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rancher engine rebuild

16599 Views 56 Replies 8 Participants Last post by  dennisdamence1414
So I'm rebuilding my rancher 420 motor and I have a couple questions. 1. How do I get the valve spring seats out? Mine are broke off. 2. How do I get the flywheel off? I've heard you have to have a flywheel puller or you can use a bolt??? But I was thinking I can just leave the flywheel on and just leave the crankshaft in that half of the case. can someone fill me in on that? 3. What's the easiest way to split the cases without damaging anything once you've got the clutches and everything off? And lastly, shouldn't I go ahead and have it bored while I've got everything taken apart? I've never heard it run so I don't know if it smokes. Oh and one last thing, does anyone have any suggestions as to what I can do about a stripped oil drain? The previous owner stripped the plug out and it wont get very tight so I figured why not go ahead and knock that out so it doesn't come back to haunt me.
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Ok so I'm having a bit of an issue. I finally got a fly wheel puller and split the cases and I figured out whats wrong with my oil plug. The little ring thing at the top broke off and I tried putting jb weld on it and after I let it cure a little bit of tension it broke off. Any body ever had this happen before? Any ideas on how I can fix it?????
Bite the bullet and a new case is the "fix". You might get a machine shop to weld a chunk to it and then tap it for the plug. If you do that in the inside of the case remember to have a channel the oil can drain out of though. My best advice is to replace the case and be careful when tightening the drain plug.
Powersportsnation would probably have a used case half.

If it were me, I'd stick a fumoto valve up in there with some loctite, and put a clamp on it to make sure it doesn't get flipped open with trail debris.
ok so I found this pipe fitting in my shop and it fits almost perfectly into the drain hole. What I was thinking is either cut a notch in it shave it down so it could drain completely, maybe stick a dermal in the drain hole to shave it down a hair, and screw it into the hole probably throwing in some Loctite and get a plug for the fitting and I'm back in business. I just wanted to get some input on this idea before I go and screw something up


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Is there enough there to get a nut on it to secure it? Then possibly a simple hole drilled into the fitting and nut after everything is installed. Otherwise every time you try to remove the drain plug the fitting will want to come out as well. I have jb welded some piggyback drain plugs into them (with a slot cut into them) and they will break the cold weld if you don't hold the hold the outer part with a wrench.
From what it looks like there's not enough as is to ad a nut on top. I could cut back the strip that housed the original threads to make room for a nut or just hope Loctite can keep it in place. But it sounds like your saying this idea could work.
I think if you cut a drain notch in it once it's screwed into the case it would work. Use some RED loctite and it won't come out.....
So my counter balance is grinding against the crankshaft and the end is wobbling when its just sitting in the case. Does this mean it's bent? just wanted to check and be sure before I get into this. My next there any chance a foreman 450 counterbalance would match up to a 420's?
Because aluminum and steel expand at different rates nothing is going to last to hold that plug in place unless you can get a nut on it and "lock" it in place. Like I said a new case is the best option, especially at the point you are at now.

If the end of the balancer wobbles it has to be bent. How that happened I wouldn't have a clue. I would have to look up the parts but I'm just guessing it is different from the 450.
That's interesting. The 420FM I rebuilt last year had a balancer that was hitting the crank as well. I bought a used balancer for $15 shipped from It worked fine. You might see if they have a used case 1/2 too.

Wonder if this is an inherent problem with the 420 when a motor starts to go south?
ok so I'm finally getting everything put back together and before I put in oil, the airbox, and fuel tank, I decided to do a little test to see if she'll turn over, turned the key and the neutral light isint coming on. Shifted around a but5 and determined that its in neutral and the light still wont come on and allow it to turn over. I'm thinking when I out that rear cover back on I didn't get the gear indicator right and it either broke or went in backwards. So my question is, is there any other factors that can cause this? Can I just modify it to where it doesn't have to even be in neutral to start? because that would be awesome. And if worse comes to worse, can I remove the rear cover without taking the motor out of the frame again?
First of all, been there, done that. First thing to check is the plug where your gear indicator switch plugs into the wiring harness. It's on the right, right under the seat.

On the Foreman I just got back together, mine did the same thing, and it's because that plug wasn't making a good connection. If I held the right brake back, it would turn over, but not start. Without the brake held back, even in Neutral, I got nothing.

My Foreman has a display, and the gear indicator was blank until I got that plug in there good, so luckily for me that told me something wasn't plugged in, and my gear indicator plug wasn't all the way in/ making a good connection.

As for the rear cover, I pulled the rear swingarm and removed the rear cover on mine. It was a pain, but it can be done. I hate working on a motor in the frame, but it can be done. You could probably do it by going in from the top and sides with the airbox out of the way, but for me it was easier to pull the swingarm and go in that way.
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I cracked the cover off to just take a peek and the indicator came out of its socket in the cover. I was able to twist the pin around and get the light to come on and hear the relay clicking. My main concern is what to do once I get the cover off. Should I replace it or can it just be put back into palce
What indicator? The green N light?
yes. I went ahead and ordered a new one and pulled the swingarm off. Should be ready to go by Thursday. Do I HAVE to give Hondabond 3 days before I put oil in it and start breaking it in?
I'm still confused. What pin are you talking about that has come out? Are you talking about the gear position switch?
the little indicator that goes into the gear shift drum. The part the bolts to the cover stayed in place while the pin that went in backwards stayed in the gearshift drum when I pulled it apart. But now I've got it all back together, put oil in it, went to start it, and the battery is weak -__- but I noticed when it did turn over a slight hissing and some coolant around the bottom of the cylinder. Could this be because I over filled it? I also got a little too much coolant so I need to drain it and fill it with more water. But if its a bad o ring could I still run it some and not have to take it all back apart?
Well she fired up and there's a noise coming from the exhaust, probably just loose. My real concern is an awful screeching inside the motor not sure if its top or bottom end. But this is a brand new cylinder and piston so could it just need to run for a moment to get oil to the cylinder?
Ok so an update: if ally got up the courage to start it again and it runs fine. No noises. Until about a second later there's a EEERCH and it stops
Honda rancher 420 - YouTube
Here's what I'm talking about
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