Launching

[FloydV]

Take off with your foot on the shifter side or reverse, your shift pattern.

I was thinking about taking off with the left foot on the peg, but was not sure if it would affect my ability to launch straight. I hadn't thought about reversing the shifter. Will the stock parts flip ? No the next question. Will habit come into play with my downshifting? Heck, I’m a newbie at all of this and throwing something else for my nimble mind to have to remember going down the track may be an issue.

I have two bigger issues than getting my foot up. Mainly my 60’ times suck. I’m not rolling the throttle on quick enough on the start. The second is my reaction time. I ran two classes, one was on a pro tree and the other was a full tree. My reaction times were not good but running on a different tree each round didn’t help my learning curve any. I really hope to get it where I can run the 9.90 class. I ran two classes for the seat time. No doubt I need it. The bike is capable but I’m not sure I am. I need way more seat time than I may have time for. They are running a 6 race series (5 in OK, 1 in KS) I hope to run all 6.  

I first ran it last fall. Lowered 1â€, with pipe, Pilot Power rear, 17/40, I went 15.55 @ 138 with 1.835 60’ (however most were in the 1.94-2.06 range. Never drag raced a bike before so I was happy.  Went out this time lowered 2.25 rear, front lowered 1†but strapped and pulled down another 1-1 ¼â€ or so, 16/40, MT rear @ 20lbs, shift light, rear shock rebound @ 0 clicks. Best runs were in the 10.20s  (10.24 10.28 10.26) with 60s in the 1.83-1.86 range. I think the biggest thing is the fear of looping it out on the start. I’m launching about 6500, slipping the clutch. I’m not rolling on full throttle to about 40’ or so. I truly believe there is easily 2 tenths in the 60’. I ran another busa in eliminations and his 60’ was 1.68 so I know it is me.

Your fear of looping is ligitimate. There was a video of a guy at a strip in the background while someone else was being filmed. All of a sudden when he took off, the bike went straight up in the air and fell back and to the left.

I asked him what happened, and he said that the rear wheel had been spinning all night, and that time it caught. The whole thing went down in a second.

 

[Revolution]

bump

 

[Professor]

I hope to have an update on my progress after the Sept 23rd PMRA. I was hoping to loose 20#s before then but it ain't gonna happen.

 

[NightCrawler]

I know this is an old thread but I know some of the members who posted are still around.

I run at my local 1/8th track and can't get anywhere NEAR what you guys are running. I have the Brock Hindle and a power commander ... nothing else. With that setup I ran a best of:
60ft = 2.030
1/8th = 6.888 @115mph

I thought maybe I was afraid it'll wheelie and decided to drop it 3 inches. I went out there tonight and ran a best of:
60ft = 1.993
1/8th = 7.055 @114mph

The reason I became slower is I'm not doing burnouts so my rear tire constantly breaks traction. I don't do burnouts for 2 reasons. 1) Tires are expensive as *you know what*

and 2) I don't know how to come out of it. I've been told to grab the front brake, rev up to about 7000 rpm, and dump the clutch. The thing is I was never told how to stop the burnout. I don't want to experiment at the track and risk dumping my bike, so I simply choose to not do it.

Another reason I seem to be so far behind you guys is because I leave at idle. I tried to launch at 4000rpm but stalled at the tree.

Any advice you guys can give me I'd really appreciate. Next time I hit the track I'll see what the 20psi in the rear will do for me.

Oh ... and as for the lowering, I have Soupy's links in the rear and I strap the front.

Thanks ...

 

[Professor]

You really need to do a burnout to clean the tire and build a small amount of heat in it. Not an excessive burnout, just 2-3 seconds will make quite a bit of difference. You need the tire to stick on the launch. If you start spinning off the line, it could start kicking out and get a little dangerous.

Burnout, apply the front brake, bring it up to about 3000 rpm and slowly release the clutch until it start spinning as you start loading the engine you will need to increase the throttle. Once it starts spinning you can slowly release the clutch. Just pull in the clutch to stop it as you close the throttle. Don’t worry about rolling burnouts. They look cool but can get you into trouble.

Once you are comfortable there, start working on your launches a bit harder. 3000-3500 RPM and release the clutch and roll the throttle at the same time. The trick is to not just throw away the clutch. Release it progressively with the throttle roll over about a 3 second period of time. At the 60’ you still will not have the clutch all the way out.

Once you are comfortable with the technique and how the bike is reacting, then shorten the 3 second time frame just a bit with each pass. You can also raise your starting RPM a couple hundred rpms as well.

Some guys are much better at it than I am. Looking at my logs, it is taking me 1.75 to 2.50 seconds to reach full throttle. The 1.5 -1.75 usually results in wheelies and me having to roll out of the throttle (and sometime the front wheel in the air past the 1/8)

Here you can see a data log of one of my runs. I was launching it at a bit higher rpm than normal. You can see the Throttle on the Blue trace. See how the rpm (black trace) initially comes up and then start going down as I am releasing the clutch. You can see I’m about ½ throttle initially and releasing the clutch. I’m pausing a bit as the front tire is leveling out but still releasing the clutch slowly. ( it also looks lie I let off the throttle a bit as it was coming up) Then as the clutch is almost out I’m rolling the throttle. For reference the red trace is the gear 1 volt 1st gear 2 volt 2nd and so on. It looks like I ran this one about 1 second past the 1/4 to the 5th gear shift.

Study the RPM and the Throttle and you can kind of tell what is going on with the clutch. I wish I had an analog sensor to use on the clutch.

 

[NightCrawler]

Thanks! That's WAY more info than I was expecting!

I'm going to try to go back on Wednesday and giving it another shot. Since I didn't want to do a burnout, I thought about dropping my tire pressure but didn't. I chose not to because I rode my bike there and had I taken too much out, I wouldn't have had a way of putting any back in. Also there was no way for me to measure exactly what my tire pressure was.

When I go back I'll do both.

Thanks again for the advice.

 

[Professor]

I have ridden mine to the track a few times. I carry a tire pressure gauge and drop it to 20lbs. After racing I look for someone in an enclosed trailer that has an air tank or compressor. They have always been more than willing to let me have some air. As a backup, there is a station a mile or so from the track to get air on the way home.

 

[reconscout]

If it were my bike I would not strap it down so much.You said you strapped it down 1 1/4''to 1 1/2'';maybe thats abit too harsh for launching.
You need some suspension up front it actually helps with transfer and with control launching;it will transfer the power smoother and not so abrupt as to break the rear tire loose or chattering effect.I would only strap it down 3/4 of an inch and maybe just a 1/2inch being that you have the 1 1/4 riser too.
On the rear with your weight I would turn the rear springload 2 more revolutions from the stock setting so that its not creating too much dead squattingbottoming it out with your weight.Set the comp and rebound the same as you have been
Other than that just feather the clutch and ride that wheelie out QUICK shift to keep moving forward carring momentum threw the wheelie, get low in the saddle leaned forward with your throttle arm pulling downward all the way down the track .I think you have the time in your grasp without any new mods.Key in on your suspension for you and the most air without tire spin.
Wish you luck.

 

[dadofthree]

What are you running now Professor

 

[Professor]

(reconscout @ May 27 2007,23:23) Other than that just feather the clutch and ride that wheelie out QUICK shift to keep moving forward carring momentum threw the wheelie,

Hmmm.... I think I'll try this. I'll had to do a bit of rewiring to make both my button and autoshift work at the same time but it sounds like a goo idea.

 

[frisbee]

Took mine to the track last Friday . Launching isn't easy , I only got a few runs in but my 60' was consistant 2.00

. I got to let go of the clutch faster .

 

[Professor]

(dadofthree @ May 27 2007,23:43) What are you running now Professor

In the PMRA this month, I ran a 9.95 and backed it up with a 9.98 @ 139.88 in qualifying. The rest of the good qualifying passes were in the low 10.02-10.05. I dialed in a 10.02 and was running right on that path until the tire started giving up and had to bump it to 10.10 in the finals.

 

[NightCrawler]

(frisbee @ May 28 2007,01:04) Took mine to the track last Friday . Launching isn't easy , I only got a few runs in but my 60' was consistant 2.00  

. I got to let go of the clutch faster .

Trust me, I feel your pain.

 

[Professor]

(frisbee @ May 28 2007,00:04) Took mine to the track last Friday . Launching isn't easy , I only got a few runs in but my 60' was consistant 2.00  

. I got to let go of the clutch faster .

Work your way up to it.... at your own speed. I am usually in the mid 1.6s I have had low 1.6s and a high 1.5. But I am not as comfortable there with my stock swingarm. I just wish I had the time to go to the track more often to test and tune.

 

[NightCrawler]

Hey professor, do you remember what rpm you were at during the launch in your avatar?

 

[Professor]

(NightCrawler @ May 28 2007,01:17) Hey professor, do you remember what rpm you were at during the launch in your avatar?

I was launching around 5000 then.

 

[NightCrawler]

At 5,000 and it came up like that? Was that the peak of it or did it get higher than that?

I'm asking because wheeleing at the track is what I'm trying to avoid. A slight tire hover I can deal with ... but not much more than that.

 

[Professor]

(NightCrawler @ May 28 2007,01:35) At 5,000 and it came up like that? Was that the peak of it or did it get higher than that?

Maybe a bit higher, it sure felt like it.

The launch RPM was not a factor as much as the clutch control. You can look at the sequence of photos. That is 2nd photo after launch.

I've had a few higher in the top of 1st and in 2nd gear. They don't bother me as much now. However anthing much about 6-12 inches, slows it down. That is one of the reasons I lowered my launch RPM. I could run a bit better 60s, but I was less consistant. Consistancy is what wins races in bracket E/T classes.

I'd like to cut another tenth or 2 off of the time, but I'm no hurry. It should come with experience.

 

[bradsbusa]

 

[NightCrawler]

Hey, I took some of the advice from this thread to the track last night. I didn't run any break-neck times but I did notice I was much more consistant than before. I also broke my previous best time of 6.888 with a 6.884 and then broke that one on my very next pass with a 6.814. My very first pass was a 6.95.

I know I could have cracked 6.7xx but something always seemed to botch my runs. On one pass I hit the limiter in both 1st and 2nd gear and managed a 7.012. On another pass the bike jumped out of second gear and I managed a 7.191. On the 6.814 pass I noticed the bike slipped a bit in 2nd gear and then caught again. It never did that before and I'm not sure what the cause of it was. That was my final run so I wasn't able to see if it'll do it again. Yet still, I firmly believe had it not done that I would have run a 6.7xx which is one-tenth faster than my previous best. 1/10th doesn't sound like alot, but I think it is considering I'm running 1/8th and not a 1/4 mile.

I dropped my psi to 18. I thought about 20 but since I'm a lightweight I thought I'd need a bit more traction. Next time I go I'll try 25 and if I spin I'll drop it one psi each pass until the spin is gone.

Another thing I did different was launch with both feet on the ground as opposed to my left foot being on the peg on the ready for the first shift. I felt much more stable and that gave me that much more confidence.

Now as far as my times are concerned. My times still aren't up to the level of some of the guys here, but from one week to the next I improved DRAMATICALLY! Last week my average on a combined 6 passes was a 7.395. I didn't break 6 seconds on a single pass that day. This week my average on a combined 5 passes was a 6.967 and I crack 6 seconds in 3 out of 5 passes. I did that by changing only 3 things. 1) My tire pressure. 2) My lauching stance (2 feet down this week). And 3) ... well ... let's just say burnouts can be fun.

I'm stoked as to how much the advice here has helped me. Thanks fellas!