Carb slide spring ???

[Bill Hilly]

I have a TBR7 with aftermarket exhaust ,and pod filter. I am running the stock carb with a 115 main, and what I assume is stock 36 pilot. I have the needle shimmed just a hair. The bike runs great, and has good power for what it is, but I do sometimes get a hiccup when I just let go of the throttle after running wide open . I can quickly roll off it, and get no hiccup. It doesnt seem rich, and takes throttle great. The slide spring in this carb is WAY stronger in this carb than what was on my Brozz. It's a handful to compress to remove the cable,and the Brozz was a breeze. I was wondering if I could either replace the spring, or cut a little from the stock one on the TBR7, and possibly reduce the hiccup ??

[Thumper]

I am not sure what you are concerned about. Throttle off "performance"? Throttle off quietness?

Personally, I would concentrate on throttle-on characteristics and transient changes like shifting. Maybe you can find a weak spring and swap it out before you try the spring-ectomy!

[Megadan]

If you get a hiccup rolling off from WOT then you are likely hitting the transition at 3/4 throttle where it goes back to the needle and either seeing a brief moment of a rich or lean spike. The spring won't cause a hiccup itself. It's just a spring. If you are positive your main jet fueling is good then experiement with that needle shim. Take it out and see if it goes away - if so then it was a slightly rich condition. If it gets worse then you know it was a lean issue. If it happens just off of Wide open but before the 3/4 throttle point then it may be your main jet fueling is just ever so slightly off and you are experiencing a momentary surge.