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Lock Out/Lock-Up Tuning


SlowerThanYou

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I s there traction compounds on the track when you race? What kind of spring set up would you use on tracks without any traction compounds?

 

In general, more traction - more weight Less traction- less weight.

Assuming all other variables stay the same.

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Brian, from your experiance whats the most important tips to setting initial/static- weight/pressure. Also for the guys trying to grasp this, is it better to start light on the base pressure and move up to achive the proper initial hit or start heavy and drop the pressure. (im assuming starting light will be a fast death of a clutch for most average tuners).

 

 

Im hoping this thread will take off..

 

Chris

WheelmanChassis

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I s there traction compounds on the track when you race? What kind of spring set up would you use on tracks without any traction compounds?

 

Yes, all our tracks use some type of traction compound; some better than other's. I guess they are better than your track, sorry. You would have to be on the lighter side with your base pressure. The clutch is not going to totally fix your problem. You need to look at something different.

 

I've never done these items, but have seen many successful racer's use these techniques. Jr, dragsters will roller coat their tires with VHT traction compond. They cover their tires with saran wrap then remove it near the starting line. That alllows them to get close to the starting line without picking up everything in the pits.

 

The second one is to put the VHT into a small squirt bottle. Street racer's use this technique. Squirt a little VHT in front of both tires & do a small burnout/spin in the compound. Then roll to the line. I'm pretty sure you would have to cut down the VHT with methanol. If the track will allow it, this would be the method I would use.

Can you use three different wieghts on the arms ? In a way like clutch timers

 

I'm assuming, you are talking about splitting the 6 arms into pairs of 2. Then add equal amounts of weight opposite of each other.

 

I know people that have done that, but it's not what I prefer to do on my current set-up.

Brian, from your experiance whats the most important tips to setting initial/static- weight/pressure. Also for the guys trying to grasp this, is it better to start light on the base pressure and move up to achive the proper initial hit or start heavy and drop the pressure. (im assuming starting light will be a fast death of a clutch for most average tuners).

 

 

Im hoping this thread will take off..

 

Chris

WheelmanChassis

 

We try & keep the initial/static /base weight as evenly distributed as possible on the clutch pack. Plus, we like the ability to make small pressure adjustments with that weight.

 

If I was to start all over, learning what I have learned. I would start on the heavier side on the base pressure & also on the arm pressure. To prevent the fast death of the clutch as you put it.

 

Now, for my current method of clutch tuning. We have a general window we like to set-up for. Our main goal is not to bog down the motor. A bog is much worse than excessive wheel spin when it come to affecting ET.

Professor,

On asphalt, what distance (how many feet) out are we trying to get the clutch to lock up? How do I know if I have too much weight on the arms?

Thanks

 

Professor, LOL! I have a hard time educating myself sometimes. Luckily, I have another clutch fanatic (Tedder), that we have both learned this stuff together.

 

On your 1st question. It's going to vary on many different factors. Here's a generic answer between 20'-50'. I'm open to more discussion on this later. We know approximately where we want it to lock up on asphalt & still learning on 300' with our set-up. Tuning without 60' timer it would help using a data logging system & is a benifit even with the timer. The bottom line is, your 60' will tell you if you are going in the right or wrong direction.

 

2nd question. I have to address at a later time.

When refrencing light base pressure are we talking 6 stock spings? Or what % lighter than stock?10-20% or more?when you run dfferent pressure springs 3,3 how do you calculate the pressure?

 

I'm going to refer you to post #4 of this thread. We measure each spring & add them together to get the total base pressure. I'm pretty sure I also covered that the spring has to be measured at the installed height. The picture I posted, was not at our installed height & was for reference only.

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  • 2 weeks later...

Ok heres my question. I have a 10 mill cub making roughly 120hp on gas. Now I said roughly so that means just that. I cant seem to get a 7 plate to hold in it. So I went with an 8 plate. Any suggestions on where to start with springs and weight.

 

I use a dd lock up with heavy weight. I run 500ft dirt.

 

I'm going to stress a few basic key areas. This applies to anyone that's tuning a clutch/lock-up.

 

Maybe, I'm not explaining somethings right. You need to know your springs installed height. Need the springs pressure at that installed height times 6 if you are running six springs. Finally, you need to measure the arm weights with a scale (we use grams).

This is a baseline you can make adjustments too without chasing your tail. There are others factors that come into play also, but these are the basic key areas.

 

All my quad stuff is headed for Gilbert, LA. When it returns, I will show how to measure the installed height of the springs.

 

Brad,

It would help if you had the above information. With the information you gave me above. I'm assumming you have not run the 8 plate set-up yet. With everything being equal between the 7 & 8 set-up. You have more holding/clutch than the 7 plate. As a minimum I need the actual weight on the arms in grams & where the clutch is slipping/not holding.

Edited by SlowerThanYou
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[/quote

I am trying to decide between using a 1-4 m5 m6 or a 1-5 override. When the clutch is locked up is it difficult shifting into 5th and 6th manually?

Thx

 

IMO the 1-4 manual 5 & 6 is the most reliable & forgiving transmission you can run. As for shifting 5 & 6 we use a shift kill. It still allows for full throttle clutchless shifts.

Edited by SlowerThanYou
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for all out racing.. anyone ever try running a slider instead of a lock up. no clutch handle. have to be towed back to line or burp the throttle back to the line or pits.. i mostly run lockups with a air clutch.. just curioes if and dragracers or dunners have tried a slider.. steve

 

A few people have tried the slider on a 2 stroke ATV without much success. That's not saying they will not work. I would probably try one under the right conditions.

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what is this slider you speak of?

A slider is a centrifical style clutch used in a very good amount of drag racing motorcycles. It uses engine rpm to to apply the clutch using weighted arms much like a standard lockup, only differance being a std lockup is hub driven. A slider is more applicable and benificial in a situation when traction is very consistant like asphalt.

 

my .02

 

chris

WheelmanChassis

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Chris,

 

It's been a while since you commented. I know the subject has strayed a couple times. Maybe you could get us back on track or provide some input?

 

Bryan

 

Ok, so after you get the base weight measured and a baseline arm weight put on to start, all things recorded in my racers log its time to go to the track. I say its best to start with the same setup/tune up that you normally run as a baseline with the only differance being the clutch, this will give a better idea of what the changes have done to your times.

 

So, I roll into the beams, reach my desired launch rpm the lights come down , I dump the clutch and bbbboooooooooggggg!!!

 

Now assuming my gearing is right for speed/rpm in high gear at the end of the track, and my launch rpm stays consistant. Whats the next change these guys trying this should make?

 

IMO, I would reduce the amount of base weight on the clutch resaulting in more "slip" for the initial hit. OR If I belived the bike was very close to making a clean launch, I would raise the launch rpm at the line. Now with all this being said, If the bike did launch it would most likely suffer from excessive tire spin needing further clutch adjustments.

 

Bryan from your exp. what would the proper adjustments be, and how do the people reading go about these changes, and in what increments do they do them in for best results.

 

 

Chris

Wheelman Chassis

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