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Please help yamaha 350

734 Views 31 Replies 4 Participants Last post by  Mech
Hey everyone. New to the forum. Have used it just a bit here and there for some advice, but this is my first time posting. TLDR at the bottom. First a bit of backstop.

Got a cheap non running buggy with a yamaha 350. Got the engine out torn down and cleaned. Heads, piston, and jug were absolutely trashed. Went ahead and split the case to look for any further damage, but everything looks clean. So with help from a shitty online manual and multiple YouTube videos everything is put back together the way it goes. Shifts through every gear, forward and reverse work. Everything was fine. Test fit the other crankcase half, bolted 4 or 5 bolts down, got the shifter arm on, everything was fine. Took it back off, put some yamabond 4 on there, torqued all 15 bolts down to 10 ft lbs ( I know torque spec is 7.2, we'll get to that in just a moment). The main shaft is locked. It maybe moves an inch and a half both directions but won't go further.

This first time I thought what the hell, it's whatever I took it all back apart thinking maybe I had screwed something up. This was my first time working on one of these, so I am liable to **** up. Got it apart, and everything was working again. Cleaned it, put yamabond back on, and this time I set the torque wrench to exactly 7.2 lbs. Tightened everything up, and what do you know, still locked. Backed the bolts off to where they are barely touching, and it's tight but spins, back them all the way off, and it spins fine.

Any one else been in this situation? I want this thing back together and running again, but at this point I'm so tired of cleaning this yamabond off the case it's not even funny. I pretty much know its a tolerance issue, but i am unsure of where to go from here. Any assistance would be vastly appreciated. More than happy to upload pictures if needed.

Tldr: When I tighten the bolts on a yamaha 350 even below torque spec, things refuse to move freely.
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That top bearing looks a,bit proud of the case to me. Can you see the other side to check if it's seated all the way?
I'm more suspicios of that shaft with the circlip on.. I bet that's meant to have a washer against it.. Possibly one of those washers on the other shafts...

You need to tell us the exact year and model prefix or suffix so we can check it in a book Fish..
Mech may be right. The corresponding bore shows a wider wear pattern the the od of the circlip.
This shaft with the clip looks to go in this bore. The wear on the case around the bore looks to me wider than the clip. But if the shaft is binding with the case apart that ain't it. I'm thinking that might be where the washer that fell out might have come from. Could it be it needs to be assemblled with the forks positioned in another gear? I mean like in first or fourth maybe. I don't think it's washers or seals but something is in the wrong place to give that hard stop. The first transmission I worked on was with my uncle on a 65 falcon.
The picture in the
Wheel Crankset White Gear Automotive tire

Automotive tire Rim Gas Automotive wheel system Circle

book showed the guy holding the main shaft backwards as he slid it in. We were holding it like he did for about an hour before Uncle Ray spun it around and it slid right in. So pictures can bite you.
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What is this thing, what's it called ? Grizzly, Bigfoot, Porcupine? It's a Yamaha 350...... And yearish? 80's, 90's, guess.
I was thinking the same as mech find a diagram. Yeah the forks almost have to be right. I think something is out of phase or place. I love a puzzle. Here some bait. Let's go fishing.

I'm really interested in seeing what that drivetrain looks like.
So that thing had a briggs or such originally hunh? Yeah toss the rats nest. Not much to rewire really, if you'd like I'd help over the phone, maybe draw you up an electronic map.
Starter, ignition, and charge circuit for the motor. Use on old ford style solenoid for the stater, underhood fuse box from an OBS chevy truck. Riding mower ignition switch. Then what lights, key switch, neutral light, photon torpedoes, pulsed laser cannon? Easie peasie.
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