Should Have Started with a Bigger Pilot Jet
Close
    
    
Results 1 to 5 of 5
Like Tree15Likes
  • 10 Post By Welder
  • 3 Post By Tweaker
  • 2 Post By Welder

Thread: Should Have Started with a Bigger Pilot Jet

  1. #1
    Senior Member Welder's Avatar
    Join Date
    May 2015
    Location
    PNW
    Posts
    104

    Should Have Started with a Bigger Pilot Jet

    I have two 2015 TWs. Both ran lean as heck new from the factory... backing firing on decel, needing choke for the first mile of riding even after a long warm up period or else any throttle would kill the engine, surging at light load and throttle, rough running rolling off a closed throttle, and common single massive detonation events in warm weather with a warm engine during cranking to start up. My bikes are all stock with the 2015 Teikei carbs. I am close to sea level.

    I tried adjusting the idle mixture screws which helped, but not near enough. The only problem it completely eliminated was the back firing on decel. I found opening the screws beyond a certain point, about 1.5 turns, had no further effect on idle speed, and they were still too lean. I tried running with the screw out 2-3 turns but it seemed to make little difference after about 1.5 turns out.

    I just put in a 34 pilot jet and the bike ran instantly better. Started right up, ran way better when cold, ran better when warmed up. It was 36 F out and raining / frozen raining. I will do some experimenting with the idle air screw when time allows, but for right now I notice the same thing as with the stock pilot jets.... after turning the screw out a certain amount, about 1 turn now with bigger pilot, it seems to have little effect on idle speed.

    BTW I also <previously> tried shimming the needle and bigger mains as that seems a popular thing to do. Running both bikes side by side in warm weather, the totally stock bike ran crisper in the mid to full throttle range, and out ran the rejetted bike. I pulled the shims and went back to the stock main jet.

    Anyhow I will experiment more with screw adjustments when it isn't late, dark and raining. But for now I can see I was wasting my time with everything else until the bigger pilot jet went in. It appears to me that should be the place to start when trying to make the TW run right.
    Last edited by Welder; 03-05-2017 at 08:41 PM.

  2. #2
    Senior Member Tweaker's Avatar
    Join Date
    Dec 2015
    Location
    San Diego
    Posts
    822
    I only upped the main jets on my bikes because of the aftermarket exhausts called for it. The shims on the needle may improve throttle response depending on the bike. The bigger pilot jet did get rid of cold bloodedness on my bikes.
    Welder, littletommy and grewen like this.
    Twin 2014 TW200's made side by side on the assembly line, Moose rear racks, Protaper Bars one with risers, DG oval pipes. rejetted carbs, 130 main jets, 2 -.020 shims on the needles and @ 2 1/2 turns on the pilot screw, #34 pilot jets, Aserbis hand guards, Shinko 241 front tires, weld on foot pegs, 14-55t sprockets, Ricochet skid plates and 90 degree fuel filters.

  3. #3
    Senior Member Welder's Avatar
    Join Date
    May 2015
    Location
    PNW
    Posts
    104
    52F and not too wet today. I went with 1 1/8 turn on the 34 pilot (other wise 100% stock) and it starts and runs great! Wish I would have done this 2 years ago.

    I still haven't changed the wife's pilot yet, will do soon. Like mine used to, it CRACKS sometimes on turning over. One big detonation event. I have to think that over time this would bust up the ring lands. Seems crazy the bike is delivered like this.
    littletommy and jtstdub like this.

  4. Remove Advertisements
    TW200Forum.com
    Advertisements
     

  5. #4
    Senior Member Deepseadan's Avatar
    Join Date
    Sep 2016
    Location
    So Cal
    Posts
    215
    Quote Originally Posted by Tweaker View Post
    I only upped the main jets on my bikes because of the aftermarket exhausts called for it. The shims on the needle may improve throttle response depending on the bike. The bigger pilot jet did get rid of cold bloodedness on my bikes.
    So I'm heading to chaparral tomorrow to pick up a few things and thought it would be a good time to grab a couple jets. Since we live somewhat close and similar elevations, what did you settle on for your carb jetting (just pilot and main)? My 2016 still has the stock 126 and 31 and I want to richer it up just a bit. I know you went up on the pilot a bit, but how about the main? My tw still has the stock exhaust.


    Sent from my iPhone using Tapatalk
    Current bikes 2016 KTM 500 EXC, 2016 Yamaha TW 200

  6. #5
    Senior Member Tweaker's Avatar
    Join Date
    Dec 2015
    Location
    San Diego
    Posts
    822
    Chaparrall may have to order the jets my dealer didn't stock them. Take the numbers with or call them to order then pick up no shipping charge. You could get a #34 pilot to try and a 128 main. I don't know if you need a 130 main jet with a stock exhaust. Also there is #125 jet maybe for high altitude along with the stock #126. I think it might be good to order an extra bowl gasket too.
    Twin 2014 TW200's made side by side on the assembly line, Moose rear racks, Protaper Bars one with risers, DG oval pipes. rejetted carbs, 130 main jets, 2 -.020 shims on the needles and @ 2 1/2 turns on the pilot screw, #34 pilot jets, Aserbis hand guards, Shinko 241 front tires, weld on foot pegs, 14-55t sprockets, Ricochet skid plates and 90 degree fuel filters.

Sponosred Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Similar Threads

  1. Replies: 78
    Last Post: 08-08-2016, 05:46 PM
  2. Pilot Jet vs Pilot Screw adjustments
    By Tee Dubbs in forum Technical Help
    Replies: 10
    Last Post: 05-23-2016, 05:04 PM
  3. pilot jet
    By greendub in forum Technical Help
    Replies: 9
    Last Post: 08-27-2013, 07:16 PM
  4. Pilot Jet
    By Joe in forum Technical Help
    Replies: 2
    Last Post: 01-11-2012, 07:34 PM
  5. bigger pilot jet?
    By DDavis in forum Technical Help
    Replies: 3
    Last Post: 10-25-2011, 01:02 AM