Machining a 10" secondary to 10.4"

[PowerJoe]

Ran into a problem

So I ran into a little problem...

Since I machined .060" off of each side I need to remove one .060" shim from behind the clutch to maintain the alignment with the primary clutch. The problem is the DD shaft is too long to allow for this and now when you tighten the bolt holding the clutch onto the splined DD shaft it does not "clamp" the clutch to the shaft. The clutch actually floats back and forth like and old style clutch with a keyway. I have read on here that you don't want to do this with the DD setup but don't know if anyone has tried it. My only other option would be to remove the shaft from the DD and shorten it, but I really didn't want to get into that.

As anyone run this floating style setup on the DD sleds? Any of you guys that have done this before run into this problem?

 

[fradiecat]

Is the bolt bottoming out or running out of thread?
Add a washer to the bolt and see what happens.
Seems obvious, but that's what we tend to overlook the most.
Keep us posted.

 

[PowerJoe]

No the bolt is not bottoming out. You can look inside and see that the shaft is now protruding through the splines on the clutch.

 

[diggerdown]

The whole idea of using a larger diameter secondary is give you a little lower starting gearing, all this is doing is letting it shift into a higher top gear.

 

[MNM7141]

Power Joe - You need to add washer(s) to the outside of the bolt to get it to clamp down. I can't remember if I had to add just one or two - I try to check and post. Good Luck! Paul

 

[Wood]

The whole idea of using a larger diameter secondary is give you a little lower starting gearing, all this is doing is letting it shift into a higher top gear.

You're actually reducing the effective clutch gear ratio so you will be in a lower 'top gear'. You are also reducing the amount of overdrive and increasing the belt contact area at full shift....all good things for more consistent performance and reduced belt slip.

Even though .050 blends the 2 diff. sizes when I drew it up in CAD,
The 046 belt sure seems loose. I can almost squeeze the belt together
between clutches and make it touch.
Maybe another .010 off each side?

You need to go a min of .060 for the 046. You can go less if running an XS813 or Polaris belt.

So I ran into a little problem...

Since I machined .060" off of each side I need to remove one .060" shim from behind the clutch to maintain the alignment with the primary clutch. The problem is the DD shaft is too long to allow for this and now when you tighten the bolt holding the clutch onto the splined DD shaft it does not "clamp" the clutch to the shaft. The clutch actually floats back and forth like and old style clutch with a keyway. I have read on here that you don't want to do this with the DD setup but don't know if anyone has tried it. My only other option would be to remove the shaft from the DD and shorten it, but I really didn't want to get into that.

As anyone run this floating style setup on the DD sleds? Any of you guys that have done this before run into this problem?

Get the updated adjuster from AC or BDX adjuster if you're still using the old style plastic junk. You can't have any float with the DDrive, clutch must be tight.

 

[PowerJoe]

Wood - Thanks for the info.

Yes I am thinking that only machining .050 off each side was not enough. I think the belt deflection was just about right, but it was without any adjustment or deflection adjuster installed. I would like to get the belt so tight it will squeal and then loosen the belt a little bit, but I would have to machine more off in order to do that.

It looks like the newer AC or BDX adjuster would solve my problem I just couldn't tell fromt he pictures how they actually worked. Do these newer adjusters still vent through the bolt?

 

[Wood]

Yes, they still vent. You will need to get a lot of extra shims if you go with the AC adjuster.

 

[PowerJoe]

Update

I put about 200 miles on without issues. Here is what you need to know.

1. I only machined .050 off of each sheave and it is barely enough. I will run into belt deflection issues as the belt wears, but right now it is OK. I would machine .060 off so you have some deflection adjusment to work with. I don't know how much more you can go without running into problems with running out of sheave surface at full shift out.

2. You have to run the BDX deflection adjuster or the 07 and newer cat adjuster. I ran the BDX and it worked good.

3. You will have to set the alignment/offset using the floating method as the offset bar is no longer relivant.

4. You will need to trim some of the foam from the underside of the clutch cover/guard.

 

[North]

Bump. Is there any way to tell if this mod has been performed on my secondary? I bought my M7 used and the file I received with the sled has a pamphlet on the 10.4 conversion, but my secondary does not measure 10.4". The belt is a stock 36. Is it even possible to run the 36 on a machined secondary or is that a dead giveaway that I have an unmodified secondary?