300 4x4 running rough
 

Hey all, thanks for the add. New member here! Am running out of ideas. I have a 1993 Honda Fourtrax 300 4x4. It' been a great bike for many years but lately been having issues. Most of the time it will idle fine, but given any throttle it sputters and will backfire sometimes. Seems like it' low on power as well (when it' not sputtering). In the spirit of maintenance and bringing this thing back up to par, I've drained the metal tank, cleaned the pet cock valve, replaced the plug, the fuel lines, the carb and now the ignition coil but it doesn't seem any better. What's next? Where do I head now?

I once had one that spluttered at just over idle, if you got it revving past that it seemed OK. Changed carb to a known good one and it still did it, so fitted a new CDI, instant cure. However be very sure it isn't the carb before buying a new CDI, Chinese "knock offs" need setting up, and be sure you know what year/ model you have, a HM3 CDI for example, is different to an HM5, which is different to a HM7.

I bought a new carb. Not sure if the Jets are right or not, but basically no improvement from before. Thinking about trying one of the cheap cdi boxes, but how do I know for sure it' the right one? If it says it' for a 93 model is that good enough?

If you are sure it is a 93 bike, a 93 CDI should be OK. Honda colour coded the wiring plugs, Off white, green, red, and the last CDI had a single big connector plus two wires with bullets on the ends, sticking out for the fan motor wires. I would remove the float bowl on your original carb, remove and blow through the jets, and the holes they came from, clean the float bowl, re-assemble and try the bike with that carb on, before fitting more new parts.

Thanks merryman, will give that a try, perhaps Friday evening and see if it does any good. Wish me luck!

did you ever find out what the problem was. i have a 2003 rancher 350 that is doing the same thing

At this point, I'm thinking it was the cdi box, but ive not had a chance to really get it out and test it yet. Will post back this weekend to let ya know. I would have initially thought it was carb, but that didn' seem to change it at all when I replaced the carb.