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Thread: Tuning honda 300 question

  1. #1
    djleblanc79 Guest

    Default Tuning honda fourtrax 300 question

    I have a 1996 honda 300 fourtrax. I recently put a dynojet jet kit with a 128 jet, a K&N air filter and a Supertrapp IDS2 Quiet core series with 10 disc and the exhaust pipe is turning red when idling.

    Any suggestion...
    Last edited by djleblanc79; 11-08-2009 at 11:20 PM.

  2. #2
    Join Date
    Aug 2008
    Location
    Blackfoot, ID
    Posts
    117

    Default

    Questions:
    What was the stock jet size?
    Was the float height changed?
    Was the pilot air screw adjusted?
    Were any other jets changed as part of the dynojet upgrade? Drilling?

    Personally, I'd oil the K&N up so it was fully saturated and drain. Then I'd remove diffuser discs in sets of two until things returned to normal. I'm thinking 6-7 total discs is more than enough to let your 300cc motor breath.

  3. #3
    bschultz Guest

    Default

    Sounds like your Pilot/idle jet circuit is lean or possibly an intake (boot) leak. Have you checked with DynoJet tech services?
    The "quiet core" is usually good for about 2 main jet sizes up from stock, a freer flowing air filter and maybe an air box mod with 12 discs installed. More aggressive tuning mods would most likely need the race core to be installed for more exhaust flow.

  4. #4
    djleblanc79 Guest

    Default

    Quote Originally Posted by djleblanc79 View Post
    I have a 1996 honda 300 fourtrax. I recently put a dynojet jet kit with a 128 jet, a K&N air filter and a Supertrapp IDS2 Quiet core series with 10 disc and the exhaust pipe is turning red when idling.

    Any suggestion...
    Stock jet was 125, float height was not changed, pilot screw was screwed in and unscrewed 2.5 turns, no other jet was changed, a DD32 hole was drill in plastic by needle.

    I also tried changing jet to 132 and 124, same result, exhaust pipe turning red at idle.

  5. #5
    bschultz Guest

    Default

    You mention the headpipe at idle, does the glow go away during riding with partial or full throttle?

  6. #6
    djleblanc79 Guest

    Default headpipe turning red

    I can only run the back on stands right now because I am working on the front knuckle, but the headpipe startes to turn red after a little while running and giving some throttle.

  7. #7
    bschultz Guest

    Default

    You can try reducing the number of discs; however I would check with the Tech Department at DynoJet. It sounds to me like you have an intake leak.
    If DynoJet doesn't have any suggestions you can always go back and set a baseline with stock jetting and 5-6 discs.

  8. #8
    djleblanc79 Guest

    Default

    Quote Originally Posted by bschultz View Post
    You can try reducing the number of discs; however I would check with the Tech Department at DynoJet. It sounds to me like you have an intake leak.
    If DynoJet doesn't have any suggestions you can always go back and set a baseline with stock jetting and 5-6 discs.
    Intake leak problem were. This is all new to me so I don't know a whole lot about 4 wheelers.

  9. #9
    bschultz Guest

    Default

    The rubber boot between the carb & cylinder.
    Is it idling high, have you adjusted the fuel mixture screw?
    I don't see anything about drilling a hole in the slide in DynoJets instructions?
    Have you contacted the tech dept, at DynoJet?

  10. #10
    djleblanc79 Guest

    Default

    Quote Originally Posted by bschultz View Post
    The rubber boot between the carb & cylinder.
    Is it idling high, have you adjusted the fuel mixture screw?
    I don't see anything about drilling a hole in the slide in DynoJets instructions?
    Have you contacted the tech dept, at DynoJet?
    Last night I decrease the plates in the exhaust to 8 and installed a 150 jet. The redness stopped put don't know if its too lean or rich because I cant run it around. I have adjusted the idle, thats find. I drill a hole in the bottom of the rubber boot in the carb as per dynojet instructions, the hole was actually in the plastic nearby where the needle slides. I didn't contact Dynojet.

    I hope the problem is fixed, what do you think?

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