major problems launching and shifting on tarmac

[csrmel]

i run a strutted banshee with american racer tyres. the rest of the bike is pretty typical. 4mm crank, aggressive dune port cyls. cpi's, lightweight frame. struts instead of shocks. 16t front sprocket. bla bla bla.

i have a wheelie bar to keep the front end down since im using a stock swinger.

i have major problem launching. its like i have too much traction or something. i rev the piss out of the motor when the lights go yellow. when i launch, the motor just bogs down real bad when i let out the clutch. the motor literally bogs down to idle rpm's. i try to feather the clutch but that just makes me shoot off to the left or the right and almost crash. it only does this at the drag strip. the exact same setup launches like a mofo on the street. i can launch to freakin hard on the street that i bent my handlebars. i can beat the snot out of all kind of cars and bikes on the street. its just crazy how quick this thing is. so i think the problem is due to the increased traction of the drag strip. they spray sugar water or someting on the track to make it like flypaper. my feet stick to the track. the american racers are almost like gummy bears. by the way i tried increasing tyre pressure up to 20psi. i couldnt tell if it helped or not. but the bike launches so freakin hard that you have to actively work to hold onto the handlebars. it just bogs so bad though. this cant be right.

 

my motor runs good. real good. i have done plug shops and got it jetted really well. i dont think its a motor or chassis problem, although i could drop the rear end down about a foot more if you guys think that will help me launch. i could also drop the front sprocket. those are the areas where i think i am having problems with. my wheelie bar works great. but i launched so hard the last time i was at the strip that i broke the wheelie bar in half.

 

 

 

the other problem i have is shifting. for some reason on tarmac i have a really hard time shifting. i will miss 3 to 5 gear shifts during the 1/8th mile. this really kills my et. basically because of all the missed gear shifts and poor launching, im on par with 400ex's in the 1/8th mile. and i know this banshee should be destroying them. even a stock shee can take 400ex's in the 1/8th. so i have a major problem here.

the funny thing is that this doesnt happen when i drag or ride in the dirt. on the dirt i can nail those shifts perfectly each time without trouble. but as soon as i hit tarmac i miss shifts like you guys cant imagine.

 

the ONLY thing i can think of is the different boots i use for dirt and street. the thing is that my drag strip wont allow my dirt boots to be used on the strip so i cant test this idea.

 

im sure some of you have run into this problems before. wondering what yall think.

[625banshee]

Dont rev it at all until the lights come down, you might be getting your clutch to hot, and try adjusting your shifter up or down due to your shifting problems.

[SlowerThanYou]

On the dragstrip you need to slip the clutch. You can do it manually by slowly releasing the clutch lever, use an air clutch or use a lock-up/multi stage lock-up. On the street, the wheel speed from lack of traction allows your motor rpm to stay high and in the power band.

 

One other thing that will help you on the track. Have your seat cut with hump on the rear or have a bracket made to keep from sliding back on the seat. That will also help prevent you from pulling on the bars on way or another when slipping the clutch and shifting. I've been there and done it when I first started. We are starting our fourth year 1/4 mile asphalt drag racing. Bryan

[highroller355]

try to line up in the mddle of the groove , to the right or left of groove will make you launch that way and shoot you towards the wall or the other lane tire pressure will do th same so make sure there both dead on, also ride that clutch out ,even if you ride it out alot until you get use to it, ride it out the first few times like you dont have a wheelie bar, if you come out to hard the wheelie bar is there to help ,so no big deal. it takes alot of practice. its not just rev up and dump the clutch. hope this helps good luck

[dajogejr]

Mel...have you thought about a longer swingarm? Maybe you wont' have so much weight transfer to the rear tires....

16 tooth up front is gonna be tricky on a sticky track, these motors like to spin and keep the R's up.

You're getting so much traction, you will have to learn to slip the clutch out very slowly to keep the R's up.

 

PM tedder. He uses a dual stage clutch for pavement with very good luck...maybe he can help.

[375hp banshees]

ha,ha, I knew something was up when you said you put in a thicker base gasket... practice practice slip that clutch & hold on... how does that port job do when your riding in the slow trails w/ your niece (was it)

[csrmel]

i had thought of a longer swinger but i would like to try and use the stock one. theres no rules that i know of preventing me from using it, so id like to try and make it work. besides that, if i go to longer swinger i need new chain, new brake line, probably lose my sprocket skid plate too. its an option, but something i would rather save for a last ditch.

 

i did mess with clutch slipping, but that burns the crap out of the clutch so bad. i would be changing clutches once a month i think. perhaps that is the price of speed.

 

the dual stage idea sounds cool, but thats probably way expensive.

 

375, this bike rips on the trails. its missing a lot of bottom end power, but the top end is so explosive, the first time i rode it after breakin it in the power caused the handlebars to get ripped right out of my hands. i almost fell off. it was fun but scary. you should come to palm beach and ride sometime. at low rpm's its totally predictable. with my nephiew or neice on the seat i can tool around the yard all day and not have a problem as long as i keep the rpm's below the point at which the cpi's start working, its as predictable as a 300ex. the whole key it to keep the rpm's below the cpi's working rpm's and like i said its just a loud 300ex at that point.

Edited March 20, 2008 by csrmel

[dajogejr]

I don't know of anyone with a drag bike that TRULY drags with a stock swinger.

I think you're starting off on a bad foot right there due to weight transfer issues.

 

PM Tedder on here, he's a nice guy and will be more than happy to give you ideas and pricing on a dual stage clutch.

 

No offense, but we've given you ideas..

 

1. Slip the clutch more

2. Longer Swinger

3. Dual stage clutch...

 

But it seems like you're resistant to all of these ideas...I'm not sure what else to tell ya. I understand none of us are rich, and this sport costs money.

If that's the case...and spending a few bucks to do this right can't be done, I'd leave it alone and as is....and deal with it.

 

I'm sure a dual stage clutch might be a little pricey at first, but if you have to replace your clutch every month, sooner or later that will add up beyond the price of a two stage, I'd say probably within a few months.....

 

I don't see anywhere in your sig about a lockup or override....are these options not avaiable in your racing classes?

 

Without a lockup and override, in my opinion, a strong running banshee engine is worthless to drag race. I know you want to have a trail and drag bike, but the simple truth is you are going to have to make sacrifices for track AND trail if you're trying to do them both on the same bike....

[SlowerThanYou]

Attached photo is the multi-stage lock-up Tedder & I use for 1/4 mile drag racing. The initial cost is around $900 with machine work needed. The secondary cost to learn how to set it up is double the initial cost. It took us about 3 years years to some what master this system and many clutches. Would I do it again, you bet and I'm sure Tedder would agree. Bryan

 

 

http://i143.photobucket.com/albums/r143/BL.../Lock-up001.jpg

Edited March 23, 2008 by SlowerThanYou

[bigboybanshee]

You just have to practice slipping the clutch off the line when you're on asphalt. I did it with mine and had a clutch last me all year, using Jeff's clutch and a lock-up. When I shifted, I kept the throttle pinned and slipped the clutch as I shifted, stock transmission. Sounds like a lot of your problem is in the chassis though, there's no way you'll be able to manage drag racing on a stock swingarm. You need at least a 6 over swingarm, and you'll want to set it up so the swingarm is sitting parallel with the ground, and adjust it from there...same goes for your a-arms, when looking at the front you'll want the bottom arm to be straight across...it helps with weight transfer throughout the bike. Got a pic of your setup?