Joe i have a couple of ? i do have both cat and doo, but have spent years with cat clutches a nd do know how to set them up pretty good , compared to the tra,it always seems on the lake that the doo twin`s lack in top end vs similar powered cat`s. but you put a simialar hp triple . aganist a mach z or mach 1 and usually the doo triple will take it. is it all in the clutching, i read some where once that the tra woked better when it was run at a higher rpm like it does on the triples . vs under 8000 or less like it is on the twins. just wondering if you have any thoughts on this? and second can you get the tra clutch to run as cool (sheave temp.) as the more open cat primary? when ever compare temps when stopping my 925 cat clutches are always much cooler than my 600sdi clutch. in the cat i run big spring pressures front and back and a lot of flyweight (88 grams)) i don`t get much belt slippage with the cat. looking at the different in sheave color. is that my problem with my 600? am i getting belt slippage? i do have many different shades of color on the secondary sheaves. this summer ii`m going to get your clutch kit for the 600. hows is the backshift and acceleration with your kit vs. stock? and i`m not sure if i`m going to get another sdi 600 or a 500ss trail (old 600) do you hace a clutch kit for the 500 ss? thanks

Joe i have a couple of ? i do have both cat and doo, but have spent
years with cat clutches and do know how to set them up pretty good ,
compared to the tra,it always seems on the lake that the doo twin`s lack
in top end vs similar powered cat`s. but you put a similar hp triple .
against a mach z or mach 1 and usually the doo triple will take it. is
it all in the clutching.

JOE]...I think it's the clutching. If the engine has the power to push
the sled to a very high mph, however the mph is lower than expected, I
would check the clutches. Me, I would go right to the secondary and
check the temperatures to see what the clutches tell me.

i read some where once that the tra worked better when it was run at a
higher rpm like it does on the triples vs under 8000 or less like it is
on the twins. just wondering if you have any thoughts on this?

JOE]...Maybe whoever said this really had their tachs off. So to run
an engine at 7850 actual rpms the tuner has to run the tach at a little
over 8100 "tach" rpms. I have seen 50 rpm low at 8000 to 250 rpm higher
than 8000.
Whoever wrote this article I would also like to read the reason how
they quantify that answer of running higher rpms. Our 800 mule, if you
took it for a ride you might say "that rpm theory is blown out of the
water" as it's run at 7500 rpms.

and second can you get the tra clutch to run as cool (sheave temp.) as
the more open cat primary?

JOE]...Have seen 100~110 degrees with our 800 sled and I have had many
report back to me saying the same thing.
On the other hand I have had two sleds with my kit that consistently
run 150+ degrees. "Mind you I still think they are slight overreving"
Install stock clutching again and even hotter. Go back to kit...still
hot. Align engine, take run...hot, try to center secondary on
jackshaft..still hot! What the Fk? Extreme example of this sled
blowing 5 belts in 900 miles and the other sled had 1800 miles on it's
belt and kept on going. I just don't get it. I know overrev causes
excessive slippage and very hot primary, lack of secondary spring force
causes excessive heat and I've seen a cure by changing to the green or
purple secondary spring.
***In the end I know from much testing that hot clutches can be cured
by eliminating overrev, choosing a proper gear ratio [usually lower than
stock] and the use of high "rate" secondary springs.

when ever compare temps when stopping my 925 cat clutches are always
much cooler than my 600sdi clutch. in the cat i run big spring pressures
front and back and a lot of flyweight (88 grams)) i don`t get much belt
slippage with the cat.

JOE]...I would not doubt then you use the Green Cat secondary spring?
It's a monster. I love that spring in cat stuff, even the 440's.

looking at the different in sheave color. is that my problem with my
600? am i getting belt slippage?

JOE]...I cut n paste part of a page from some of my notes...

When torque is applied the belt is nothing less than like a steel band
under tension, no different than a chain with an abrasion/heat/oil
resistant coating.
Regardless if there is slippage causing blistering heat or less slip
with mild temperatures, in the end the belt is like a steel band when
the fuel trigger is applied, it is a direct 100% connection between the
two sheaves.

What causes efficiency is Lack of belt grip.
Where at any shift point on the [Secondary], the belt speed is higher
than the sheave surface speed.
If there is blistering heat, the sheaves are not clamping the belt as a
point on the belt passes thru the sheaves.
Start to apply clamp on the belt and efficiency will rise, temperatures
will lower, friction will be IMPROVED.

From the [Primary] point, you have to put the flyweight in to push the
sheaves at governed rpms. If the weight is too light, then a point on
the belt [noting belt rpm] will merely spin thru rotating around primary
sheave surface ''slower'' than it should be.

The only time I like to associate the word ''extreme'' when it comes to
the secondary describing the heat that is found.
Time to change the secondary details to get rid of the heat. Must
supply spring forces and angles ''Required'' to clamp the belt for the
speed/shift ratios that the sled is going at, which in turn will reveal
cool clutch surfaces.

i do have many different shades of color on the secondary sheaves. this
summer i`m going to get your clutch kit for the 600. hows is the
backshift and acceleration with your kit vs. stock? thanks

JOE]...Backshift incredible, accleration about 3~5 lengths vs stock in
1000' depending on traction. Heh, you'll find the corner/corner, point
shoot quite fun.

Thanks alot Joe for your answers. i use a black- magic, black/ red secondary. best spring we have ever tried for the big torque twins. thanks again