jeepwm69

Welcome aboard. Post up a pic of your meter on with the headlights on so we can see what you have. @AKATV will be along shortly.

Try without first. If it acts like it's running lean get a programmer. I did one on my wife's 09 DCT Rancher. I put a Weisco programmer on with the top end, but I honestly think it would have run fine without it. Didn't make much of a difference at all over the stock 420 cylinder. Not worth doing unless your original 420 cylinder is gone too far to be bored oversize again. I was curious as to the 520 top end, but you have to either turn down the outside of the bottom of the cylinder (Reduction Boss sells those ready to bolt on) or grind the cases a little to clear the bigger jug. I've gotten away from 420's and am sticking with the older machines, so never got around to the 520 swap.

It does look like a warm coil might point to a bad ECU on these EFI machines, as that Foreman was doing the same thing.

@Mach 1, mine was a bad ECU as well. The track records for ECU's on these new EFI machines doesn't look great for the long term. I've replaced one on a 420FA, and one on that 2012 500FE now. Thanks for reporting back with what you found. Buying a new ECU is always a little scary since they're pricey and not returnable if it turns out to not be the problem.

When you have the machine in a specific gear, the wire associated with that gear should be grounded if you check the wire. Troubleshooting info on the GPS in the factory service manual

Hard to tell without seeing things. You should have a ground wire from frame to back of engine, and another from starter bolt to battery negative. # 8 and 9 here https://www.partzilla.com/catalog/honda/atv/2000/trx450es-a-fourtrax-forman-es/battery You have an N showing on the meter and a strong green light on the N indicator on the meter?

No adjustments that I'm aware of. @toodeep you have any ideas on this one?

Ok, that actually makes sense. You have two clutches in that machine (DCT, Dual Clutch Transmission). One is for 1,3,5, and the other is for reverse, 2, 4 So, given that you started having this problem when you disassembled and reassembled the engine, I would guess you didn't get something back together right on the 2nd clutch. That said, first I'd do some testing and make sure that the solenoid on the front of the engine is working properly. The DCT's run off of oil pressure to engage the clutches. Go to the toolbar at the top of the page, click on the "service manuals" button, and download the factory service manual for your machine. We don't have one for a DCT Rubicon, but for your engine troubleshooting the one for the 2014-2019 420 DCT should work fine. Look in section 13, which will show you how the system operates, and then you'll have to try to figure out what exactly isn't like it should be. The DCT's are complicated, and a PITA to work on, which is why I got rid of the wife's DCT Rancher when she decided she liked my 05 Rubicon better.

This a true ES machine or a DCT?

Battery condition? Have you adjusted your clutch?

Welcome aboard. Does it shift properly with the emergency shifter? You say 1st and 3rd, does it skip 2nd or ?

Honda East Toledo? I used to buy all my stuff from them. Rocky Mountain ATV and Motosport seem to be cheaper and have free shipping over $75

Took it for a spin and got 1/2 down the street and it started running like crap. i thought “Now what?” but it would smooth out with starter fluid, so I drained the tank and put some fresh gas in, and after feathering it for a few minutes it smoothed up and ran great. Took the mini-me out on the farm, dug out a beaver dam to make her a “waterfall” and it did fine on that trip, so back to the owner tomorrow Thanks again for the input guys!

Food and beer tastes good.

well it wasn’t going to fix itself! Lol. Thanks for all the time you and Retro spent advising. We all hate to throw an ECU at a problem since you can’t test them, they’re $$$, and you can’t return them. I’m just glad it’s fixed.