Greetings my fellow Forum members. Been a LONG while since I have been in and posted here lol.

I am having an issue with the carb on my 98 Foreman 450ES. I replaced the carb within the last couple of weeks. Since installing it the bike starts fine (with no choke even) but as soon it starts it seems to rev up and stay rev'd up (not full throttle though as I can hit the throttle and it will go further). The idle adjustment **** (**** that when screwed in meets the throttle) is backed all the way off. Adjustment to the fuel mix screw/needle does not seem to make a difference.

NOW to the (maybe not so smart) part here, is that the carb is not a stock Honda Keihin carb lol. I went with an after market "knockoff" or "look alike". Honestly in comparison to the rebuild parts, tools, time etc it was about the same cost. The only thing I did with the aftermarket was put the stock choke plunger in the new carb (mistake maybe?). I cannot locate any vacuum leaks that I can tell (but I am not an expert lol).

At any rate, I would like to get some input, help, etc to try and fix this as this is my winter tool for VT snow! Yes.... smack me for aftermarket but a 23 year old machine I am trying to not spend tons of money on it any more than I have too or have lol (gotta keep the CFO happy or she will ring my neck)!

Any and all help is GREATLY appreciated.

 

Most likely thing is the throttle butterfly sticking slightly open. Clean the old carb out, no rebuild kits, no expense, and put it back on. If it really has "had it" a holed diaphragm for example, take a good look inside the new carb, check the butterfly closes, check the dashpot isn't sticking and use the new choke plunger. Honda used two different lengths, depending on age of bike so you may have fitted the wrong one for that carb.

 

meryman TYVM. I took a closer look today and could see where the butterfly was not closed all of the way. I took the aftermarket back off and gutted it for every part I could use in the old carb (after verifying a match of course). Slapped the old carb back on and gave it a quick test. BINGO, BOBS YOUR UNCLE it is all back in working order and runs good. Need to do some fine tuning ect (a little backfiring on de-accel) but all is good.

 

450s always did backfire on the overrun. Only bike where I have had to fit new silencers because of them blowing the baffles out and becoming VERY loud. If the owner wasn't too fussed, we used to stick a tube of perforated metal (from an old tractor air filter) up the end of the silencer, this quietened them a bit.