I have a 2001 450s that has a K&N,jetted and Supertrapp pipe that I think should have more top speed.It tops out now at 46-47 and I'm running 26" Mudbugs. While adjusting the valves we checked the jetting.(All the mods were done by first owner)The Dynojet stage 1 jet kit came with,118,122,126,130&134 main jets.The 134 is what was installed but instructions called for the 126 for my altitude.So we took the 134 out and went down to the 130.Big mistake,top speed dropped to 44 and the plug was white,way lean.So back in went the 134 and speed went back up to 46-47.The plug was still fairly light colored,should I try to find a larger jet?I know the tires are affecting the speed some.I ride with some friends that have Praire650's,I know that I can't run with them in the straights but its all I can do to keep up with a 360 priarie and 350 Rancher [img]i/expressions/face-icon-small-disgusted.gif[/img] .As a matter of fact the 350 Rancher can get me on top end.HELP,I want more speed!!!!

Thanks,
Brian [img]i/expressions/face-icon-small-disgusted.gif[/img][img]i/expressions/face-icon-small-frown.gif[/img][img]i/expressions/face-icon-small-disgusted.gif[/img]

 

That engine was desinged with low end torque in mind. I've had two of them and neither one had any top end power or speed to speak of. Wish I could help, but that thing is a tractor. Reliable as one too.

 

Does your supertrapp have adjustable baffles? You may wan't to looking into adding a few discs if you can to increase your backpressure a little. It may run a little richer and give you a little more top end.

 

Actually adding disks to a supertrap system decreases back presure causing a lean condition, you would want to remove baffles to richen the mixture, unfortunatly this may be counter productive as increasing back presure causes a loss of top end and increase in bottom end.

Those jet sizes sound low, my 03 Foreman 450ES has a 145 main stock, I have a Supertrap IDSX and Uni filter with a 150 Main and a second air intake snorkle I have not taken it out as of these mods so I cannot report on the performance change.

One more thing by going to 26" tires your speedo will read low, you are actually going faster than 46 - 47, thats what mine does stock, but my buddies Rancher 350 would go exactly the same speed as my stock Foreman, I am hoping to have a little better snap now.

I just looked on http://216.37.204.202/Honda_OEM/Hond...e=13&A=75&B=17 Ronnies atv honda microfiche and it says you should have a #130 stock for a main jet, I would think about a #140 if I were you.

 

Thanks for the replys.

03Foreman-I had thought about taking out some of the disks but i'll probably leave it alone and find afew larger jets to try out.I'm also thinking of getting a Warn 424 kit which may help some by freeing up the front end.I also noticed that the front end needs to be lined up.Right now its toed out which can't be good for speed.

Brian

 

You can take some of the guess work out of it and get the dial a jet it has five settings, just a thought.

 

Dial a jet?How does it work?Where to get it?

Brian

 

Search keyword dial-a-jet, I'm thinking of getting one for my kodiak.

 

Well I took out my foreman with all the mods I mentioned earlier, with one exception I went with a #140 jet after reading the following article, I think I may try a #145. First problem after raising the needle to the highest postion and putting the carb back together I put the top cover of the carb on wrong, a vent hole has to line up correctly, it ran like crap, but I found the problem pretty quick, fixed it and took it for a good ride. Rev's way quicker now, it actually pulled the front wheels of the ground when I speed shifted 4th gear, top speed is still only 49mph but before it would get up to 44 real quick then ease its way up to 47, now it goes rite up to 47 then eases its way up to 49 (maybe a rev limiter). On the 6 inch deep snowy, twisty, hilly trails where I could only go 35 before I had no problem taking it to 40 plus. I have not done a plug check yet as it is a little difficult to do a correct plug check on a semi auto quad (you can't pull the clutch and shut it down).

I would definatly recomend to anyone going with at least a #135 and rasing the jet needle even on a stock Foreman as the Honda dealer told me they jet them way lean so they meet the "CARB" standards in California.

Has anyone put a cam in a Foreman 450 or 400???? how hard is it and did it make a big difference.

http://www.atving.com/editor/review/...kit/review.htm