1968 penton 175 prototype found

[goliath]

hi i found v335 last week it seems to have had a yellow frame and it has the black cast iron big bored cylinder that has a 60 mm piston anyone know anything about the 3 175 prototypes they built here is
video of Tom Penton talking about them mine must be the first one they built here is my picture site of bike been apart for many years no one knew what the motor was to replace piston
http://s624.photobucket.com/user/goliath99/library/1968%20Penton%20V335?sort=3&page=1
https://www.youtube.com/watch?v=AgT5qLiKfAc

[Paul Danik]

The machines that Tom Penton discussed were built on the later frame known as the CMF, or Chrome Moly Frame. The top end that was mated to the Sachs bottom end was of KTMs own design, as shown in this picture. The engine in this picture has a KTM bottom end, not a Sachs bottom end that was used in the machines that Tom discussed.

http://www.pentonusa.org/GalleryServerPro/default.aspx?moid=192&hr=1

The engine you have looks to be what is known as a 152cc conversion where a Yamaha 305 piston, the 305 Yamaha being a twin cylinder, is installed in the earlier cast iron Sachs cylinder. Those conversions are not exactly commonplace, nor are they extremely rare, but they do exist in sufficient numbers. Those engines are found mostly in frames such as yours which are known as Steel Tank Pentons as they have the medal gas tanks. As for the yellow paint, apparently over the years someone thought it was a good idea for some reason.

Hope this helps.
Paul

[t20sl]

I had a 152 that was built @ Penton hdqtrs.  If I remember correctly the Yamaha 305 pistons had to have the locating pin for rings moved or they would have lined up with a port.  I had to replace piston a couple of times during the time I had the 152 motor in a 1969 Six Days 125.  
Ted

[goliath]

alright in your model history page it said the fist prototype 152 was made in early 69 bronze silver sides then later that year more were made the cromoly framed bikes dident come out till 71 read for yourself my vin is late 68 dont you think the would have tried this combo before the custom painted one was built i can tell you this bike been apart for 40 years has 2 paint jobs over the yellow no silver under any of yellow paint the cad coating on the parts that were yellow they are brand new after i stripped paint here is the info on models also i looked tom pentons ama records up he won the cross country 176-200 cc in 1969 so he was not in the service then and what did he ride i wonder    
http://www.pentonusa.org/prodyears/prodyears1.asp

[Paul Danik]

You ask, what did Tom Penton ride to win the 176-200 cc Cross Country in 1969? I would say it would have been exactly what V 335 is, a 152cc conversion.

You say, V 335 has been apart for 40 years, that would mean it was disassembled in approximately 1975, it is a 1968 model, that is a large window of time where the 152cc conversion could have occurred.

 But, most likely it was done in the early years of its use. It could have been ridden for a year, or two, or three before the conversion was done, possibly when the 125cc cylinder could no longer be bored any larger using a 125cc overbore piston. Or, it could have been done when the then owner saw that he could ride the Penton in the larger capacity class, just as Tom Penton had done. Those kits were available thru Penton imports as an accessory item.

If you click on the link below, you will be taken to a thread discussing the Penton that Tom Penton mentions in the video, and if you scroll down in the thread you will see one of those machines sitting in the bed of a pickup. That engine was built by Carl Cranke and has a Sachs bottom end with a KTM Jackpiner topend grafted to it.

http://www.pentonusa.org/forum/topic.asp?TOPIC_ID=15782

V 335 is a very nice find, and it is great that you have such an interest in figuring out its heritage.

Paul

[goliath]

thanks for info this bike was raced or built by a pro got all the tell tale signs and has to much custom stuff like the rear frame supports wired spokes a custom made 6 bolt sprocket hub to fit a 68 wheel if someone wanted a 6 bolt hub in 69 you buy a 69 wheel you dont make a one of a kind hub, has alloy rims  with dents so it was rode hard i removed the rest of the paint from swing arm with paint remover to see if it had been blasted under yellow paint and it was not sand blasted ,now for motor what did they use as a top connecting rod bearing mine has a brass bushing yamaha needle bearing is 16x20 mm sachs is 16x19 mm the new aftermarket rods look like they are 20mm and the notches in my piston are to do with matching ports ,so if my bike has all these mods who do you think built a 68 modified race bike i can only think of one
i am putting bike back together with yellow frame someone is going to recognize it. also this bike is in Canada  
thanks Udo

[Paul Danik]

Lets address items one at a time.

The six bolt hub. The original four bolt hubs would often brake if the rubber drive cushions were not properly maintained, and possibly some even broke if the drive rubbers were maintained as that drive unit came from a street application and was found to not be durable enough. Most machines that came with 4 bolt drive units were upgraded to the later hubs at some time, what is rare, is to find a machine with the original 4 bolt hubs and drive units in proper operating condition.

Wiring the spokes. A rather common practice "back in the day".

The brass top end bushing. The Yamaha piston used in those conversions had a larger wrist pin diameter than the Sachs piston, so the brass top end bushing needed reamed out to accommodate it. The earlier Sachs engines used in the Penton had aluminum rods and brass top end bushings. The later engines had steel rods with a needle bearing on the top.

Alloy rims. What is unusual is to find the original very soft Boraini rims still on an early Penton, many early bikes eventually had upgraded rims. When the original four bolt rear hubs broke many times a complete, later style wheel assembly was installed, including those rims.

The notches on top of the piston. You answered that question properly, they were cut into the piston to match the ports.

Who built the bike you ask. My guess is that the modifications and updates occurred over a period of years as the weak links in the original design started to show up, and as the conversions like the 152cc kits became available. As far as who did them, possibly several owners over a period of time, or one owner who kept the bike for many years.

The yellow paint. As far as thinking it was Tom Penton, or something the Pentons did themselves as a "special". If the Penton Family, or any of their team riders did any special modifications to their machines to test a "new idea", or possible future modification, they took extra care to not bring it to the attention of everyone. They surely would not paint their motorcycle yellow. I have seen hundreds, if not thousands of photos of Pentons over the years, and have never seen a Steel Tanker painted yellow by any of the Penton folks.

Please post some photos of the bike when you do get it together, sounds interesting.

Paul

[goliath]

Thanks Paul i will take better pictures of rear hub to show you and i am going to ask Helmut Clasen about this bike it might have come from him
Thanks udo

[brian kirby]

I pretty much covered all these topics on a Facebook discussion. V335 is a great find, but I dont think there is any special about it beyond that its an early Steel Tanker with a 152cc kit. The bikes Tom is talking about in the YouTube video are clearly CMF bikes with KTM top ends on Sachs bottom ends, he is asked when these bikes were made and he says after he got out of the Air Force, Paul or others can probably say when Tom was in the Air Force, but I know it was after the CMFs came out.

Brian

[Paul Danik]

Udo,

   You are quite welcome, and by the way, Welcome to the Penton Owners Group message board family Please keep us abreast of your progress.

Paul

[goliath]

ok i took some better pictures of motor and the other special parts as you can see i have a black top end which is odd also had black front motor mounts to match cylinder, home made looking rod bearing also motor has been ported to the max no amateur built this hope this will help you pros identify it
thanks udo
http://s624.photobucket.com/user/goliath99/library/1968%20Penton%20V335?sort=3&page=1

[firstturn]

Thanks for the pictures.  I really do not see anything out of the ordinary.  Like Paul said it is a nice find on a early 1968 Penton.  I have several of the piston pin bushing.  Thanks for sharing.

Ron Carbaugh

[Dale Sonnenschein]

This is an interesting read. Thanks Paul for the info. There was a penton dealer the next town over from me back in the day. He also sold Saracen. I never heard of the pentons getting the 152 kit but a friend of mine has a 125 Saracen with the 152 kit. He's owned the bike since the early 70s. Saracens had Sachs engines in them. I'm working on buying the Saracen from him. Hopefully he will let it go soon.

73 Jackpiner
73 Husky 360 WR/RT
76 Husky WR360
78 husky cr250
82 husky wr430
10 ktm 250xc
02 bmw r1150r

[brian kirby]

I'm even more certain that is the 152 kit from Penton because it has the alloy "high compression" head, not the stock "butch" iron head or the standard alloy top end head. Almost all of the 152 kits had the high compression head like in your pictures. As Paul mentioned the bushing was used to adapt the Yamaha 16mm wrist pin to the Sachs rod which had a 15mm wrist pin. Pretty much all standard 152 kit stuff.

Brian

[brian kirby]

And as several have said, even if its not some kind of prototype its still great to find a very low number Steel Tanker like v335.

Brian