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 Clutch in a Penton Flat tracker.
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TedG
Advanced Member

64 Posts

Posted - 06/15/2012 :  01:26:36 AM  Show Profile  Reply with Quote
A while back I posted about a project to turn a very tired 1975 Penton 400 into a flat tracker. Well the project is almost done and I have a pretty complete record in Facebook. Here: http://www.facebook.com/media/set/?set=a.143804929028297.36507.100001963717291&type=3&l=5c4962da54

Anyway after sitting for 15 years, granted I cleaned it up and it has all new gaskets and seals, the thing started on the second kick and is just as hairy as I remember it, even more so now that it is a lot lighter.
On to the clutch, I had forgotten how bad a shape the clutch was in. It had the sintered bronze plates that were worn very badly. The clutch dragged horribly and would slip when it got hot. So I found some new bonded plates on ebay and put them in. The point to this whole message is if you take the time to dial in the clutch by starting with the screws showing 2 or 3 threads and pull the clutch and use the kick starter to turn the tranny, you can see any runout in the pressure plate. If you take the time to make sure the pressure plate has as little runout as possible the clutch by adjusting the bolts 1/2 turn at a time you will be rewarded with a clutch that releases evenly and it is a small miracle how much drag you can remove from the clutch.
I had forgotten about this method (I used to work in a Penton dealership) and now that I remembered, I thought I would share.

Edited by - TedG on 06/15/2012 01:43:40 AM

brian kirby
Advanced Member

1603 Posts

Posted - 06/15/2012 :  09:37:39 AM  Show Profile  Reply with Quote
I use a dial indicator on the pressure plate. I tried it your way (the old school way) and could never get it right. Someone here said to use a dial indicator on the pressure plate, and it fixed it the first try.

Brian

Edited by - brian kirby on 06/15/2012 09:38:04 AM
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TedG
Advanced Member

64 Posts

Posted - 06/15/2012 :  2:06:35 PM  Show Profile  Reply with Quote
Brian,
For sure the dial indicator is the way to go. My pressure plate had come corrosion on it and can't find a clean path for the indicator to go although I should fill the rough spots with JB weld and smooth them over.
This is also one of KTM's poorer designs the push rod end should have a top hat/flat area to insure the pressure plate releases/enguages evenly.

Edited by - TedG on 06/15/2012 3:12:58 PM
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TedG
Advanced Member

64 Posts

Posted - 06/18/2012 :  5:24:46 PM  Show Profile  Reply with Quote
Got a chance to ride the thing up and down the street and it slipped like crazy, released well but....
So I added in a couple of steel plates to tighten things up a but. I lost some of the clean release but it doesn't slip anymore. It does release much better than when I started and it is acceptable.
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Paul Danik
Advanced Member

2296 Posts

Posted - 06/19/2012 :  07:39:24 AM  Show Profile  Reply with Quote
Hi Ted,

Your story reminds me of something that happened " back in the day " when a guy picked up a new 400, shortly there after he complained about how the clutch was slipping, turns out he was burning the knobs off the rear......

By the way, congrats on your new position as a Board Member of the Ohio Valley BSA Owners Club. That organization has always been a great group of guys and obviously that tradition will continue, I see that all around good guy Steve Szewczyk is also now on the OVBSAOC Board...

Paul
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TedG
Advanced Member

64 Posts

Posted - 06/19/2012 :  12:53:04 PM  Show Profile  Reply with Quote
quote:
Originally posted by Paul Danik

Hi Ted,

Your story reminds me of something that happened " back in the day " when a guy picked up a new 400, shortly there after he complained about how the clutch was slipping, turns out he was burning the knobs off the rear......

By the way, congrats on your new position as a Board Member of the Ohio Valley BSA Owners Club. That organization has always been a great group of guys and obviously that tradition will continue, I see that all around good guy Steve Szewczyk is also now on the OVBSAOC Board...

Paul


Paul, you must have me mixed up with someone else. Although I was a BSA mechanic I have never heard of Ohio Valley BSA.
As far as spinning the wheel, I know the difference. The flat track tires have good grip on the pavement and won't spin up in the higher gears.
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SouthRider
Advanced Member

USA
294 Posts

Posted - 06/19/2012 :  4:37:59 PM  Show Profile  Reply with Quote
Wow - I vaguely remember the shop manual showing that the approved method was with a dial indicator, likewise - we could usually get them pretty close by eye....

That is an absolutely gorgeous bike you have built, your machine work is fantastic.

If you can get your hands on a 40mm Lectron it will add several extremely tractable horsepower to that bike. It kind of becomes like a very powerful turbine engine with a big Lectron. You wouldn't want it in the woods, but on a flattrack - look out!

Clark

PS - If I remember correctly the later year models did upgrade the pushrod assembly, and also the exterior clutch arm assembly. There were probably 3 or 4 versions of each - getting better over the years. If the exterior arm is getting wonky it will try to pull sideways and increase the stiffness noticeably.

_____________________________________________________________________________________

"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."

1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax

Edited by - SouthRider on 06/19/2012 4:41:58 PM
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TedG
Advanced Member

64 Posts

Posted - 06/19/2012 :  11:27:51 PM  Show Profile  Reply with Quote
quote:
Originally posted by SouthRider

Wow - I vaguely remember the shop manual showing that the approved method was with a dial indicator, likewise - we could usually get them pretty close by eye....

That is an absolutely gorgeous bike you have built, your machine work is fantastic.

If you can get your hands on a 40mm Lectron it will add several extremely tractable horsepower to that bike. It kind of becomes like a very powerful turbine engine with a big Lectron. You wouldn't want it in the woods, but on a flattrack - look out!

Clark

PS - If I remember correctly the later year models did upgrade the pushrod assembly, and also the exterior clutch arm assembly. There were probably 3 or 4 versions of each - getting better over the years. If the exterior arm is getting wonky it will try to pull sideways and increase the stiffness noticeably.

_____________________________________________________________________________________

"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."

1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax


I have a Lectron carb but I think it is a 38mm. I have to look. I also have the manual and I will look for the dial indicator method. But there is a big hole eaten away at the pressure plate almost to the edge from sitting for 15 years. As for the actuator, you are absolutely correct, but again finding a newer style has been fruitless. I put a brass bushing in mine and it is better but not great. I am on the hunt for the new style actuator.
Thanks
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Steve Minor
Advanced Member

USA
1109 Posts

Posted - 06/20/2012 :  10:11:55 AM  Show Profile  Reply with Quote
Ted....I got a pretty good artice on Clutches written by Bobby Lucas a few years ago if you are interested. It's in PDF format and I'll gladly sent it to you in an email. Drop me a note to my email if you'd like to see it.... sdminor@bellsouth.net

Steve Minor
Wilmington, NC
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SouthRider
Advanced Member

USA
294 Posts

Posted - 06/20/2012 :  5:34:29 PM  Show Profile  Reply with Quote
Ted,

The 38mm will work also. Generally speaking you will get slightly less horsepower than a 40, but better midrange. The trick with Lectrons is that they just flow so much more air than a stock carb, and are easier to jet.

Speedy Clausen in Canada can help you with the right metering rods and a place to start with jetting the 38. We put 40's on the Rokon automatics back in the day & they would outrun most street rod small blocks for the first 1/8 mile - even with knobbies on pavement.

I see that Al Buehner is sold out of the new style actuating arm. Try Terry Everett too - he sometimes has NOS parts that aren't listed on his website. Also - I believe that the newer pushrod was the top hat style.
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rob w
Advanced Member

USA
2667 Posts

Posted - 06/20/2012 :  9:22:40 PM  Show Profile  Reply with Quote
quote:
Originally posted by TedG

quote:
Originally posted by SouthRider


Clark

PS - If I remember correctly the later year models did upgrade the pushrod assembly, and also the exterior clutch arm assembly. There were probably 3 or 4 versions of each - getting better over the years. If the exterior arm is getting wonky it will try to pull sideways and increase the stiffness noticeably.

_____________________________________________________________________________________



........... I am on the hunt for the new style actuator.
Thanks




There were two style clutch actuators for the Type 51,52,54, & 55 engines. A new style came out on the 1977 engines, but was short lived, and replaced back to the older style in '78 thru '80. So I don't believe the 2nd design could have been any improvement over the earlier one.
Al B offers a super trick repro version.
I'm about to start making more repro push rods, which will be available from Alan.

Bob
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ALB
Advanced Member

USA
233 Posts

Posted - 06/21/2012 :  09:52:23 AM  Show Profile  Visit ALB's Homepage  Reply with Quote
Hi Ted,

I have been following your project. I enjoyed viewing the photos that you have posted. Simply amazing how you have transformed that bike.

If you refer to the owners manual, it shows that the distance between the disengaging lever and the pressure plate should be 42.5 to 43.5mm. If the measurement is less than this, there will not be enough "push" against the pressure plate to release all the plates. In the book they say to "bend" the disengaging lever. DO NOT DO THIS. Remove the lever assembly from the bearing plate assy. Check the pin inside the barrel that presses against the push rod. Almost all of the pins in these engines are worn "flat". Replace the pin. I carry these in stock. A little bit of wear makes a big difference in the pull of the arm and operation of the clutch.

Installing a sleeve into the bearing plate will make the movement of the disengagement lever smooth and even. Most bearing plates are worn out causing oil leakage and the levers are wobbly. This "looseness" of the lever assy greatly affects the operation of the clutch. I have replacement bearing plate kits made of aluminum, with steel sleeves and a grease fitting inserted.

Everyone should keep in mind that these engines were built and designed to last a few years. The repair manuals were written to deal with problems resulting from racing conditions not 30+ years of "Old Age". At this period in time we are dealing with problems concerning age related wear and tear and because we are restoring these bikes to last at least another 30+ years, repairs have to be performed a little differently than what the books show. And most important, maintenance must be performed more, on a regular basis. Many of you have heard me talk about how dependable these bikes were. They were too dependable which caused many owners ignore doing routine maintenance on them. We now have to deal with that lack of maintenance.



Alan Buehner
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TedG
Advanced Member

64 Posts

Posted - 06/21/2012 :  6:02:54 PM  Show Profile  Reply with Quote
quote:
Originally posted by ALB

Hi Ted,

I have been following your project. I enjoyed viewing the photos that you have posted. Simply amazing how you have transformed that bike.

If you refer to the owners manual, it shows that the distance between the disengaging lever and the pressure plate should be 42.5 to 43.5mm. If the measurement is less than this, there will not be enough "push" against the pressure plate to release all the plates. In the book they say to "bend" the disengaging lever. DO NOT DO THIS. Remove the lever assembly from the bearing plate assy. Check the pin inside the barrel that presses against the push rod. Almost all of the pins in these engines are worn "flat". Replace the pin. I carry these in stock. A little bit of wear makes a big difference in the pull of the arm and operation of the clutch.

Installing a sleeve into the bearing plate will make the movement of the disengagement lever smooth and even. Most bearing plates are worn out causing oil leakage and the levers are wobbly. This "looseness" of the lever assy greatly affects the operation of the clutch. I have replacement bearing plate kits made of aluminum, with steel sleeves and a grease fitting inserted.

Everyone should keep in mind that these engines were built and designed to last a few years. The repair manuals were written to deal with problems resulting from racing conditions not 30+ years of "Old Age". At this period in time we are dealing with problems concerning age related wear and tear and because we are restoring these bikes to last at least another 30+ years, repairs have to be performed a little differently than what the books show. And most important, maintenance must be performed more, on a regular basis. Many of you have heard me talk about how dependable these bikes were. They were too dependable which caused many owners ignore doing routine maintenance on them. We now have to deal with that lack of maintenance.



Alan Buehner



Al,
For sure the that pin is worn out. I will be contacting you about another one. I am not happy with the sleeve that I put in there (I did that 15 years ag0) I may have to do another one or get one of your plates. I am going to read up on where you talk about the disengagement lever and the pressure plate.
So tell me those Penton stickers I got from you didn't set that bike off!
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TedG
Advanced Member

64 Posts

Posted - 06/21/2012 :  6:06:43 PM  Show Profile  Reply with Quote
quote:
Originally posted by SouthRider

Ted,

The 38mm will work also. Generally speaking you will get slightly less horsepower than a 40, but better midrange. The trick with Lectrons is that they just flow so much more air than a stock carb, and are easier to jet.

Speedy Clausen in Canada can help you with the right metering rods and a place to start with jetting the 38. We put 40's on the Rokon automatics back in the day & they would outrun most street rod small blocks for the first 1/8 mile - even with knobbies on pavement.

I see that Al Buehner is sold out of the new style actuating arm. Try Terry Everett too - he sometimes has NOS parts that aren't listed on his website. Also - I believe that the newer pushrod was the top hat style.


Thanks, I will do that, I don't want to adapt it over to the Lectron if I don't have all parts necessary in hand. I still have the metering rods that came with the thing so maybe I am good to go. It is brand new but close to 25 years old. So we will see. The good part is because there is no air box anymore putting on a new carb is a breeze.
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TedG
Advanced Member

64 Posts

Posted - 06/21/2012 :  6:09:01 PM  Show Profile  Reply with Quote
quote:
Originally posted by rob w

quote:
Originally posted by TedG

quote:
Originally posted by SouthRider


Clark

PS - If I remember correctly the later year models did upgrade the pushrod assembly, and also the exterior clutch arm assembly. There were probably 3 or 4 versions of each - getting better over the years. If the exterior arm is getting wonky it will try to pull sideways and increase the stiffness noticeably.

_____________________________________________________________________________________



........... I am on the hunt for the new style actuator.
Thanks




There were two style clutch actuators for the Type 51,52,54, & 55 engines. A new style came out on the 1977 engines, but was short lived, and replaced back to the older style in '78 thru '80. So I don't believe the 2nd design could have been any improvement over the earlier one.
Al B offers a super trick repro version.
I'm about to start making more repro push rods, which will be available from Alan.

Bob


What would be very cool is if you could make a push rod that had a top hat on it so it would release the pressure plate evenly like most Japanese bikes have.
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ALB
Advanced Member

USA
233 Posts

Posted - 06/22/2012 :  09:37:21 AM  Show Profile  Visit ALB's Homepage  Reply with Quote
The reason the KTM push rods do not have a "top hat" on them is to reduce to the contact area to prevent friction. I have pulled the rods out of more than one engine where the ball was fused to the 2 rods.

On another engine when I removed the bearing plate, the rod came out with it. When I went to pull the rod out of the bearing plate, it would not come out. The end of the rod was "mushroomed" inside. How and why that happened - I have no idea. But it happens.

Fused rods to the ball or even the bolt on the pressure plate are indications of a lack of lubrication and most likely caused by the clutch cable being adjusted too tight without any free play in the clutch lever. This will cause the rods to be constantly pressing against the spinning pressure plate, thus creating friction, heat, then welding of the surfaces together.

Alan Buehner
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