Today the weather was just great for November, so i decided to install my new Mikuni HSR42, install went good , i did have to file the top barrel fin just a little, set the idle and AF mixture screw. Throttle response is impressive, even feels like it pulls harder, low speed cruising is smoother and engine revs up quicker. So here is my question, when cruising at around 35mph and i give it full throttle it will hesitate, i have read the tuning guide and frankly a little confused. What would you recommend to eliminate this hesitation? Do i move the c clip down to the 3rd notch or is it jetting or accelerator pump adjustment.

Motor specs are 88ci with S&S air cleaner, stock headers with SE slipons and a SE203 cam

Carb setup is 165 main, 50 AP pump, 20 pilot and needle clip on 2nd notch, this setup is what i have found on this forum from other members and went this route

THX for any and all assistance

 

Bump 1 for assistance

 

There was an article written by Joe Minton for the June 2008 issue of American Riders magazine. Google Joe Minton for all you want to know about Mikuni tuning.

 

Thx , read the article seems to be more for EVO motors, also my jetting seems to be in the norm

 

I'd try the accelerator pump adjustment first. If it doesn't help try moving the needle. Hard to tell if it's rich or lean from your description...could be either. If it's a lean hesitation, move the needle up (move c-clip down). If it gets worse you need to go the other way to lean it out.

 

Flat slide carbs like the HSR you have dont like it when the engine is lugged down. and you twist the throttle wide open without down shifting. The CV carb would only lift the slide as much as the engine needed, as opposed to the carb you have now which lifts as far as you twist the throttle. This can cause what feels like a bog.

I agree with previous poster. Tinker with the accelerator pump settings.

 

Im thinking the acc pump adjustment would an issue from a start like at a red light but your saying your cruising at 35mph. Im thinking needle adjustment so the safer option would be to go richer (clip down one) since this time of year the air is cooler and more dense. I have to assume with the jetting you mentioned, you might be just a hair lean.

 

The accelerator pump is in play EVERY time the throttle is twisted no matter what.

 

Thx guys, will try lowering the clip on the needle, anu other suggestions, bike does pull strong when I accelerate , only when I give it full throttle quickly does it bog

 

Probably the accelerator pump if that's the case.