Clutch taper repair

[Danbot]

Searching led me to no information on taper repairs on clutches.
At the end of last season my clutch bolt snapped, and the clutch popped off, making for a long weekend of hanging out at camp watching sled vids while everyone else rode the pow.
Anyways, When the clutch came off, the taper made contact with the end of the still spinning crankshaft for a moment leaving a small mark on the clutch taper. I sent the clutch out for full checkup, balancing, and to get the taper touched up. They shop told me that the machinist says he can repair the taper but depending on the material needed to be removed the clutch may sit "a little" closer to the engine.... makes sense.

If I understand how the float on the secondary works... the float is on the inboard side of the clutch under power. Is this correct?

It would seem to me that no more than a couple thousands of an inch would be necessary to be removed in re-setting a clean taper in the clutch, but until my clutch is ready I don't have those specs from the machinist.
Going with this assumption for now.... will I need to compensate for this small difference in the float or would it be considered insignificant?

I know I should be directing these questions towards the shop with my clutch, and I will.... but I am getting a little upset with this shop with some other issues including but not limited to: trouble getting the proprietor on the phone to discuss this. I won't rant about the shop... but they are a reputable mod shop and I'm still not expecting shady business, but I'm getting impatient, and maybe panicking a little

Indydan, you will be getting my hard earned Canadian $$ for clutch work in the future! Should have gone to you first

 

[skibreeze]

I don't see any issue at all, I've even seen the reamers sold to clean them up. If there was alot of material removed, then just set the secondary inwards the same amount.

 

[markoo]

get new crank from polaris. it comes with a new clutch.

 

[ghostwhite]

There should be plent of adjustment on the secondary shaft to still retain perfect alignment. Just have to rearrange or get new shims.


But this is the Quick Fix IMHO

 

[Danbot]

Thanks guys, I feel better!
I think I have one of the good crank/case combo's.... not gonna %^$#%$ with it! lol.

 

[Danbot]

I had someone call the shop for me today... (I am working days til weds) and was told the big holdup on my clutch is they are having a hard time getting the angle specs on the crank snub / clutch taper. He needs this to make the taper repair.
I need to get this info asap so this crap doesn't interfere with my first trip planned for the end of the month! I'll be calling around when I finish work in the middle of the week, but it would be awesome if someone here could help so I can get the info to them on monday morn. Anyone?

 

[markoo]

Sorry I thought your crank end snapped. when I reread your post I noticed only your bolt snapped. Clean the taper up and put it back on. The secondary should float enough to compensate for the offset.

 

[Danbot]

Sorry I thought your crank end snapped. when I reread your post I noticed only your bolt snapped. Clean the taper up and put it back on. The secondary should float enough to compensate for the offset.

TTT
That's whats being attempted!
I need the angle specs for the taper so they can machine it.

 

[indydan]

recutting the taper

Dan, If your going to have the taper recut make sure you do a few things before you drive your sled.

Before you do anything check crank runout with indicator, assuming crank is perfectly straight ( rare ) but lets assume. install clutch and check runout on clutch shaft where belt normaly sits as close to the inner sheave as possible this will be close to the area you just checked it on the taper itself. if number is relative to crank runout then proceed to next step. ( note most clutches that have had reamers aggressively used in them am ruined. ) and most recut tapers are done incorrectly. so that being said double check everything...........( a remember ) a crankshaft is a terrible thing to ruin.


*note* after taper has been recut install your clutch and get it torque properly then install puller and make sure the clutch comes off with a nice crisp pop. If removal pop sounds good then reinstall and follow torque proceedure. ( if it doesn't pop then its junk )

Normal troque sequence #1 = install the clutch to torque spec, which is normaly a multiple step process at the very least. after first torque drive sled around the yard with multiple stops and restarts then retorque clutch repeat this process until blt does take anymore torque.......... then after your first short ride check torque again if it takes more troque you didn't get it torque correctly before you rode.

clutch bolt torque proceedure is one of the most important final steps that the factories do not stress enough. 70 foot pounds is plenty on on the modern day sleds ( note ) the old polaris 7/16 bolts were only 55 and thats enough if torqued correctly. all the domestics should be 70..........polaris had an update of ( 96 ft pounds ) for the 755/900 motors..... they were NUTS!!!!!!!! ( out of their minds ) thats more then the bolt can take.

Dan

 

[sks rider]

Dan, If your going to have the taper recut make sure you do a few things before you drive your sled.

Before you do anything check crank runout with indicator, assuming crank is perfectly straight ( rare ) but lets assume. install clutch and check runout on clutch shaft where belt normaly sits as close to the inner sheave as possible this will be close to the area you just checked it on the taper itself. if number is relative to crank runout then proceed to next step. ( note most clutches that have had reamers aggressively used in them am ruined. ) and most recut tapers are done incorrectly. so that being said double check everything...........( a remember ) a crankshaft is a terrible thing to ruin.


*note* after taper has been recut install your clutch and get it torque properly then install puller and make sure the clutch comes off with a nice crisp pop. If removal pop sounds good then reinstall and follow torque proceedure. ( if it doesn't pop then its junk )

Normal troque sequence #1 = install the clutch to torque spec, which is normaly a multiple step process at the very least. after first torque drive sled around the yard with multiple stops and restarts then retorque clutch repeat this process until blt does take anymore torque.......... then after your first short ride check torque again if it takes more troque you didn't get it torque correctly before you rode.

clutch bolt torque proceedure is one of the most important final steps that the factories do not stress enough. 70 foot pounds is plenty on on the modern day sleds ( note ) the old polaris 7/16 bolts were only 55 and thats enough if torqued correctly. all the domestics should be 70..........polaris had an update of ( 96 ft pounds ) for the 755/900 motors..... they were NUTS!!!!!!!! ( out of their minds ) thats more then the bolt can take.

Dan

So indydan, you think 70ftlbs is enough?

 

[indydan]

So indydan, you think 70ftlbs is enough?

sks, yes 70 is plenty. if you want to go to 80 ft lbs you can.

I have used 80 ft lbs sense the domestic bolt showed up, but i have drop to 70 ft pounds on my Torque Master paper work because the cat bolt is alittle smaller and 80 is pushing it.

If the torque proceedure is done correctly at 70 ft lbs, thats better then 96 ft lbs done incorrectly.

What the result were looking for is...........( a solid no slip lock ) And both tappers should be polished with scotch-brite and then clean and dryed with electric motor cleaner..........Then torqued to spec, the first torquing rarely gets the clutch seated deep enough to lock them together. If the clutch gets a chance to spin and lock itself chances are it doesn't stay square and the danger is it welding itself to the crank if it over spins.

The better you get your clutched torque the better it will come off with a nice crisp pop.

if you had to use grease or any other extreme measures to get your clutch off chances are it was not installed correctly.

A way to fully understand this is to have a torque wrench every where you go and double check your clutch bolt torque every sled your buddies have............. you will find some very interesting data and alot of loose drive clutches.

Dan

 

[danduvall]

Searching led me to no information on taper repairs on clutches.
At the end of last season my clutch bolt snapped, and the clutch popped off, making for a long weekend of hanging out at camp watching sled vids while everyone else rode the pow.
Anyways, When the clutch came off, the taper made contact with the end of the still spinning crankshaft for a moment leaving a small mark on the clutch taper. I sent the clutch out for full checkup, balancing, and to get the taper touched up. They shop told me that the machinist says he can repair the taper but depending on the material needed to be removed the clutch may sit "a little" closer to the engine.... makes sense.

If I understand how the float on the secondary works... the float is on the inboard side of the clutch under power. Is this correct?

It would seem to me that no more than a couple thousands of an inch would be necessary to be removed in re-setting a clean taper in the clutch, but until my clutch is ready I don't have those specs from the machinist.
Going with this assumption for now.... will I need to compensate for this small difference in the float or would it be considered insignificant?

I know I should be directing these questions towards the shop with my clutch, and I will.... but I am getting a little upset with this shop with some other issues including but not limited to: trouble getting the proprietor on the phone to discuss this. I won't rant about the shop... but they are a reputable mod shop and I'm still not expecting shady business, but I'm getting impatient, and maybe panicking a little

Indydan, you will be getting my hard earned Canadian $$ for clutch work in the future! Should have gone to you first

i think your machinist should of welded the damaged area then machined it down to oem specs! just my .02

 

[Danbot]

Dan, If your going to have the taper recut make sure you do a few things before you drive your sled.

Before you do anything check crank runout with indicator, assuming crank is perfectly straight ( rare ) but lets assume. install clutch and check runout on clutch shaft where belt normaly sits as close to the inner sheave as possible this will be close to the area you just checked it on the taper itself. if number is relative to crank runout then proceed to next step. ( note most clutches that have had reamers aggressively used in them am ruined. ) and most recut tapers are done incorrectly. so that being said double check everything...........( a remember ) a crankshaft is a terrible thing to ruin.


*note* after taper has been recut install your clutch and get it torque properly then install puller and make sure the clutch comes off with a nice crisp pop. If removal pop sounds good then reinstall and follow torque proceedure. ( if it doesn't pop then its junk )

Normal troque sequence #1 = install the clutch to torque spec, which is normaly a multiple step process at the very least. after first torque drive sled around the yard with multiple stops and restarts then retorque clutch repeat this process until blt does take anymore torque.......... then after your first short ride check torque again if it takes more troque you didn't get it torque correctly before you rode.

clutch bolt torque proceedure is one of the most important final steps that the factories do not stress enough. 70 foot pounds is plenty on on the modern day sleds ( note ) the old polaris 7/16 bolts were only 55 and thats enough if torqued correctly. all the domestics should be 70..........polaris had an update of ( 96 ft pounds ) for the 755/900 motors..... they were NUTS!!!!!!!! ( out of their minds ) thats more then the bolt can take.

Dan

Thanks Dan, if the taper repair go's through I will follow your instructions. The crank runout has already been checked and is well within spec. At this point I am still doing part of this shops work by looking for the taper specs on my own. The clutch has been sitting there for the last week waiting to be machined while they have been waiting for phone calls back with this info.

Thanks for the help everyone, but my quest remains....does anyone have the taper specs I need? A new clutch @ $550 cdn + balancing is my other option.

 

[High Velocity]

Dan, have you checked with any Polaris dealers to see if they have the correct tapered reamer to lightly touch up your clutch. What a shame. That clutch had nothing for miles on it when you got it.

 

[Danbot]

Dan, have you checked with any Polaris dealers to see if they have the correct tapered reamer to lightly touch up your clutch. What a shame. That clutch had nothing for miles on it when you got it.

Tell me about it Ken, the mark in the taper was very minor too. I am just trying to do the right thing with it, feels like that has gone wrong.

 

[Danbot]

Dan, have you checked with any Polaris dealers to see if they have the correct tapered reamer to lightly touch up your clutch. What a shame. That clutch had nothing for miles on it when you got it.

Ken, I went with another shop that could do the balancing as well. I'm starting to suspect that the angle specs I am searching for are a Polaris secret.
I sent Chris @ Carls Cycle an email asking for help, fingers crossed.

On the plus side........ it's snowing like hell out there! I barely got my Supra home from work.

 

[Z-Man]

What is the best way to hold the clutch/crank so that you can get an accurate Torque on it? Is there a tool for this?

 

[Danbot]

What is the best way to hold the clutch/crank so that you can get an accurate Torque on it? Is there a tool for this?

You bet, a clutch holder tool. Also best for holding the clutch when removing it with a puller. The SLP tool I linked is good, and affordable.

 

[Z-Man]

You bet, a clutch holder tool. Also best for holding the clutch when removing it with a puller. The SLP tool I linked is good, and affordable.

Thanks, I will have to add one of those to my order for a clutch puller.

 

[millwall]

Hope this helps, taper measurement on a CMM.
Angle = 5 deg 44 min or 5.737 degs
Video shows measurement in a cone format
http://www.youtube.com/watch?v=vb17x8D9lWM