Thunder products anti movement washers

[KnappAttack]

If you're running stock power an option is the Umatek clutch. I have a couple customers running them, they are very quiet.

I run the stock clutch and I grind the roller pins shorter so they don't slide back and forth and I also shim the buttons with Polaris shims to keep the clearance at the minimum of spec. I also use the knockout kit, but it has been met with skepticism. Personally I like it.
These mods do take time and may need upkeep every few thousand miles.

Have a Thundercat with a 240 tune in the shop now. Owner installed a new PB80 on it. It was purchased from MCB I believe he said, bought from them and they mentioned they'd set it up for the 240 tune. Was only turning 8600, but he was also running a Ultimax belt on it too, I pulled it apart to pull some slugs and man am I ever impressed with what they have done with the PB80 over the years. It now has a steel spring cup on it, which should eliminate and cup failures, and they installed a bearing on the clutch for the Cat guys so they can keep the tight belt deflection on them, and it came with the heavy turbo slugs in it also. I ran the PB80 for years on my old Doos including the turbos. Precision Sports ran them on their 300 HP turbo 1200's also with a billet spring cup they made. I would have ZERO concerns running the PB80 whatsoever on the 300 HP Winders. In fact, I've been told they lay down better track HP then a Yamaha primary and even the TAPP. They are a nice quiet simple clutch and they flat out work. Never going to get drag race engagement, but for the trail thats not needed anyway. Didn't know CVTech changed their name to Umatek.

I'm also having really good luck with the Knockout kit. I fully believe if you load it with grease and install the ring properly its works well. Some people don't get them installed properly, (I've seen the pictures). They need loctite and set to the correct depth so the o-ring holds the grease in.

 

[74Nitro]

Have a Thundercat with a 240 tune in the shop now. Owner installed a new PB80 on it. It was purchased from MCB I believe he said, bought from them and they mentioned they'd set it up for the 240 tune. Was only turning 8600, but he was also running a Ultimax belt on it too, I pulled it apart to pull some slugs and man am I ever impressed with what they have done with the PB80 over the years. It now has a steel spring cup on it, which should eliminate and cup failures, and they installed a bearing on the clutch for the Cat guys so they can keep the tight belt deflection on them, and it came with the heavy turbo slugs in it also. I ran the PB80 for years on my old Doos including the turbos. Precision Sports ran them on their 300 HP turbo 1200's also with a billet spring cup they made. I would have ZERO concerns running the PB80 whatsoever on the 300 HP Winders. In fact, I've been told they lay down better track HP then a Yamaha primary and even the TAPP. They are a nice quiet simple clutch and they flat out work. Never going to get drag race engagement, but for the trail thats not needed anyway. Didn't know CVTech changed their name to Umatek.

I'm also having really good luck with the Knockout kit. I fully believe if you load it with grease and install the ring properly its works well. Some people don't get them installed properly, (I've seen the pictures). They need loctite and set to the correct depth so the o-ring holds the grease in.

Thanks for the info Mike.
I should also mention, that on a Winder clutch, with the cost of weights and rollers from yamaha you're not far off the price of the Umatek clutch making it a no-brainer.

 

[journeyman]

Never going to get drag race engagement, but for the trail thats not needed anyway. Didn't know CVTech changed their name to Umatek.

Interesting info.

As we spoke a while back, I tested a similar version of this clutch MANY years ago when dad and I ran piped Exciters, the Magnum Gold clutch which I believe Duane Watt was selling at the time.

That is what we found, it wasn't a good drag race clutch, the other Exciter with the Yamaha clutch would blister it off the line, but I felt it was putting more track HP down because it would reel the other one in and go by on top end even if he got an incredible lead on me.

 

[Daveo99]

Have a Thundercat with a 240 tune in the shop now. Owner installed a new PB80 on it. It was purchased from MCB I believe he said, bought from them and they mentioned they'd set it up for the 240 tune. Was only turning 8600, but he was also running a Ultimax belt on it too, I pulled it apart to pull some slugs and man am I ever impressed with what they have done with the PB80 over the years. It now has a steel spring cup on it, which should eliminate and cup failures, and they installed a bearing on the clutch for the Cat guys so they can keep the tight belt deflection on them, and it came with the heavy turbo slugs in it also. I ran the PB80 for years on my old Doos including the turbos. Precision Sports ran them on their 300 HP turbo 1200's also with a billet spring cup they made. I would have ZERO concerns running the PB80 whatsoever on the 300 HP Winders. In fact, I've been told they lay down better track HP then a Yamaha primary and even the TAPP. They are a nice quiet simple clutch and they flat out work. Never going to get drag race engagement, but for the trail thats not needed anyway. Didn't know CVTech changed their name to Umatek.

I'm also having really good luck with the Knockout kit. I fully believe if you load it with grease and install the ring properly its works well. Some people don't get them installed properly, (I've seen the pictures). They need loctite and set to the correct depth so the o-ring holds the grease in.

Would you have to make a different cover with a different profile to get the PB80 to get drag race engagement? Or is that just too much work in comparison to make a flyweight style clutch drag race well?

 

[KnappAttack]

Would you have to make a different cover with a different profile to get the PB80 to get drag race engagement? Or is that just too much work in comparison to make a flyweight style clutch drag race well?

It would never make a good drag race clutch. Not what it's designed to do. It engages smoothly as its designed to do. That said I've won many drag races with it on my old 1200's Doo even lining up against much more powerful machines including turbo Cats and RX-1 Yamahas at the bean field nationals. When I ran it on my turbo 1200's it would spin so the track so hard that even wanting more RPM would be futile. The old 1200 is an absolute TQ monster and adding a turbo to it makes it even more so. PB80 is fine without big engagement with the proper machine powering it with the proper setup. Works really nice on the 998 Cat I had in the shop here. So smooth and I love it with Cats tight belt deflection secondary setup. Could to the same with a Cat wide belt on a Winder secondary with proper machining of the secondary and the helix.