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Discussion Starter #1
Hello to All,

I have a 2017 Honda Rancher 420. Can you guys give me some feedback? I would like to know if the fuel controllers out there, Dobeck, Dynojet, etc. really make a difference in power or the way the 420 runs? I do not want to change the Exhaust and would use a Uni Filter if I needed to. Any recommendations, opinions, advise or experience is what I would love to get from the forum members. I ride in Northern MI at 500-1500'.

Greg Nolan
 

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No. You won't get any noticeable power gain.

I put a 500 top end on my wife's 420 along with a programmer and the difference was barely noticeable.

If the new 2020 Foreman 500 top end (520CC) top end will bolt onto a 420 that might be worth the coin, and would of course require a programmer, but otherwise save your money.
 

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No. You won't get any noticeable power gain.

I put a 500 top end on my wife's 420 along with a programmer and the difference was barely noticeable.

If the new 2020 Foreman 500 top end (520CC) top end will bolt onto a 420 that might be worth the coin, and would of course require a programmer, but otherwise save your money.
Mustve been a different experience from me. I put a 500 on a 420 & it was big time noticeable, but not all machines are the same i guess.
As for fuel, is it worth the extra $$ & bother? (depending on the programmer) it likely isnt.
 

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Hope this isn't a thread derail.
I've been thinking about doing this with my 420. Did you just do the Foreman cylinder and piston, or did you also use a Foreman head? I know the Foreman uses bigger valves.
The thing holding me back on doing the swap is the programmer part. What programmer did you use and what changes does it make?

No. You won't get any noticeable power gain.

I put a 500 top end on my wife's 420 along with a programmer and the difference was barely noticeable.

If the new 2020 Foreman 500 top end (520CC) top end will bolt onto a 420 that might be worth the coin, and would of course require a programmer, but otherwise save your money.
 

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I put a 500 cylinder and piston on an 09, kept the 420 head, but the 500's use the same head as the 420's.

https://www.partzilla.com/product/honda/12200-HP7-A01?ref=c2703c16e2cda3b342affaae863ed6b443c9b5f7

I used a Weisco programmer.

It got a little more oomph, but not at all what I expected given an addition 55CC's.

Kind of reminds me of the Borla header, Jacob's ignition, and Weber carb I put on my Jeep back in the late 90's. I had the engine rebuilt when all of that was added, and expected a LOT more power. I got a little, and at a HUGE cost.

The 500 top end on a 420 isn't worth doing unless your 420 cylinder has to be replaced. I had a 420 I was rebuilding at the time that had a cracked cylinder, so I put the wife's 420 cylinder on that project and bought a new OEM 500 cylinder for hers. Was very disappointed in the result.
 

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Interesting, I hadn't looked up the part number on partzilla to do a cross referance.
I got a extra head in a deal I did buying a 07 Rancher earlier this year. The spare head had larger intake and exhaust valves, so I just assumed it was from a Foreman.

I put a 500 cylinder and piston on an 09, kept the 420 head, but the 500's use the same head as the 420's.
 

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The 07-08 heads were different than the 09-up. The 09-up actually use the same valves as the 500. The 07-08 used the same valves as the 400AT Rancher, so I'm guessing the extra head was a later one.
 

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I changed the cylinder and piston, kept my stock head. Mine's an 09, and the heads are all the same on the 420's and 500's from 09 up. If you used a head from an 07-08 it had different valves, but most say the cooling ports in the early models don't allow for adequate cooling with the Foreman cylinders. I do know Toodeep over on Hondaforeman.com was one of the first to do the 500 cylinder swap, and he did it on an 07 420FM and used his stock early head.

It was a power increase, just not much of one, and certainly not worth what it cost.

I got a much bigger bump in useable power with a small GR (FM secondary). After swapping those gears into the wife's AT it would wheelie on pavement.
 

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Discussion Starter #10
Yeah, the trouble with forums is that people get far away from the initial subject or question and go off on totally unrelated tangents. I was just looking for peoples experience with Fuel Controllers for the fuel injected Rancher 420. I get a sense that most don't think they are of any significant value, reading other posts.
 

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If you are somewhat electrically inclined, you can bypass both the cold air intake & the O2 sensor, by getting the values with an ohm meter, & installing resistors you can trick the ECU into thinking its running leaner & in colder weather than it is. The bike will richen up & you will have more power. Wont be night & day & if you arent used to the machine you likely wont notice it. A fuel "controller" will give you better performance than putting resistors in, but costs wayyyy more. Again...only if you are are somewhat electrically inclined.
Its not for everyone.
 

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Yeah, the trouble with forums is that people get far away from the initial subject or question and go off on totally unrelated tangents. I was just looking for peoples experience with Fuel Controllers for the fuel injected Rancher 420. I get a sense that most don't think they are of any significant value, reading other posts.
Short answer, no, don't waste your money.

When I answer a question I normally like to provide a reason that I gave the answer that I did.

If 55 more CC's AND a programmer doesn't help much, then just a programmer sure as hell isn't going to be worth it.
 
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