All about clutches on the GSXR1300 Hayabusa/Part 3 of a 3 part





Shortly after the 2nd part of the article came out (about an hour) I got a phone call from a good friend and multi class champion racer Andy Baumbach, he told me, “Your 60’ is still high, you need a multi-stage, it is more adjustable.”

Multi-stage lock ups / clutches

Multi-stage set-ups operate in much the same way as a single-stage, although they have more adjustability.

What makes the multi-stage different from the single is the fact it has the ability to attach springs to the centrifugal arms as well as by adding weights to them for a greater range of tuning.

 

 

 

 

This allows you to better apply the power as you are coming out of the hole. On bikes that have multiple stages of boost or nitrous progressions this is an incredible benefit. Take a Pro Street bike for example, it leaves on 5 -7 lbs. of boost, once it gets out 100’ it ramps up to 15 lbs. by the 1/8th it is probably going to be at full boost. With a multi-stage you can adjust for each of these increases in power.

 

Engine or Rear wheel driven multi-stage

 

There are two forms of multi-stage set-ups, either engine driven or rear wheel driven. The top part of the hat of an engine driven multi-stage is attached directly to the basket and no bolts are used to attach the pressure plate to the hub. In a rear wheel application the unit is attached to the hub just like on a single-stage set-up.

 

I’ll give you a scenario and you determine whether an engine driven or rear wheel driven set up would be best for you:

 

You throw the clutch at the line, the tire hooks up hard and you feel the engine start to drive through the clutch.


1. With a rear wheel driven lock up the tire is planted and does not come up to speed to engage the centrifugal arms as the lock-up is attached to the hub and not the basket. As a result you continue to burn through the clutch, your only hope of saving the clutch is to either let out of it, or hope the rear wheel eventually moves fast enough to engage the arms.

 

2. With an engine driven lock up the basket is being driven regardless of what the rear tire is doing, as it drives through the clutch the rpms are going up and the centrifugal arms start to lock up the pressure plate and eventually get you moving down the track. In this instance you would have to make some adjustments so you do not do this again, although you may still have a clutch left and you more than likely were able to get down the track.

 

How a multi-stage works in more depth

 

Hays Machine Works supplied me with their Pro Street Convertible Multi-stage for this article. In the multi-stage mode I am about to describe, it works in the same fashion as other engine driven multi-stages. But, it does have a significantly different feature than its competitors I will discuss later.

 

An engine driven unit is made up of two pieces, the top hat and the pressure plate. In between these two pieces is your first level of engagement, the static spring pressure. With the Hays unit an assortment of different springs are sent with it.

 

Because the top hat is attached to the clutch basket and the static springs are in between it and the pressure plate, this forces the pressure plate downwards on the clutch pack. (In my instance on the Track Pac Clutch kit supplied by SpencerCycle.com that I am testing.) With this set-up alone you would blow right through the clutch pack on launch as the static pressure is not enough to keep the pack compressed.

 

This is where the next line of tuning comes in to play. There are six centrifugal arms on the top hat that apply pressure to the buttons on the pressure plate as you build rpms. As mentioned earlier, there are holes in the arms you can attach different spring configurations to; this provides more range as to when pressure is applied. Along with attaching the springs in different configurations, you can also use different weight springs, going one step further you still have the option of adding or removing washers to each of the arms.

 

 

You need to determine how far you want to go and how anal you are when fine tuning your bike. The multi-stage is definitely designed for those of us suffering from OCD.

 

The slider

 

We are not talking about the “gut grenade” hamburgers here or the pitch Ted Williams thought was the best pitch of all time.

 

The slider is a feature the makes the Hays Machine Works Pro Street Convertible Multi-stage unique in the market. It can be a single-stage, a multi-stage, a slider or a multi-stage slider. You are basically getting 4 potential setups for the money.

 

 

Have you ever noticed bikes in the staging lanes that have no clutch handle or a rider at the line that has his hand off the clutch handle while he is still in gear? They can do this because they have a slider clutch. The slider is rpm activated and does not come on until the rpms hit a pre-determined point.

 

The way this is accomplished with the Hays Machine Works product is instead of placing the static springs in between the top hat and the pressure plate the springs are put on top of the top hat. Studs are supplied with the kit to screw into the pressure plate allowing them to come up through the springs on the top hat. Nuts are applied to the top of the studs applying pressure to the springs, in turn pulling the pressure plate up off of the clutch pack. The opposite of what happens in multi-stage lock up mode.

 

 

In this arrangement the centrifugal arms are solely responsible for moving the pressure plate down on the clutch pack. As in the multi-stage set-up engagement is determined by the weights and springs you use on the centrifugal arms.

 

The advantage to this setup is that all you have to do is turn the throttle wide open at the hit. Just like riding a scooter… albeit a fast one.

 

A few more things to consider

 

1. Air gap

 

When setting up these types of systems you need to be mindful of your air gap. To find what your clutch stack should be all you have to do is measure from the bottom plate of the hub to the outside edge of the clutch basket. This is your total stack height, just subtract the air gap you are trying to achieve from that and you will know what stack height you need to run. Check with the manufacturer to find the optimal gap.

 

2. Clutch Cover

 

You are going to need a clutch cover for a multi-stage. The factory one will not cover it. MPS supplied me with a cast one although there are some pretty nice billet ones out there if your wallet is deep enough. Check to make sure you have clearance with the cover you are using to make sure everything is free, especially the centrifugal arms.

 

 

At the track

 

The bucking is gone, the engine dying as soon as I release the clutch at low rpm is gone and the bike is launching once again without my having to perform spur of the moment cloud inspections.

 

Most importantly… This is the most incredible performance piece of equipment I have ever put on my bike. It is simple to set up and you do not need a degree in engineering to work with it.

 

I literally throw the clutch at the hit. The bike launches perfectly smooth, at first it feels so soft you wonder if you are going to have a decent 60’, then you look at your ticket and you just had a 1.54 when it felt like a 1.8 60’. And this was with the base set up Tim from Hays Machine Works gave me right out of the box.

 

I was only running the 1/8th and ran back to back 5.9 passes 4 times in a row. I actually thought I was on a wheelie bar bike.

 

I have not been on it enough to make changes and only leave at 6K, I know I can leave harder now. As it is, I am going to leave it alone until I get used to it then start to experiment.

 

Being an ET racer I am not worried about posting big numbers, but if you were, this would be the ticket to them.

 

The whole day I could not stop myself from smiling like a kid in grade school who just got the best tricycle at recess.

 

It is amazing I actually ran the bike all these years trying to finesse the clutch to be consistent when all I had to do was put a Hays Machine Works Pro Street Series Convertible Clutch in.

I am still smiling!

 

 

 

Thanks to the following who helped with this article:

 

Tim Hays for supplying the entire clutch set-up to review and explain in detail, Brock Davidson for his information, product and technical critique, Doug Ray for prompting me to write the article, Brian Livengood because he helps with everything, Dan Rudd at MPS for supplying the clutch cover, Mark Paquette for giving me some pointers on tuning a multi-stage, albeit from the standpoint of a 700hp Funnybike, Don Chavous for his astute observations at the line and Andy Baumbach for his support in trying to get me to run an 8 second pass.

 

Read all installments of the 3 part Series, choose below

 

All about clutches on the GSXR1300 Hayabusa/Part 2 of a 3 part series

 

What has happened so far…

 

We left the last installment with me replacing my old clutch basket and hub in an effort to stop the Busa bull ride.

 

Just a quick note,you can read each installment in the “Tech Dept.” section by clicking the tab in the menu bar.

 

The old components had definite wear on the hub due to the steels digging into it from hard launches. (Hard by my standards, someone like Keith Dennis may beg to differ.) Also on the clutch basket there was wear from the tabs on the fibers slamming into the basket.

 

Grooved hubs, baskets and warped steels

 

The bucking I described in the first part of this article could be caused by the aforementioned findings. The grooves could be keeping the fibers and steels from merging smoothly together as you release the clutch. If any of the steels hang up in a groove the bike may lurch as soon as they snap free of the groove and slam into the fiber. At the very least it would seriously hinder your consistency in releasing the clutch smoothly.

 

Having warped steels could cause this also; as you are slipping the clutch and if any of the steels are warped they would start to catch the fibers on the peaks of the warp causing surges in power until the clutch was completely released. This is why it is important to check your steels periodically on a flat surface. If they rock, they are no good.

 

Both of these situations probably would not cause the problem to the degree of severity I was experiencing; although, they were a contributing factor.

 

Performance Clutch baskets

 

The stock clutch basket is good up to 210 hp or so. This seems to be the general consensus if you talk with engine builders and performance parts suppliers. Anything over that and you are running into the likelihood of the basket literally coming apart. When one does come apart it is not a pretty picture. It leaves metal in your oil pan and can get between the gears of the basket and the crankshaft.

 

 

For applications above this range you will want to invest in a billet clutch basket. While there are many companies who manufacture billet clutch baskets, the one in this article was supplied by Hays Machine Works for my use.

 

A billet anything is made from one solid block of material. When machined correctly there are theoretically no weak areas or stress points. Therefore the billet item is less likely to come apart.

 

In the case of the Hays Machine Works basket there is a feature built in that allows you to upgrade to a multistage clutch in the future; also built by Hays which is driven by engine speed as opposed to rear wheel speed. It also is designed with “Surface Area Reduction Technology” to help the clutch fibers move with less friction.

 

 

On the back side of the basket you will notice there are a series of springs. Some heavy and some lighter. These springs are a form of buffer to help soften the shock in the input shaft and crankshaft of a hard launch. Under normal riding circumstances they probably will last the life of the motorcycle. Yet in a drag racing application they will get abused like a temporary laborer.

 

 

Over time, the springs become compressed and start to loosen up in the spring pocket. This allows the basket free play to snap into the springs instead of being cushioned and therein lies the heart of my bronco ride problem. I had anywhere from 1/8 to 3/16 of an inch play in the spring pockets of my clutch basket.

 

 

As I started to ease the clutch out, the clutch basket snapped forward that distance slamming into the springs. Next, as I let the clutch out more, the springs were more than likely already bottomed out from the momentum and the bike bucked forward from having no cushion left. When I eased the clutch back to try and soften the launch the springs released starting the whole sequence over again.

 

It took three years of drag racing for this to happen with my clutch basket.

 

Talking with Tim Hays of Hays Machine Works about this issue he had this to say, “We have tightened up the spring pocket for this problem.” Tim mentioned it is important from a performance standpoint to not have play in this area as it will adversely affect the consistency of your launch.

 

Billet Hubs

The hub takes a beating from the steels slamming into it. Overtime they become gouged. I attempted to stone them smooth in a last ditch effort to make the bike launch smoothly. It was a 3 hour waste of time and effort to file each cog.

 

 

Hays Machine Works sent me a billet hub to evaluate for this article.

 

A billet hub has two major advantages:

 

1. The Back Torque Eliminator is no longer needed as the hub fits directly onto the input shaft.

 

2. They are stronger then the factory hub.

 

The Hays Machine Works hub pictured below incorporates their “Surface Area Reduction Technology” to the design. This allows the steels to move more freely on the hub.

 

 

Pressure plate and single-stages

 

This is an area that makes or breaks a winning run down the track. Whether you are ET, heads up or grudge racing, if you do not slip the clutch just right you can blow a race or worse yet end up on your back.

 

If you do not use a single stage on a 230+ horsepower motorcycle with stock clutch springs you will notice pretty quickly that you are bouncing off the rev limiter and your back tire seems to be spinning all the time. In fact it is you driving through the clutch. The way to fix this is by increasing the static pressure of the springs by going to thicker ones. The higher in static pressure you go the more difficult it is to pull in the clutch and you run into the possibility of cracking your hydraulic clutch housing.

 

The first level of help in this area short of a Single-stage set up is the Brocks Performance Clutch Cushion. By its “simplicity carried to the extreme” design it helps the release of the clutch, lessening your margin of human error. It does this by adding a small amount of slippage as the pressure plate comes down on the clutch pack.

 

The next level is the Single-stage lock up. It allows you to use lighter springs for your static spring pressure on high horsepower applications.

 

A single-stage uses centrifugal force to apply weight to the pressure plate. As your RPMs go up your clutch pack gets compressed more. This allows you to throw the clutch off the line and not worry about trying to slip it as the single-stage does that for you once set up correctly.

 

 

It is called a single-stage because the arms are controlled solely by their weight which is typically adjusted by the addition or removal of washers. Adding weight causes the device to lock-up earlier and removing weight causes it to lock up later.

 

Track time

 

With a single stage the goal is to get the first part of your launch smooth by allowing the clutch to slip some. I started with 6 springs that were slightly heavier and longer than stock. This turned out to be too much static spring pressure, when I threw the clutch the bike bogged. Next I removed three of the springs and added 3 stock Hayabusa springs. On this launch the clutch noticeably slipped as the engine rpm’s went way up. Once the weighted arms came on I took off. This resulted in a 1.8 60’ and 9.50 pass.

 

Next, I took one of the Hayabusa Springs out and added back one of the heavier springs. This resulted in another noticeable slip of the clutch although not as bad as the first one. On this run I had a 1.7 60’.

 

Brock Davidson had sent me some spacers to use when adjusting spring pressure a while back. I used 2 of them to put on the two Hayabusa springs. This was the trick. I threw the clutch and ran a 9.21 with a 1.585 60’. The bike left smoothly with a slight power wheelie. I screwed up and short shifted 2nd and 3rd on this pass.

 

 

After letting the bike cool, I went back and made another pass. This was a 9.03 with a 1.61 60’. My fastest pass ever. On this run my 60 foot was off because I did not go to wide open throttle as quickly as I should have.

 

I have to admit, the single stage is nice and it is easy to use. Yet I can already see there is more room for tuning. As I have it set up now, it is on the edge of being set right, I think I can lighten up a hair more on static spring pressure as the front wheel wants to come up slightly on the hit. This is the type of thing the Multi-Stage set up allows you to tune for.

 

All about clutches on the GSXR1300 Hayabusa/Part 1 of a 3 part series

 

 

Why this whole article came into being…

 

I have been trying to get a 250 hp turbo Hayabusa to run an 8 second ¼ mile since 2008. (Korry Hogan once told me to put Jeremy Teasley on it. Problem fixed.) Granted it has not always had that much hp as I have gone through some major learning curves in the development of homemade air filters, figuring out the finer points between a clutch slippage and 2nd gear going out, having a turbo header break and now failing clutch components.

 

This year the bike has made the most horsepower it ever has. Unfortunately I had not been able to race it for the first half of the year because I was waiting for parts to come in during the rebuild process and then the turbo header broke. Once finally together, I took it to Test and Tune to get ready for the 2nd half of the Atlanta Dragway NHRA point’s series.

 

On the 1st pass the bike stood straight up in the air, I chopped the throttle and got back on it as soon as it was coming down only to launch it off the ground again, both tires, when I twisted the throttle again. I just chalked it up to being rusty on a high horsepower bike as I had been borrowing stock Hayabusas for the first half of the season.

 

On the 2nd pass the bike literally leapt from the ground, not once but four times. Every time it came up I pulled the clutch in a bit to slip it, as soon as I pulled the clutch the RPMs went through the roof so I let it out just a hair and it would leap into the air again. The back tire left the ground leaving 4 distinct patches about 3 feet from each other.

 

I almost had to clean my leathers out after this pass and now can fully identify with what a bronco rider goes through.

 

On the return road I started trying to slip the clutch from a standstill to see if it was just me. The clutch just grabbed and killed the engine as soon as I started to let it out. I tried it again and it started bucking once again when I started to ease the clutch out at 2,000 rpms. Something was definitely going on in the clutch area.

 

This is my adventure on how to fix this problem. I will cover all the performance clutch set-ups including back torque eliminators, billet baskets, billet hubs, single stage lock-ups, multi-stage lock-ups, sliders and how they supplied a solution to this issue.

 

The Clutch’s special purpose

 

Without this mechanical component forward locomotion in a regulated manner would be nearly if not entirely impossible with any combustion engine driven vehicle.  (I know; someone is going to write to me about CV transmissions…)

 

A clutch has two main purposes; firstly, to apply engine power to the drive train without killing the engine from applying too much load at one time and secondly, to allow the engine load to be disengaged to allow down-shifting or up-shifting. (It could be argued its other purpose is to piss me off as  described earlier.)

 

In the case of a clutch for a manual transmission as found on the Hayabusa, it is our job to slip the clutch in order to move on down the road from a standstill. In drag racing the clutch is a significant factor between a great 60’ and low ET… or a run you hope nobody witnessed.

 

How does it work?

 

It is rather simple in fact. The main players of parts found in the clutch department are as follows:

 

1.      Input shaft

 

2.      Clutch basket

 

3.      Hub

 

4.      Back torque eliminator

 

5.      Clutch fibers and steels

 

6.      Springs

 

7.      Pressure plate

 

There are a few other parts also, but these are the major ones.

 

 

The crankshaft has a drive gear which turns a gear attached to the base of the clutch basket. By itself the basket cannot drive the transmission. The clutch basket fits over a caged bearing on the input shaft to your transmission. It is called the input shaft because this is where the power from the crankshaft is converted into rotational energy for your transmission.

 

 

The next part to help things move along is the clutch hub. It fits on the input shaft. It has three cogs in it that fit into the back torque eliminator. The back torque eliminator has splines that match the ones on the input shaft. This item, along with the hub is what directly turns the input shaft, although they need another item to help.

 

 

 

The clutch fibers and steels fit onto the hub within the clutch basket. A fiber goes on first alternating from there out with steels and fibers. You will notice the fibers have tabs that stick out and the steels are round with cogs in the middle. The tabs on the fibers are driven by the clutch basket; the steels drive the hub when the clutch pack is compressed together. This brings us to another set of components.

 

 

 

Next the pressure plate is added to the hub and six springs are installed in the pressure plate. This is what supplies the static pressure to compress the fibers and plates together when the clutch handle is released. (Spring pressure only. This will be an important discussion later.)On the Hayabusa, the static pressure from the factory is around 240 lbs.

 

 

In a nutshell here is how it works together. You are holding the clutch in at a traffic light. The light turns green and you ease out the clutch. This allows the pressure plate to slowly compress the fibers and plates. As they do so, the hub slowly starts to turn driving the input shaft which in turn drives the output shaft causing your front sprocket to turn the rear wheel and you are off to your destination.

 

Now think about what you are doing at a drag strip… The bike is revved up to 6,500 rpms, the light changes, the clutch is thrown almost all the way out, because you want it to slip some and all of the clutch fiber tabs are slammed into the billet basket as the steels are slammed into the hub. If everything went right, you are not sitting on your ass looking down the track as your bike is flipping through the air, but instead you are rocketing towards a great ¼ mile.

 

Back Torque Eliminator (BTE for short…)

 

Its main purpose is to prevent the back tire from locking up during aggressive downshifting. It is made up of two parts and it accomplishes this by actually allowing the torque eliminator part to jump over the the ring which locks onto the three protruding studs in the hub I described earlier. This action in effect causes the input shaft to still turn without locking the back wheel and causing an inopportune slide in a curve.

 

 

 

But who the hell is using a Hayabusa in a curve to begin with?

 

At the drag strip the BTE is just a part to scare the crap out of you when you throw the clutch and you hear it start making a chunking noise as it tries to lock into place from your abrupt take off.  You’ll swear the first time it happens that either your chain is jumping teeth or your transmission just deposited a pile of metal into your oil pan.

 

Fortunately there are numerous ways to do away with this component.

 

You can try and weld it together on your own if you are intent on destroying your entire clutch assembly. I am not saying it can’t be done because someone had done it to my bike when I first bought it. But it is not an easy process unless you have developed a jig to do it correctly. Even after doing that you need to make sure it is balanced so your entire assembly does not vibrate or wobble.

 

Personally, I would buy one from Brock’s Performance like the one shown, as you know it is going to work. Other companies make them also and by getting one it allows you to use a stock type clutch hub which can be purchased for less than the billet hubs.

 

 

Another option for bikes that start hitting the 250 hp range is getting a billet clutch hub which eliminates the BTE components completely.  I’ll get into these in more depth in the next installment.

 

Coming up next…

 

Billet Baskets and why you need one

 

Billet Hubs and why you need one

 

Single stage lock-ups

 

Research

 

Tim Hays www.haysmachineworks.com

 

Brock Davidson www.brocksperformance.com

 

Brian Livengood www.livengoodmotorsports.com

 



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