Shimming Clutches

[Rock Doctor]

RD
Do you know if the stroke is the same on the 27hp or 29hp as the 20hp Kaw? In other words has anyone ever looked into just changing the stroke on the 20hp Kaw to gain more displacement? I love to stroke engines, both of my vets are stroked ( 383, 416 ) and my airboat has a 500 Cadillac engine stroked to 530ci.

The 27 and 29 are the same engine, I believe, but the 20 is noticably smaller. You might be able to stroke the 20, but you might run into cooling problems if you do. Just a thought.

It took a little looking, but I found schematics for all 3 engines on line, back when I was researching this project. I don't have those sights favorited anymore though.

RD

[LarryW]

Thanks for the updates, glad you got the power back.

[crowhater]

Lord what a difference! I put a shim between the spring on the primary clutch and I turned the centers of the weights around. One side of the center of the weights was smashed flat from sliding against the drum so I turned that side down away from the drum. High gear now pulls as hard as low gear and I can turn with ease, it almost feels like you are slipping the tracks on the pavement when you take off. Another added benefit I discovered is you are able to raise you idle rpm a little and you can still shift gears without grinding. Now at idle I can even have the lights on without the 12v light on the dash coming on. I also found my lost top end speed, it is still slower that it was with tires though.


RC
Do you know if the stroke is the same on the 27hp or 29hp as the 20hp Kaw? In other words has anyone ever looked into just changing the stroke on the 20hp Kaw to gain more displacement? I love to stroke engines, both of my vets are stroked ( 383, 416 ) and my airboat has a 500 Cadillac engine stroked to 530ci.

[coosaridgerider]

Call airdam cluthes.com They may be able to help.They are located in vicksburg Miss.

[Rock Doctor]

After instlling my Adair tracks my Conquest really labors in high gear and lost a great deal of top end. What about shaving weight off the primary clutch weights? Is the 27hp Kaw really worth the money for 7 HP? I read it is a direct replacement and takes a couple hours to do the swap. My 20hp only has 60 hours on it.

Shaving weight off the Primary weights has a similar effect to shimming the Spring (I have NOT tried shaving the weights, it's hard to put shavings back on if you decide you went too far)
The 27hp IS really worth it IMHO. 30% power increase is nice (another option is the Fuel Injected 29hp)
It is NOT a direct replacement. The engine mount needs slight modifications, the Crank Shaft needs about 5/8" cut off, and the "Step" in the Crankshafts are different (Stock 20hp is a squared off step and the 27 is a Radius Step. I just slightly modified the mating surface on the clutch to match the step in the shaft with a dremel)
It took me 2 hrs to pull the stock engine, and 3 hrs to install the 27hp engine.

There is a guy on YouTube that made videos of his upgrade to the 29hp. Guitarhack42 is his user name. Nice guy, if you contact him, tell him "Grizzly Adams" sent you.

Here is his vid one of the swap

RD

[crowhater]

Down here they sell it at Academy but I still order mine either direct or off EBay.


Thanks Rock Doc! I was not talking about moving the clutches away from the engine or alignment. After instlling my Adair tracks my Conquest really labors in high gear and lost a great deal of top end. What about shaving weight off the primary clutch weights? Is the 27hp Kaw really worth the money for 7 HP? I read it is a direct replacement and takes a couple hours to do the swap. My 20hp only has 60 hours on it.

[Rock Doctor]

I have a 2000 conquest with a 20hp law and Adair tracks

Now for my question! What does shimming the primary clutch do for you? How do you remove the primary clutch? Do you also shim the secondary clutch and if so how do you remove it?

Hi Crowhater,
Right or wrong, I have a couple thoughts here, and they depend on your referance to "Shimming"
Primary Clutch- The clutch itself can be moved away from the engine a bit with shims. Like CRR mentioned to align your belt. OR. The Spring in the Primary clutch can have a shim placed under it to increase your spring pre-load. This will increase the RPM where your Primary will engage. Care must be taken with this, only ONE shim can be placed in there and it can not excede the thickness of the wire that the spring is made of. Too thick of a shim will "coil bind" the clutch. What I use is a piece of welding rod (1/8"), rolled into a circle the same diameter as the Primary Spring coil. Drop it under the Primary Spring and put the clutch together. I have a vid showing this.
The Primary clutch has a Hex Head bolt through it into the end of the Crank Shaft (I think it's a 12mm hex). Back off the bolt and slide the clutch off the shaft.
Secondary Clutch- Can also be shimmed to align to the Primary. OR. Shims can be placed between the clutch halves. This will set the distance between the clutch halves while at rest, raising or lowering the belt in the clutch slightly.
Last question? How do you remove the secondary clutch or how do you remove the shim?
Clutch has a bolt through it into the end of the trans input shaft. Pull bolt to remove clutch.
Secondary Clutch has a Snapring holding it together. Rotate the clutch halves a bit to put a little more tension on the spring. Tap the Helix down a bit to take pressure off Snapring. HOLD everything together, (This is easier if you have 3 hands), pull the Snapring. Carefully allow the clutch faces to rotate back, so the slider buttons push on the Helix Ramps. The slider buttons will push the Helix up and off the shaft. I have a vid of this process as well. CAUTION, this clutch WANTS to fly apart once the Snapring is removed.
There are a # of holes that the Secondary Spring can be placed in. Stock position is hole 3. I like to run in hole1 which is a HIGHER preload. In this position the Secondary will Upshift Slower and Backshift Faster

Hope that helps

RD

[LarryW]

coosaridgerider, I bet the shim your talking about holds the clutch apart more. This will allow you to run a wider belt if secondary clutch will accept it and it will take a little bit more rev to get it to engage. That will in a way gear the whole thing down a little vs engine rpm. I had a little comet 40 clutch I used a wire on the inside of it to hold it a little further apart to run a wider belt.

One the secondary clutch I also did the same thing but you can just use a wire or a C clip on the shaft between the pulley faces to hold them apart. You do that to run a tad wider belt. That will actually decrease performance on a normal width belt so dont do it unless your upping your belts width.

[coosaridgerider]

Shims are used behind the clutch to align the belt.I have heard of people using a plastic shim in the clutch to make it perform like it had a shift kit in it.A guy that rides a local creek did this to a polaris sportsman.He said he cut the shim out of a plastic milk jug and put it inside the clutch but i'm not sure where it goes in the clutch.The next time i go down to the creek i will find out.

[azz7772]

is that product only available on line or do any store chains sell it?

[crowhater]

I have a 2000 conquest with a 20hp law and Adair tracks. What does shimming the primary clutch do for you? How do you remove the primary clutch? Do you also shim the secondary clutch and if so how do you remove it?

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