Slipper clutch goodness!

[Duck-Stew]

Mmmmmm......  It's a right tasty mod.

Last year, I wandered through my local Duc shop and one of the techs motioned me over to his tool box. 

Him : 'Hey Stu, you wanna buy a slipper-clutch?'
Me : 'Uh.  Sure *&%^# (name changed to protect the guilty), watcha got?'
Him : 'Here.'

-Box was labelled Yoyodyne 48T slipper-

Me : 'Aren't these like uber-expensive?'
Him : 'Yeah, but that's not what's in the box man...'

-opens box-

Him : 'It's a stock 2004 749R dry-slipper clutch.  The customer swapped it out for the Yoyodyne one, and left the stocker with me.'
Me : 'Ok, I get it...how much?'

Suffice to say, my wallet was empty but I now had a slipper clutch.

-=Fast forward to today=-

I got a few moments last night to do the install and had to wait until today for a test-ride.

WOW.  If you've never ridden a Duc w/a slipper clutch...totally different story man.  I love it!

Not to mention, I got better frictions, about 2lbs fewer rotational mass (with an AL basket) and the slipper benefits ta-boot.

Very nice addition. 

Me before :  [moto]

Me now :  [moto] [moto] [moto]





 

[yotogi]

Congrats Stu!

Which bike did you install it on? Did you go from a wet to a dry-slipper, or a dry to a dry-slipper?

[swampduc]

Awesome, Stu!
How long did the job take?

[junior varsity]

And I'm jealous. I'm not sure what the gains were for the original purchaser to go from OEM slipper to 48T slipper. slightly lighter, slightly lower clutch wear because of 48t design... Was it enough to warrant the additional costs without first wearing the original out? I'm not really sure.

[Alexandre]

And I'm jealous. I'm not sure what the gains were for the original purchaser to go from OEM slipper to 48T slipper. slightly lighter, slightly lower clutch wear because of 48t design... Was it enough to warrant the additional costs without first wearing the original out? I'm not really sure.

its only money man

[junior varsity]

at least he's helping the economy!

[Duck-Stew]

Congrats Stu!

Which bike did you install it on? Did you go from a wet to a dry-slipper, or a dry to a dry-slipper?

Installed it on Allegra (my '95 M900) so it was a dry standard to a dry slipper conversion.

Awesome, Stu!
How long did the job take?

Took my time,  in hand and it took me like an hour or so including cleaning out the clutch housing.

And I'm jealous. I'm not sure what the gains were for the original purchaser to go from OEM slipper to 48T slipper. slightly lighter, slightly lower clutch wear because of 48t design... Was it enough to warrant the additional costs without first wearing the original out? I'm not really sure.

I've ridden a bike with a 48T, 6-ball STM slipper in it and it's noticeably smoother than this 3-ramp style is...  but for $1200-ish bucks...  IMO, not really worth it.

With a little more spring adjustment, I think I can fine-tune this one to do whatever I'll need it to for this bike.  Full-on competition?!?  This may not be a good choice for the discriminating crowd.  For a street ridden M900?     [moto]

[junior varsity]

For a street ridden M900?     [moto]

OOHHH ABSOLUTELY. I wish I was discerning enough to care about the difference - I know a slipper isn't a slipper isn't a slipper, but its not a non-slipper and I can discern that much. I'd like to hear more ride impressions as you get out and play around on it, specifically where it makes a standout difference over the non-slipper.

[Duck-Stew]

OOHHH ABSOLUTELY. I wish I was discerning enough to care about the difference - I know a slipper isn't a slipper isn't a slipper, but its not a non-slipper and I can discern that much. I'd like to hear more ride impressions as you get out and play around on it, specifically where it makes a standout difference over the non-slipper.

After riding both, you would know the difference... 

So, I was on the freeway yesterday at 75mph in 6th hovering around 5K rpm.  Pulled the clutch and popped it into 4th and let the throttle go to idle.  Before, this would pull the bike down to like 55mph within 5-8 seconds (never timed it).  After like 20 seconds, I was slowing past 65mph and the rpms weren't dropping anywhere near as fast as a direct acting clutch..

After more riding, I'll be able to fine-tune this one slightly (with spring tension) and will post up a ride-report on it.   

[yotogi]

Forgive my ignorance about the functioning of a slipper clutch, but if it is slowing you down that differently, does that mean that you are putting more wear and tear on the clutch plates themselves as they "slip away" the excess inertia in the rear?

[Duck-Stew]

Kind of...  They're actually 'floating' between the pressure of the pressure plate springs and the internal spider spring (If I'm understanding slipper clutch physics here).  Since they're 'floating', they're not transferring (anywhere near as much) torque as it would be if they were engaged.

So, short answer:  Yes, they're wearing out quicker.
Long answer: Sort of...but not really that much.

[LA]

I used a Yoyodyne for about 15,000 mi. and loved the thing.  It's a must have item, but I must not have the $$$, cause I don't have one on this bike.

48 tooth plates are a good deal more expensive though.  The 12 tab Yoyo was well under $1000.

The only time I didn't like mine was when it came time to bump start the bike - it had enough battery to run the fuel pump, but not enough to turn over.

LA

[moto]

Alot of people say a slipper is not necessary on the street--and that it is for track use only.
Since I don't ride my bike in town except to get gas, I would't know.

I do know it really comes in handy up in the hills on the down hill turns- especially if there is a little moisture on the road.
The rear wheel no longer hops around when I don't match the RPM's just right or if I'm on the brake too hard.

The lighter assembly allows the bike to rev up a little faster and the clutch feel is much better. Some slippers ( like the Surflex) have very easy clutch pulls that are as light as a cable clutch. The clutch is also a little quieter because the basket, plates and drum is billet aluminum--not steel.

A good time to upgrade to a slipper is when it is time to change a basket and friction. We have complete slippers with Surflex friction plates for under $1000:Corse 4 Spring Slipper Clutch w/ Surflex Plates . I know people spend almost that much on cosmetic pressure plates, billet keepers, polished springs, mediocre friction plates and aluminum baskets.

-M

[Norm]

I consider a slipper clutch a safety item on any big twin as I do a steering damper on ANY motorcycle. I don't like to see them used as a downshift aid, however many people do. I use a stiffer spring so it will only prevent wheel hop when you screw up a downshift (and you will). You just haven't lived until you experience wheel hop going into a tight downhill corner - I'll show you my scars sometime.

[Rob Hilding]

On my slipper bike -





I don't need no car