xp clutches ,what to watch for

[maxwell]

if your tra clutch doesnt eat belts, keeps track speed similar to other brands, and holds rated rpm how is it not a good clutch?

i guess i just havent been spanked by a sled with a p-85 yet. maybe this year!

 

[HagmanMod1]

10 minutes with a lathe and any tra will be like a race tra machine the fins off behind were the ring gear goes

 

[d8grandpa]

After seeing you guys and the work you have done to the numerous 800R's you have serviced over the past 5 yrs mine included if you say Poo clutch is the way to go then get my parts Al I'll be out to see you and Pete and get her done. Is there snow there yet I'm starting to get the shakes andI'm having whiteouts its getting bad. Cheers[/QUOT


The P85 is actually a Team clutch not a Poo clutch, it is just the one Poo uses. So any Doo peeps don't have to be worried about contaminating their ride with any Poo parts.

 

[OOC ZigZag]

LMAO good to know.

 

[sledshedrevy]

biggest reason no one has had there butt kicked by this set up is that we believed that the doo set up was ok,had the set up under my bench for years , simply there are very few out there . not for long thou . really , all ya have to do is look at the simple physics of the two arms .and or really look close at the travel arc the tra arm makes and see if that doesnt start ya to really wonder , what if ,
forty years at this , thousands and thousands of chassi dyno runs , 4 hill climb titles , gives me a pretty good feel as to weather the set up is gettin it all out there or is leaving it on the table . i kick myself for not doing it sooner .
on the series 3 motor i used the thunder shift arms to achieve a gain , when the r motor showed up it showed a lot of issues , motor and primary clutch wise .
what we achieved with the thunder arms was accelorating you quicker thru the usable range the tra worked thru .
found the happiest in a single cam angle and correct end load spring ,
althou this set up was ok in our snow conditions the room for improvement really showed up once we saw factory hp increase and we didnt see the track speed gain and we werent getting around in our usuall play ground any better .
now with the approach changeing on clutching i am seeing a signifigant lift out of my personel sleds with the clutches i am useing .looking forward to this season
a lot .
keep in mind that these are the things i see here and may not apply in your riding conditions and terrain .if ya have ever had a chance to ride with me it tends not to be in open slopes and the trees are definately more apealing so getting around were i riide asks of different type of clutch set up .

 

[teeroy]

you bring up some very good points on the difference between operation of the TRA and everyone else's clutches and how they work. the TRA is a great clutch for instant "push" from the arms and were the setup to beat in hardpack drag racing. they hit harder at engagement but their effficiency falls off at full shift exactly as you describe. I've slaughtered many F7's off the line with my old MXZ 800 only to have them run me down at the big end.

the problem with your theory IMO is that unless your mountain sled is geared at 50 mph at full shift, the TRA arms are not at that point of inefficiency yet. if you are geared at 19/45 and a theoretical top speed of 88mph, and pulling 45-50 mph trackspeed you are still well within the effective range of the TRA. with aftermarket parts there is more to be had, as good or better gain than going to a P-85. you have found what works for you and probably a lot of other people that just want to ditch the stock TRA and go with something different.

where I completely agree is the part of your explaination of early failure of the TRA components. it is a terrible chain reaction that once one part of the TRA fails, the rest is not far behind. and once that happens, the cost of the changeover to a P-85 looks very reasonable.

these are the rambling thoughts of a dyed in the wool 'doo rider. your opinions may vary.

 

[sledshedrevy]

thanks Teeroy . i to have been a dye hard doo guy . hence the extreme serch in what the doo can and can not do . there limitations have been a combination of lack of selection in some areas , even thou they offer a ton of stuff for there primary they lack in the spring selection for there seconderies.
actually when you look at the graphs the chassi dyno makes ,you can make the tra look perfect with the adition of weight in certian parts of the arm . mind you as i have stated before the tra is likely the best trail clutch out there .
i feel in the diagnosis of the tra in the mtns , yes they can feel adaquite.
typically we find that the track speed combined with the tracks we have today allows the majority to be happy with it .
but unless some one shows them up they wont pull ther head out of the sand on makeing the mtn clutch as efficient as there tra is on the flats .
if ya look at the tra , mtn use , you see that no one uses the top one inch of the primary , unless you gear it way down to lower the load it is seeing .
lack of arm push happens a lot sooner than you are realizing , actually nearly as soon as the arm starts to climb the steep part of the ramp ,
in riding them in the deep stuff , clear belt guard and hood you get to see were the belt is riding . you would be shocked as to how little it moves off the bottom of the primary .
the belt contact patch doesnt even up till one to one , for both clutches .
doo was the closest in 08 when they tryed the straight 42 helix with the 417 ramp .
had they offered a secondery spring with 20 to 30 lbs less end load they would have been a lot happier , the 305 lb one they are stuck on over works the primary
the 42 angle compared to the 47 degree angle has more sidde wall pressure than the 47 and desnt need the big sidde load , yes the 47 needs it as the 47 has much less side wall pressure on the belt than the 42 .
to compensate , weight gets added and lately the 350 lb finish to the primary spring is added
shallow out the helix more and you add more weight and more end load primary pressure .

now compare this to a say 38 degree or 40 degree helix with 260 lbs of end load spring
allows you to soften primary spring end load and not use as much weight in the pins .
this set up shifts up and back a lot quicker and isnt fighting end load pressures
but gives as much side pressure tothe belt as is needed .

2009 they decided to throw a reverse angle helix at the secondery and a different ramp 441 in the primary .2010and 2011 they followed this pattern
works fine , or so we think .definately adaquite for the average guys riding , covers a broad range of applications snow condition wise .they added the 350 finish in the primary spring in 2010 and allowed us to oporate the tra clickers on 3 in the deep stuff.
sounds like 2012 has a new approach again.
still wont allow the tra to shift out any further under load .your still locked in to a certian speed zone .i think it could be better .

or is it a matter of economics.. doo guys spend more on clutching than the other 3 brands combined
parts dept loves it . i guess someone has to keep the parts mill turning .

 

[teeroy]

I got my primary/alignment/gearing (read: belt eating issues) solved early on with my '08 (no thanks to 'doo), but was still unimpressed with it in deep snow across a flat field. pulled very well in deep snow and clutches were a lot cooler after the changes, but there was no top end on the flats in loose snow. it would hit 60mph and that's all....got it a little better now doing about 70mph with a weaker finish rate on the primary spring and a DJ helix but still not where it should be. I'm sure there is more to be had in the secondary but just gave up on it because it works great in the mountains. sucks having buddy on his '06 600 SDI 'gade kick my ass across a untracked field around home....have you noticed this problem at all and if so how did you address it? I'm convinced a lower finish rate on the secondary spring would be a big help, but as you mentioned, there really isn't a lot of options for the QRS spring selection. thought about ordering the TNT QRS spring as it has a slightly lower finish rate. your thoughts on the issue would be appreciated.

 

[sledshedrevy]

on the same track in thinking with you .
if you look at the side load pressure need for a 36 degree straight helix its about 200lbs
now if the grape vine is correct the new doo secondery spring is 260 finish with a 40 degree helix
maybe we will have our spring .
at least by my figureing that would be dead on , but lends its self to this question , what ramp did they feel would work for them with it .
when you lay 410
412
413
414
415
417
434
441
the 417 engages sooner by 1mm in thickness over the 415 and 413 and would be my choice
25grams of tip weight and adjusting down to get it to run on clicker 3 at 5000 to 7500ft
160/260 primary spring

now here's something to watch for on xp that hit a wall . tracks can be to tight with not enough sag in them
what happens under full power if the rea springs arent stiff enough and say the rear shock is a bit weak ,
the rear suspension colapses and puts enough tension on the track that it acts like a brake .
you loose a few ways when this happens , one ya cant see it happen but it kills the clearence , as the track isnt reaching out into the snow and you add the running board drag to it and it becomes a bit of a pooch in trying to get around .
less snow and you are hooking up regardles
when i ran my chassi dyno i was surprised at how much of an effect there was in the powers ability to pull the tunnel and skid together , exactly what happens in the deep snow but doesnt show up on harder packed snow .

your ok on a softer secondery spring as long as yourun between a straight 38 for 163 tracks and 40 degree with the 154 track and 42 for the 146 track .
011,s are different due to the track change , a tooth or 2 on the gearing helps them with the added load of a track with no holes .
the spring end load needs to addressed by doo and yes if they offered more we could definately use it

doo race has used the team secondery for many years and i have to , due simpply to the fact they dont offer secondery springs choices , teams range from 200 to 300 end load pressures
when we use the team we use a 180 280 spring with a 48/42 ,046 helix
primary tra 415 ramps with 25grtip weight and a 160/350 primry spring
154 x 2.5 track no holes and 19/45 gears rev chassi
flat out flys and you will likely let off as things get blurry, least for me LOL's

now that is my partners sled and is what i have to beat , hence the wandering into the p85 realm
mine
is loaded at 10/62grs and 130/330 primary spring
secomdery team 140/240 spring with a 58/42 ,046 helix
19/47 same chain case as his and now we have a race
that set up handled some good pump gas turbos in deep snow climbing

long and short yes .softer sec spring will allow us to open the sec more and close the primary more .
now with a felt marker you can mark the primary when doing tests in deep snow and follow your gains and losses noteing the differences and dont expect it to ever get past 3/4 inch from the top , thats about were it achieves the one to one ratio , in deep snow if you can get it to that point you have good track speed .

one other killer that shows up similiar to what you have described is in the primary clutches floating half lower bushing .
with it tore down , place the empty floating half back on the fixed sheave stem .
now pull it 90 degres to the shaft . pushing in and out you should see no more that 12ths clearence
bushing may appear like new visually but can have up to 1/16inch clearence
this allows the floating half to cock side ways just enough to strangle the top part of the up shift and delays the back shift a hair ,
usually requireing a higher clicker number to maintain rpm
anything over clicker 3 over 5000ft means something isnt right
least looked at bushing next to the primarys floating half one , which is easy to change and is dirt cheap ,is the clearence on the floating half on the secondery's bushing .same effect can happen , if this one is to loose as well .
both clutches can have worn floating half bushing and work just fine in flat conditiions, the deep snow and slopes askes for a lot tighter clearences .

the lighter clutching set ups have a better range when it comes to longer clutch and engine life versus the heavy weight and high spring rates , we will only be able to achieve this in the doo clutchs when we can get a better selection of sec springs .

 

[Longhairfreak]

Why would someone want this nightmare? Just doo poo and your done.