Bonneville America Forums Forums Technical Forums Performance Mods Scrambler Help

Had my Scrambler about 2 weeks now and have about 500 miles on it. I've removed the AI, put a K&N Filter in and backed out the idle screws to 2 1/2 turns. A big difference and runs real strong but has some occasional hesitation when blipping the throttle from idle. Any recommendations?
Also, I have ordered the Thunderbike Scrambler mufflers and Norman Hyde Bellmouth. Can anyone help me with a staring point for jetting and set-up?
Would appreciate the input.

Finally got a chance to see a new blue & white Scrambler (and two new 675s) last weekend at Trebour Motorcycles in NJ. Great looking bike - congrats!

I think you haven't gotten any responses to your post since there is a ton of info posted and opinions on this site about what you can do to tune you Bonneville engine. Probably no one knows where to even begin in making a recommendation to you.

That said, you might want to start where I did - and where I bet everyone else does to... check out Pat's web site! It's got great carb info and it's a nice long detailed read about drinking, er, "tuning" theory. Click on www.Dinqua.com

Otherwise, seems like your already doing all the right things. Good Luck!

First, try backing out the idle mixture screws a bit at a time. I find it works best for me anyway, to adjust one side for best idle speed, then readjust the speed and go do the same for the other side. Readjust the speed again, then go back and repeat the process to get a bit finer adjustment.

Speaking of thunderbike, the one thing that will do the most to wake up the Scrambler engine is a set of cams. It looks like they use the same valve timing as the 900 Speedmaster engine, and that will diminish the effect of any other mods you make.

Hey Mark
Funny! I found the same thing with mine!

The demo bike didn't do it but my bike (AI removed, Triumph off road pipes) has the slight hesitation you mention.

Thanks for the pointers GB.

How do you find the TOR's on your Scrambler?
I have ordered the Thunderbike Mufflers.
I found the the TOR's on the Bonneville a little disappointing.

A slight hesitation on accel. is almost always a lean condition.

The times that this isn't the cause, it's because the ignition timing isn't advanced enough.

REVIEW: Hesitation can be cause by either/or leaness in carbs/retarded spark timing.