Lock Out/Lock-Up Tuning

[sleeper06]

And IMO you won't figure out final gearing till your 60' is consistent

[SlowerThanYou]

Same would apply to gearing changes correct? Like changing from a 17t to an 18t counter. You would want more base pressure right? If you had to guess how much more pressure would you need?

 

Here's an example of a change we regularly do when converting from 1/4 mile to 300'. This is a drastic gear ratio change of roughly .40. We change the base pressure around 50 lbs. This is not all do to the gear ratio change, but also has to do with surface resistance/drag change also.

 

[Eric_04]

Im still amazed how many people have lockups of some sort installed and have never done any tuning what so ever. I was at some races last weekend (300' dirt) and couldnt believe how many people had a lockout and were still just riding the clutch slipping it out so they didnt bog the motor. Probably due to the fact they had the stiffest springs they could find in the clutch on top of having a lock out. I am in no way trying to offend anybody at all, Im just simply shocked how overlooked working on the clutch is. My background is snowmobile drag racing, and the vast majority of races are won and lost with clutching. Its a constant battle between getting the chassis to handle the power, and once you get that a step better then you smoke the belt. So then you go back to more clutch tuning trying to grab the belt harder, then youre back to doing wheelies and bending and breaking drive train parts again. Its a never ending cycle in an attempt to go faster. These are 600+ horsepower snowmobiles by the way. Now obviously snowmobile clutches are much different than an atv or bike, but the theory is similar. And there are certainly some interesting things from the snowmobile world that I think would work quite well on clutching setups on an atv. .

 

One thing I have noticed in this thread(which has tons of great information and has given everyone the basics to get started) is that the vast majority of the advice is based from asphalt tuning. While it obviously translates to dirt and sand, I just dont think you will be able to see consistent results from such minor spring and weight changes as you would on asphalt. There is huge variety by me, where I was at last weekend the track was practically sand, and paddle tires arent allowed. The track was groomed and watered twice in the morning and had "some" bite in it. It was not touched in the afternoon and was dry and very loose and everybody was spinning hard all the way down the track. If a person had a clutch properly set up for the conditions in the morning, they would have definitely had "too much" clutch in it for the afternoon. But would it have been faster to soften it up and burn through the clutch to try and drive away from the line with less wheel spin? In my opinion, no. That to me would have been chasing a deteriorating track. Not much you could do other than let the tires work and hope you find some decent traction. You may have been better off making chassis adjustments to try to find more traction in this case. I guess what Im getting at, is that bringing awareness to clutch tuning is great. However, many other things affect the overall setup. And a lot of it just comes down to judgement decisions. And that only comes with time and experience. Ive learned more by doing things wrong than doing them right, I can say that for sure. The only thing that makes me slightly apprehensive about this thread, is that people like myself that will be running dirt with no paddles with conditions that change from one class to the next, is that you will not be repeating 60' and 300' et's to the thousandth pass after pass. Should they be close? Absolutely. So I guess all I can say about that is dont get caught up in chasing a track thats going away.

 

Hopefully my post helps a few people think about some other things affecting overall setup, which in turn affects the clutch. My best advice, that applies to all racing, is to test and test some more. Keep solid notes and take ACCURATE measurements. Taking half ass measurements is a total waste. And do not worry about somebody elses setup. Whether it be clutch setup, chassis, whatever. Your machine is different, it will not be the exact same. Somebody elses spring pressure does not matter to you. Not only is their machine different, theyre probably trying to accomplish it in a different way than you are as well. 60' is SUPER important. If you immediately get out 2 or 3 lengths on somebody, it takes a lot of power for them to drive around you in less than 300 feet. Anyways, thats all I have for now. I could type about this for hours, but this is already too much for now and its past my bedtime. Good luck everybody, and dont be afraid to change things. The worst that wil happen is it will go slower and you have to change it back. But you will have learned something in the process.

[sleeper06]

Another thing highly overlooked is launch rpm , imo all the clutch tuning you do can be null and void if rpm isn't consistant. You can chase your tail with spring pressure not realizing you left a little hotter than last pass . Every bike likes a diffrent lauch rpm and there's to much human error and adrenaline at the line to be consistAnt . As with any form of drag racing you need to eliminate variables

[Tedder]

Most people don't know this but Bryan and I first met because of clutch tuning. When Chuck Wilburn originally came out with the Banshee multi-stage he put us in touch with each other and the rest as they say is history. Since then we've become very good friends and although living at opposite ends of the Country we've managed to meet up at several racetracks, visited in our homes and burned up countless cell phone batteries discussing clutch tuning lol. Even though our basics are much the same we each go about things a little differently so I thought I'd share how I've gone about primary clutch spring tuning to show that there's more than one way to "skin a cat" and give others something to think about.
I've got 3 multi-stage units and multiple inner/outer baskets with most machined with slight differences.
Anyone who's tuned clutches knows what a huge difference in lockup performance can be had from minor spring pressure changes. I needed an easy way of getting fast, repeatable results capable of registering very small pressure changes.
This has been my simpleton way of doing things over the years.
*All* of my measurements are taken at a 1" compressed height.
My drill press has an adjustable stop built in (with digital readout) so that once set with my 1" gauge I can quickly check a basket full of springs.

 

[SlowerThanYou]

Wow, got some other people discussing on this subject. Including the Great Tedder, that was the last person I thought would share his clutch info.

 

Anyway, it's good that other member's are sharing their clutch info. That's what I hoped would happen! Maybe some more advanced info will come out, but I'm taking mine to the grave. LOL!

[penguin]

how is chuck doing I haven't talked to him in years. I got one of his first lockups back in 04. I showed up at a local track near him in Byhalia MS  for a 1k$$ shootout.  track was short 60' no one told some of us, I ended up in the sand trap and busted an override trans all to hell..and their excuse was no one expected a 5 second banshee to show up  but to late then...  but  that's when I meet chuck and later I ended up testing one of his lock ups and it was amazingly tuneable    I been reading your post and its been spot on from what I learned from chuck, like you said countless phone calls on different set ups tips and tricks  ... even track temps have played a role in what clutch set up we would use    good rite up guys... listen to these guys its great advice  

[Tedder]

This lockup thread is one of HQ's best IMO and I don't want to start muddying it up with a bunch of "chatter" but there hasn't been anything added to it in some time.                     

Chucks doing great. I still talk to him a few times a year but rarely about tuning since he's moved well beyond dealing with Banshee stuff which is to bad for us. He started out on the asphalt with Banshee's and after he'd given them up for two wheels he did some innovative retrofitting or designing of successful drag parts for both Motorcycles and Banshee's. The most well known for the Banshee were the Wilburn Ignition (basically a reprogrammed Schnitz box that was used by many serious drag bikes back in the day) and the Multi-stage clutch (used by many until the slider was developed) but he often ended up being bashed over price or by guy's doing shitty installs or those who just weren't any good at tuning.  

[pipmaster421]

I run on sand got a 421 cheetah plus10 swingarm and three forward in the front what would be a good weight to start with to get a base line and friend yes stock springs and 17 grams and 21 grams on every other finger

[stpltn]

I've read through this a couple times and have seen it was mentioned a little. Primary ratio gears. Some said they were confused if the higher or lower gear spun the basket faster or slower. I thought the higher the gear the faster the basket spins.

 

So if you have an engine with 2.86 gear and have a good baseline setup. Swap it out to a 2.54 or 2.36 or what ever is the next size higher. It would in turn spin the basket faster. 

 

So wouldnt a higher basket speed speed would need stiffer base pressure so the clutch doesn't slip as much to where you can get enough grip to spin the back tire to then in turn spin the lockup.

 

If you have a higher primary gear then wouldn't you need less weight as the basket speed is faster yet?

[Tedder]

The 2.86 stock ratio seems to be pretty popular with a lot of clutch tuners.

 I mainly run 1/4 mile and use multi-stage clutches which have tower springs to control the lockup arm application as opposed to most other designs which start applying pressure to the outer pressure plate as soon as the basket starts spinning. 

I use 2.68's which spin the basket at a little faster RPM than the OEM ratio.

Banshee basket speeds aren't high to begin with so it's tricky balancing arm application during launch with having enough clamping force at shifts (especially 5-6). A bonus to using that ratio is it also allowed me to drop one tooth in front.

[Dm554banshee777]

This topic hasn't been brought up for a little bit... but there seems to be enough information about static pressure and arm weight in this thread for beginners to get a good idea what to do.

I would like to bring up how to get more life out of a clutch such as differant plate treatments. STY, you mentioned cryo treatments? Is this worth the money? Also I've had an idea of bead blasting steels on low pressure to resurface glazed steels.. I'm curious if anyone has tried this with any success. 

[SlowerThanYou]

On ‎7‎/‎22‎/‎2017 at 9:52 PM, Dm554banshee777 said:

This topic hasn't been brought up for a little bit... but there seems to be enough information about static pressure and arm weight in this thread for beginners to get a good idea what to do.

I would like to bring up how to get more life out of a clutch such as differant plate treatments. STY, you mentioned cryo treatments? Is this worth the money? Also I've had an idea of bead blasting steels on low pressure to resurface glazed steels.. I'm curious if anyone has tried this with any success. 

Nice! I like it, brand new BHQ Member & 1st post is in this thread.

I don't know what you consider more life out of the clutch is? This is our definition of useful life & it has been mentioned before. Peak performance for heads up racing we get about 100 runs. After that we use the clutch for Bracket/Index Racing for another 100 runs. After that we retire the frictions, they start breaking. The steel/aluminum plates can usually get used longer with very thorough inspections.

This was our results & I consider our clutch management program one of the best.

Never bead blasted the steels, but don't see why it wouldn't work. As for cryo treatments, didn't see a difference on the steel plates. All of our aluminum plates were cryo treated & hard coated. I consider this a must for the aluminum plates.

 

[Tedder]

I think Bryan mentioned a little about scotch pad prep earlier in the thread which works well but be careful when it comes to blasting the steels. Different textures can be had depending on the media used but fibers can be destroyed quickly with an overly aggressive surface. Especially if you're setup for slippage on a 9000rpm dump the clutch hole shot. As a bracket racer I've found that I really like the standard vibratory finish that most steels have when new and will fine tune after some break in time as engagement characteristics and ET's change quickly and a lot as the surface "settles in". 

[Dm554banshee777]

I have a question.. Im beginning to get fairly serious in the clutch tuning world and have realized that everyone seems to have a different way of doing things. In your clutch tuning thread, You recommend pulling base psi and watch as your 60ft improves, then start adding or taking away arm weight. My background is 300ft sand/dirt drags and I've talked to many about the subject.. some are more willing to share info than others.Ive been doing most of my tuning your way.. low base pressure and a decent amount of arm weight for down track lock up.. This seems to work but as bikes get lighter.. and e.t are getting faster ( example: 0-425 record is now 3.51) I see people trying new things. Something Ive noticed is the super light small motor bikes seem to be pulling very high Mph for their engine sizes, and when I listen to them go down the track, their rpm stays very high (which I assume is peak power range for them). So my question is.. Would running high Base psi and Very little to no arm weight help a smaller motor stay in peak power? To have just enough base psi to get off the line and 60ft decent.. but not enough arm weight to drag the motor down between shifts.Less arm weight would also mean less rotating weight to turn.. I would think this way could allow some slippage between shifts. The main goal Im trying to figure out is the slip between shifts. If you have any insight on this I would love to hear it. Thanks.