I just rode home a 89 Springer that's been chopped. The engine is original but been hopped up with new pistons, cams and some other things. Riding home on the fwy, when I came to a hill and openned it up a little for the climb, the bike started to "stutter". Then, the engine cut down to almost idle speed. I released the throttle and as I drifted over to the slow lane it engine came back to full power, then no problems. It felt like it was either flooding or not getting enough gas. When this happen, I was in a moderate wind hitting me from the right side. It has a S&S carb and a velosity-like stack air screen, which I've heard don't work well except for show or drag - could that possibly be my problem? I don't have any more details 'cause like I said it's been heavily modified and I don't know what is all there yet. The engine work was done at a reputable shop. Thanks for any imput.

(Now that I think about it, I had a Buell once that would act like it was going to die whenever riding through a strong wind hitting the carb side of the bike. I went up to a 42mm flatside and the problem went away).

 

hey bro ,

I dont know if this might help you, i had the same problem after $150.00 by mechanic he couldn't figure it out . He told me it was a short , so after trying for about a month i pulled spark plugs thats what it was a faulty spark plug , now it runs great no sputtering try to turn off so give that a try before you start spending more money.

 

Open the plug at the bottom of the carb See if any water finds its way out At high speed any water in the float area could block the high speed jet

 

Velocity-like stack air screen? Your pant leg wasn't getting sucked into the velocity stack, was it?

 

Thanks for the info. I checked the plugs and they have a milk chocolate color on em- I'll switch them tomorrow.
For the plug at the bottom of the carb, is that the only screw at the bottom of the bowl - will it be self evident on this S&S?
I thought about my pant blocking the velocity stack but that's not the case (plus there's a screen on it).
The problem definately happens under load. At higher rpms in 1st, 2nd, and 3rd the bike will spudder a little on the straights but when I'm in 4th, going freeway speed and start to go up a hill, if I give it more gas it feels like it will die. The bike climbs but it maxs out at @ 1/4 throttle openning - any more and it will cut out (or at least cut down). Do electrical or ignition issues cause these symptoms or does it really sound like a carb problem?
Thanks again

 

Ya know, what you are describing sounds like the high speed (main jet) circuit of your carburetor is not working, like sqdealgeorge said. It might not be water but that circuit usually doesn't come into play until about 1/4 throttle.
Whatever it is, I hope you find it quick and it's a cheap fix.

 

Thanks. T've re-jetted OEM carbs - never S&S. Is it pretty straight forward? How can I tell which is the high speed jet?

 

i had a problem like that and it was a crack in the fuel line at my s&s . check it out .

 

Will do, thank you.

 

It sounds like a fuel supply problem. It could be the tank is not venting properly, or there is a kink in the fuel line, petcock not working properly, float level off, crap in the needle and seat, or main jet too small or clogged. We just had a similar problem with a custom tank, the painter sealed it and the sealer was coming off and wrapping around the filter screen on the petcock. Also check all of your electrical connections including the grounds.
Hope this helps.