Gearing Recommendations

[V8Pinto]

I'm running a stock 06' Busa in production class at El Mirage and later this year at Bonneville. Last run was 180mph (roughly 190 indicated) at about 10,500 rpms at about 90 degrees outside. I don't know if it'll pull that last 500 rpms or not.

Mods planned before Bonneville:
Short stacks (rubber)
Hogged out stock mufflers
BMC race filter
ram air seals
Gearing
Re-map (haven't decided on Teka or PC yet)

Any recommendations on gearing? I'll be running stock rubber. I am running a TRE also (homemade).

 

[thepushercg]

for top end your not going to get any more on a stock bike by changing the gears.
plenty you can do for the quarter mile runs. only thing you can do for the top end runs is more horsepower then gear changes. a cheap way to get the 195 plus is nos

the stock busa gearing is more than the bike can use now at 17/40

 

[coop65sr]

I agree with what Joseph said.... I've got 16/42 gearing and that definitely gives a lot more torque on the low end but takes a little off the top end...PCIIIusb and a custom dyno map are a good start...

How did you make your "home-made" TRE if I may ask??? I've been thinking about installing one but have the resources to make my own with some good guidance.....If you can help I'd appreciate it.....thanks, Chris

 

[V8Pinto]

I removed the pink wire from the harness connector and soldered a 6.8K resistor from that to the black wire. I can take some pics if you like but I found it by googling. It was essentially a free mod as I had a resistor laying around.

What rpm does the stock rev limiter kick in?

 

[Fairclough]

If your going to Bonneville you will need to soften up your gearing 18/37. I ran a GSX-R1000 in 04' with a built motor and i had close to stock gearing, once it got past 7000rpm all hell would break loose i thought the clutch was slipping, i was actually polishing my rear tire, John Noonan was tech at World of Speed that year and pointed out the tire spin issue. Bonneville is a humbling experience all i could muster was 168mph. Add lots of ballast, weight does not affect your top speed, just how long it takes to get there.

 

[V8Pinto]

Is the traction better or worse than at El Mirage? I've calculated about 15mph wheelspin at 180 (no ballast) at El Mirage.

I was considering a lead filled swingarm but am concerned about the handling difference and my inexperience under those conditions.

Did the gearing improve your traction? How about your rpm at the big end of the track?

Thanks for the tips. I'm all ears.

 

[AZIROC]

... extend your ECU/rev limter???

 

[Fairclough]

You want to put the weight under the rider if possible so the suspension acts like you are just a larger rider, and on the swingarm, when you extend your arm you take weight from the rear. One of the problems i had at Bonneville was trying to ride like i was at the drag strip, best advise i've been told is to get into sixth gear and modulate the throttle for traction.

 

[Fairclough]

The gearing will soften your acceleration (so you wont spin as bad) 18/37 are tall gears the busa wont pull this without a power adder, so don't expect to top out in sixth. The taller gearing is easier on the motor (your not pulling redline for 2 minutes) and you have a little cushion if you do spin the tire. Bonneville is pretty slick about 20% wheelspin. Hope this helps, and hope to see you out there.

 

[dadofthree]

I was planning on going 17/38 for a run at Maxton with a stock Busa. Sounds like I would be wasting my time.

 

[V8Pinto]

(Fairclough @ Jun. 30 2007,16:18) You want to put the weight under the rider if possible so the suspension acts like you are just a larger rider, and on the swingarm, when you extend your arm you take weight from the rear. One of the problems i had at Bonneville was trying to ride like i was at the drag strip, best advise i've been told is to get into sixth gear and modulate the throttle for traction.

The "Get into 6th and modulate the throttle for traction" was a real eye opener for me. I also am a drag racer by design and I had to re-learn everything to run land speed.

At 150 with a crazy spinning tire, the light finally went on in my head that "I need traction to go fast, not more throttle" and I backed off and went faster. <chuckle>

 

[Fairclough]

Yeh i know, i would pull up and Monte would give me the wave and i would blast off down the course like i was e.t. racing at the track. People think you just go out there with a fast and powerful bike and just hold the throttle to the stop, i just wish it were that easy. If you come out this year, i'll be there Sept 12th thru 15th, Look me up.

 

[NearDeath]

yup, need more power for more gearing...