jeepwm69

Not really. You have some sort of issue under there so I’d just pull it and see what you find.

Well @AKATV actually rebuilds meters and does an amazing job of it BUT once water gets in there it usually fries the circuit board where they aren't worth trying to fix. That sunburnt screen he can have looking like new though if the board isn't fried.

https://www.ebay.com/itm/404545900564?itmmeta=01HSXRSKQ9YCSDNHDXGZFDDFMZ&hash=item5e30d09014%3Ag%3Axn4AAOSwH7NlKEtu&itmprp=enc%3AAQAJAAAA8FqroTwajSPCJLwGp2%2Fq4SYhTUL%2B95FnY6J7lv7ULVLTN9B17TZaGyocIdl4376O6rQJEWv4ccQsiz%2BAhwOt9j%2BO%2F1siYTmPLmONxtpjrxsLkb5Qj4vDTexAQtAa2iT5cYkjknMNTFnZJWiMWo%2FMMpstrJ%2BiTIUNWQ2%2F81PHAF0ttOekTqzCK0moAlHxcuA351XvpH9t2l7g6OaYtz5HwOfqhUzZNPsH3OAx%2Fv7%2Bqm6GNgVqIiryGCjbRLlqYIO8nUXoaFskvp3ANQsVL6%2B%2B1EjA5g3rSb%2FSmThQ%2FawE51Jeof3OEHyQUvoOUha6t4BY6w%3D%3D|tkp%3ABk9SR-C75rjPYw&LH_ItemCondition=4

That 424 might get you a bit of cash. The 300 424's are super expensive, and someone can mod that 350 to fit a 300 by cutting and welding to get the length correct. If you want to go back to full time 4x4, check ebay. https://www.ebay.com/itm/375292677310?epid=1723070222&itmmeta=01HSXRRBWS476BES648KFN4K7C&hash=item57612fccbe%3Ag%3AJZQAAOSwFntl5pFG&itmprp=enc%3AAQAJAAAA0PSIb3heye2jOZaCy%2BrScg1WglXyAloXgM%2BktUfUlrihPL0fnmjF4skd%2BQ3mmpsMSHL5dCvPudwfF%2Bf%2BFKP7xAGZ4Pop79Ztru2kCwGel%2FmJtvguZAixDJvdUi7RvjUc4lfmnTPFmHNoat3i4DO6zgc0VkWnqANNt1lH84jVFfdFSEcjtClaa1xd4hWrkSSrQJK4abtDvFi4CA3ARTgcRa0tUQIFyKSGiZWyUaRFDkp5%2FePVRKFLgZ7eJZHqwXY1ZlqJ5ZMgYQ59W1ciGj%2BgBl4%3D|tkp%3ABk9SR8C-4bjPYw&LH_ItemCondition=4

Yep. Stock front driveline. Most people on the 350's do a 400AT front diff swap, which gives you selectable 4wd with an electric switch on the handlebar (stock looking). Should be easy to find a front driveshaft cheap if you want to go back to full time 4x4.

Was out of town for a few days visiting the in-laws. Going to try to dig back into this thing this week. @Melatv and @retro, IF one of these connections I redid is the problem, wouldn't I be able to check that by checking for resistance between the ECU plug and the wire a bit on the other side of the repair? The rats gnawed the wires pretty close to the ECU plugs, and it didn't give me a lot of room to work. So, at this point, I can either buy a new harness, fix this one, or buy a new ECU. I hate throwing money at machines. If I can verify that my splices are ok with a resistance test, I'd lean towards a fried ECU. If my splices are bad, wouldn't they show resistance?

Yeah he does great work! Glad he got you fixed up!

Welcome aboard. The good news is, your front driveshaft being out is likely most or all of your problem. The computer that shifts your transmission does so with input from the speed sensors. Both of your speed sensors are in the front diff, so the fact that you have your front driveshaft out means the rear speed sensor (in the back of the front diff) and your front speed sensor (in the front of the front diff) are recording different speeds. The computer isn't sure what to do with that info so you get no speed detection and no shifting. Put your front driveshaft back in and see what you get, and report back.

Welcome aboard. When you do the initialization, can you hear the shift motor move one way, then the other during the initialization procedure? Are angle sensor and TPS OEM parts or aftermarket? Rubicons are a weird breed, and while I'm trying to learn more about them as I've picked up a couple, troubleshooting them can be quite tedious. There is a guy who seems to know them exceptionally well. He's not on here much but if we can't figure out your problem, that guy will usually respond to emails. Let's see if we can figure it out here first.

Should be able to order a cover on ebay, leave out in the warm sun, then use a staple gun to install. i used to get them from user “kentscovers4u” or something like that, but doesn’t look like he sells on ebay anymore. not hard to do. Staple front first, then stretch as tight as you can get it and staple rear, then pull each side down tight and staple, then do staples all the way around to make sure it doesn’t pull loose. I think @Fishfiles would just buy vinyl from a local fabric shop to do his seats, but not sure exactly what he would get.

Gotta pull the front cover. It's # 18 in this schematic. https://www.partzilla.com/catalog/honda/atv/2009/trx420fa-a-fourtrax-rancher-at/gearshift-fork If you stand the machine up on the rear rack it will sit upright, and you can pull the front cover off and check it out. Turn your fuel petcock off and cap the vent line on the gas tank before you do so.

You sure you got the part number right? Partzilla shows -600 for that model. https://www.partzilla.com/product/honda/34901-HP5-600?ref=c42eceee2efba0855ec94f260f23924e74c46a90 I know the Foreman bulbs from that era were Honda specific and no aftermarket bulbs were available. That -600 Rancher bulb looks like a Honda-only bulb to me.

Looks good! Bet that's fun to run around on.

Try baking your original CDI and fan control unit. Preheat oven to 450, put both in with plugs facing up for 7 mins. Take out, let cool, see what you get. People have been baking them with pretty good results for a long time. I think it was @AKATV who actually nailed the temp and length of time down. I've resuscitated a 450 fan controller and a couple of CDi's that way now.

Welcome to the board. Is your foam still in good shape?

Yep, first thing I'd do is get an OEM regulator on there. Even if you have to order a used one. The aftermarket electrical stuff never works long on these Hondas, if at all.

01-04 were the same, and 05-14. that 01-03 manual was just the 2003 dated manual. The 01-03 is what you should use.

It does appear error code 4 is TPS. Have you downloaded and looked at the factory service manual? There's a "service manual" button in the toolbar at the top of the page. The 01-03 Rubicon manual will work for your 04. I haven't had a lot of experience with the Hondamatic machines yet, but am trying to learn on them. Most likely you have an electrical issue of some sort, but they can be a PITA to troubleshoot.

Made an offer on that ebay wiring harness and ECU, which not only was rejected, but then the listing was pulled altogether as "no longer available"..... The 2012 and 2013 were oddball years, so finding another wiring harness isn't going to be fun. I'll keep poking around on this one and see if I can get anywhere.

I doubt your battery is the issue if your voltage readings are correct. Did you try initializing the system yet?

I actually had three. I bought one for my oldest kid (that 300 that Shade did the engine on), which is currently mounted on her 300. Had one for the big 300 I planned on building until my 29.5 Outlaws got stolen. I traded for those tires, and at that time SamUK was going to build me a GR, so I wouldn't have a lot in it, but tires got stolen, and SamUK disappeared, so I don't see myself ever spending $1K on tires, and another $500+ for a GR to have a big slow moving toy, so I doubt that machine ever happens. And then I have the little one who is almost 5. She'll get a 300 when she's older, so the last one is for her So i had plans for all 3. Big bike for me is unlikely to happen, other two are for kid's machines. MSRP on them was $369. I had two new ones and one used one that I put new bearings and seals in. Sold one new one, other new one is on the eldest's 300, and the used one will go in the little bit's bike.

Welcome aboard. Does it drive in auto mode? You need a good strong battery on these for them to work right. If you have a good battery on the machine, try initializing the system. Machine in neutral Hold up and down shift buttons in and turn key to on position Hit up, down, up on the shift buttons, then open and close the throttle within 5 seconds. That should re-initialize all the computer crap. See if that changes anything.

I don't think the valves really have anything to do with the mechanical aspect of the shifting. They divert oil pressure to the dual clutches. Is that correct @toodeep? (otherwise I'd tell you to remove the valve and see if it will shift with the valve not in place, but I don't want you to do unnecessary work and i think toodeep has more experience with these than I do)

I figure with what they're bringing now that someone will start making them again eventually. Money got tight last month and I think my ideas of building a big 300 one day will probably never happen so I listed mine and quickly sold it. Got me through the month and I still have a used one in the drawer for the 300 I'll do for the little one when she's older.

Honda made a hydrostatic 4wheeler. You should get one!