S&S Single Bore Tuned Intake tuning

[ERICDOG]

I know there are alot of these installed out there and have a question on tuning. I installed this and the xxx power booster (purple) at the same time. Running 74/31 in the super G. Feels great around town - plenty of torque. However, when I get to highway speeds it bogs when I get on the throttle in the higher gears. This happens anywhere from 60 and up. The bowl vent screw has been removed... Help...

 

[mcgroom]

It sounds like you need to up the primary jet.....try a .079.

In the S&S Carb Manual, it speaks of stumbling at greater speeds....50-70mph when the primary jet is to small. This is the range when it kicks in.

A lot of guys are running .079/.029

If you have the low end, leave the .031 and see what happens.

 

[mcgroom]

http://www.bigdogbiker.com/forums/how/4943-how-adjust-your-carb-check-jetting.html

Here is a good starting point.

Have had the same problem when I first came on here.

Make sure that you adjust every time you rejet. Both before start-up and after running your bike for a good 15-20mins of normal operation....it will change from the initial setting.

 

[lee]

yeah you're main jet seems to small - I would probably increase one size at a time - also get your accelerator pump screw 1 1/2 to 2 turns out - this is what gives it a burst of fuel when opening the throttle quickly

 

[ERICDOG]

Thanks mcgroom! Will up my primary jet next week. Appreciate the help!

Lee - with the current jets, I backed off on my accelerator pump about a quarter turn each time ending up at about a full turn off when she started sneezing pretty bad at speed. It was begining to perk up until then. We'll see how the new primary works next. Thanks!

 

[mcgroom]

Eric,

When you roll the throttle back, does it stumble?

If it does, turn the accel. screw all the way in just until it seats, do not torque down, then back it out 1.5 turns.

Then with your bike running, check to make sure you get the responsiveness you are looking for when rolling the throttle back. Back the accel screw out 1/4 turn until your bike responds the way you would like it to.

Hopefully this helps a bit.

 

[Gas Man]

What pipes you got?

I agree, go up on the primary jet... super easy to change... I think you can get to it from even just the bowl plug.

 

[ERICDOG]

Got the V&H BRs on there right now and considering the V&H 2 into 1 radiuses. Love the look of the S&S tuned intake and intown throttle response, and if the larger main corrects the highway response, I will be extremely satisfied.. Thanks!

 

[V]

What pipes you got?

I agree, go up on the primary jet... super easy to change... I think you can get to it from even just the bowl plug.

Gas is right you can get to the main jet from the bowl drain plug. The jet kit from Big Dog for the Big Radius and Mean mothers is a 31 and 78 I believe. Its not worth buying from them but it gives you the reference of what the dealer should do when installing pipes.

V

 

[Gas Man]

I always suggest everybody just quit fuckin around... buy the damn high range jet kit for the super G and be done with it. That way you have what you need.... its only like $45

 

[lee]

I always suggest everybody just quit fuckin around... buy the damn high range jet kit for the super G and be done with it. That way you have what you need.... its only like $45

totally agree - unless you can guess exactly what jet you need, which you can't, there is no other way to do it

 

[Chopper Dave]

I always suggest everybody just quit fuckin around... buy the damn high range jet kit for the super G and be done with it. That way you have what you need.... its only like $45

yep......I bought the high range jet kit for the super G
here is what it looks like......

 

[stlmikie]

ihave a pal that has just the opposite problem. In 1st and 2nd gear if you nail the throtle it stumbles on its face but higher in the gears it dosn't do it. What do yous guys think it may be?