Clutching for added power

[lancelarue]

Thought I would throw this out there.
Let's say you have a mod motor and your clutching is really dialed in good. Temperatures are nice and low and balanced almost perfect.
Now you make some more modifications and even though your driven is set up to be real sensitive, the rpm is too high with the new mods.
Would you
A: just add weight to the drive and start dealing with the driven to match again, or
B: Just drop end load on the drive spring to get the rpm where you want it and keep the weight / shift force the same?
This is what I've been doing here lately. So far so good. Sounds almost too simple!!!!!!!!!!!!!!!!

 

[winter brew]

Generally that's what I would do first....either add weight or less primary spring. Gearing is another thing to look at if you added much power....more power will pull taller gearing, then you get to go back and screw with clutching all over again.

 

[geo]

Your assuming that everyone has the spring selection Doo has. This is untrue LOL.

 

[lancelarue]

Amazing, every time I think I know something I get slapped alongside the >>>( loss of memory plays here too!!).
So customer has his clutching "dialed". I mean slight heat is really close. So I build him a set of high compression domes for his 800R and tell him, don't add weight, you're already balanced-- drop the end load on the drive spring. Keep the "shift force" the same. Calls me and says his primary is making heat. I think DUH!!!??? What was I thinking? More hp, same helix angle,(he has a Shockwave so we can cheat!) Primary won't hang on to the belt, so, I tell him to dial in some more angle to balance it out. Here comes the tricky part, if the snow load / conditions were light, that would work, but if the load was high, backshift will go away. (and it did!!) Much as I hate to add weight, only solution with this driven "QRS" to get it to hang on to the belt, was less angle & more weight bigger finish on the spring. More shift force / more belt squeeze @ the driven to take care of the + hp. This is where you really see the difference between driven clutches. Dealing with HP !!!!!!!!!!!!!!!!!!!!!!!!!!

 

[winter brew]

FWIW...i could never get a straight cut helix to work well on a QRS with a big track. That secondary likes a wiiiide angle spread to get good upshift and bacshift or maintain RPM at higher speeds.

 

[lancelarue]

Never set anybody up with a Shockwave & a big track so I wouldn't know. But on a
154" they kick some butt!!!!!!!!!!
I would think they would work even better on a big track if you get the primary balanced with the driven-------- Perfect angle for all conditions.
We have to deal with a huge altitude variation here. And super heavy coastal snow and big hp because of the big air density = biiiig loads! In all honesty I have to say we don't run stock ramps either. They suck.

 

[geo]

`Bin trying to figure out if particular driven (ie QRS) has a specific combo that is THE combo because of side pressure ratio. Only so many springs available. Your helix angle change was predictable and as it should be.

I have a question or two though LOL.. If you drop finish pressure on the primary do you not add "shift force" for at least the last half of shift. Was the added shift force "uncontrolled" because of the lighter spring balance, so did this throw out the secondary balance and cause poor backshift causing the primary to heat up? Did your customer experience more compression braking with the soft spring set-up? If you have the correct ramp for the engine power would you not be able to lower a clicker, same as dropping in elevation, and not change a thing in either clutch?

Just thinking how limiting some secondaries are also.

 

[winter brew]

Never set anybody up with a Shockwave & a big track so I wouldn't know. But on a
154" they kick some butt!!!!!!!!!!
I would think they would work even better on a big track if you get the primary balanced with the driven-------- Perfect angle for all conditions.
We have to deal with a huge altitude variation here. And super heavy coastal snow and big hp because of the big air density = biiiig loads! In all honesty I have to say we don't run stock ramps either. They suck.

I was saying I couldn't get it to work well without changing the angle....I always had to change the angle for a hill, then change for the flats, then change for snow conditions....while I can get a wide spread progressive to do all those things every bit as good without ever opening a side panel. Using helix angle to tune RPm is sort of a clutching "no-no"....it works, but is not ideal.
The Shockwave DOES work good if you don't mind making adjustments and replacing rollers more frequently....the ramps are narrower and tear up rollers pretty quick.