1990 YFM350 VIN JY43HPW05L00xxxxx

[Gwbarm]

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. 

[ranchhelper]

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.

[Gwbarm]

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. 

[Gwbarm]

Sorry i attached the wrong manual

[Mech]

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.

[ranchhelper]

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

[Gwbarm]

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. 

[Mech]

#66  Easier for who Rancher ?

[ranchhelper]

For everyone following the thread.

Process of elimination. The Start Stop and Neutral relay are SPST NO. So that leaves reverse.

[Mech]

Is the cdi unit providing an earth for the start circuit when either the brake switch, or the neutral relay, is closed ?  Not all cdi do. The one in that diagram does.

[ranchhelper]

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 June 15, 2024 by ranchhelper
correction/addition

[Gwbarm]

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.

[ranchhelper]

Ok. The filters came in. Look good, like copper screen (metal), similar to the original yamaha. I pulled out the original one and there was a little bit of metal in some of the folds. Keeping in mind it has a wet clutch, I'm not too worried for now. I put the new filter in after draining everything, and refilled with 2.5qts for now, of 10w40 ATV oil.

NONE of these forums seem to have a straightforward 'This is how you change the fluids' guide. Really gets me, because I'm sure Yamaha used the same plug for the 19mm oil and ???? unknown driver size for the rear differential. I've figured out through trial and error what the original driver for the engine oil plug, but it's made out of such cheap potmetal that I needed to slot the outer flange and bang it out with a screwdriver and hammer. Searched the web, looked at various forums. NO part numbers, anywhere. Looked in the PDF's, the so-called 'service manuals', which just refer to it as the oil plug, but give zero details as to the size of the driver to use, details about the plug, or part numbers. That's the official yamaha manuals, too. What a joke: Insecure male-zoids, make needlessly obscure instructions, as a kind of job security to attempt to offset their insecurity. 

One forum pointed to this: https://goldplug.com/?s=90340-12007-00 https://goldplug.com/shop/ap02r/ 
With the MP-01T and AP-02R being the correct magnetic plugs for the front and rear, but not specifying which goes with which. It does not have a front diff, just RWD Only. But no actual yamaha part number can be found. I did check partzilla: the differentials, front or rear, are completely excluded from the parts listings. It's not even a category to click on. 

[Mech]

https://www.partzilla.com/catalog/yamaha/atv/1990/moto-4-yfm350era/drive-shaft

The genuine service manuals are designed for trained mechanics. They assume a certain level of competency.

[ranchhelper]

All excuses exposing inadequacies, that I won't stoop to using,

The rear differential plug uses a 6mm.

 

[Gwbarm]

I agree the service manuals, leave a lot to be desired, and they do assume you know what you are doing, well if i knew i wouldnt be buying the service manual,and my favorite line, reverse procedure to put back together, no tip tricks or anything, they dont always go back togrther as easy as they come apart.

Yes the yamaha drain plug is crap, i think it was 18 or 19mm i cant remember exactly, my differential plug was no better also stripped 6mm allen  and i had to chiesel it off.

[Mech]

Well I don't agree... 

The modern manuals are excellent, well most of the jap ones anyway, and availiable, which they weren't years ago. We are lucky !

Compared to forty years ago, when only dealers had manuals, and the manuals were terrible, the manuals these days are brilliant, well laid out, well written, good diagrams and photos, and they do tell you everything you need to know. They don't say reassembly is a reverse of disassembly, if there are in fact detail that need attention, such as timing marks or critical clearances. They do generally mention everything you are going to need to know, but they are written for mechanics that are familiar with the systems involved. And even mechanics have to read them carefully.

Things are more complicated these days and so we need to browse right through the manual familiarising ourselves with the layout and what is in each section. EFI for instance will be covered in it's physical components in the fuel section, but the diagnosis and trouble shooting will be covered in the EFI section, and the electrical details will likely be found in the electrical section. It's best if we have noted that if we want to get the best out of the manual. It's also best idea to check if there is an appendix for your particular year or model, and have a look in there before reading the rest of the manual, noting which parts or operations are going to be different for your bike compared to the general model the manual covers.

The manuals are written for mechanics as I said (and the manuals say too), and they do assume you are familiar with common workshop practice. There are more detailed manuals called "technical training manuals", and they are what dealer mechanics get when they do the courses. The technical training manuals are very detailed and explain design and operation in great detail. Some of those can be found online. There are also often other manuals mentioned at the beginning of a service manual, and those mentioned manuals cover the special components, such as an automatic trans for instance.

There are alternatives to the genuine service manuals, such as Clymer or Haynes, which are aimed at the home handyman, and they do suggest tips and the sort of practical advice about how to do certain steps that a mechanic would take for granted, and the genuine manuals don't mention. Those are probably a better option, or a handy addition, for some people.

 

Edited June 21, 2024 by Mech

[Gwbarm]

Im sure you are right Mech, most of the manuals i read are from the 60s and 70s, i should not have made that comment, because i really havent looked at any modern manuals, i think the last one i used for any length of time  was for the Yamaha and it was 25 years old. My problem with it was it took me forever to find what i was looking for, i could just do it quicker than it would take me to find the section in the manual, i dont look at them everyday so im sure its from inexpierience.

[ranchhelper]

On 6/2/2024 at 9:47 PM, ranchhelper said:

I found one (for a lot more) but it's for a 92' 350. Idk if they use the same airbox...

https://www.ebay.com/itm/403997392440

Got it. Worked!

On 6/19/2024 at 11:12 PM, Gwbarm said:

I agree the service manuals, leave a lot to be desired, and they do assume you know what you are doing, well if i knew i wouldnt be buying the service manual,and my favorite line, reverse procedure to put back together, no tip tricks or anything, they dont always go back togrther as easy as they come apart.

Ha! You were right the first time, this ^ time!

Funny rubber part came with the box and hoses, not sure where it goes. And, I guess the airfilter gets sandwiched in the box? Is that how it seals? Against the inside face of the box?

There was also a single missing clamp, out of the 4, as stated correctly in the Seller's item. Where do I get more of these clamps?

It was $110, but the Seller had a 100% rating, people well-pleased with the quality of the items and the packaging, and that's what I go for. It was well-worth it. I wanted to wait to order it, until it was clear the other parts seemed good - good compression, spark, turns over. Oil filter looked ok, seems like it was changed once in the vehicle's history. Oil looked good coming out, diff oil looked good too. 

Cylinder has carbon build-up. I can see that through the sparkplug hole. I have LucasOil gas additive... unless you have other ideas.

The rear hatch storage held the original 10 amp glass fuse inline assembly! Had an old wasps nest in one end, but it's intact. I used a standard waterproof blade fuse holder instead; no one has glass fuses hanging around. And someone wants $44 for the original yamaha part on ebay!

I'll either edit this to add the funny rubber part that came with the box, and something oddball about the front suspension - one strut is original, one has been replaced with an aftermarket that is adjustable. Need advice on getting a matching pair. Nothing too funky or performance, just reasonably good quality replacement parts.

[ranchhelper]

[Gwbarm]

The air Box has its own little seal that fits in the grove for a watertight seal. I also noticed you didnt get the filter adapter left top, no biggy a lot of the newer filters are self supporting now so you can figure out how to adapt it, it is still available from yamaha 75.00 the seal is also still available. Clamp is also still available.

Lucas makes good products, good choice.

Not really sure about the rubber part i could not find it on the air box diagram bit it appears to be a smaller hose adapter or clamp.

I havent bought any shocks lately, but they are expensive, many aftermarket ones on Amazon, you can just measure yours or find ones that  fit a 90 model.

You are moving right along! Great work!

This diagram is from a 92 model like the one you purchased you can look it up on any OEM parts dealer Like Motosports, Rocky Mountain, or Parzilla 

 

[ranchhelper]

Here is a clearer diagram of the filterbox and hoses. The part with the rubber hoses and clamps and box are the same as the '90.

18, 20, and 21 are all 90450-56001-00.  Whereas 19, the inlet to the airbox, is 90450-58002-00, and that plastic opening, as depicted in the diagram, is slightly bigger than the carb/airfilter side. Both ends of the carb-box hose, and the frame/steel pipe end of the intake rubber hose, use 56001. 

Quote

The air Box has its own little seal that fits in the grove for a watertight seal.

Ok I don't think I have this. It looks like an O-Ring that goes all the way around, right? I may have it, might not. Didn't look really close when I went to go measure clamps and openings. Later: It's part 1VJ-14462-00-00, and it just a piece of rubber cord, like an O-Ring that isn't connected to itself. Instead of $15 with shipping, I can probably find that in the aftermarket.

Quote

I also noticed you didnt get the filter adapter left top, no biggy a lot of the newer filters are self supporting now so you can figure out how to adapt it, it is still available from yamaha 75.00 the seal is also still available. 

I do not know what you mean.  Do you mean: https://www.amazon.com/gp/product/B0C69T95BQ

Do you mean the part circled in red?

What's the 75.00? $75? To hell if you think I'll spend stealership prices on a $20 part. 

Quote

Not really sure about the rubber part i could not find it on the air box diagram bit it appears to be a smaller hose adapter or clamp.

That is the rubber bumper that fits around the YFM350 frame, where the box has the inset (where the airbox narrows in the front to accommodate the frame). It's to support the airbox and prevent it from rubbing. A zip-tie goes around the center of the the bumper/sleeve, to secure it to the frame tube.

Quote

I havent bought any shocks lately, but they are expensive, many aftermarket ones on Amazon, you can just measure yours or find ones that  fit a 90 model.

There's a lot of pairs for the Yamaha Banshee 350 YFZ350 1987-2006. I wonder if they would fit.

https://www.ebay.com/itm/166313759167 $99 for a pair.
 

[Gwbarm]

I meant part # 7 in the diagram, but you have it with the new filter from amazon, great i didnt know they came with that part, no i didnt mean you should buy that part thats why  isaid you could adapt it but dont have to with that filter, nice kit, i must have missed that when i was adapting one to my Big Bear, but it mounts differently from mine, good find!

 The shocks you found look nice i would measure the ones on there now to see if they are close to the same, may work they are adjustable to some degree.

[ranchhelper]

Made this a couple of days ago. Noticed brake issues in the rear and play in the rear axle.

Would like any helpful advice on replacement of the rear axle bearings, and replacement of the pads. Part #'s etc.

[ranchhelper]

I'm guessing from this 89' diagram I need the following to fix the axle play:

• 2HR-W0045-09-00 Rear axle right side dust cover
• 93399-99913-00 Rear bearing, right side
• 3306-00809-00 Bearing, left side
• 93210-40740-00 O-Ring
• 93102-46377-00 Oil seal, Left side
• 1YW-25367-00-00 Dust cover, left side

 

To do the brakes, I need:

4BD-W2536-01-00 front brake shoes
2HR-W0045-09-00 rear brake pads
https://www.ebay.com/itm/271396668162 - they do not list what the part numbers are.

Would like to hear replies if these are correct or I need to get something else.

 

[Gwbarm]

I agree Brakes and bearings would be good. Usually the brakes are packed so tight with dried mud and stuff they will hardly move, yours is moving good. It was hard to tell exactly where the play was coming from on the video it actually appeared that the whole axle was shaking, so is your play from left to right or up and down.

[ranchhelper]

> does it go up or down or in and out..

Axle bearings are bad. I don't even want the disappointment of test driving it, but the motor runs fine. Shifts good etc.

Here's a how-to I watched: 

That's close enough, to figure out whatever small differences there are.

 

That Ebay vendor gave no part #'s. Those look like the ones for the 89, but they are selling them as for the 87-88. Hard to believe they are different, but mech would know.

This will be ordered soon next month, and I'd like to order all those parts at the same time. I guess Partzilla has the pads and shoes if I get stumped, and there's no reason to split the order between them and ebay.

Order all the bearing parts, the brakes, the 1x clamp, some o-ring material for the box. The official o-ring material is $15... it's good enough to have anything that will seal it, and be reusable in that gap.

 

Does anyone sell seats? 😄

[Gwbarm]

Great video! Thanks for sharing. Those guys are like a 2 man wrecking crew, they definately knew what they were doing, did a great job, never seen anyone use a claw hammer to install bearings, but whatever works. Good size job but it will be right when you finish. and it definately needs it. 

[ranchhelper]

Has anyone spec'd out the rear bearing and seals? Not by yamaha part number but by actual size.

So I spend $15 for the bearing instead of $55 ea x2

https://en.50factory.com/parts news/86356-bearings-and-seals-rear-wheel-yamaha-big-bear-350-moose-racing.html

Right bearing dimensions: 50x80x21 mm
Inner diameter of the bearing: 50 mm
Outer diameter of the bearing: 80 mm
Bearing Thickness: 21mm
Left bearing dimensions: 40x70x15 mm
Inner diameter of the bearing: 40 mm
Outer diameter of the bearing: 70 mm
Bearing Thickness: 15mm
Dimensions of a spi seal: 56x80,5x7 mm
Inner diameter of the oil seal: 56 mm
Outer diameter of the oil seal: 80.5 mm
Oil seal thickness: 7 mm
Dimensions of a spi seal: 46x70x8 mm
Inner diameter of the oil seal: 46 mm
Outer diameter of the oil seal: 70 mm
Oil seal thickness: 8 mm

 

[Gwbarm]

WOW! You are efficient, no i havent done any of that, if they say they fit i order them if they dont i take them back. I do agree you can get good bearings a lot cheaper than OEM, good call.