NO BS clutch/belt reports from turbo 1200 owners

rotax · Oct 26, 2009

How are the clutches/belts holding up to a boosted 1200?
I see that the 12 uses the TRA4 (I think) primary..that could be a plus in itself.

I honestly never had many belt/clutch issues on my '05 Rev, but I ran a Team 2ndary...and lots of clutch side venting...

Also, any chain/chaincase related issues on the boosted 12s?

It appears the engines are working out well..yes? Just still have some concern about Doos drivetrain after the last few years of reports from the 800s..

triple7 · Oct 27, 2009

From what I have been seeing and hearing, most people are not using the TRA for the primary. The one I saw had a Comet on it, and it worked well. Didnt seem to have any belt or clutch issues.

Jake

rotax · Oct 27, 2009

triple7 said:
From what I have been seeing and hearing, most people are not using the TRA for the primary. The one I saw had a Comet on it, and it worked well. Didnt seem to have any belt or clutch issues.

Jake

Yeah, I see PLites has a diff primary clutch 'option' as well. Not sure if thats the same thing your talking about.

MtnDoo · Oct 27, 2009

PL is running the Polar.
Some are having success with STM.

MCX is the only one I know of that runs the TRA.

MD.

brycter · Oct 27, 2009

we use the STM Primary and did not blow one belt in 800 miles. After we found a clutch to hold the power it was perfect. the only thing that you have to keep an eye on is the 13 wide chain. broke 3 and then took reverse out and run 15 wide hyvo. i have 300 miles on that chain. looking for a belt drive to put on.

Teamleader · Oct 27, 2009

MtnDoo said:
PL is running the Polar.
Some are having success with STM.

MCX is the only one I know of that runs the TRA.

MD.

Mcx is not running the tra, he is using the Comet.
I am using the tra on my mcx without any problems.
The problem that have been with the tra on turboes is that they have been mounting it wrong together without using 10tns of pressure on the guvenour cap. I have been doing this and also using locktite on the cone and also change to the V-1300 bolt and there is no way that this clutch will rotate now and cut the bolt of. We are having 4 1200 turboes and we all are using the tra clutch.

Mr.Olsen

brycter · Oct 27, 2009

I tried everything that i could think of with the tra and could not get anything to work. we even tried a splined rt1000 tra that had the gov cup modded. and it still didn't hold. go with the STM and ride.

Dynamo^Joe · Oct 27, 2009

The TRA4,5,7 you take the chance of tearing the clutch off the crank not because of over torquing the clutch bolt - rather what is happening the governor cup is slipping on the taper face that causes the bolt to tighten up while under full throttle.

As the engine is at full throttle the governor cup starts to turn on the taper thus tightening the bolt till it stretches, necks then breaks off.

This is a primary clutch that blew off the crank at 90+mph and hit me in the leg. It flew back behind the sled then zooOOOOoom...it freakin PASSED me. hahahaha...oh i was laffing at that sucker go, because it passed the guy I was drag racing. It made a left turn right in front of him crossing over and going about 200 feet into the salad.
260hp FPP 1200

Other TRA4 that have blown off were from the levers being too heavy. The RT1000 steel levers and/or the dalton brute levers - the sliding sheave can't take the strain of the flyweight.

Must use the TRA7 forged sheave, this is strong enough.
www.cjmotorsportsonline.com has a fix that stops the TRA from slipping and over tightening the bold.

Dynamo^Joe · Oct 27, 2009

Jamie Bellman will be making a TRA2 primary clutch - forged then cnc machined.
It will handle the 270 hp engines they use.

http://cs.amsnow.com/snocs/forums/t/63730.aspx

I think Jamie will lose his shirt for $900 bux, I have no doubt that in the end their clutch will cost about $1400 bux but will be worth it and able to run all the stock brp levers including all aftermarket steel and billet aluminum.

Anyone wanting one, I would contact Jamie

Teamleader · Oct 27, 2009

Dynamo^Joe said:
The TRA4,5,7 you take the chance of tearing the clutch off the crank not because of over torquing the clutch bolt - rather what is happening the governor cup is slipping on the taper face that causes the bolt to tighten up while under full throttle.

As the engine is at full throttle the governor cup starts to turn on the taper thus tightening the bolt till it stretches, necks then breaks off.

This is a primary clutch that blew off the crank at 90+mph and hit me in the leg. It flew back behind the sled then zooOOOOoom...it freakin PASSED me. hahahaha...oh i was laffing at that sucker go, because it passed the guy I was drag racing. It made a left turn right in front of him crossing over and going about 200 feet into the salad.
260hp FPP 1200

Other TRA4 that have blown off were from the levers being too heavy. The RT1000 steel levers and/or the dalton brute levers - the sliding sheave can't take the strain of the flyweight.

Must use the TRA7 forged sheave, this is strong enough.
www.cjmotorsportsonline.com has a fix that stops the TRA from slipping and over tightening the bold.

I am using green locktite on the taper for the gouvenor cup and then it is not going to rotate. That picture is telling me that there is something else that have caused the sheave to break, no heavy arms can resault that type of damage.

brycter · Oct 27, 2009

270 Hp is not enough. We get 240 Hp @ 10#. Yes damage is caused by heavy arms. The whole Stock tra cannot handle the weight & torque that the built 1200 will build.
I am running 4 76 gram weights in the STM and will have to through more when the motors start getting built to 360- 410 hp. Don't waste your time there is alot of guys out there that have tried alot of different stuff to make the tra work and they still all fail. I don't know about you but clutch and crank end problems are the last thing that i want in Zero degree temps.

DaveB · Oct 27, 2009

Teamleader said:
That picture is telling me that there is something else that have caused the sheave to break, no heavy arms can resault that type of damage.

Joey said that clutch came off and won the race...I suspect it broke AFTER removing itself from the sled. He said "Other TRA4 that have blown off were from the levers being too heavy"....not the one in the picture.

Duke · Oct 27, 2009

Did anyone try tho Polar last year? Is the stock chain strong enough, what are some options?

Dynamo^Joe · Oct 27, 2009

DaveB writes)clutch came off and won the race
Joe writes)Oh hahaha....oh man I had a good laff. I never thought of it like that - the clutch won the race. heh heh...:face-icon-small-hap

That particular picture shows a failure of the thin wall sliding sheave and could not take the weight of the dalton brute levers with 25g in clicker 1.
1) clutch bolt breaks.
2) governor cup separates from fixed sheave
3) levers push governor cup out of the sliding sheave
4) as governor cup starts going air mail to china, the sliding sheave still doing 8300 rpms (approx) the levers have nothing to push against (remember that the "ramp" that the roller runs on is going air mail) the levers (under centri force) whack the casing of the sliding sheave.
5) the impact of the levers cause the sheave to turn and form a "triangle" shape however as the rpm of the airborne sliding sheave starts to diminish then so does the force of the levers exerting on the sheave casing/wall.

Other primary have failed to where the clutch bolt failed, stretched and the sliding sheave assembly did the "ballroom blitz" underneath the hood bouncing around.

I just got off the phone with Mark over at CJ's and coached him through how to post pictures on line over at dootalk in the Turbo section.
Look for a post coming up from the member name "Dragster"

Mark is showing his mod TRA primary I do believe its TRA4 assembly however the TRA7 440 race primary forged sliding sheave.
http://www.cjmotorsportsonline.com/photo_gallery.asp

Fixed sheave

Dynamo^Joe · Oct 27, 2009

Dragster made a post
:devil:

brycter · Oct 27, 2009

Not bad. That might work if the pins hold.

Dynamo^Joe · Oct 28, 2009

I think this is a very strong unit. There are 6 pins in shear. Plus the friction fit of the taper with the addition of the clutch bolt torque, stainless pins. I doubt it would fail.

bgoetz · Oct 28, 2009

Go with the comet 108 exp get some 83 gram cat weights green/yellow spring,polish the sheathes,couple shims and rock it.It's alot cheaper and it works.

Teamleader · Oct 28, 2009

bgoetz said:
Go with the comet 108 exp get some 83 gram cat weights green/yellow spring,polish the sheathes,couple shims and rock it.It's alot cheaper and it works.

Hi=)
Not more than 83??? Mcx are using 94gr. Which tickness on the shims, and do you have the part nr for the 108 Exp???

Reegards Mr.Olsen

gus bohne · Oct 28, 2009

Seems like a weak low end clutch designed exactly for what it was suposed to be used on. PERIOD> no power adder...stock dog 4 stroke.

The effort put forth to make due with the stock clutch is valiant ..

On a cpi kitted 800 rev, we use 80 grams x 4 with a 200-320 to hold 8300-8500 rpm. this is with a micro screw on 4 weight STD diameter.
Using RT driven with stock cam and spring..OR cat driven 54/40 with sno pro green in 2nd hole, Roller cover.

4.67 @ 109 come and geeeeeter you 4 strokers..

gus
btw thats at 20 psi lol

NO BS clutch/belt reports from turbo 1200 owners

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