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Powerbloc in my 81 SRX
Posted: Tue Jan 27, 2015 2:41 pm
by rlester
My 81 SRX 440 has an older 3 puck powerbloc clutch in it. It works great for trail riding, we have put 1000kms on it and it has been flawless. Engagement is around 4500rpm.
I would like to do some drag racing with it, and I need to raise the engagement close to 6000 (from the research I've been doing this seems about right). Does anyone know what color spring I need? There is an extra spring in the toolkit that has about a full coil more that the spring I'm using now and I'm going to test it tonight. There are no color markings on either spring though.
I've had a few people say this clutch is no good, but so far it has worked excellent.
Re: Powerbloc in my 81 SRX
Posted: Wed Jan 28, 2015 7:13 am
by Vmax540
Never even saw one although, I remember hearing about them. I did a search...
http://vintagesleds.com/bs/index.php?topic=49974.0 "You tune the clutch by adding or subtracting weights from the puck."
Re: Powerbloc in my 81 SRX
Posted: Wed Jan 28, 2015 11:15 am
by vmax-540
I don't think that is a strong enough for the HP or RPM of the 81 SRX, I would upgrade to a 102c, Polaris P85 or something like that.
Re: Powerbloc in my 81 SRX
Posted: Thu Jan 29, 2015 12:39 am
by rlester
Yeah I realize this clutch isn't the best, but I'm just not in a position to spend the money on a new clutch.
Yesterday I picked up a used spring that was a half inch taller than my original one. Strange, but the engagement stayed at 4500. Then I took out four weights from each puck, leaving one in each. WOW, now it engaged at 5500 and only a slight bog until 6 grand! I think I'm in the ball park!
Today I bought a new Gates 6303 kevlar belt to replace the aging max 1080. Crap. Back to square one. Engagement with the new belt is back to 4500 as the new belt is wider than the older, worn one.
I'm thinking of running with the older belt and tightening up the secondary so the belt rides higher.
Thoughts?
Re: Powerbloc in my 81 SRX
Posted: Sun Feb 01, 2015 5:10 pm
by chrisrider63
Would a polaris p85 work with the yamaha secondary?? Those powerblock clutches are too heavy and is what throws the cranks out.
Re: Powerbloc in my 81 SRX
Posted: Mon Feb 02, 2015 1:45 am
by Bob Vehring
Your kinda missing the boat here, yes engagement is important but when racing, thats over in a tenth or two. Whats most important is holding your engine right on the rpm target for the length of the run. That is a function on a comet or Pol. of the arms and their profile. IDK how or even if, that can be dealt with on a PowerBlock. Weren't those the same as the old Comet Duster.
I have a new Pol. on my VM. Taper was a different dia. so it has a shim inside. The Sec also had to machined to work with the wide belt.