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1990 YFM350 VIN JY43HPW05L00xxxxx

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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. 

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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.

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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.

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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. 

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On 6/8/2024 at 7:39 PM, Gwbarm said:

So what are we up to on the wiring?

The dash lights and relays work as they should. I am thankful that the PO didn't actually mess with the original wiring harness as suspected. The neutral relay, the START button, and the starter solenoid was bad. 2 new relays with the same SPST NO nature as the neutral and stop switch/engine cut relays came in, and I have swapped-in a replacement.

I may have restated the above in an earlier post, but that is a re-cap. Everything including pressing START when the ATV is correctly in NEUTRAL works as it should. Only the relay is not hooked-up to the starter, and I won't do that until I've put new oil and filter in it.

I am waiting for the KN142 cartridge-type oil filter to come in, ordered over a week ago with the other parts. Apparently it was not Bezos 'Prime', and I missed that. I could not find the equivalent in stock at Walmart, because I have the fluids and would have bought one of them, there-and-then. Maybe someone knows of a compatible filter, because they do have a dozen filter cartridges. 

It looks like the procedure is to remove the screw holding the cooling lines to the frame, the shift lever, then to remove the 3 socket-head cap bolts keeping the N12345 cover on, and the filter should slide out.

The airbox and hoses are ordered. They are close in year make and model, and I will not be 100% sure that they will fit until they arrive.

Edited by ranchhelper
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You have been busy, sounds like its coming together nicely. Good choice deciding not to rip out the existing harness its usually easier to repair the existing one. Sometimes i can find Wix oil filters ot Oreilys but not all the time, so you did good to order it. The last time i just ordered the Yamaha one from Amazon, it came in a 2 pack.

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