Penton Owners Group

This is kind of off topic.  I love my Marzocchi shocks on my 1976 MC5.  I have several spare CZ frames and motors on the shelf and I am thinking of buiding a "long" travel CZ with moved forward shocks and updated front forks to race in the post-vintage classes.  I would appreciate any input on post-vintage shocks, Marzocchi's or others, that I may look for to put on this bike.  I know Falta back in the late 1970's switched to Marzocchi's for his factory bike.  I know there are some travel limitations depending on the class.
Thanks for any input as I am completed knowledgeless (if that is a word) about post-vintage era shocks/forks.

Lloyd Boland

hi lloyd, the best thing  to do is go to the ahrma website //www.ahrma.org and click on the handbook segment on the left hand side of the page. in there under sec 12 is the rules for pvmx. the info you are seeking is listed there. if that doesn't help you or if you have any other questions, drop me a line at [email protected]  and i will try to help you out.
:) chi jer

Jerry, thanks for the advice.  I am an AHRMA member and I know the different travel lengths for the different classes, but I don't know which forks are best and which forks to use for the different classes.  I realize the travel distance is the most critical, and also the issue of double brake actuators on some hubs, but what forks work the best?  If I am going to go looking for a set of forks to purchase, I want the ones that work the best for the appropriate class.  Also, what about diameter size, 35mm, 38mm, etc?  Thanks for your AHRMA website.

Lloyd, there's a guy out this way who has '77 Penton Marzocchi forks on a '74 red frame CZ with longer-travel rear suspension. You should be able to run the Historic class at AHRMA events with that.

The setup seems to work good for this guy, but longer front forks can make steering tougher if not balanced out in the rear, as you know.


Jon McLean
Lake Grove, OR

Thanks Jon.  I am actually going to try to set up the bike demensions as close to the MC5 I have.  I am going to move the shocks forward on the swingarm and on the frame similar to the MC 5 and try to get similar height and steering angles.  Sounds llke something fun to try.  I have a guy down here that I frequently do battle with and he is on a '82 490 maico, and my poor little 250MC5 just get hammered on the straights (I am 230+ without gear), but it is usually close and sometimes I win.

Hi Lloyd, I am riding the Historic open class on a 76 250 GS with "Zokes" front and rear.



Thomas Carmichael


1970 125 Six Day
1976 250 Hare Scrambler

Tom, I have a late 1976 (possibly 1977) MC5 250 that I ride in the Historic class with Zokes on the front and really like them.  I guess what I am asking, if I build this project, I will probably be riding it in the age class and I have to compete against those GP and Ultima bikes, ie the 1982 Maico 490s of the world.  I really like the Zokes and if I go that way, I could also use the bike in the Historic class. On the other hand, I am just wondering if I give up too much to the GP and Ultima class bikes or should I go with something like the 1984 YZ 250 fork.  If I was sure I was jst going to ride only the Historic class I would definately go with the Zokes.  
Thanks for your help.  I know I seem to be talking in circles, just don't know which way to go yet.  I think I want the best of both worlds.  I may have to build 2 bikes.
Lloyd

I am faced with the same thing. Riding PV 50 plus I have to race my mc-5 Penton against GP and Ult class bikes. I wanted to stick with a penton and I wanted to keep it legal for the Historic class.  I went with a 400, ported it a decient amount, went with a 40mm Bing and 78 snake pipe, and went with an internal roter ign.  Im running the stock Zokes on the rear and went with 38mm Zokes on the front using the "fluted" rods from a 80 or 81 fork and the shorter 78 tubes along with a spacer on the rod to keep the travel at 9 inches (im sorry I cant remember the spacer length and it would depend on which top out spring was used anyway). Once you have arrived at the proper travel just slide the tubes up until it sits just the same as a stocker (measuring from the bottom of the steering head with the stock forks). The bar mount is swept back so this is no problem.  Oh, by the way Renthal Mini High bars work great with this set up!
I may still have a pair of extra fluted rods Im not sure, then all you would need are the 78 forks. Historic legal 38mm front end.  Ive even holeshotted some 490 Maicos on this bike and feel it is competive against anything on most tracks. To give you an idea of what the motor is doing I had to go up from the stock 185 main to a 195 and may have to go to a 200! But anyway this same suspension set up might work well on your CZ project and you can adjust your front ride hieght and travel from between 9 and 10.8 inches very easily.

Thanks Mike.  I think on most of the tracks we ride, the 9" of travel is adequate.  I would prefer remaining in the Historic class and appreciate the info on the forks.  I think I will try to make this a Historic project, I can always change forks and shocks if I need more travel.  I think after the Holidays, I am going to have to start looking for the Zokes.  One last question, I see the Historic class for the KTM is 1977, were the 1978 forks the same?  Which years for the front forks would be legal for the Historic class, as long as the travel is corrected to 9":  1976, 1977, 1978, etc?  Is there a limit on the fork diameter in the Historic class, 35mm vs 38mm, etc?  When did KTM/Zokes go to 38mm?
Mike, if you run across the fluted rods, let me know.  I can be emailed at [email protected].
Thanks again.
Lloyd.

Lloyd,

38mm is the limit on fork dimeter in Historic. If you want either 35mm or 38mm Zokes, the easiest way to find them is look for Can-Am forks. The are Zokes and for some reason dont sell as much as the ones for Penton/KTMs. There are several sets of Zokes on eBay right now for Can-Ams and they are all reasonably priced. Can-Am 175s had 35mm forks and the 79-81 models have stock 8.75" of travel, perfect for Historic. If you have to have 38mm look for 250 Can-Am forks, some of the early 250/370 Qualifiers had 35mm, but all of the 250/370/400 MXs had 38mm from '78-'81 in various travel lengths.

Brian

'72 Six Day (on loan from Ernie P.)

Here are some eBay item #'s

These are 35mm 175 forks

300104573394
110129422498

This one is a 250, and it does not say the diameter but they should be 38mm if they are from an '80

300098056211

Brian

'72 Six Day (on loan from Ernie P.)

Re CanAm vs KTM Marzocchis, watch to b sure you have the right front axle setups. I know in some years, the 38mm's look identical to red-leg KTM 38mm's but the CanAm axle was larger on both right/left side, so needed retrofitting to work.

Jon McLean
Lake Grove, OR

Ahh...I didnt know that, good information.

Brian

'72 Six Day (on loan from Ernie P.)

Thanks Jon for the axle info.  

Then, do you have to stay with Can-Am front brakes or are they interchangable with the KTM?  Is one better than the other?  I understand the double action brakes are not allowed in the Historic class.  Is the only difference in the actual axle dimension at the fork attachment or is the entire axle larger?

Thanks,

Lloyd

Not that sure about the CanAm front wheel and brake options. I was given a set of 38mm Marzocchis that turned out to be maybe '81-'82 CanAm forks--had tapered bearing triple clamps the same width as KTM clamps of that time. The axle clamps are a good 1-2 sizes larger on both right and left sides.

Haven't ever seen the variations of CanAm front wheels, but if they had a double-actuated brake setups, it would probably work great. The hot setup for PV is to swap in the double-brake and wheel from an '83 KTM for better stopping power. KTM Dan from up in these parts outfitted his 495 with an '83(?) Honda CR125 front wheel and double-actuated brake, swears by it.

If you want to stay true to the intent of the Historic class I would stay away from the double leading shoe.  The conical KTM brakes from 79-82 work very well. I wouldnt buy the english or Itilain brakes that came on some 83's. I would also go for only 78 forks from a KTM.  That was the first year for 38mm for KTM and the tubes are the shortest I believe. If Can Am will need the measurments from 78 ktm to compare. Best set up if you are going to limit the travel to 9 inches so you are not eating the fork tubes as the longer the tube the more you will have to slide it up in the trip tree.  The actual best set up is the 80 or 81 forks using the 78 tubes.  80 and 81 had better bushings in the sliders, but any will work well with the fluted rods (or the Hi-Point kit from back then). If you really want to go all out the enduro models from 82 and maybe 83 had 38mm forks that had less underhang below the axle and look just like the 76-77 35mm forks(but the tubes are too long).

Thanks Mike.
I feel like such a novice on this Penton/KTM and post vintage stuff.  I don't want to make a large financial error and get the wrong forks, or have pieces that don't match.  I noticed that dual action brakes are not allowed in the Historic class for AHRMA:

"12.5j) Disc brakes are prohibited (except OEM on Rokon and Yankee). Hydraulically assisted drum brakes are prohibited. OEM Yamaha and Honda motocross and off-road dual-leading-shoe front brake hubs are allowed only in the Gran Prix and Ultima classes."

So, I should be looking for 1978 KTM fork tubes, 1980-81 sliders, with fluted rods and look for 1979-82 KTM wheels/hubs/brakes.  Has anyone remanufactured the "Hi-Point kit"?  OK, if I get these parts, will they be interchangable, is there a danger that someone as stupid as me can't figure out how to put this all together without the wheels falling off, or is there someone out there that has special expertise in this?  I have rebuilt a few engines, transmitions, etc and have reconditioned several forks, I just don't have any misconception about my own ignorance.

As always, thanks for everyones support and input.

Lloyd Boland

If you're planning to run AHRMA Historic class, check the rulebook. Last I saw, forks were limited to 35MM max.

Historic is limited to 38mm.

Brian

'72 Six Day (on loan from Ernie P.)

Big Mac, Originally I thought it was 35mm also but the rule book states 38mm if I am reading it correctly. ("d" below)

AHMRA Rulebook:
"12.1 HISTORIC—CLASSES AND ELIGIBILITY

The Historic classes are intended to represent the "first generation" of long-travel bikes that were commercially available in the 1975-77 period. The time frame is provided only as a guideline, as some 1977 models are of the second generation long-travel bikes that would clearly outclass the earlier models if allowed to run together. For this reason we do not classify motorcycles strictly by the year they were produced, but by some similar characteristics that were possessed by the majority of these first-generation long-travel motorcycles, such as suspension travel.

12.1.1 Historic classes technical specifications. The following specifications apply to all motorcycles, regardless of the year of manufacture, that fall within the scope of the Historic classes.

a) Regardless of original specification, no Historic class motorcycle may have more than 9 inches of suspension travel at the front and rear wheels. Period aftermarket suspension modifications, including shock reservoirs, are allowed in the Historic classes, provided they still meet the 9-inch travel limit.

b) No water-cooled motorcycles.

c) 35mm leading-axle Husqvarna and Betor forks are allowed, provided travel is limited to a maximum of 9 inches. Early 9-inch-travel Simons forks are allowed. Fox Factory Forks are prohibited.

d) 38mm is the maximum diameter of fork tube allowed for the Historic classes."

(I had this nightmare last night of going off a jump and having both front sliders fall off the tubes in midair.  I woke before the landing.  Good thing, I hear if you die in your sleep you won't wake up.  I think I am thinking too much about this stuff.  Any good psychs in the group.)

Thanks for the warning.

Lloyd


Brian, thanks also.

Yes, 38mm is the max, but they mention the later longer than 9" travel 35mm Husky forks as OK to retrofit if they are limited to 9".

Brian

'72 Six Day (on loan from Ernie P.)

Hi Lloyd, you once told me you could'nt draw a straight line with a ruler, kiss the ruler goodby. I think I have a pair of 38mm Zokes from a 78, will ck.

BFN,
Tom Brosius

Tom,
I think I said that 3 years ago when you were doing the new side panels on my MC-5.  Wow, what a memory.

Thanks for looking for the shocks.

Lloyd

Lloyd, To keep things simple just look for a set of 78 forks.  I have an extra set of the fluted rods for you. Other than changing the bushings in the bottom of the fork tubes the fluted rods go right in  (I have the bushings also).  When you get the forks email me at [email protected] and I will talk you thru it. Usually numerous forks in the ebay stores under "vintage KTM" or "1978 KTM" after the general listings. Make sure you ask if they have spun the tubes to assure they are straight!  FYI Terrycable also made a fork kit for the 78's.

Have  a nice set of 38mm Zokes from a Can-am Qaulifier 40.5 inchs in lenth. More then likely need seals, but very nice. Have thriple clamps and maybe wheel. Thanks

Thanks everyone.

Tom is sending a set of '78 forks Zokes off a KTM.  

Mike, I will email you about the fork tubes.

Jon, thanks for the offer.  Let me see how these work out.  I will let you know.

Happy Holidays everyone.  

Lloyd Boland

Lloyd feeling a bit of the blues, Dan Fogleberg died

Souvenirs

Here is a poem
That my lady sent down
Some morning while
I was away.
Wrote on the back of
A leaf that she found
Somewhere around Monterey.

And here is the key
To a house far away
Where I used to live
As a child.
They tore down the building
When I moved away
And left the key unreconciled.

And down in the canyon
The smoke starts to rise.
It rides on the wind
Till it reaches your eyes.
When faced with the past
The strongest man cries...cries.

And down in the canyon
The smoke starts to rise.
It rides on the wind
Till it reaches your eyes.
When faced with the past
The strongest man cries...cries.

And here is a sunrise
To set on your sill.
The ghosts of the dawn
Moving near.
They pass through your sorrow
And leave you quite still...
Sitting among souvenirs.  
 

Wow - I didn't see the Fogleberg Obit.  Cripes - I must have worn out my turntable's needle on that Souvenirs album. Played it endlessly.  Saw him in concert at Vanderbilt in Nashville in 1975 or so.  Like my third or fourth real date.  She was reeeallly impressed by, um, my concert selection.  

For me this is one of those obit moments where you call your high school best bud that you haven't talked to in 5, or 10, or 15 years and say hey.

I know it wasn't your intention, and we are waayyyy OT here DKWRacer, but thanks.