User Tag List

+ Reply to Thread
Results 1 to 5 of 5

Thread: Bike carbs running rough on 4age red top..

  1. #1
    Bodger zaks's Avatar

    Join Date
    Apr 2005
    Location
    phils.
    Posts
    181
    Thanks
    15
    Thanked 1 Time in 1 Post

    Bike carbs running rough on 4age red top..

    I installed r1 carbs on my redtop, got it to idle and run but after running for a few minutes, it began to run rough and the motor will stumble from idle going to the main jet. I adjusted the float level and it was better, but it began to run rough again, same problem as before..I replaced the pump to a low psi type, same thing, I cleaned the carb thoroughly, same thing, repalced main jet from 1.80 to 1.40, same thing, no overflow issues or dirt, any ideas what could be causing it to run rough? I'm at my wits end!

  2. #2
    Mechanic

    Join Date
    Dec 2011
    Location
    Northamptonshire
    Posts
    731
    Thanks
    37
    Thanked 34 Times in 32 Posts

    Re: Bike carbs running rough on 4age red top..

    Are you using the original bike pump? If not they will run crap.

  3. #3
    Bodger

    Join Date
    Jul 2009
    Location
    yorkshire
    Age
    51
    Posts
    68
    Thanks
    1
    Thanked 5 Times in 5 Posts

    Re: Bike carbs running rough on 4age red top..

    Theres a thread on oldskoolford about bike carbs n he was having similar problems with his if youre a member have a look I dont know how to do links his was something to do with air correction jets.another thing to check is for air leaks on hoses I run a pinto on thunderace carbs with 130 bhp and main jets are 155 also use facet fuel pump restricted by filterking to 3psi and they run spot on had them checked on rolling road.

  4. #4
    Bodger zaks's Avatar

    Join Date
    Apr 2005
    Location
    phils.
    Posts
    181
    Thanks
    15
    Thanked 1 Time in 1 Post

    Re: Bike carbs running rough on 4age red top..

    Quote Originally Posted by scooter View Post
    Theres a thread on oldskoolford about bike carbs n he was having similar problems with his if youre a member have a look I dont know how to do links his was something to do with air correction jets.another thing to check is for air leaks on hoses I run a pinto on thunderace carbs with 130 bhp and main jets are 155 also use facet fuel pump restricted by filterking to 3psi and they run spot on had them checked on rolling road.

    Hiall, I am thinking of checking the coil as leaks and psi issues are all spot on, Im using a bike pump and no issues with overflow and transition when engine is cold..I'm thinking that when the copil heats up that is when the engine falters, I'm at a loss however if the 4ac coil is 9 or 12volts? many says that all 4k and 4ac's use 9V coils..

  5. #5
    TURBOSPORT SPONSOR Turbosport Subscriber
    Turbosport Moderator
    Turbosport Administrator
    Graham's Avatar
    My Race Car
    My 1st Project
    Join Date
    Feb 2006
    Location
    Ely, Cambs
    Age
    56
    Posts
    25,099
    Thanks
    310
    Thanked 2,476 Times in 2,250 Posts

    Re: Bike carbs running rough on 4age red top..

    years ago when most cars ran on 9v coils with ballast it wasnt rare for the ballast to fail and be bypassed, the only issue with that was the points/condensor would suffer due to running on 12v the whole time, it rarely effected the coil. you could certainly try another coil without making any other changes, coil failure due to running 12v wont happen overnight

+ Reply to Thread

Bookmarks

Posting Permissions

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