300/440/550 650 sx carb problems

[addicted]

Need some help. I finally got my ski together and started. Problem is that I can't get it to idle on the hose. It's a stock 1990 650sx with the only mod being a 44sbn and a westcoast intake manifold. Stock pipe and compression.

I searched and searched for jetting, and there was little consistency in the threads. Some say 120/220 others 110/125, ect ect. I have it at 120p 190m.

I tried 12 on the popoff and it was dribbling. Tried 17 on the pop and it stopped dribbling, but here's the thing, It isn't consistent. It will sputter and die, or rev to the moon almost like an air leak. The engine is sealed, but there is a good amount of slop in the throttle shaft. Could that be my trouble? Am I way off on the jetting? I am at 650 feet and the temp is around 70. It won't hold an idle unless I play with the throttle no matter what I do. It is getting fuel and spark and compression is good.

Any ideas?:hail: :hail: :hail:

 

[Crab]

Mine has a sloppy shaft also and did the run away if set the idle too high. There must be an air leak at the throttle shaft. mine runs a 170 main.

 

[addicted]

Is yours modded? I know group k says that the 650's need a humungus main jet to stop seizures. I think I'm super rich since i have a big carb and a stock motor.

Is the throttle shaft rebuildable, or should I get a different carb?

Thanks!

 

[Crab]

B pipe, carb, the plugs burn clean at 1 turn on the main, or I can get them dark at 1.5 turns. I don't think its ported, but never had it apart to check, it screams with this setup.

 

[john zigler]

you need to fix your loose throttle shaft. that is an air leak if it is loose. you can get shaft repair lits. i may even have one here for a SBN 44.

zig

 

[addicted]

Let me know Zig.

 

[john zigler]

Let me know Zig.

OK, sorry, i only have one here for a 46mm. no 44's in stock.

the kit includes new shaft, throttle plate, screws, new bushings, and seals. retail is about 30.00

again, i would get this fixed before you try to do any tunning.

good luck.

zig

 

[addicted]

No big deal. I actually think I may be getting another carb alltogether. My buddy has a tigerpoop that he is planning on parting out, and I'm pretty sure it has a 44sbn on it. I think the jetting might be pretty close too because it's a 650 as well.:dunno:

 

[addicted]

Well, I got the carb off the tigerpoop. That engine looks ALLOT like the kawi motor. . .

Anyway, after a rebuild, primer install and sanding the tigershark logo off the top of the flame arrestor:cool2: , the thing purrs:Banane01: :Banane01: :Banane01: at least on the hose.

It is jetted much differently than most of the recommendations that I have found for a 44 on the 650. It has a 112.5 pilot, 107.5 main, and popoff is about 33. I have not run it in the water yet, but maybe next week. It was snowing here again:banghead:

I am looking into what stock jetting is on the shark, because the specs on the engines are nearly identical. It would be cool if it was just drop in and go. We'll see.

Anyway, there will be a 44 sbn for sale soon with a leaky throttle shaft and a k&N f/a. If anyone is interested, let me know.

 

[Cliff]

my 650 sx runs on a 120 and 140. much more rich than your set up. my ski has westcoast intake, pipe, ex. manifold and sbn 44. also bored .025 over. humidity is terrible here in the summer.my carb came new with a 100 and 125 and it would try to run away from me on the trailer. maybe you can try this if your set up dont work for you.