1990 YFM350 VIN JY43HPW05L00xxxxx

[ranchhelper]

VinDecoderz says it's a YFM350 (Moto4 350) trim YFM350ER

Is that a Big Bear? Or a Moto 4? Or are they the same thing?

I've google'd around for information, and was able to find a (czech board in english) that had a Yamaha service manual for the YFM350X series, LIT-11616-YM-37. The 'Warrior' type. I'm trying to get something more accurate. I'm not sure which manual I need. Pictures included in this post.

I'm also looking to get a wiring harness for it.

[Gwbarm]

It appears to be a Moto 4. I had the same trouble with their codes on my 400,  YFM 400 can be Big Bear or Kodiak the letters after tells you more.

[ranchhelper]

The flaps all say MOTO 4 embossed. Maybe hard to see in the photos. I am/was not sure if that was separate from a Big Bear, etc, or in addition to the model #.

Has someone done a document explaining the differences? E.g. will a wiring harness for any 1990 YFM350 work on a MOTO 4?

I'll ring a stealership next and try to get the harness part # out of the guy.

[Gwbarm]

You may be right about the Moto 4  flaps being on the Big Bear, but what makes me think its a Moto 4 is the way the front fender wraps around the gas tank and the seat comes up and over that, the Big Bear didnt do that. Is it 2 wheel drive or 4 wheel Drive, all the Big Bears of that era were 4 wheel drive only.

[Mech]

This looks like a fair price..

https://www.heavy-equipmentmanual.com/products/1987-1990-yamaha-yfm350er-moto-4-atv-workshop-service-repair-manual

[Mech]

I think that's probably a 1989. My data says so and Babbits agree..

Have a look here and see if it all looks like your bike..

https://www.babbittsonline.com/oemparts/l/yam/5003893df870021f60a0a008/1989-moto-4-yfm350erw-parts

[ranchhelper]

Here are some available wiring harnesses on ebay. They want a lot of money for them. 

Here is pages 348-350 of the 1987-1997-yamaha-big-bear-350-service-manual.pdf, both as a PDF and PNG image files.

Here is an Amazon offer of a wiring harness from the same year of a YFM350X Warrior https://www.amazon.com/Caltric-compatible-Complete-Harness-1992-1995/dp/B09JC8YZ5J/
Despite the link saying 1992-1995, the text says "Caltric Complete Wire Harness Compatible with Yamaha Warrior 350 YFM350X 1990 1991 1992-1995 Wiring Harness"

@Mech Whether it's a 1989 or 90, that harness should work, no? I'm thinking you and several other people like @Gwbarm can have an eyeball at these, and figure out if that Warrior harness at ~$35 would work sufficiently. I included the ebay images for completeness; and you know, someone else may need this post in the future. Not because I can afford to buy them (I can't). There are several other Amazon offers for wiring harnesses https://www.amazon.com/dp/B0BVVY5W4S and I'm wondering if they are all that different, or can be modified to work.

Part number from that babbit website: 2VA-82590-10-00

Video of the electrical system:

 

Pages 348-350 from 1987-1997-yamaha-big-bear-350-service-manual.pdf

[ranchhelper]

@Gwbarm2 wheel drive. Fine by me, less to fail/fix.

Further inspection of electrical:

It seems the harness is in decent shape, with the exception of whatever happened with the solenoid. So I can keep it, but there are some parts that need to be sorted-out.

If either of you have a similar model, I would like to see what your layout looks like in a video. Just shot this with the Telegram app, saved to gallery, and uploaded to youtube as an unlisted video.

[Mech]

Well Mch, in my experience it's fairly unlikely that any other model wiring loom is going to fit. All manufacturers change their components, and wiring, every year or two, and to make sure things won't be used on the wrong vehicle they change the plug shapes and colours and pin positions. Even if we swap plugs and reposition the pins, we don't know that the electronic part or stator is going to be compatable with the other parts.

Yamaha use several different key switches, some have more wires and they have different internal contacts. They use at least three different types of stator, and each type comes with several different plugs. There are cdi with numerous differing numbers of pins, and pin positions. It's takes a lot of cross checking to make sure everything on a bike is all compatible.
 

If you look a part up in partzilla and click on it as though you are going to buy it, it takes you to a new page with the part shown, and if you scroll down a bit it has a list of every other bike that part fits. If a bike isn't in that list, then it's part is not going to fit your bike. Here's what it says about your wiring loom...  There are no other compatible yamaha wiring looms.

https://www.partzilla.com/product/yamaha/2VA-82590-10-00?ref=58321c07f0aebcb46e55e4a5f60303e0d3f12fcd

 

Edited May 28, 2024 by Mech

[Mech]

Wiring mostly only breaks where the wire goes into the metal terminal on the end. It's pretty rare for a wire to break inside the loom. The exception is up around the steering hear where the wires flex, but that's not at all common these days. The other common fault looms get is they chafe through the insulation and short to the frame, but that is a simple visual check.

You can probably tidy that wiring up and use it again..

[ranchhelper]

@MechThank you. It's 'ranch' like the dressing, my bad. I asked admin to change it and add the 'A' so it's easier to read.

Of the two mystery wire issues, one in the front under the tank and one in the rear under the seat, the rear has a black & blue w/white stripe wire coming from the loom underneath the seat near the battery and near where the starting solenoid should be, and there's a connector with a red w/white & blue w/white wire connected to it, in the video. The wire then just terminates in stripped wire, like the connector was cut-off something (original solenoid).

Then, the solenoid that is there, has got what looks like a white w/green and a white w/red wire, coming out as control wires (to fire the solenoid), but not connected to anything at all, again just dangling in air.

So here's what I propose as a theory: the starter solenoid failed on the previous owner, then a very bad attempt was made at rewiring it. Looking at the 1990 - and 1987; there is no '88 or '89 - wiring diagram from the above PDF, the control wires for the solenoid would be from the harness, black & blue w/white, going into a connector with red w/white & blue w/white wires. So some other year/make/model of bike/ATV had a solenoid that had a white w/green stripe & white w/red stripe control wire, and they swapped the other solenoid in as a replacement. 

Feel free to post a link to a suggested replacement solenoid. That one on it now, might work, but it looks sketch, and I'd prefer to start over fresh with whatever is the best, without going overboard. Then I'll strip out their weird wiring repair stuff and try to figure out what those connectors are upfront in the video that seem to be wire-nutted into that romex, where those two connectors aren't connected to anything.

Accuse me of being lazy, but to pull off that stator cover and try to fix-up those wires that go into the stator/generator, where the outer jacket is missing, to protect the individual conductors, do I need to drain the oil? I'm going to do that anyway, drain the oil and check some other things before trying to fire it up. I assume that cover is a dry cover... It's been ages since I worked on motorbikes. Oil brand suggestions etc would be welcome. I normally use Mobile 1 0-40 syn  on everything, but I understand with the integrated clutch that motorcycle engines are different. I don't remember all the details.

Edited May 28, 2024 by rnchhelper
add photos

[ranchhelper]

[ranchhelper]

I found a standard $10 starter solenoid. With the connector meant for the YFM350 (amazon).

I looked around for an exhaust and the best i can seem to do is $160. Since it seems to have a standard sized pipe past the heat-shield, is there another more generic exhaust for a 350cc engine?

Carbs... carbs all over for $40 new. Any suggestions?

Apparently, Walmart sells the Valvoline ATV motor oil for wet clutches. Or Rotella T 15-40w is supposed to work. Suggestions?

Any opinions on those NOCO batteries? The black lithiums. Or what do you suggest? I can stick a small solar panel on the back, with a built-in regulator, to keep a lead-acid charged.

This is going to be really loud with that rust hole jn the exhaust.. can't wait.

[Mech]

When I want a side cover off for a quick look I jack that side of the bike up.

Yamaha cdi usually have some system to know when the electric start is being used. One way is to branch off a wire from between the start button and the start solenoid and send 12v into the cdi while the start button's being pressed. The other system takes the key switch's 12v  right through the cdi and then to the start button, and then when the start button's pushed the voltage drops slightly and the cdi recognises that as a start signal. It's a good idea to be sure which system you have before trying to diagnose the starter not responding to the button. It's important if you want to fit some other cdi too.

If you do take the side cover off you should take some photos of the stator.. there are several different versions.

[ranchhelper]

@Mech that is very helpful information! There is a post you probably have not seen yet, as it is awaiting approval.

Here is a photo of the forward mystery wiring. This is just underneath the left side of the gas tank, extending down. Two wires were cut from the back of the 3-pin coming off the harness, and 'hot wired' -nutted- to the romex, with black going to one main terminal on the solenoid, and white going to the other. The same terminals had both the heavy red wire and heavy black wires connecting to them. Don't ask me what the prior was trying to do.

Here's the notes about the wire color codes: I looked at both the 87 and 90 wiring diagrams, and neither have a 3 pin and 4 pin connector that correspond to these. That's why an actual pragmatic layout wiring diagram would be useful, to show actual people what goes where... oh but then insecure designers would be afraid of being less needed. I guess..

These colors are as accurate as I could determine. There may have been some color fading. Where I put multiple options, it was not clear.

White 3-pin connector:
Yellow w red stripe
Black w green? Yellow?
black

Black 4-pin:
Red
Red w yellow stripe
red w black stripe
brown

[Gwbarm]

Well it appears you have been busy. You definately have a project, thats a good thing if you like working on them. As far as the wiring harness goes yours looks fairly descent, you can professionally repair your existing harness easier than replacing it. What you have to do is study the wiring diagrams, very carefully to determine where the butchered wires go and what it connects to. The dangling down cable you were referring to goes into the carb, that is your choke cable. You may have somethings missing like the starter cutout relay i didnt see that which might have been cutout and wired together. You should have a plug next to the soloenoid that controls the power going to the starter, maybe. It looks like your air box is missing and the hoses that connect it to the carb. You can see diagrams of what all is missing by looking up your model on Babbits, or Partzilla. The white with red and white with green may go to your pickup coil im fairly familiar with Yamaha wiring, but havent worked on one that old in a while. The only problems you may encounter with your harness if you want to put it back to original is if plugs have been cut out or missing. Your in a good place a lot of us know these older bikes, look forward to helping you piece it back together. Where would you like to start. My advise would be , do not get overwhelmed, take it one piece at a time, one day at a time. It will eventually come together. I know iv been right where you are many times, a great learning expierience.

[Gwbarm]

I think the first thing i would do is evaluate the engine and transmission, make sure the engine has good compression. Then jack up the rear wheels where you can turn them by hand and make sure it shifts though the gears correctly. Of course they can be fixed also but i like to start with engine and transmission then see if it will run.

[ranchhelper]

@GwbarmIf I can get a member who has a 1989-90, to tell me what goes into the 3-pin  and the 4-pin connector, just under the left side of the tank, then I can fix up the rest well enough to do as you say, the engine etc. It feels and looks solid. Just janky electric is my guess at this point.

[Gwbarm]

The only yamaha i have to show photos of is a Big Bear and its 10 years newer than yours but may show where the starting componets hook up.

 

T

The battery and soloenoid and relaus sit on top of the plastic on this one, yours will be different but around your battery tray there should be brackets or something similar to hold the components. Black coming from starter to soloenid, red to battery, Plug in with blue, blue /white and red going to start switch 2 black boxes are relays. The other is fan controller. Behind aall that is the air box which i didnt see on your photos, mine was missing also.

[Mech]

I'm not familiar enough with yamahas to be much help here, but I would definitely say repair the old wiring rather than trying to jury rig some other model wiring in there.

To figure what the cut wires are for I'd look at what's near by on the frame or engine, and then go check a or several wiring diagrams looking for those coloured wires being shown connected to one of those things I'd identified near the wires. I'd also keep referring back to partzilla to see what other model wiring diagrams I should be looking at.

When I looked a few parts up it seemed that your bike shares parts with wolverine, moto4, BB and kodiak, and over a range of years.. To identify exactly what components you have on your bike is going to take a lot of familiarising yourself with the bike and looking through partzilla, and even then It might be tricky to know the exact details about electronic parts. The shape, colour and pin locations of plugs, and wire colours, are clues when looking at wiring diagrams and identifying parts.

 

[Gwbarm]

Im looking at the plugs trying to see what they may be for, can you tell what the other end hooks to , i couldnt tell from the photo

 

[Mech]

Rancher, you could use the continuity setting on a meter and test from one cut end, to the end of any other wires the same colour, anywhere on the loom. That would give a good idea about what the cut wire's meant to be for.

[Gwbarm]

This videa may help a little with your wiring:

 

 

[ranchhelper]

The 3-pin and 4-pin plugs go into what I thought was the main harness. But following them around, they all go directly to the START switch, engine stop, and mystery switch above those in the video below:

The 3-pin goes to start/stop. The 4-pin goes to a black slide switch above those that is unlabelled. I'm sure any owner is going to know what that switch is for, and I'll watch that 1988 video @Gwbarm posted now.

[Gwbarm]

I was thinking that is where they went to, so it appears that part of the harness is missing, they should continue back to the soloenoid and probably end up at the CDI for safety precautions, and probably your 2 relays are missing, i havent seen them in any of your photos or the CDI, is it there or also missing. They might have deleted them and wired it direct with the romex.

[ranchhelper]

Does anyone (like a CLYMER etc) have a practical layout guide for the harness? As if you had no other vehicles to look at, and someone gave you a harness, and the vehicle, where would it go? How would it route?

I kinda agree with @Gwbarm but am having trouble finding something that shows practical wire routing.

[Gwbarm]

I understand your frustration, i looked for the same harness layout when i was rewiring the Big Bear, never found exactly what i was looking for. The closest thing that helps somewhat, is the cable routing section of the manual. It shows a diagram of the frame and where certain componets are located. A little help but not much. What i ended up doing was studying the wiring diagrams to the point of having them memorized, wire colors components and wiring, using the cable routing diagram as a guide, it does show a few electrical components there. Looked at all the U tubes i could find where they were working on the harness and just pieced all this information together to figure it out. I have not used Clymer or Haynes much, but sometimes they have more practical information there and maybe a diagram, that will help, im not sure. I looked a little havent really found a manual for yours yet, mostly i find the one for the 200, yours is the 350, right. So i am still looking i will let you know what i find.

[Mech]

The manufacturers service manual, well the japenese ones anyway, always have all the information you need. It's best to read right through the manual familiarising yourself with the sections and what's where. In this case the manual will probably have a diagram showing the main electrical components position on the bike. It will have a routing diagram showing exactly where to route each branch off the main loom. The routing diagrams are often in the form of plans  and side views and it takes a while studying them to get the three dimensional view. And there should be a wiring diagram showing wires and plugs. The three different diagrams are likely in different sections of the manual.

The real trouble here is that we don't have the exact manual. It should be possible to find a wiring diagram that will have the same components and wire routing, but probably different colours and plugs.

I'd refer to partzilla to see what other models the voltage regulator, stator and cdi all interchange with. If there's a model that shares all those parts, then it likely shares the kill and key switch as well, and the wiring diagram will probably work with your bike.

Edited June 1, 2024 by Mech

[ranchhelper]

@Mech There are several links to pay sites which claim to have the 1987-1990 YFM350ER service manual, and the price varies from $10 to $25+. No way to tell if that's really it, or what kind of guarantee if it isn't what they say it is. I don't have more money right now because I spent what I had to get the ATV.

[ranchhelper]

1 Cdi Unit Assembly 3HN-85540-00-00
2 Screw, Pan Head 98580-06020-00 $5.59 2
3 Washer, Spring 92995-06100-00 $2.95 2
4 .Washer, Plate 92990-06600-00 $2.95 2
5 Reverse Switch Assembly 24W-82540-00-00 4GY-82540-10-00 $27.19 2
6 .Gasket 90430-10171-00 $2.95 2
7 Ignition Coil Assembly 1UY-82310-41-00 $130.39 1
8 Bolt 90109-06723-00 $5.59 1
9 Bolt 97011-06020-00 97017-06020-00 $2.95 1
10 Washer, Spring 92995-06100-00 $2.95 1
11 Plug Cap Assy 1UY-82370-20-00 3NS-82370-00-00 $27.19 1
12 battery BTG-GM14A-Z4-A0 CB1-4A200-00-00
13 Wire, Plus Lead 1YW-82115-00-00 $35.19 1
14 Cover, battery 24W-82129-00-00
15 Damper, Locating 3 5X2-24183-00-00 5Y1-82122-00-00 $5.59 1
16 Pad, battery 371-82121-00-00 $6.39 3
17 Rectifier/Reg Assembly 1YW-81960-A0-00
18 Bolt, Hexagon 97313-06016-00 97D95-06016-00 $2.95 2
19 Washer, Spring 92995-06100-00 $2.95 2
20 Washer 92901-06600-00 92990-06600-00 $2.95 2
21 Main Switch Assembly 2FJ-82510-02-00 2FJ-82510-09-00 $68.79 1
22 . Cap, Key 24W-82579-00-00 $23.19 1
23 Label 29U-83585-10-00
24 Starter Relay Assy (Ms5d-611) 4KD-81940-00-00 $83.99 1
25 Nut 95380-06700-00 $5.59 2
26 Washer, Spring 92995-06100-00 $2.95 2
27 Pilot Light Assembly 2HT-83530-00-00
28 . Bulb, Meter 12V 3.4W 4G1-84744-00-00 4G1-84744-00-XX
29 Hose (L540) 90445-082F3-00 90445-084J0-00 $13.59 1
30 Fuse Holder Assembly 59V-82150-00-00 2NL-82150-00-00
31 . .Fuse (30A) 705-82151-00-00 705-82151-01-00 $3.84 2
32 Wire, Lead 2JX-82541-00-00
33 Wire Harness Assembly 2VA-82590-10-00
34 Wire, Lead 1YW-82507-00-00
35 Relay Assembly 1UY-81950-91-00 1UY-81950-92-00 $54.39 1
36 Relay Assy (Aca12115-1) 29U-81950-93-00 $55.99 1
37 Relay Assy (Aca12115-1) 29U-81950-93-00 $55.99 1
38 Wire, Lead 59V-82541-00-00
39 Band, Switch Cord 437-83936-01-00 $5.59 4
40 Band, Switch Cord 437-83936-11-00 $3.19 3
41 Clamp 90464-14117-00 90464-15152-00 $3.99 1
42 Checker, Pilot Lamp 38W-85774-00-00

https://www.babbittsonline.com/oemparts/a/yam/50038943f870021f60a0a02f/electrical-1#