ktm/penton

[Mike]

Greetings; recently aquired 1978 ktm 250 mc-5. lower end locked up ;purchased 2nd lower end on e-bay also locked up! Is this a common malady? Would like to repair this bike for local vintage racing. Will this bike be compettitive with comparable jap bikes? Thanx in advance;Ktm virgin

[Steve Talbott]

Hi Mike, To give you an idea of the best performing bike for its time,A friend of mine and I were restoing two 1973 model bikes last year. He a Elsinore myself a Harescrambler. We finished roughly about the same time. After a few minor adjustments on each of our machines,we were ready for our own shootout.The mighty Penton left him out of the hole,in the turns and at top end! The handling was about the same we decided. So I hope this gives you some insight on the heart of these machines.Is it worth it to you to find out? Steve

Steve Talbott

[Larry Perkins]

1978 MC5 was a replica of the previous year World Championship bike.  The bikes were not that different from each other and were obviously very competitive.  They were a professional machine and in The Day the only place that the Jap bike beat it was in price of bike and replacement parts price.  There are at least 7 or 8 riders leading National AHRMA class standings aboard Pentons so I guess they are still pretty competitive.  In a big Pro Vintage race in Texas recently the holeshot was pulled aboard a 400 Penton.  Thye KTM powered MXers were a potent offering so I guess my opinion is-That dog will hunt.

 

[Chris Brown]

Mike,
I love my MC-5 400, it still keeps up with modern bikes on the trails (if they're not going too fast :-))
It's basically a Penton 125 with a 400 motor in it. Suspension was improved substantially in the previous 5 years.
You could take your motors apart and find out if the crank bearings are just rusted, or see if one of the gear shafts or gears are binding. The old bikes are really quite simple to work on.
The KTM ranks with the Maico in performance, and exceeds all of them in dependability. The Japenese bikes are copies (always have been, always will be) of European bikes and technology. It was particularly apparent in the earlier days of the sport. The only other popular and competitive bike of the day was the Husqvarna, and they were quirky handling. The bikes that were winners then are still the most envied and most competitive today.
Put your bike together and go racing! You'll have a ball.
Chris Brown

78 KTM400 MC-5
73 Jackpiner (sold)
72 Six Days (sold)
92 Honda CR250R

 

[Mike Lenz]

Mike, You have a very good bike there. I own one also. After racing all my childhood and young adult life, when I got into this vintage obsession a few years ago, thats the first bike I wanted. It was {and is} a very good bike. Having raced one in pro mx back then I feel the weakest link were the forks. They just never worked as well as the earlier 35mm ones. The fix is a Hi-Point fork kit or using the "fluted" dampening rods out of the 81 models. With those you may need to use more/longer top out springs to be legal, depending on which class your competing in {and probebly to just make it turn}.This is a bike some are even getting away with racing in AHRMA's PRE78 class do to it being a very similer model to the 77's. I support this in the open class. As potient as the old 400 motor was its no match for a 420 or 495, or a 490 maico,ect. However in the 250 class I feel it belongs in the 78 class, and is very competive with a little suspention work. The hot set up is to run fox forks or 40 mm forks from the 82-84's. The 83/4 40mm marzooks worked very well. Use the 78-80 triple trees bored out to 40mm. this allows you to slide up the tubes for good cornering. The 80 trees are the best, they are wider and have two clamping bolts on the top tree. IN the rear I tried just about everything, until I put on Works Preformance. they just came out in 78. They are THE answer for the rear. Worked even better than Fox airs. You may want to see if they would build you a little longer ones ,say 13.75",or maybe even 14 inchers to maximise rear wheel travel. If you want more out of the moter and dont mind pipeness Carl Cranks porting specs from 74 are still more radical than the 78 stock porting. With this porting you will NEVER be passed down a straight! Have fun!
Mike