Found a good used TRA from a '95 Skandic 503. How diff. is the calibration needed for my '85 Form.Plus? Anyone know the arm weights I might need or the spring? Thanx-

Here is specs for Skandic.
Ramps :284
Spring : RD/GR


Rollers are the same.

The clutch parts for a 521 (Type 537) in a TRA equipped PRS sled is:

Primary spring Yellow / Blue 100 ~ 290 lbs 420 438 093
Levers 420 448 195
Ramps "144" obsolete but can be substituted by a "286" ramp

Thanx a ton, gentlemen!

just an FYI that is all 85 plus had a RSSR clutch and the if memory is still some what usable the sled had a silver hood.

The clutch on it is toast,( its a black conical shaped), so I need a new one. My hood is black but the build date is Oct. 1984. I'm guessing someone replaced the hood.

slayer what's the serial on your sled if you don't mind?

Ctr distance and offset r changed
rssr: 35 mm and 33 mm offset
TRA : 27mm and 36 mm offset
Also white spring 414-6056-00 engagement up 400-500 rpm
yellow 414-6055-00 up 300 more

a 142 ramp lowest engagement
144 is stk
145 is most aggressive
u could also run a 147 ramp and a 228 ramp also

just more options to play with

I s the "147" or "228" the #'s stamped on the arm? Thanx for all the help, guys! I'm just learning this clutching thing-

Are these the ramps you speak of?
Click to view attachment

145 is the best ramp to run IMO
with a new 414-6056-00 white spring engagement 4200-4400, w/ the stk BL/YL 3800-4000
FYI: BL/YL= 130-230
White= 150-240
Yellow= 160-270

Yes the # is stamped on ramps

Cool. I just bought the ramps.

Ya the Plus had a silver cab I believe it went black in 86 then to the familiar red we think of when we hear the name Formula Plus

neat story on the 85 Plus here
http://www.snowgoer.com/output.cfm?id=2232991

Yep,'84 was grey ,'85 was black,and red after.

Good read.

85 was grey,86 was black ,87-93 red

No 84 Plus, they still had the Blizzard 9700 Plus in 84

Right,i was a year off.