What have I got?...Please help.....

[seanguthrie]

Did KTM have different setup that they sold in their country or origin?
I do a lot of work on old Triumphs and always come across differences in models that were imported to the US as compared the the English models.  Mostly is's controls and little things but I have ran across some pretty extream differences in same year frames.  I'm sure it was do to the jigs they used but I have always wondered that about Penton's.


74 250 Hare scramble
2 68 Six Day (projects)

[Keith Meatyard]

This might be a dumb question....but how does air get into the airbox?

Keith Meatyard

[454MRW]

Well, normally the triangle portion that is filled in on the top of your airbox mates up with a pan that is attached to the base of the frame backbone and air enters the oval slotted holes in the frame backbone under the tank, effectively drawing air up high away from any water level if in high water such as a stream crossing, and also reducing the amount of dust that enters the airbox. In your case it would have to enter from the side panel which would have to be vented, (modified). Here are some pics from eBay showing the pan and stock rear frame section on a 73 250 HareScrambler and another clearer pan pic from a Six Days. Mike





Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[Knute]

Cool new pics Jim.  Overall, the left side and under-seat area look to have more of the same style mods.  From the new angles we can see the following:

Frame - The front steering stem and gusset area is definitely pre-74.5, so the 306 serial number is appropriate.  The rear 74.5-later downtube also looks very original, so the mystery remains.  Also, is it just an illusion or does the horizontal frame tube running over the engine look kind of funky?  That could be where a splice occured...I'd love to see a close up of that area when you get a chance.  Also, the section that connects the high-breather frame has obviously been cut out and some new bits have been fabbed in to hold the front of the seat, the top of the airbox, and the rear fender.  I don't see any sign of rear seat mounts, so I'm not sure what's going on there.  The left engine strut is still intact and is the 73-early 74 steel style.  Most likely, the right strut was removed to make servicing the carb easier, as the pipe is in the way on the left side.  As you guys have noted earlier, I don't see any sign of the left side pipe mount, which would normally be a tab welded to the frame tube in the area above the engine.

Engine - The R56 stamping is interesting.  When you get a chance, check the same area of the left case and see what's there.  Typically the left case carries the matching last 4 digits of the right case.  These numbers will help indicate if the right case was replaced or if the cases were replaced as a matching set...I've seen both.  Of course the black cases and the date clock indicate a 1973 engine and I think I'm seeing a small kickstarter, which would most likely mean the engine has the small, 73 kickstart shaft.  The clutch cover is the newer, post-73 style, which was offered in a version that fit the small shaft, or perhaps someone has bushed a large shaft cover to fit.  Also, I'm not sure what's going on with the stator wires, but they originally exited from the notch at the top, rear of the ignition cover area.

Airbox - Keith, that's certainly not a dumb question.  Most likely, the airbox cover/number plate was louvered and let air flow directly to the filter.  This style of cover/number plate seemed to be more common with the MXers and Europeans.  Maybe someone can dig up a picture of one and post it for us.

If I had to guess, the internal rotor ignition, mx pipe, laid-down Ohlins, and the airbox mods would lead me to believe the old girl was MX'd back in the day.  Should be a fun project!

TEAM PENTOVARNA
Kent Knudson
Kevin Brown
Gary & Toni Roach
James & Adam Giddings
Dennis & Cory Buttrick
Derick Kemper
Nicole Hays
Josh Gaitten

[454MRW]

Here are a couple bike that feature the popular European louvered left hand side panel. Mike




Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[Jim Clayton]

G'day once again,
                 Thanks MRW for posting those pics...I see now exactly what the frame/airbox join would have originally looked like. I'm still deciding whether to retain what I have, or change it back to original. I think the original setup may have been changed because the pipe sits a little higher than I think it should....the bottom plate would have had to be removed to allow room for it. I have some more pics to hopefully either pique your interest, or maybe clear some queries...

Firstly...a '72 works factory bike with a vented sidecover...a rather neat job, too....



Next...the ignition cover...showing the notch where the wiring exits is at the top front....



This pic shows the rear fender mount...it consists of the top plate trimmed down and thn bent back double, presumably to add some strength...



The remains of the rear tank mount can still be seen....



The left hand crankcase has the same R56 stamp as the right...



...and, finally, the frame tube that looked rather skanky in one of the other pics...no obvious sign of a graft here...



 The rear seat mounts are actually  at the top of the elongated 74.5 down tube...I think this may have been done of necessity, as the frame may not be of a standard length any more.

   - Jim

[SouthRider]

You have to remember the era we were in - when the 250 Penton came out it was a BEAST, and had a motor that was immediately acknowledged as the most powerful 250 available. It was also un-ridable by 98% of the riders, and could only be described as a pros bike. The powerband was truly like a light switch.

The next versions were de-tuned to be easier to ride. Then Penton again completely wowed the industry with the first laid down shock production motorcycle available with an amazing amount of rear wheel travel for it's time.

It's not a big leap to think that some MX'er somewhere wanted to create what they hoped would be the killer bike - an early engine fire breathing monster with long travel rear end. (A Honda killer - they had terrible frames & suspension then)

This could have been done by an individual, a shop, a distributor, or even possibly be a factory prototype or works bike.

I would tread carefully with the restoration until you find out a little more about the history of this bike.....

_____________________________________________________________________________________

"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

[Jim Clayton]

Oohh...you beat me to it Mike[] I knew nothing of a European habit of venting sidecovers...but here in Oz back in the '70's, it was a fad for a while. In such a dry environment like West Oz, the likelihood of a wet race meeting was low....so holes would be drilled through the airbox to improve airflow. Ocasionally airboxes would be removed altogether, and a foam elemant clamped directly to the back of the carb.
   Thanks once again for yours, and everyone's...enlightening comments...I'm learning !
   - Jim

[Jim Clayton]

- Southrider,
                You're exactly right. I DO need to find out more about this bike's origins. If it was modified by a shop or distributor for a sponsored rider, or if it should be a prototype[:0] or factory bike[:0][:0] then changing it would be sacriledge...I'd only clean it up. To this end, I'm attempting to contact the guy who was the Australian importer from '69 to '74. He was also the distributor here in WA at that time. I don't actualy know this guy, but I do know a couple of people who do...so hopefully I may get to the bottom of the story that way.

[rob w]

Jim, I would be interested to see the frame number stamped into the frame's steer tube. Then we could tell if it's the factory stampings. If you can not find any witness marks of two frame sections welded together, it seems to me it must have been stamped at a later time.
Bob

[Jim Clayton]

Bob, of course...I should have thought of posting this pic before....

[brian kirby]

I love mystery bikes like this!

Brian

[454MRW]

The pan that allowed air from the frame backbone to the top airbox entry is actually 2 layers of metal with an air gap between them for the air to travel to the lower opening into the airbox. That rear piece at the front of the rear fender has not been doubled over, it was always 2 layers joined together in the rear. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[Jim Clayton]

Of course. You're exactly right Mike - I should have realized that. Where the two plates have been cut and joined on mine is such a neat job, it looked like one piece folded over. Thanks once again!
   - Jim

[Daniel P. McEntee]

I have been following this with great interest. I've done some work on a '74 frame to try to restore it to original configuration, and I have a '73 250 with a 309 serial number. It has to be a build up of some kind. In looking at the picture of the top of the airbox and the rear fender mount, there is a tab welded in to attach the top of the air box to. With the typical pan in place, this is normally a recessed area in the pan for the bolt to go through. This bracket looks typical of what you find elsewhere on the '73,'74,'75 frames for mounting the pipe, side covers, etc. and looks like it's factory welded and it never had the pan. Is there any significant difference in steering rake from '73 to '75? The reason I ask that is due to the fact that someone else brought up about the engine and it possibly being a custom built item. Could this be a one off factory built chassis, or complete bike? It's origins may have been in Europe and somehow it ended up down under? Very neat to see and great photos so far, but it would be neat to see in person to look for evidence of a frame graft. The only thing I don't like the looks of is in the same shot I mentioned before, and you can see the inside of the rear down tubes and shock mounts. You could apply paint stripper to strategic places to carefully remove paint to look for grind marks. But I'm guessing you won't find any if the bike was manufactured this way for whatever reason.
   Type at you later,
   Dan McEntee