Page 5 of 5 FirstFirst ... 345
Results 61 to 69 of 69

Thread: GN250 running too rich?

  1. #61
    Join Date
    9th April 2015 - 16:03
    Bike
    Bandit 1200s, gsx600f
    Location
    Wanganui/Manawatu area
    Posts
    109
    Quote Originally Posted by globe View Post
    So after a bit of a break from the mighty GN, back into it.

    Did a bit of research and it looked as though the white plastic washer on the needle goes below the e clip accorded to the parts cats. Swapped it over this morning and it ran fine through to half throttle then nothing, No acceleration just sat there. Occasionally it made a low popping sound but generally nothing until i backed off the throttle, then fine again. Did a plug chop (on the stand albeit) at WOT and it came out black so that suggests running rich in the top end. What I don't understand though is that moving the needle up (by swapping over the plastic washer thats about 2-3mm thick) richens it up considerably and this eliminated the flat spot at 1/4 throttle I had before I moved this. Hows that work? Is this suggesting lean out the main needle or jet and get a bigger pilot jet?

    HT lead and coil are fine as I have replaced them.



    Thinking of getting a new (wrecker) original carb, or sending it to a mechanic, sigh....
    Every carb (90% suzukis) I have ever been into has had the white plastic spring retaining washer on top of the needle, above the clip.

    How many clip grooves have you on your needle? Have you a small steel washer below the e clip on the needle?

    If you still have a fuel leak then your float needle seat is not sealing. It could be hard seat rubber (try soaking just the float needle in brake fluid overnight), crap between the rubber and the valve seat, float height set wrong, float needle jamming in the housing (try polishing the inside of the housing with battery dril/cotton bud/autosol.)

    When you cleaned the carb what did you use to clean it? Did you get it on the rubber of the float needle? See where I am going with this?

    Photos would definitely help.

  2. #62
    Join Date
    5th January 2017 - 07:44
    Bike
    Yes
    Location
    City of Sails
    Posts
    94
    Quote Originally Posted by oldiebutagoody View Post
    Every carb (90% suzukis) I have ever been into has had the white plastic spring retaining washer on top of the needle, above the clip.

    How many clip grooves have you on your needle? Have you a small steel washer below the e clip on the needle?
    5 clip grooves, at the current setting, e clip is on top notch, white washer under steel washer on top, that gives a flat spot at 1/2 throttle ish, and WOT. From 1/2 to WOT feels like it lacks power. The setting before I had e clip on middle notch, white and steel under, they were the symptoms in my last post. Prior to this white washer and steel on top and middle notch.

    Quote Originally Posted by oldiebutagoody View Post
    If you still have a fuel leak then your float needle seat is not sealing. It could be hard seat rubber (try soaking just the float needle in brake fluid overnight), crap between the rubber and the valve seat, float height set wrong, float needle jamming in the housing (try polishing the inside of the housing with battery dril/cotton bud/autosol.)

    When you cleaned the carb what did you use to clean it? Did you get it on the rubber of the float needle? See where I am going with this?
    Fuel leak solved cheers. The washer around the fuel jet had perished and i replaced, problem solved.

    Quote Originally Posted by oldiebutagoody View Post
    Photos would definitely help.
    Photos of anything in particular ?

    Cheers

  3. #63
    Join Date
    9th April 2015 - 16:03
    Bike
    Bandit 1200s, gsx600f
    Location
    Wanganui/Manawatu area
    Posts
    109
    Yeah my gut feeling is that you have assembled the needle washers in the wrong sequence.

    try assembling with the small steel washer UNDER the e clip, e clip in the 1st notch down from the top, white plastic washer ON TOP of the e clip.

    being a CV carb, you will note the white plastic washer has a ring on it to locate the long spring under the carb cap. That spring regulates the fluttering of the slide under vaccum and if it is not located on that washer there is no balancing pressure on the top of the slide. If you have that white washer UNDER the e clip I am wondering how exactly you have it sitting?

    EDIT: This is all from memory, so I am admitting you could well have a plastic washer UNDER the e clip, but there shouls be a notched plastic washer ON TOP also.

  4. #64
    Join Date
    5th January 2017 - 07:44
    Bike
    Yes
    Location
    City of Sails
    Posts
    94
    OK, had another look at the exploded carb diagram and turns out I was getting my ideas from elsewhere. Reset with the white washer on top, the steel one underneath and took it for a spin, runs lovely on everything 50% onwards. Still a bit "boggy" in the 1/4 to 50% range.

    That was with the e clip on the middle notch

  5. #65
    Join Date
    6th May 2012 - 10:41
    Bike
    invisibike
    Location
    pulling a sick mono
    Posts
    6,057
    Blog Entries
    4
    Quote Originally Posted by globe View Post
    .



    Photos of anything in particular ?

    Cheers
    your mitti's tits

  6. #66
    Join Date
    5th January 2017 - 07:44
    Bike
    Yes
    Location
    City of Sails
    Posts
    94
    Hopefully this photo will help. This is the needle assembly taken apart. From bottom to top around the needle I now have it in the following order

    1. (Steel washer)
    E Clip
    3. Plastic washer
    2. Spring
    4. Plastic holder

    Before I had number 3 the thick white washer below the e Clip.

    Cheers
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Inkedfile-16_LI.jpg 
Views:	15 
Size:	831.9 KB 
ID:	335776  

  7. #67
    Join Date
    9th April 2015 - 16:03
    Bike
    Bandit 1200s, gsx600f
    Location
    Wanganui/Manawatu area
    Posts
    109
    Quote Originally Posted by globe View Post
    Hopefully this photo will help. This is the needle assembly taken apart. From bottom to top around the needle I now have it in the following order

    1. (Steel washer)
    E Clip
    3. Plastic washer
    2. Spring
    4. Plastic holder

    Before I had number 3 the thick white washer below the e Clip.

    Cheers
    Okay, looking at 1/4 to 1/2 throttle area now to get rid of the boggy feeling. That is where the needle clip setting is having its effect. You need to lean it out, so take the e clip up to the second ring down from top. If its better but not quite right move it right up to the top. It won't affect idle, so for the moment leave the idle mixture screw alone until you have 1/4 to 1/2 throttle sorted.

    Then perform the idle mixture adjustment if it bogs down taking off from a standstill such as at lights when the engine has warmed up. There is a small transition stage between idle circuit and needle movement which if either or both are too rich can make it bog taking off from standstill, so the trick is to get needle setting right, then the idle mixture using the correct adjustment process one at a time otherwise you will get confused and chase your tail again.

  8. #68
    Join Date
    5th January 2017 - 07:44
    Bike
    Yes
    Location
    City of Sails
    Posts
    94
    Quote Originally Posted by oldiebutagoody View Post
    Okay, looking at 1/4 to 1/2 throttle area now to get rid of the boggy feeling. That is where the needle clip setting is having its effect. You need to lean it out, so take the e clip up to the second ring down from top. If its better but not quite right move it right up to the top. It won't affect idle, so for the moment leave the idle mixture screw alone until you have 1/4 to 1/2 throttle sorted.

    Then perform the idle mixture adjustment if it bogs down taking off from a standstill such as at lights when the engine has warmed up. There is a small transition stage between idle circuit and needle movement which if either or both are too rich can make it bog taking off from standstill, so the trick is to get needle setting right, then the idle mixture using the correct adjustment process one at a time otherwise you will get confused and chase your tail again.
    Good one thanks,what I have found is that moving the needle also seems to affect the response throughout the range, is that normal? For example when I had the white washer on the wrong side it was WOT that was causing the problems and 1/4 to half was OK, doesnt seem to follow the logic I have read everywhere and the good people on here are telling me, cheers

  9. #69
    Join Date
    9th April 2015 - 16:03
    Bike
    Bandit 1200s, gsx600f
    Location
    Wanganui/Manawatu area
    Posts
    109
    Quote Originally Posted by globe View Post
    Good one thanks,what I have found is that moving the needle also seems to affect the response throughout the range, is that normal? For example when I had the white washer on the wrong side it was WOT that was causing the problems and 1/4 to half was OK, doesnt seem to follow the logic I have read everywhere and the good people on here are telling me, cheers
    Ignore symptoms, could be another issue interfering with correct operation. From experience I can tell you where your issue lies and the above stated process is how to negotiate your way out of your problem. Everything to do with carbs is a negotiation, a trade off. There is no perfect, only settings that will give acceptable performance depending on intended use.

    Get one thing sorted at a time, make one change only at a time, otherwise; which twiddle that you just did made the thing run better/worse?

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

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