Riding style- Clutch slipper vs clutch drop

8secBusa

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When i was at the track Saturday.I read how most fast guys target getting the clutch out quick vs slipping it with higher rpm. Prior to satuday, with a 16/42 gearing and no TRE, I left the line at 8000 riding the clutch. When I tried getting the clutch out quick at lower rpm, the motor bogged. Saturday I changed to 16/45 and added a TRE, I focused on dropping the clutch. I was amazed at how the combo allowed me to get off the clutch almost instantly. The thing Rpm'S SO fast, I almost couldn"t shift fast enough. This did result in my best ET ever.

Funny thing, I was getting low 1.5 60ft times, with this new technique my 60's dropped to high 1.5's. But my 330 times improved dramatically. Everthing got better, MPH, ET..
 
You might get more input by posting in the racing--1/4mile forum rather than busa problems forum.
 
Front tire clearing the 60'lights triping it with the rear...maybe?
 
Humm,
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You have to take time at the track and try different things to find what works best for you. I find stock in the front and 6 up in the rear works good for 7000 rpm launches and 1.4 60ft for me. The length of your wheel base, height, and rpm depend on you. Dont be scared to try different gearing and rpms launching. I want to be out the clutch 20ft past the tree, but my bike is long and ables me to do so. Air shifter and shift light really helps. You can focus on the track and not on your tack.
 
When i was at the track Saturday.I read how most fast guys target getting the clutch out quick vs slipping it with higher rpm. Prior to satuday, with a 16/42 gearing and no TRE, I left the line at 8000 riding the clutch. When I tried getting the clutch out quick at lower rpm, the motor bogged. Saturday I changed to 16/45 and added a TRE, I focused on dropping the clutch. I was amazed at how the combo allowed me to get off the clutch almost instantly. The thing Rpm'S SO fast, I almost couldn"t shift fast enough. This did result in my best ET ever.

Funny thing, I was getting low 1.5 60ft times, with this new technique my 60's dropped to high 1.5's. But my 330 times improved dramatically. Everthing got better, MPH, ET..
A few questions since I'm running 16/43 ... I hope you don't mind.

1 - Are you totally just dumping the clutch at launch now?

2 - At what rpm are you leaving with the 16/45 gearing?

3 - At what rpm were you shifting at with the 16/42?

4 - At what rpm are you shifting at with the 16/45?

5 - What was your best 1/8th time with each gearing?

Thanks ...
 
Don't mind at all. Trust me, I was amazed at how much harder it built speed when I started letting the clutch go early.
1) I don't dump the clutch, but I would say I transition it out within 10feet, a slow 1 count.
2)I leave at 5200-5300
3)I always shift at 10500, I tried shifting at 10,10.2,10.75,11,000, 10500 netting the best et& mph
4) With 16/42 best 1/8mile was 6.15-6.20, now with 16/45 it averages in the 6.05-6.10 range.
 
Kool. Thanks.

I noticed I do 2 things different from you.

I leave at around 2500rpm & I shift at 11,000rpm.

I'll try the earlier shift first and then slowly work my way up to the 5000+ launches.
 
3)I always shift at 10500, I tried shifting at 10,10.2,10.75,11,000, 10500 netting the best et& mph
Just wondering....Based on factory tach, autoshift, or shift light?

The factory tachs usually have an error. As shift lift will typically be accurate but may have some human delay. An auto shift usually takes out the human delay element.

I played with my shift light and would end up setting it at 10,200 for the best et/mph. I was foot shifting so the shift was likely closer to 10.4-10.5. When I went to an autoshift I'm shifting at 10,400.

You results look about the same as mine"¦. Just confirming how you are getting there.
 
I am shifting off the factory tach w/an air shifter which seems instantanious. My dyno guy said that the factory tachs are usually lazy. How much difference is your shift lift vs your fac tach at a given rpm?

My dyno sheet shows peak HP at 10100, so over shifting at 10.5 seems right, but not if the tach is way off.
 
8SecBusa - Can you post some of the main details of your bike for reference.

thanks

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just reading this interesting post and thought all you guys would have some good insight for my curent delimma right now i am running 15/43 sprockets and cant decide to go with 16 or 17 but the 15 i think really needs to go. any pros or cons of either or both (16 or 17) would be great. i am right now getting engine work done adding about 25hp and im afraid going from 15 to 17 the extra hp is going to be disappointing. thanks in advance for all your input.
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i think if i go with the 16 ill still be in 4th at the lights. PROFESSOR if you read this i know you will have answer. i think 16 will give me better 1/4 time and mph if im still in 4th right?
 
Bquin, details:
07 Busa
Lower links, strap down in the front, 4-6" over extentions
Orient Express Pipe, PC, TRE, Small air box mod, cheap spacer clutch mod,16/45 gearing, MCR tire
 
i think if i go with the 16 ill still be in 4th at the lights. PROFESSOR if you read this i know you will have answer. i think 16 will give me better 1/4 time and mph if im still in 4th right?
I usually run a 16/42 but tried a 16/43. It worked for my but would bring my rpm high enough to make the 4-5 shift on my autoshifter. (I'm crossing in the 139-140 range) Obviously I don't want to shift right at the lights, the 16/42 worked better for me. I now have a way to block out the bike from shifting to the higher gears but have not tested it yet.

The 15 vs 16 vs 17 issue is the load on the chain. The load the sprocket puts on the chain is going to e distributed a bit further with the more teeth you have. Compared to a 16/42, a 17/45 or 18/47 is going to be almost identical. (within 100-150 rpm @ 140mph)
Most do not go this route because it will take a longer chain. They usually start out making the change to a stock bike and stay with a stock length chain. I personally would not want to spin a 47 or 48 sprockets on my bike because of the weight and looks.

I think the bike makes plenty of power not to need to aggressive of gearing in the first 330 foot. But a lot of that is going to depend on riding style. I think you are going the right way in getting away from the 15t sprocket. You'll just have to do some testing to see how it works.


I'm making changes to my bike over the winter that might make me change my gearing. I hope to be seeing another 4-5mph at the end. No telling what I will end up with.
 
Bquin, details:
07 Busa
Lower links, strap down in the front, 4-6" over extentions
Orient Express Pipe, PC, TRE, Small air box mod, cheap spacer clutch mod,16/45 gearing, MCR tire
How do you like the MCR compared to the shinko? What psi do you run it at? Last year I ran a shinko @9-15 psi,giving me a best 60' of 1.52. Our launches are almost the same to the letter. I haven't been able to hit a track yet because of weather. The only difference is I ran a 16/46, which would hit the limiter just as I entered the traps in 3rd, so a 45/44 is on my list. I also have a line on getting the MCR for under a $100.00 each.
 
professor, whats wrong with the looks of a 48t sprocket! haha I run 16/48 gearing, but also have 7 inch slick with wheelie bar. this winter i put a 2 step on it>so i'm not real sure where i will launch at now. I'm hoping to dump the clutch around 7000. how does that sound? I also have my auto shifter set at 10400 and i run through the traps at the end of fifth gear. Then when i spray the 100 shot i use about half of sixth. At least that is the way it was at the end of last season!

talk to you later
 
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