340 salsbury series

delray

delray

Well-Known Member
#1
#1
I needed to replace or repair my splines on my driver unit. the original style came cast aluminum and I did have a NOS unit,but the cast units will not hold up to a lot of power. especially under any high stall with a strong motor.


they did first make a replacement part made out of billet aluminum. that's the piece that I have been running and it's just wore out. then they got smart and made it out of steel.
you can see in the older catalog you could purchase this item. as we all know in the jr dragster world things got bigger(motors) and they drop the 340 series and now use bigger and stronger,more adjustments and made out of billet and will hold up to tons of power.

now with the new minibike craze this torque converter is a excellent replacement part for any small block hot rod engine when going with the 2 piece unit that uses steel spline and billet pulley. when using this with a built motor that has just a billet/aluminum flywheel it balances very true and the engagement setup superior over a 20 or 30 series unit and you don't get that unwanted vibration that a lot of people get when running a 20/30 series with a light billet flywheel.
unfortunately no one whats to get on the bandwagon and start making them again. personally think there could be a market for these again if people new how well they work.
here is my billet unit. I will be machining the splines off and saving the back half pulley
.

next was to make a new set of splines. first step was to make the center shaft.


make all my rough cuts



I will have to tap for the threads and broach it for the long keyway to hold both pieces on the crankshaft.


finish part next to the nos part on the left. that was a big help. with the nos part never ran I could get good measurements off of it to make my new splines. part on the right is another billet unit I have. so I could make another one off of that. otherwise I would have to machine out a chuck of billet to make a pulley again.
 
delray

delray

Well-Known Member
#4
#4
here is a picture diagram on how this driver is setup. the unit runs on 3 rollers and uses two sets of stall springs for the rollers. no matter what you do or give it. this thing is always consistent and is very well balance and light with the pulley machine out of billet aluminum. just can't get that with a comet 20 or 30 series.
 
joshua. c.

joshua. c.

Well-Known Member
#5
#5
I think there's a market for the 340 as well but only for the unit with the stronger back plate and spline. comets just aren't made for high power and high rpms and there built to reach full shift with a stock governed motor. there is a hole in the market waiting to be filled right now for a reasonably priced better torque converter for all the high powered supper fast mini bikes out there. If I found an inexpensive clutch that worked significantly better than a comet for racing Id buy at least 3 or 4 to replace all my comet units. hay Delray you seem to have some good tools and machining skills, think you could tool up to crank some new ones out yourself?
 
ole4

ole4

#6
#6
joshua. c. said:
I think there's a market for the 340 as well but only for the unit with the stronger back plate and spline. comets just aren't made for high power and high rpms and there built to reach full shift with a stock governed motor. there is a hole in the market waiting to be filled right now for a reasonably priced better torque converter for all the high powered supper fast mini bikes out there. If I found an inexpensive clutch that worked significantly better than a comet for racing Id buy at least 3 or 4 to replace all my comet units. hay Delray you seem to have some good tools and machining skills, think you could tool up to crank some new ones out yourself?
Click to expand...
The 330 and 340 series are rated to 8500 rpm, its stamped on the retainer. That is well past a governed motor. They were used on jr dragsters in the early days.
 
delray

delray

Well-Known Member
#7
#7
joshua. c. said:
I think there's a market for the 340 as well but only for the unit with the stronger back plate and spline. comets just aren't made for high power and high rpms and there built to reach full shift with a stock governed motor. there is a hole in the market waiting to be filled right now for a reasonably priced better torque converter for all the high powered supper fast mini bikes out there. If I found an inexpensive clutch that worked significantly better than a comet for racing Id buy at least 3 or 4 to replace all my comet units. hay Delray you seem to have some good tools and machining skills, think you could tool up to crank some new ones out yourself?
Click to expand...
josh it was only about 10 years ago you could buy the steel spline and half billet pulley for less then $70. today if i wanted to invest some money i could have a local guy make both parts on a cnc and then i would still have to sell them for alot more then $70 for the pair and still would never recover from it. making them on a manual mill/lathe would take way to long. for example it took me over a week to make that spline. i don't think alot people understand that 30 series is not design to hold up to a full built clone motor that can turn 7000 or even 8000+for long time without having some kind of problem with the torque converter. if the real comet company was still in business today they would of came out with a jr drag 340 unit again with the steel spline and billet pulley. even if they sold it for $200+ for the driver and driven/belt people would buy them all day,until china took over.....lol
 
delray

delray

Well-Known Member
#8
#8
ole4 said:
The 330 and 340 series are rated to 8500 rpm, its stamped on the retainer. That is well past a governed motor. They were used on jr dragsters in the early days.
Click to expand...
ole4, I am starting to wonder if only the billet 340 units had the 8500 rpm stamp on them. both my billet units had this but my stock NOS casted aluminum unit does not have that on it.
 
ole4

ole4

#9
#9
My cast ones have that on them The salsburys had a press in button that did not have it but keep in mind in the early JR dragster days they used them on flatheads and those motors would turn up past 8500. Hell the light rollers and heavy springs don't engage until 5600 rpm.
 
delray

delray

Well-Known Member
#10
#10
here is something else I found in both billet units I had. they came with brass bushing. stock ones I have only seen plastic.

last summer I ran the unit on my hs-40 engine I built. ran a stall speed of 3800. it was so consistent ever time I pulled up to the line to run it and buzzed it right up to 7200 rpm's.
 
ole4

ole4

#11
#11
I love them and I have had the same experience very reliable and repeatable. I have accumulated a lot of spring kits and roller arms over the years and some are brass and some nylon. I can just chuck up some derlin rod and make them pretty quickly which is what I first did till I got a bunch of spring kits.
















I love mine
 
massacre

massacre

#12
#12
I looked into a Salisbury for my dragbike but went with a Polar clutch setup instead.
They are pretty cheap to buy used, and parts are readily available.
If I had the ability to make my own parts, I would have went with the Salisbury though.
 
delray

delray

Well-Known Member
#13
#13
massacre said:
I looked into a Salisbury for my dragbike but went with a Polar clutch setup instead.
They are pretty cheap to buy used, and parts are readily available.
If I had the ability to make my own parts, I would have went with the Salisbury though.
Click to expand...
I too look into the polar setup at one time. could not find anything used/cheap and new ones where way out there in price$$$
for drag racing might be good to have, but for most people that just want a good reliable torque conveter. they are not a ideal unit to install on a minibike for a guy that just has a hot rod clone motor that spin's only 7000+ rpms.
unit is self new is expensive and then there is option tool's and parts you can buy and don't forget you will need to also purchase a third bearing support and they take up a lot of space. that can be hard sometimes on a minibike.
I wish you where closer massacre. I would really like to try that unit on your bike.
drag racing testing only of course...lol
 
massacre

massacre

#16
#16
ole4 said:
Polar clutch sold today on eBay for 200 bucks. I was tempted but the driver hangs way out and requires outboard bearing.
Click to expand...
They are not that expensive to buy used. But like you said you need a crank support on both sides.
I went into it not knowing if the crank support bracket would even fit in my chassis lol
But was able to make it work without widening or stretching the frame. Stock Arco frame.
Making it work in that frame was quite the challenge, but I know that that clutch will work amazingly every single time.
It is unbelievably consistent.
But so are the Salisburys

I can take some measurements of how wide it actually is if it will help you.
My Bikeis drag only so only goes really fast in a straight line for a short distance.
Not the best choice for an all around rider.

The Polar driven is nice since it has rollers instead of buttons so it works so smoothly
Feels like driving a boosted engine, power and speed just keep coming faster than you think it will lol
Also Polar is designed for 450lb jr dragster, my bike weighs 100lb.
Before the Polar clutch, the crank support and jackshaft bracket and setup, the bike weighed 75lb.
Some of the added weight was the added engine plates to accommodate the added drivetrain, some of it was the clutch itself and the additional components.
 
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delray

delray

Well-Known Member
#18
#18
I called them couple times in the past and was told they where going to build it. that's was at least 2-3 years ago. I never ask about the steel sleeve setup. did you just call them this week? if they are going to build it with the steel sleeve they need to get moving with it. I personally think there is a big market for this type of unit for the guys that are building clone motors and what I mean by building clone motors is the guys that just putting bigger valves,7000-8000+ rpm cam's,stock bore up to 2.815+ mikuni 22 or 24mm carb's. nothing super crazy like a 3+ bore /big stroker,welded head and block externally and 55 degree porting with a 28+mm carb,alcohol,electric start only...etc...bad ass motor.
 
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