best disc clutch for a 250 two stroke on a jackshaft???

Best I would say the Birky. And actually cost wise probably still the birky being it lasts so long. I just have never run one or know what's involved in setting them up.
 
I run a Bully 4 disk I modify from a 3 disk., I had thought about a Birky, but I use a pretty small rear pulley ( so I can use a regular bully ratios, without modifying the clutch weights, levers, springs), I would have had to make a adapter..
 
I use a modified bully 3 disc to a 4 disc
works fine locks up about 5000 with weights un all the levers and black spr I ngs
im getting about 6 to 8 thou wear per weekend
 
Kevin Birky built mine for my TRX250r and it hooks up very well, I bring it in at 4500rpm. I believe Kevin has built some for guys with the PK250's as well. He can set it up for what ever engagement you would like, I also believe he is setting them up with a 2:1 ratio.
 
Wes Snow said:
Where did you buy the 3 to 4 disc conversion?
Thanks
Click to expand...

I got a clutch from Mike( Azrcr) It was a 3 disc converted to a 4 disc. Some thing Mike came up with years ago. It worked so good I stole the Idea and sent the dimension changes to Tim. They work awesome. The thread said best clutch. The old style Bully converted to 4 is a excellent clutch but I don't think it would rank as the best clutch. It is a very simple clutch and well known and easy to find base clutch.
 
I have a couple of 4-disk Tomars we run on or opens. They have been pretty rock solid through the years and you can buy then new from Tomar.

DK
 
I've run a tomar 3 disc on an SA clone and was always happy with it. seems on par with the bully clutch as far as design, definitely a thought in my head is to get a 4 disc TD44

Tim, Tim, or Mike, what's involved in modifying the 3 disc to a 4 disc? seems like squeezing an extra 3/16" worth of disc and floater in there would be quite a chore?
 
Yeah, i've been converting them since before there were 4 disk clutch's., I'll convert a bully for 100.00 plus parts., the drive plate and pressure plate's are turned down, (caution.. you can't go to much or you'll take the heads off the spring hi-loc's) I replace them with bighead Ti hi-loc's after re-countersinking the holes., then install .065 floaters..

If your going to do it yourself, you'll need holding tools for the plates to turn on the lathe, I surface grind or turn floaters down from used thicker ones, or get new ones from buller.. You retain the use of the 3 disk basket and all other parts..

I don't know if you can convert a Tomar, I'm not sure how much material there is on the drive and pressure plate's.. or if the basket is deep enough..
 
I know on both of the PK-250 we have only ran the Bully 4 disk Turbo Clutch. Never seen anybody run a PK-250 with a Birky Clutch.
Not saying nobody has one but have not seen it on anybody's I have looked at.
I had a Birky clutch on my 150 and it was a nice clutch set-up.
Guess it all comes down to how much you want to spend and what you like.

JMO
 
cherry. i have been using the bully 3 disc on every thin that i use a j-shaft on w/ great success yami-animals ,no problems w/ the 250 torque. should do the job! 4-45- engage ment justin ran the 3 disc on the 450 and it did well. w/ roller levers and red spg, low engagement and last forever? have gregg jones kart and engine here now he likes the 4 disc bully and so does grady? your choice!?? john hilton bully dealer for ever!
 
CHERRY said:
I know on both of the PK-250 we have only ran the Bully 4 disk Turbo Clutch. Never seen anybody run a PK-250 with a Birky Clutch.
Not saying nobody has one but have not seen it on anybody's I have looked at.
I had a Birky clutch on my 150 and it was a nice clutch set-up.
Guess it all comes down to how much you want to spend and what you like.

JMO
Click to expand...


Both Jeff Drugan and John Garde run a birky with their pk's and have for a couple years now.
 
The 3 disc bully I have is pretty beat up, to the point it's probably not worth anything more than an emergency second stringed. I might go out to the garage and pull the bully off though and look at the modification deal. Sounds like a fun lathe project.

How thick is a new bully friction disc?
 
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