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I wouldnt think a rotary tiller engine would have enough power to till and drive the ATV wheels very effectively. To drive it , it would just be a matter of fabricating a drive shaft from the tiller PTO to the ATV wheels and a lot of fabrication for mounting wheels to the frame. I would rather use my time to build something fun, once you get the tiller built, then there is work involved.

So what are we up to on the wiring, cut out relay neutral relay and reverse relay, is the new soloenoid working good. I have looked high and low for a free manual for that bike seems to be non existant, the one Mech found seems to be the best.

Numbers don't match. Easier just to say what their roles are.

You Guys are spoiled by your parts availability ! Over here the selection is limited and expensive.. Good find with the fender.

That looks very good, good find!

If you have a timing light put it on and watch to see the spark isn't dying when it gets hot. Check the idle mixture, make sure that turning it either way has the effect it's meant to. Check the fuel flow to and through the carb is sufficient. Undo the drain bung on the carb and make sure it keeps flowing even after the bowl is drained.

Sorry about the slow reply. Been away on a family emergency. In that PDF service manual you posted the relays are numbered in the wiring diagram. That's where I get the numbers, but the index says what their role is. Check the idle mixture screw turns before you go to far on that carb. In my opinion a seized idle screw is a more difficult problem to cure.. The rest will probably be fairly easy to clean up. Not sure about that main jet removal. Is that a plastic housing the main is mounted in ? Never seen that before, perhaps the whole plastic tube slides out then there's a flat to hold the brass or something.. I'm short of time but I'll check the manual if I get a chance.

Probably better to just buy a mid-size tiller and keep the quad to ride around I think. Machinery is designed for a purpose, and designed to the finest detail to ensure they have every thing they need and nothing in excess. A quad bike engine isn't designed for that sort of work and won't have the power needed, nor the cooling capacity.. An industrial engine is designed to run slowly and economically producing power at low revs, and they can keep producing that power for hours at a time without overheating.

Mail call! Fedex came by and delivered the front fenders I needed. Wasn't too thrilled with the packaging, but the plastics look brand new! Very pleased! Now I've gotta take the front, rear and fuel tank plastics and go throw some paint on them!

I just saw a video on TikTok where some guy took the rear end off an ATV and bolted on a roto tiller in place of rear wheels. I wish i saved that video to post here....good thing it was 4 wheel drive...lol but, it seemed to work. I'm not sure how he made it bolt on to the drive....

My first thought is it might be running too lean by mixture setting or could possibly have an intake manifold leak. Im assuming oil is good and filter changed and getting good oil flow. When it shuts down and its hot will it start back up, Also make sure all your cooling fins are not caked with debris. I dont remember if that model had a cooling fan i dont think it did, but if its there check for proper operation.

Sorry i attached the wrong manual

So I have an 89 Yamaha moto 4 250cc and when I ride it, itll get hot after like 10-15 mins and then will just die and turn off. It's has new carb rebuild, new air filter, new battery, new spark plug so I don't think it's a crack in the spark plug Can anyone help me?

Good you got it going. Did you have to replace the pump.

I did find this manual not sure if its your year but might help bruin_350.pdf Never throw the OEM carb away, fix it and keep it for a spare if possible.

It's right dickered. Yeah like I've been saying it's MIKUNI so it's clearly OEM. Ordered a new one (aftermarket). Can't get that jet out. It will rotate but not come out. 100% it was originally cause by that corn gas garbage produced by the midwest/western corporate farms. That land needs to make food, instead of pandering to artificial subsidies and contributing to fuel contamination. It's destroying health (corn oil) and destroying our carbs.

From what you describe it sounds like someone screwed in in too tight and stripped the last thread and if you pull up on it while turning it will grab the lower threads and screw out, just a thought, it could be that the threads have disintegrated from sitting in the weather for many years and may just pull out if thats the case you can repair the carb with a heliocoil or better option get another one, is this an OEM carb or aftermarket any markings on it.

So you think it's unscrewed all the way (that's how i found it) but just needs a yank?

Looks pretty bad, but the float chamber looks OK, on the mainjet grabit with some vice grips and pull up at the same time you are turning it might grab the threads .

That looks like the main jet, and it just rotates. Took the side off (the MIKUNI black plastic) rust. Took the bowl off. Carefully punched out the float needle valve pin. Removed. Tried unscrewing what looked like the main jet. No luck. Just turns. Never seen that before on a carb. Special 'Yamaha ATV' feature? Or time for a new carb?

There's no '14 and 17' on mine. Can you just tell me which relays you mean? Pulled the MIKUNI plastic cover off the carb, during removal to detach one of the two throttle cables, and it's gross in there. Will clean and get back to everyone.

Back in business. Runs great again. Thanks for everyone's comments!

Relays 14 and 17 are shown as normally closed. And it's really the cdi unit that's acting like a relay to operate the start solenoid. If either the brake light or the start relay contacts are closed when you push the start button, the cdi provides an earth for the start solenoid. If neither the start relay contacts nor the brake light switch contacts are closed, then the starter solenoid doesn't get it's pull in coil earthed through the cdi unit.

That will work power wise ,check the size requirements needed for the battery tray.

Do you guys know if these types of batteries are all basically the same for the YFM350 models? https://www.amazon.com/CALTRIC-BATTERY-YAMAHA-YFM-350-1996-1999/dp/B01DGLS20Y Like would that work on this one? HxWxD. I assume they do, and amazon simply doesn't have a fitment guide because this model is so old. "THIS WILL NOT WORK ON YOUR 1990!"