Clutches

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Clutches - Older 440 with non-Skidoo secondary
Clutches - What secondary do I have, Roller or Button
Clutches - Mix match clutches, 03 primary with 06 secondary
Clutches - Mix match clutches, TRA-2, TRA-3
Clutches - Galling in primary clutch
Clutches - TRA vs. TRA-2 vs. TRA-3/5/7
Clutches - TRA/TRAII component swaps
Clutching Twin Pipes - Twin pipes on Summit

 

 

Clutches - Older 440 with non-Skidoo secondary
Question) Hey Joe, I talked to you a bit last season about the clutch on my 02 440. I bought it with a t secondary on it. I see you posted a setup for the 440. I was wondering if I could get your opinion on your t setup vs. your doo roller kit. I am thinking the t will back shift better, but the doo roller will be faster on top....is that assumption correct?

How do the two setups compare? I want to clutch it before the season starts and would like your input. if there is a big advantage to the doo roller, I will buy one and buy your kit (someone posted the 46-34F is no longer available. don't know if that is true or not, but that might force me to go to the doo roller if it is true.)
thanks in advance, Nick

Answer)  Nick, I don't know how you can think one setup will back shift better than another setup if you don't have any evidence of getting to try either one out. You can make an old worn out p.o.s. button secondary work better than ANY "flavor-of-the-week" secondary, IF you have the details in the clutches that suit the requirements.

If the "flavor-of-the-week" secondary has parts in it that don't allow certain actions that put a smile on the tuners face, then what you have is a "nice shiny secondary" and that's about it. I would call t up directly and ask them if they have one for your secondary and if not then get one made for it.

Other than that, the formula roller that come stock on the 02 will work better all around with back shift, upshift and top end because of "good calibration" that's proven.....unless you get the t helix and secondary spring setup I mention - Then you'll have a t secondary setup that will work similar to the infamous S4X 440 clutch kit.

I will say again, if you are stuck going with t, then do yourself a favor and call-up-directly and ask them how much $. The t "physically/mechanically" a much better secondary than the formula roller, the formula roller is delicate and damage rollers easily. If i remember right the price of a 46/34 programmed will be about the same price as a replacement set of rollers for the formula secondary and the formula secondary cannot have dents on the rollers or the shifting will suffer.
http://www.picturetrail.com/sfx/album/view/1520953
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Clutches - What secondary do I have, Roller or Button
 Question)Hello. I have been searching but can't find out how to tell if I have a button or roller secondary clutch. I have an 06 800 MXZ Adrenaline. Is there a way to tell if its a roller or button by looking at it without taking anything apart?

Answer] Normal in 2006 and 2007 for only “X” models to have roller secondary. An “Adrenaline” model usually have the button secondary.
To see for yourself, remove the secondary off of the sled and observe the helix. The button helix has a "spacer" that is not included in the helix.
the roller helix has the spacer built/pushed right into the helix itself.
Click here for picture illustration.
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Clutches - Mix match clutches, 03 primary with 06 secondary
Question) Joe, my machine is 03 440x with a 06 800 H.O. power tech. What I have for clutches is the 03 440 primary and 06 800 adrenaline secondary. What can I do for gearing, right now it has the 21:43 How can I make this mismatch work?

Answer) Great that you have an 06 secondary. The first thing to know is that in 2006 and 2007, the X-model=roller and adrenaline model=button so now you would be able to get the correct helix off of me.

The 03 440 is TRA-2 primary clutch (12 degree sheave angle) and uses a 1-3/8” belt width. The 06 800 HPV-27 secondary is VSA (Variable sheave angle, 12~14 degrees) TRA-3 and 1.5” wide belt.

You would be able to use the mixed match of the clutches by taking the HPV secondary apart and inside you’ll find 2 shims. Remove one shim and re-assemble with the clutch parts and continue to use the stock 440 BRP belt #414860700 (affectionately known by 440 guys as the 8607 belt) It is one tough belt for a little belt, this was used stock on 800 open mod sno-x chassis and worked quite well, lasted a long life and they are still economical to buy.

As far as the primary ramps, the 440 ramp is the 296 and the 800 open mod’s used the 293x’s, to which the 440 ramp is a bit thicker and will produce quicker rpms than the 293x however not to worry, I apply a primary spring with a lower final force than what normally used in the regular trail kit. That primary spring would be a grey Dalton 200/330 and apply the 23g in clicker 3, hammer down!

Regarding gearing, the 21:43 uses a 74P chain. You could gear up to 23 or 24 top gear with the same 74P chain and be geared close to a stock renegade model of that 2003 year. Each 1 tooth taller gear will give you an approximate 4mph more top end, really you could count on 6mph increase with 2 top teeth and the midrange acceleration would be strong and excellent.
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Clutches - Mix match clutches, TRA-2, TRA-3
 Question) Hi Joey, Looking to replace my primary clutch on an 01mxz800. Do you know if I can put a TRA-3 on, taking off the TRA-2 that came with the sled?

Answer) The TRA-2 is 1-3/8 belt width. The TRA-3 is 1.5 belt width. To get the TRA-3 primary to work with a TRA-2 secondary clutch, upon disassembly, observe there is one shim down in between the sheaves.

To get 1.5 inches width, install a 2nd shim on top of the present shim, then re-assemble. With that 2 nd shim installed the clutch will now be 1.5" belt width. You'll have to re-adjust the belt deflection when everything is back on the sled and calibrate the clutch to the new personality of the sled.
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Clutches - Galling in primary clutch
Question)...Tonight, I noticed that the clutch at the very inside of the face of it down at the bottom of the sheave has some pitting. It seems to be in an area that is not a big problem but I wanted to get your opinion. Is this normal. Is it going to cause a future problem?

Answer) Short version...
That pitting is called Galling and right at the stub is partly from the bushing and button clearance inherent in the primary clutch. Under load there is a major clearance and a minor clearance side. The major side is front of engine; the minor is towards the clutch. The distance across the o.d. of the sheaves is farther away on the major side than the minor side.
For galling to happen at that area on the stub;
i] the clutches" have reached full shift, however...
ii] The sled itself has not necessarily achieved speeds reaching theoretical o.d. or even 1:1.
The reason for the primary galling like that is because the clutches achieved full open for a moment in time.

Answer) Long version...
There is a point where the clutches are up shifting, the speed is increasing and the sled reaches a speed where it’s at a "governor point". You top out in mph and I can safely bet at least 10 mph below the rated 1:1 ratio in stock clutched Doo sleds as of lately. You stay on the throttle and the sled basically does not gain anymore speed however the secondary is still opening. The sled maintains the same speed, however the secondary still opens, and you maintain peak mph by virtue of belt slip.

At that "governor point" the combination of final helix angle and the secondary spring final force cannot overcome the push from the primary. The primary pushes the secondary open but the power is not going to ground, rather creating heat. Keep this up for more than 10 seconds....BOOM! The belt shreds.

How to prove; With the secondary removed, you can either take a thick square elastic band or a couple of small plastic tyraps and put it on the helix tightly shoved against the secondary sheave. As the shift increases the sheave opens and pushes the elastic or tyrap towards the chassis trying to shove either of them off.

You take a test run and start to notice the sled peaks out, mph does not increase, brake, stop sled, measure temperatures on sheaves and look on helix/backside of secondary to see how much farther the band/tyrap is pushed back. Ideally it should be knocked off.
On the primary you can blue dye or felt marker where the present galling is located. Mark the galling up. Now with engine off, slip the belt down in the secondary a little. You start up and go for a run; the bogging evident is from the clutches starting in a slight higher ratio.

[You don't want the marker getting wiped off] Now go for your run to top end mph. When you slow down to stop grab the brake and lock it solid at about 30 mph on coast down so the belt will not go to the bottom of the primary at the stub.

Results you'll see - But wait a minute, you only achieved 100 mph when your theoretical 1:1 ratio is 106 mph. How did the elastic band get knocked off but I came up short by around 6 mph. The elastic band should only be pushed off at 1:1 or greater, like overdrive. Did I reach that?...No.

What happened in the secondary? The secondary resisted slippage, clamping the belt up to around 99 mph and now at around 100 mph the secondary components (helix angle/secondary spring selection) could not resist the push from the primary and voila, pops open to full shift . What is revealed in the primary? Answer = Galling.
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Clutches - TRA vs. TRA-2 vs. TRA-3/5/7
There are mechanical/physical features that brp says TRA-3/5/7 clutches are an improvement over theTRA-2. TRA-5 is improvement over TRA-3. TRA-7 is improvement over TRA-5

TRA-2 & 1-3/8 belt. 12 degree straight angle, years 1998~2002
TRA-3 & 1.5" belt 12~14 degree sheave angle, years 2003~present day.
TRA-5 & 1.5" belt 12~14 degree sheave angle, years 2005~present day
TRA-7 & 1.5" belt 12~14 degree sheave angle, years 2007~present day
With previous TRA-2 primary the TRA lever was held in by one fastener which needed a long allen wrench to remove the fastener, taking the TRA lever out.
The new TRA clutch, the levers are mounted in the sliding sheave with 2 fasteners and there is no need to machine the bell for slots to run an Allen wrench. With no slots, you need an improved tool for holding the TRA primary - aka the 4-fingered grunt tool .
TRA, TRA-2, TRA-3 have spline governor cup assembly.
TRA-5/7 have taper governor cup assembly.
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The TRA-3 platform contributes to achieving 12% lower moment of inertia. This means snappier throttle response and quicker acceleration due to the property of its new smaller size. The Variable Sheave Angle [VSA] helps match the angle of the belt better as the belt travels up the shift ratios and is less stressed.
Allows for a wider belt that carries more chords and increased tensile strength imposed by higher hp engines. In 2003 the angle varies from top 14 degrees to bottom 12 degrees.

TRA-3
Larger roll pin design
2 tra lever hold down bolts
Larger 8mm fasteners for spring cup cover
30mm diameter shaft for 70% more rigidity
Spline governor cup assembly.
Thinner outer rim material where starter ring gear is mounted.
Ring gear mounts farther radius from crankshaft.
Ring gear cannot be interchanged from TRA-3 to TRA-2

TRA-5 platform is designed to run cooler and HAS less overall weight then the STD TRA-3 primary.
Uses curved steel arms in flatland calibration.
Uses TRA III curved aluminum arms for high elevation.
Holes in siding sheave used to balance clutch - balance weights no longer used.
***Removal of splines, replace with taper to increase rigidity by another 30% so now instead of spline governor cup withstand 250hp now the taper tra primary can handle 300hp. The taper has contributed to the governor cup flexing less.

TRA-7
Cross between TRA-3 and TRA-5
Uses TRA-3 curved aluminum arms
Forged sliding sheave.
Spring cup bolt holes are deeper and have longer 8mm screws
Fixed half taper/governor cup fit.
Cushion drive
Most parts are not interchangeable with older TRA versions.
Taper governor cup assembly.

2003~newer consumer
600 TRA - Cast primary - Designed for 600, use soft compound belt.
800 TRA - Forged sliding sheave - Designed for 800, use harder compound belt

2003~newer race
440 TRA - Forged sliding sheave
440/600/800 race chassis - Forged Clutch
600/800 race chassis - special order Magnesium [limited quantity] - you have to be really special to get one of these - I'm lucky I even know about them.

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Clutches - TRA/TRAII component swaps
Hi Joe, I have a TRA clutch (1993 MX XTC) that is worn out and want to replace it with a TRAII (2000 Skandic WT 503) that I have on my bench. I have the two clutches apart and looks like the ramps, spring and levers/rollers/pins can swap right into the TRA II. Do you know if this is right? I don't want to put this thing together and watch it fly apart!
Are the parts are interchangeable, very different from the Yam/Cat/Pol stuff I'm used to.
-Rob

Hi Rob, Your TRA clutch (1993 MX XTC) and TRAII (2000 Skandic WT 503) parts are interchangeable.
Remove the (ramps)(flyweight pins)(primary spring) from the 1993 model and directly put them into the 2000 model.
I would not change levers, continue to use the 2000 levers as if I remember right they have a bit more beam strength to them than the 1993 model.
Replace the cotter pins, source them from a Canadian Tire or a Napa store. If the cotter pins are slight longer that will not matter, or just trim them with snips to original BRP length. Hope that helps, regards Joey
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Clutching Twin Pipes - Twin pipes on Summit
Question) I’m not sure what clutch Kit to get From you. I do have a pair of twin pipes and plan on putting them on with pod filters. I have heard and read many bad things about putting twins on Skidoo. With the pipes the rpm of the motor wide open should be 8100-8300.

Answer) Hi....The blame for Twin pipes not working on a snowmobile is sometimes the tuners fault. 90% I have encountered think the engine won’t run right, hard to jet, power band too narrow or whatever else you can blame the engine for.

Here is where the tuner makes the mistake; they think with 15hp increase that the helix angle has to be increased to make up for the added hp and this is wrong. The HP is normally increased by “increased rpms” and can reveal lower torque, so now you actually have to 1]increase secondary spring forces or 2] lower the helix angles or make a wider spread of helix angles to compensate for the lower torque the engine produces.

I give a real example of a tuner I coached. He ran a set of twin pipes that raised the “rated rpms” from 7850 to 8300. Originally using a 47/44, he thought that by the hp increase he would have to compensate by going to a 53/47 and had a tough time to get the sled to perform good at any operation other than a full throttle run to top end mph.

If the throttle was cycled or snow load changes or ground level changed, the rpms would reduce and not recover unless the sled speed was reduced. After explaining about the engine and now new requirements of clutching, he ended up going with a 47/40 and regained good back shift and proper rpms under loaded conditions.

The reduced angle "stalls" the upshift allowing the engine to produce it's correct rpms.
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