Old carb question/issue
Close
    
    
Page 1 of 2 12 LastLast
Results 1 to 10 of 12
  1. #1
    Senior Member Boarder255's Avatar
    Join Date
    May 2011
    Posts
    120
    Ive got an issue that popped up one day in the middle of riding. I was on my way home from a great weekend excursion on the TW when all of a sudden I started surging anytime I gave the throttle more than 1/4-1/3 turn. It was almost like I was running out of gas. I checked that I had plenty of fuel remaining (had close to 70 miles on that tank of gas already), I did. I limped it home thinking it had to be a carb issue. Upon my return home,the major thing I noticed was the throttle cable plate had one screw missing and the other was barely attached. This must hace been the issue for sure. So i promptly replaced thd missing screw and tighted the second. Additionally I tore the carb all the way apart and cleaned all jets and even found a questionable gasket on the top of the carb, which I changed out. Putting it all back together things were working fine (slide, float, etc).



    BUT! The bike is still surging at the 1/3 throttle position. What else could be causing the issue? I thought bad gas, but I had run nearly 1/2 tank on the gas in question. Thought could be something partially clogging the screen on the petcock, but would that change when I switch to reserve? And when the bike is stationary, I can rev it to the moon without hesitation. I have 8000 miles on the bike. Could it be the valves? I checked the at about 4-5000 miles and they were within spec. I am out of ideas. Please someone with more carb/motorcycle skills offer their thoughts.



    Thanks guys!

  2. #2
    Senior Member Boarder255's Avatar
    Join Date
    May 2011
    Posts
    120
    Oh, just so to answer the re-jetting question, the carb was running perfectly fine, no surging, great idle, and high speed. It was like someone flipped a switch during my 50 mile ride home. It wasn't even between stops.

  3. #3
    Senior Member TWBARR's Avatar
    Join Date
    Jul 2011
    Location
    IN
    Posts
    186
    Quote Originally Posted by Boarder255 View Post
    Oh, just so to answer the re-jetting question, the carb was running perfectly fine, no surging, great idle, and high speed. It was like someone flipped a switch during my 50 mile ride home. It wasn't even between stops.


    Have you checked the fuel flow to the carb? It might help to pull the petcock and clean and inspect it. Make sure you have good flow out of the fuel tank.

  4. Remove Advertisements
    TW200Forum.com
    Advertisements
     

  5. #4
    Senior Member Point37's Avatar
    Join Date
    Sep 2011
    Location
    Southcoast MAsshole
    Posts
    2,661
    stock tank or aftermarket?...if aftermarket, it could be a tank venting issue

  6. #5
    Senior Member Boarder255's Avatar
    Join Date
    May 2011
    Posts
    120
    Quote Originally Posted by Point37 View Post
    stock tank or aftermarket?...if aftermarket, it could be a tank venting issue


    Clarke Tank.



    I'll pull the gas out and clean the mesh screens on the petcock today.



    Also thinking check the fuel level in the carb bowl/float adjustment.



    Something else I noticed, on the exploded view of the carb, there is only one screw on the throttle cable plate. But on mine there are two holes for M5x0.8 12mm screws (one screw I'm assuming was lost on the ride). Can someone with an older carb (mine is a '99) confirm that there are two screws holding the throttle plate to the carb?



    Dale

  7. #6
    Senior Member small's's Avatar
    Join Date
    Apr 2011
    Location
    Martinsville Indiana
    Posts
    2,089
    Venting issue or maybe something in the fuel line.

  8. #7
    Senior Member Point37's Avatar
    Join Date
    Sep 2011
    Location
    Southcoast MAsshole
    Posts
    2,661
    Quote Originally Posted by Boarder255 View Post
    Clarke Tank.



    I'll pull the gas out and clean the mesh screens on the petcock today.



    Also thinking check the fuel level in the carb bowl/float adjustment.



    Something else I noticed, on the exploded view of the carb, there is only one screw on the throttle cable plate. But on mine there are two holes for M5x0.8 12mm screws (one screw I'm assuming was lost on the ride). Can someone with an older carb (mine is a '99) confirm that there are two screws holding the throttle plate to the carb?



    Dale


    yea the Clarke tank has a big vent port...you could try loosening the cap to see if there is any blockage or check your vent hose if you have one



    mine is a 2000...not sure if this helps but it's the best i can do right now


  9. #8
    Senior Member lizrdbrth's Avatar
    Join Date
    Jul 2010
    Location
    Desert, SoCal
    Posts
    7,369
    Quote Originally Posted by Boarder255 View Post
    Clarke Tank.



    I'll pull the gas out and clean the mesh screens on the petcock today.



    Also thinking check the fuel level in the carb bowl/float adjustment.



    Something else I noticed, on the exploded view of the carb, there is only one screw on the throttle cable plate. But on mine there are two holes for M5x0.8 12mm screws (one screw I'm assuming was lost on the ride). Can someone with an older carb (mine is a '99) confirm that there are two screws holding the throttle plate to the carb?



    Dale


    O/S carb has two screws for the plate.



    I can explain it to you, but I can't understand it for you.

    Powdercoated '87 frame, extended swingarm, YZ fork legs, ATV tire, 14/55, XT350 tank, spliced quick-release seat, disc brake conversion, beeg headlight, beeger rack, Lizrdcooler, Lizrdventz and bunch of other stuff all covered in invisible ink.

    Hidden Content

    Hidden Content

  10. #9
    Member Hotrodjohn's Avatar
    Join Date
    Jul 2011
    Location
    DFW, Texas
    Posts
    76
    Dont forget to check the mesh screen inside the carb, on the top of the float needle. Check that flow all the way INTO the bowl.
    87 (2) TW200 89 (2) TW200

    91 Honda XR250L

    97 Honda Valkyrie

    01 Kawasaki KDX200

    78 Suzuiki GS1000

    1970 (2) CT70H

    1974 Suzuki GT185

    1981 Honda C70 Passport

  11. #10
    Senior Member Boarder255's Avatar
    Join Date
    May 2011
    Posts
    120
    Ok. Checked flow out of gas tank with and without cap, and was consistent with both conditions. Cleaned the screens on the petcock draws (weren't visibly dirty)



    Shimmed and un shimmed needle, re jetted back to #114 main jet both did not have and effect (ran worse).



    What does bad gas feel like? I double checked my math this morning and I believe the surging started approx 45 miles after filling up after hitting reserve. Reserve gets me 35-40 miles. So it could be I burned through the good gas and then hit the bad stuff on my way home. Would they stay relatively seperated or would they mix? I have never had an experience of bad gas. I put some seafoam in the gas and put new stuff on top of the old... Dumb I know, but I didn't have this brainstorm until this morning. It seems not as bad. But still doing it. Thinking about dumping out the whole tank and filling with fresh gas. Thoughts?



    I will clean the screen above the float needle tonight.



    Thanks guys. It's frustrating driving my car to work when it's 80 and sunny!!

Page 1 of 2 12 LastLast

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. 1990 carb Question
    By Gene-st1300 in forum Technical Help
    Replies: 2
    Last Post: 06-14-2012, 12:44 PM
  2. Carb Needle Shim Question
    By sfsccoter in forum Technical Help
    Replies: 11
    Last Post: 09-16-2011, 12:05 PM
  3. 2010 Carb question
    By RockyTFS in forum Technical Help
    Replies: 19
    Last Post: 03-26-2011, 11:31 AM
  4. Cleaned Carb, now I have a question
    By Quicksand in forum Technical Help
    Replies: 2
    Last Post: 08-16-2010, 06:15 AM
  5. Carb question...
    By adavis in forum Technical Help
    Replies: 6
    Last Post: 08-12-2010, 08:57 AM