300/440/550 dual carb 650 goes bah,bah,bah =(

[Sidsol]

i can't for the life of me fiugure out my low and High on this damn thing.

when i had the low point to 1 1/2 turns out and the top screw 3 turns out it goes but starts to BAh.. then Bah ..then Bah like power strokes or something but seemed to run ok besides that.


I read on this site not to have turned out to much so I went half a turn low and 1 turn high ... and then the went into to high rev even with me of the throttle and the lanyard pulled. I had to put my palms over the throttle body to kill it. so i raised the high alittle more and now it gurgles and act inconsistent.

so before I do anything wrong what the hell is going on ,, almost tempted to put the tiny stock single carb back on and sell the dual on ebay i swear.

 

[Sidsol]

No one knows what is going on?

 

[550headache]

more then likely the dual carbs arnt jetted for your application. who did the jetting? what kind of carbs are they? what mm? the raceing of your motor sounds like a air leak to me. if it runs away and you cant stop it, it could be sucking air in somwhere else. which i would suspect crank seals. whens the last time they have been replaced? bad crank seals will also make ski run like and also make it impossible to tune carb or carbs! good luck!

 

[Sidsol]

sorry,, they are 38mm BN... these were used from some other 650sx so i have no clue on jetting. I suspect i have to rebuiuld the carbs or something which I do not know how . Almost tempted to pay someone ..lol

 

[Sidsol]

Also like to include that with the stock single carb it runs fine.... so not sure if its a crack seal... Could not having the pulse hoses clamped be the reason? its the only tubing i do not have clamped at the moment and just thought about it during me posting this....

 

[tor*p*do]

two 38s is a ton of air for a 650
so it is lean and that is why it is running away
I tried to put a 46 mm single Mik on a 650 and it would never run right
the airflow was too low through the big carb (or in your case 2 carbs)
to get good fuel metering through the range of throttle positions
I recommend a 44 mik as max for a 650, IMHO

 

[550headache]

i have a 550 with a sbn 46 on it. pjs used to run dual 38's on there 550's. there is a guy around who is running dual sbn44's on his 550.....dual 38's isnt too much air for a 650. just got to get it jetted in. somone has to know the jetting to get you close! dont even worry about the high jetting right now! just get the low dialed in, then worry about the high side. do you have extra jets? what size are in it now?

 

[2XLR8]

You have to run 1.5 or 2.0 max on the needle and seats with the stock springs. the mains should not be bigger than 1mm at 1 mm the highs should be less than 1 turn.

 

[Pro-pulsion]

The 42 Keihin carb, used on all Group K Hammer kits, offers better overall fuel mixing and throttle response than any large throat single carb we have tested. This 42mm carb bolts directly onto the stock '91-'93 650 intake manifold where it works in concert with the small intake runners of the Group K modified '91-'93 650 manifold to provide throttle response and acceleration that no 44 Mikuni and few dual carb setups will match. The single 42mm Keihin carb has no troublesome linkage, and it features easy "two screw" mixture tuning. Your stock '91-'93 intake manifold must be bored slightly to accommodate the larger 42mm carb throat diameter. (the early 28mm type manifold will not accommodate the 42mm carb)

http://www.groupk.com/k650.htm