely junking the motor. All the old parts will go on a shelf in my barn if it is ever to be put back to its original glory.

That's cool. I just know about all the options for building custom ATC70s and was wondering why not going that route, other than the $$$.

Back in the 70's and 80's, there were actually quite a few air cooled, two cycle moped engines with automatic two speeds transmissions. The French and Italians did, and still do make little screamers out of them. Many of them had horizontal cylinders.
https://www.treatland.tv/

[94_9K2.3T]

Wouldnt that be something shep.. haha

Yeah King! I looked into that, the only gearing that would fit in the YT60 cases would be stuff from the Yamaha Towny. They only made them for one year so parts are super hard to find. Treats sells great kits, but I'd almost rather swap a "lower RPM at a higher speed" motor into the YT. A good reliable rip. I absolutely love the ATC70 but you're right.. the pricepoint is a killer for me.

Thanks for the info Tri-z 250, I'll keep that in mind. I like the KX60 carb idea.

[94_9K2.3T]

Alright, so I decided to just give it a go. Picked up a half decent PW80 and tore it all apart. The motors are really close to the same dimensions.

Not too terrible, the bike is an 01

First thing I got to doing was the fork swap. I had to machine the spacers down and open up the axle hole in the PW forks to 12mm. Also machined the drum brake holder off of the one fork.

I had to borrow the lower bearing race from the Tri and slide that onto the neck of the PW (I cut the tube out of the triple and machined both parts to fit just right.) From the base of the bearing race to the top of the threads had to be just over 6 inches

Then I had to figure out how to attach my steel neck to an aluminum lower triple. Decided on just a tapped M10x1.25 bung that I welded into the bottom of the tube. Some red loctite should do the trick just right.

I used auto cad on my computer an a Bridgeport mill equipped with an SWI ProtoTrak and machined the parts but sadly have no pictures of the setup. (It was a long night)
Here's what I've got tho! I used the old bar clamps from the PW80 and put some ProTaper Schoolboy Pros on.

Next is the motor!

Also, let me know if I should post elsewhere. I don't really know where to go with this.

[big specht]

Here is a video of a pw80 in atc70 frame https://www.youtube.com/watch?v=EcPSgwr__c8

[ironchop]

Cool build so far

[94_9K2.3T]

It runs!!!! It's been a while since I've gotten back, but it's damn near done. First thing to do was make motor mounts, I used the existing holes and made spacers and brackets and drilled one extra hole in the frame.

Also made a new lower mount with tabs in the correct places. For the motor to fit properly I had to also make spacers to bring the mounts I made away from the frame.


After that I got to work on the rear end. I designed brackets and machined them out so that my bearings would be partially recessed. The axle is also 2in farther back and about 1/2 lower than the original position.

I used the existing holes on the frame, measuring with the old rear end.

I had to make adapter plates for almost everything, I wanted to put 7in rims from a YFM80 on it so i had to go from a 3 bolt go cart hub the the 4 bolt wheel pattern. Also had to make a plate for the rear sprocket to mount to.

The axle was about 6 inches too long and needed to be trimmed up. But so far so good!

[94_9K2.3T]

The Already too small stock foot pegs were now made extra small by the bigger motor. I decided to make my own and move them forward. Designed and machined my own brackets and pegs.


I made another adapter plate for the front end and machined the existing axle spacers to make the offset correct. This was also a Yfm 80 wheel.

Much better with the same size tires all around

After that I decided it was time for the front fender
I made some little brackets out of 1/8in aluminum and drilled and tapped my triple. Also mounted the little black splash guard. While I had the triple apart, I also filled the forks with new oil (6.5in from top with spring out and compressed) and added a 1.25in aluminum spacer above the spring for better preload.


I also got a rear brake rotor and caliper with a master cylinder. The rotor was for a go cart and the caliper/master cylinder kit was for a Chinese ATV. Hydro brakes for the win!


Next was routing the chain. There was a piece of tubing that held the oil reservoir that was just a tad too low. I decided to cut it out and weld my own piece in, just a little higher. Even if I were ever to put the YT60 back to its original glory, I would just premix. So no need for it.

Now that I had a chain and brakes it was time for a little test and tune, Jerry rigged the exhaust up (kindof looks like a drag pipe set up. )

Now that I know it runs well, I'm going to cut and weld the exhaust so it exits in the right place, oh yeah, and I'm sure you noticed, but at some point I threw a new seat cover on it. GPS top speed was 39.8mph. And I know I can squeeze more out of the top end. I'll be back with another update when it's all finalized and finished. Ah yes, and thanks ironchop, this ones been a blast.