2 out of 4 ain't good

[Anonymous]

I'm in the process of rebuilding my GS650L I've had my carbs rebuilt. The man who rebuilt them noted the factory settings and rebuilt them with those settings. The problem is the only cylinders firing are 2&3 cylinders 1&4 are cold although they have good spark I was told I'd have to get them syncronized but I've got to get them firing what did i miss?

 

[SqDancerLynn1]

take it back to that so called mechanic and tell him to fix the carbs right even if it needs sync it should run on all 4

 

[Anonymous]

1 and 4 run off the same ignition coil... maybe you pulled the elect connection to that coil loose ?

Mine died on 1 and 4 once... it turned out to be the 'ignitor box'... (CDI unit) had gone bad.

Also.. make sure you are getting good fuel flow thru the petcock into the carbs.

(offhand.. right off the bat.. it doesn't sound like a carburetion problem)

 

[Jay B]

Coil

Coil

I agree with Austin. Gotta be a wire somewhere.

 

[SqDancerLynn1]

Everyone needs to re read the question Rat said that 1&4 were cold but had good spark. to me that woud mean that it had to be in the fuel system
Additional note were the needle and seat replaced? They may have a very small filter on the inlet side of the needle. could be cloged? not getting any fuel

 

[Anonymous]

Definately not an electrical fault because 1 and 4 are getting a spark. Loosen the drain screw on the float bowls for 1 and 4. Does fuel come out ? If not, check your float heights and float valve. If you give it a quick blip of throttle does it come to life ? If you rev it high(say 5000) does it come to life ? If yes, it could be blocked pilot jets. Just for completeness sake, swap over the coils and see if the problem goes to 2 & 3. Just eliminate it for completness sake. You can balance your carbs quite accurately by using a small piece of welding rod (or similar). With the carbs removed, place the rod down the carb inlet mouth and adjust the slide (or throttle valve if there not slides) until it just grips the rod (using the rod like a feeler guage). Repeat for all carbs. It won't be perfect but it will definately be close enough to eliminate balancing as a potential problem.
If you are really not happy, take them back. However I wouldn't go back to anybody who appears incompetent. If you have no faith in this mechanic, do it yourself. Go slowly and be particular in you cleaning methods. You WILL be able to set up these carbs as good as any mechanic.

Remove the floatbowl and remove the jets. Blow them through with carb cleaner. Blow all jet housing and orifices through with carb cleaner. Set you floats. Most people then blow through with compressed air, must admit I never have, its up to you.

Good luck.

 

[moto_dan]

As The MadHatter stated, you can get the carbs in the ball park by static setting. If you have a manual it has the procedure for this. Do you have CV carbs? I know on the CV style carbs you adjust the butterfly to just uncover a specific hole in the the top of the engine side carb opening. I'll look in my manual when I get home for the specifc.

 

[Anonymous]

Make sure you have compression in those cylinders. Mine was doing the same thing. only had 60 lbs of compression in #4 and 90 in cylinder 2. I found I will need a valve job on mine. If the spark is good, fuel won't be sucked into the combustion chamber with low compression.

 

[Anonymous]

Definately not an electrical fault because 1 and 4 are getting a spark.

Just for completeness sake, swap over the coils and see if the problem goes to 2 & 3. Just eliminate it for completness sake.

Well thats odd... if it's ... 'definitely not electrical'... why do you say to swap the coils ?
You're talking out both sides... (but then you ARE a mad hatter eh?)

annnnd... if you've been on enough of these boards... you will learn NOT to trust many of the statements the asker makes... (like the spark being good on 1 and 4)

YES... 'for completeness SAKE' .... check the coils/swap the coils.

 

[Anonymous]

I found the problem.......
the fuel shut off was stuck in off position we put carb cleaner in the fuel line and using air we worked them loose reassembled the carbs and put them back on. The bike started right up sounded SWEET! wanted to road test it and a buddy gave me his plate off a '48 H-D panhead ......felt good to get some wind again after 15 years
Rat