Hi to all,
I joined this board several years ago, but for various reasons my Pentons have not been out of the shed in as many years.
I'm finally ready to get started and have some questions for someone.
I have two Six-day 125's, frame #30262530 & 30161683. I believe they would be a 1971 and 1972.
As I sort through the parts it looks like I only have parts to complete one bike. But since they are all mixed together now, I could use some help sorting them out.
The 71 frame appears bent in the rear fender loop, so I'll be using the 72 frame.
1st Question: The triple clamps are not the same, however both bikes have 32mm forks.
One set appears much beefier and slightly wider than the other. I'm assuming these are correct for the 72 frame?
2nd Question: I only have one seat between the two bikes and I believe it came from the 71. Is there any diference between these years?
The seat mounting brackets are bent so the seat doesn't fit to either frame right now.
3rd Question: I have the cross-over through the frame exhaust with the chrome heat shield. Is this correct for a 72?
I don't recall which bike it came with.
4th Question, and finally; are aluminum fenders correct for the 72? I would prefer to run these vs white plasic fenders.
Thanks in advance for any assistance.
Ron
The 71 and 72 bikes don't share components. Different animals entirely.
The 72 and 73 are similar. As are the 70 and 71.
Now both of your frames are from 1973 bikes. But one is a 125 (30262530)
and the other is a 175 (30161683). Some items will interchange but others won't . The frames are different. One takes the 175 KTM engine and the other a 125 Sachs. As for the 32mm forks, there were 2 versions. The early '72, 32mm forks were shorter and narrower. Then later in '72 and '73 the 32's were 1 1/2" taller, with wider and stronger triple clamps.
Someone correct me if I am wrong.
Dwight
Dwight Rudder
7 time ISDT / E medalist
8 time National Enduro Class Champion.
Dwight,
I am lost as to how you have figured out that one of these machines is a Jackpiner? The early Piners had a #7 stamped in front of the serial number and neither of these numbers has that according to Ron. Please set this Martian straight!
Thanks
Paul
I believe Dwight's getting that from the production year list on the site. He's a clever rascal.
Lew Mayer
I just checked and that frame number is not listed.
Paul
I figured Dwight was interpolating.(?)[:o)]
Lew Mayer
Ron,
From the information you provided I believe you have two 1973 Penton 100 (Bershires-Red) or 125 (Six Day-Green). Most of the parts for these two bikes interchange except one being a 100cc verse 125cc. As far as the triple clamps the frame numbers fall into ones that I owned that had 32mm fork (tubes). The other set may have been changed out by the owner since this was done by people back in those days.
The seat brackets(new reproduction) can be ordered through Al Buehner (see Suppliers) if he still stocks them. The original fenders for 1973 goes as follows. The early part of the year they were Alloy and then went to plastic. The bike I had that was built in that same time had plastic fenders.
I hope this helps.
Ron Carbaugh
Hi All,
Thank you all for your responses.
Both of the bikes had Green tanks and Sachs 125cc motors installed, when I got them. One is a 1251/6b - #7432186, the other is a 1251/5a. I'm planning to use the 6b, six speeder engine.
I hadn't noticed the difference in fork lengths Dwight mentioned, but yes, one set is about an 1" longer. Unfortunately this is not the better of the two sets.
Is the length difference in the damping rods?
Are the upper tubes the same length? That would be an easy fix, otherwise my upper tubes are bent and pitted beyond use.
Is there a difference in rear shock length when these forks lengths are used?
Also, my cylinder has an aluminum plate welded to the intake side and a rubber mount bolts to the plate, to adapt a Mikuni spigot mount carb.
The rubbber is cracked and not usable. Any ideas where I might find a replacement?
Glad to hear the aluminum fenders can be used. I realize how easily they're damaged, but they sure look sharp.
So is it correct to say both bike would use the same seat?
I'm pretty sure I can straighten and reuse the seat mounts I have.
I'm planning to ride this bike in the Adelanto Gran Prix Vintage class, next Febrary 2006.
Hopefully I can get it put together and still have a chance to ride it and check it over throughly before then.
Thanks again for all the assistance,
Ron
Ron.
take some measurments on the intake manifold and see if one on this web page will work as a replacment
http://www.sudco.com/catalog105/068.pdf
John D.
Quotequote:Originally posted by Paul Danik
Dwight,
I am lost as to how you have figured out that one of these machines is a Jackpiner? The early Piners had a #7 stamped in front of the serial number and neither of these numbers has that according to Ron. Please set this Martian straight!
Thanks
Paul
I didn't think all had that #7. Early ones did , I don't know about 1973 production. but the serial numbers match up in sequence. But I notice that the list isn't complete in sequence. Oh, well.
I stand corrected.
Dwight ;)
Dwight Rudder
7 time ISDT / E medalist
8 time National Enduro Class Champion.
Dwight,
The first year Piners built from June of 72 till June of 73 used the same basic chassis as the 100/125, obviously different motor mounts. KTM stamped a #7 prefix on the serial number of those machines. I thought maybe you saw something else that told you that machine was a Piner.
Ron, If I am not mistaken you can put the topend from the "A" engine on the "B" bottomend, if needed. I was told that there is no difference in the "A" and "B" alloy topends. Good luck with your project.
If someone knows differently please correct me.
Paul
Ron,
Just remember that a lot of people mixed and matched the entire bikes to keep them racing or riding. The two engines could be what they indicate(by the side cover) or they could be different since all you have to do is change the ignition cover to throw off someone. I hope this helps.
Ron Carbaugh
Somewhat straying from the topic, but--does anyone know why the Germans at Sachs, of all places, put the engine serial number on such a dunderhead place?
I am reasonably sure mine is correct, since I bought it only a year old, but every other one is suspect unless you have owned the bike since new or at least have some personal knowledge of it's provenance.
Ron, glad to hear that there will be another Penton at the AGP this coming February. I live in Southern California and pull out the Penton twice a year for Adelanto and Elsinore Grand Prixs. A word of advise for preparing the bike. Adelanto track is same year to year so the sand has gotten deeper. Last year I ran stock gearing and had problems with bike pulling in the sand. This year I plan to run a 60 tooth rear sprocket. This cuts down on the top end a bit but allows the bike to stay on the pipe and pulling on the long sandy fireroad on the back portion of the track.
Ron,
I have a 73 jackpiner the serial # starts with a 54 prefix. The bike has the green mx tank & the same exhaust you have. I have a set of green preston petty plastic fenders on it. I do know what you mean about metal fenders, they sure do look sharp.
Shaun (Dobber)
73 Jackpiner
Hey Shaun,
Someone has put your jackpiner into a 250 frame. The 54 means it was a 250.
Donny Smith
Hi Guys,
I was hoping someone would respond to my question about the different fork lengths. Is the difference in the damping rod length?
Also, do the bikes with longer forks have longer rear shocks?
Could someone advise the correct shock lengths used?
Looking down into the cylinders of the 5a and 6/b they aprear to have identical porting. Someone one has opened up the transfer at the base of the cylinder. I doubt this would make any difference.
socalmx, where are you located? I'm in Azusa.
Thanks again to everyone,
Ron
Ron, I am located in Anaheim Hills....let me know if need any help with your Penton.
Ron,
I can't answer your question as to the difference in the parts for the two front ends. I do have a set of each, but I have never compared the parts. As far as the length of the rear shocks...I always dictate the length based on what rake angle I want on the frontend.
Sorry that I don't have an original bike with the frontend you are talking about to give the lenght of the rear shocks. Not much help except to how to selectthe length of your rear shocks.
Ron Carbaugh
Hi Guys,
I'll take the forks apart this weekend and post what I discover.
Ron, good point on using shock length to adjust rake. Hadn't thought about that.
I was mostly interested what Mr. Penton thought was the correct length shock to use.
What length rear shock do you use?
Socalmx, thanks for the tip on gearing, I may be carrying a few extra lb's to.
What are you using up front on the counter shaft sprocket?
Thanks for any info.
Ron
Ron,
Subject: Shock Length
Touchy subject, but here goes. I run 13 to 13 1/2 and various spring weights. If I need a quicker turning bike I use the longer set or for a cruser (Enduro) I use the shorter length. As you made comment on the riders weight you need to figure how much compresstion you get when you sit on the bike. I still think the old Curnutts and Koni were the best if you aren't riding on a modern MX track where they fade too quick[B)]. Just my take.
Please don't start the same thread that we had on fuel mixture...this is just my opinion which Ron ask for and if it doesn't suit others, so be it[:p].
Ron Carbaugh
I run the stock 14(?) tooth countershaft sprocket. Since it is a tapered fit, it is much easier to deal with changing out the rear sprocket. Alan B should have a 60 tooth if you want to gear down.
You can play a bit with the shock positions on the swing arm and of course, move the fork tubes up or down in the triple clamps. For Adelanto, you will want more high speed stability. Since the Penton has a long wheelbase, I leave everything set in the middle. I have never had any problems with head shake at speed doing this.
I agree with Ron's choice of shocks. I have ran a pair of vintage Konis for years and just recently installed a pair of Curnutt shocks. The Curnutts were unique for their time because they had no dampening at the top part of the travel. This was to allow the rear wheel to follow the dips as well as the bumps. These shocks are hard to come by but well worth trying to find. The only caution is that they were valved/springed for specific rider weight, riding style, and bike. I spoke with Charlie Curnutt Jr. a while back and unfortunately, he no longer has any parts for the shocks.
Hi Guys,
I took the two sets of forks apart last weekend and forgot to post what I found.
I was hoping the difference would be in the dampening rods, so one set would have more travel.
But the difference is in the fork tube lengths.[xx(]
The long ones are 24-3/8" and the short ones are 23-7/16".
The springs are also different lengths, but the dampening rods appear to be identical.
RonW
Ron,
Here is what I know about the forks, maybe it will help. The shorter forks go with the single bolt narrow triple clamps and the longer forks go with the 2 bolt wider/heavier triple clamps. The top clamp on the 2 bolt version sits higher relative to the top of the frame head tube, plus the distance between it and the bottom clamp is greater, which is why it is used with the longer the fork. When you have the correct fork-clamp combination, the distance from the axle to the frame is identical (as close as I can measure ) with both sets.
From what I have observed, the narrow single bolt style came equiped on the first '72 CMF 125's, then they eventually switched to the 2 bolt design sometime before or during the '73 model run. All of the '72 175's that I have seen have the 2 bolt clamps.
So now you have a choice, weight or rigidity. I my case it usually ends up with a choice between light rust and rusted out or dented and bent.
John J Slivka
Hi John,
Thanks so much for the info.
I'm going to have to use the shorter set for the same reasons you mentioned, rusted and bent.
Only problem I have to spend another 4-5 hours polishing the single bolt clamps.[V]
Thanks again, RonW
Ron, are you still targeting getting bike finished for Adelanto Grand Prix? Regarding the forks, since they are on 32mm the steadier the better. Using the two bolt version is best way to go.
socalmx,
Still have my sights on Adelanto GP. Got to get movng on my bike!
I'm still debating on buying new fork tubes to run the two bolt forks.
Do I have a limit on shocks I can use at Adelanto? I have a pair of Works Performance 4" shaft and a pair of old Koni's. Less travel with the Koni's.
Thanks, RonW