//ArrowChat Code
Results 1 to 13 of 13

Thread: High idle when warm

  1. #1
    Join Date
    Jul 2013
    Location
    Maybee, MI
    --
    62

    High idle when warm

    Ever since I have gotten my SX it starts fine, but once you been out beating it a little and it warms up it idles REALLY high. Anybody know why? Or have an idea why that is?

  2. #2
    Join Date
    Feb 2011
    Location
    Sarnia, Ontario, Canada
    --
    3,415
    Choke plunger is likely not seating properly..running with part choke. Since on this model the choke is a bypass valve that lets extra fuel and air thru to both enrich and increase the starting idle speed at the same time.

    If you haven't already and good carb cleaning is a great idea..takes a bit of a nimble hand to get that carb out and back in the 1st time. There will probable be some swearing involved..if you have any problems PM 'Fabio'. He's an old salt at this one!!

    But I say do that and don't forget to clean the tank petcock screen and bowl also..maybe install a small inline fuel filter. Then you can forget about it again for a few years..
    Current toys..
    1986 Honda 350X..trail bomb!
    1985 Honda 250SX..my main mudder
    1985 Honda 250ES..Back in Black Trike
    Current non-trike toys:
    1990 Honda TRX300FW
    1995 Seadoo GTX
    1998 Polaris Indy Lite 340(Nearly new looking)
    1998 Polaris Touring 500
    1998 Club Car (electric)

  3. #3
    Join Date
    Jul 2013
    Location
    Florida
    --
    110
    My polaris ranger does this also, and other machines I've had. Even after cleaning the carbs and not using the choke at all.

  4. #4
    Join Date
    Feb 2011
    Location
    Sarnia, Ontario, Canada
    --
    3,415
    Quote Originally Posted by GunsShooting View Post
    My polaris ranger does this also, and other machines I've had. Even after cleaning the carbs and not using the choke at all.
    Yeah but these are Hondas!!

    Clean it right and it'll be good again for the next 10 years!!
    Current toys..
    1986 Honda 350X..trail bomb!
    1985 Honda 250SX..my main mudder
    1985 Honda 250ES..Back in Black Trike
    Current non-trike toys:
    1990 Honda TRX300FW
    1995 Seadoo GTX
    1998 Polaris Indy Lite 340(Nearly new looking)
    1998 Polaris Touring 500
    1998 Club Car (electric)

  5. #5
    Poco Loco's Avatar
    Poco Loco is offline At The Back Of The Pack Arm chair racerAt the back of the pack
    Join Date
    May 2013
    Location
    Clap Saddle California
    --
    389
    Also, test for a vacuum leak.
    Shart Guard .......Use it !

    Pink Powerwheels Barbie trike

    Wamo Big Wheel with a solid trikecycle front tire

    Mini bike 3hp Briggs and Stratton with cambells soup can exhaust

    Schwinn stingray with coaster brakes

    1985 Crash and Burn champ

    1st place National Endo Championship

  6. #6
    NO-SCALES's Avatar
    NO-SCALES is offline At The Back Of The Pack Arm chair racerFirst time rider
    Join Date
    Jun 2013
    Location
    DFW - TEXAS
    --
    225
    my sx has been doing this also. I just recently got it to stop. cleaned carb , put in inline fuel filter. still dong it. I got to noticing, it would do it at the same time , every time. then I noticed the clear inline filter I put in it was pretty empty ( sucking air ). tank was full. cap was on the on position , but cracked it open just to be sure it was getting air. still doing it. cleaned petcock ,and screen. even swapped the tank to my 185, it worked great on the 185. got to messing with the air fuel screw, turned it counter clockwise , while it was running... and it filled that filter up in a hurry. probally gave it 2 good turns on mine. they say to go 1/4 turn at a time and see how it acts though.

    im no master mechanic or anything, so im not saying THIS IS YOUR PROBLEM or anything, just giving you something to check on. id for sure put an inline filter on anyways.
    85 Honda 250sx- STILL IN PIECES!!!
    84 Honda 185s - traded off
    85 Yamaha 225dr - parts machine for now
    83 Yamaha tri-zinger 60cc - my sons first 3wheeler. $300 for zinger, $4000 for a broken leg, memories for a life time - PRICELESS
    85 Honda Big Red 250es - traded off
    86 Honda 250r - traded off
    85 Kawasaki Tecate - new toy
    84 Honda 200m - super clean puttin around toy

  7. #7
    Join Date
    Jul 2013
    Location
    Maybee, MI
    --
    62
    I am probably going to start with cleaning the carb. More specifically the choke........ When I first got this I took the carb off and apart and was soaking it for days and cleaning it as best as I could. But I couldn't take the choke slide with me when I took it apart.

    I am going to look for a vacuum leak just haven't had time. I generally use WD40 and spray it around to chase down vac leaks. Does anyone have a vacuum diagram for that so I know where all the hoses go if I should maybe find one missing or something??

    I am sure it is not the tank screen, it is brand new when I put the tank on and the bike has only had probably 3 tanks threw it since I got it going. Also it does have a clear filter in it, there is nothing in it, but it is not completely full like I would expect it to be.... It is always atleast half full though. I thought about maybe adjusting the low end mixture a little since sometimes it is a little cold blooded even when it is warm out....

  8. #8
    Join Date
    Feb 2011
    Location
    Sarnia, Ontario, Canada
    --
    3,415
    1st thing..since there are no real vacuum lines on the carb a missing tube isn't going to contribute to an air leak. The hoses are all vent lines. The only place you could have a leak if you do is the rubber carb boot or the connections between the carb and boot. Best way to tell besides spraying aerosol into the connections and boot is to wiggle the carb while it is idling. Flexing the rubber boot will cause any cracks in the rubber to open/close and change in RPM will be very apparent..

    2nd..if I'm not mistaken yours is an 85..correct? Your comment that it is a cold-blooded creature is actually pretty normal..since the choke jet is very small the 85 ES/SX are known for being difficult cold start machines.

    Consider contacting FlyingW and sending him your carb..he has some mad skills when it comes to carb rebuilding. Also one of the things he does is convert the choke jet size to make it better cold start..an improvement Honda put into the 86 and later model.
    Current toys..
    1986 Honda 350X..trail bomb!
    1985 Honda 250SX..my main mudder
    1985 Honda 250ES..Back in Black Trike
    Current non-trike toys:
    1990 Honda TRX300FW
    1995 Seadoo GTX
    1998 Polaris Indy Lite 340(Nearly new looking)
    1998 Polaris Touring 500
    1998 Club Car (electric)

  9. #9
    tvpierce is offline At The Back Of The Pack Arm chair racerFirst time rider
    Join Date
    Apr 2013
    Location
    Maine
    --
    157
    Does it require use of the choke/enricher to start when it's cold?

  10. #10
    Join Date
    Jul 2013
    Location
    Maybee, MI
    --
    62
    Nope usually just choke it for a bit and it will start....

  11. #11
    tvpierce is offline At The Back Of The Pack Arm chair racerFirst time rider
    Join Date
    Apr 2013
    Location
    Maine
    --
    157
    So that's a yes, the choke must be applied for a cold start?

  12. #12
    Join Date
    Jul 2013
    Location
    Maybee, MI
    --
    62
    No it can start with out the choke unless its below like 50*. Just cranks a bit longer until it is warmed up. Once its been running for 5 minutes or so it starts perfect. But after its been ran hard for 5 to 10 minutes it idles really high.

  13. #13
    Join Date
    Dec 2021
    Location
    NY
    --
    3
    Quote Originally Posted by dougspcs View Post
    Choke plunger is likely not seating properly..running with part choke. Since on this model the choke is a bypass valve that lets extra fuel and air thru to both enrich and increase the starting idle speed at the same time.

    ..
    Found this thread when I noticed my 350x was idling high when warm. I had recently ordered a new idle screw and got the choke plunger instead. Got a refund on the idle screw and figured maybe this would fix my idle. It did, new choke plunger and lever. Now idles smooth before and after warm up.

//ArrowChat Integreation Code //