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Jack, tried to send a note to email address but got bounced back. I live in Anaheim Hills and have a 72 100/125 (currently tanked as a Berkshire). It was my AHRMA racing bike up until a couple of years ago so not showroom condition. It is set up as in the day with Petty plastic fenders, akronts, cut off pipe, and Curnutt shocks. I would be willing to bring it to the stadium for the display if you would like to include it. Please respond to me email [email protected] or call me at 714 606-7496 and I will send you a couple of photos of the bike. Thanks, Greg aka Socalmx

Go to AMA District 37 Message Board for more details. They are saying that he hit an animal causing the crash. Very sad indeed.

Can't you run a piece of hose from the back of the carb thru the frame "tunnel" then use something to stiffen the hose and a "sock" filter?

Mark's sister Linda was THE desert cutie back then. Fun times for sure!

That was footage from an ABC Wide World of Sports. It has to be scary to swap ends on a Triumph pig. By 1972 when I started racing desert, almost all of the sleds were gone replaced by mostly Husky 360s. Pentons were not the bike of choice in the 100cc and 125cc classes. Of course there were some out there racing (Bill Friant on a 6 Day was pretty fast)but for the most part it was other brands. Trailbike 100cc was dominated by Hodaka and Harley Davidson with a few Sachs/DKW and Rickman Hodakas thrown in. 125cc to 175cc class was dominated by the killer DKWs along with a few Puch 175cc and even a Yamaha 175 MX (Monte Lee) thrown in from time to time. Mark Adent earned 1x (250 class) for 1974 on a 185cc (German Army motor) DKW then switched over to a Penton to carry the plate. It was not until 1976 as KTMs that they really became popular in the 175cc and 250cc classes.

Want to make a Berkie run? Mill the head .060, open up the ports (mimic the GS specs)and intake spigot (as far as possible with a rough finish, throw on a pipe and a 28/30mm Mikuni, and of course a button mag. That all done, you will really have a runner.

VP Racing Fuel makes non-ethanol small engine and storage fuel. Either one left in the carb and gas tank will keep issues from happening. I currently ride a WR250F and I run out the ethanol laced gas then hook up an auxiliary fuel supply to the carb filled with the Small Engine fuel. Fire up the bike, let the float bowl fill, run for a minute or two then shut off. That way I am sure that there is no ethanol gas left in the bike. The result is no more clogged pilot jets which makes me a happy camper.

I love my Curnutts and have since I purchased my first pair in 1973 from Curnutt Sr. for a whopping $35. The neat thing about them is that they are easily rebuildable. The shocks in the picture are a late model version due to the aluminum/o-ring shock bolt grommets and the machined aluminum spring tensioners.

Never seen the Johnstone bike run but as mentioned earlier, I did see a factory Honda SL125 with a pro rider (Bruce Baron) get dusted on a regular basis by a couple of Mettco riders. The only Honda 4 stroke that really did well was the Bill Bell/Long Beach Honda XL250 raced by Bob Hosford. That bike flew and was well suited to the flat-track/scrambles nature of Ascot motocross. Personally speaking I got beat very bad by Rick Doughty of Vintage Iron at Elsinore GP one year. He was riding a simple looking Honda SL100 and I was on my Penton. Simple fact was that he is a much better rider and could had beat me on a Honda Trail 90!

I forgot to mention that the only Honda 100 4 strokes that did well at Ascot were the ones that were bored out to around 150cc and ran as cheaters.

I had a 1971 SL100 that I use to race way back when. It had the following:
Sig Erson cam with rocker arms ground down to lighten up
Head opened up a bit
Webco manifold with Honda 305 carb
Filtron sock air filter
Poweroll high compression piston
Bassani reverse cone megaphone pipe/silencer

When ran against a Hodaka, Sachs, or Harley Baja it always got dusted badly. Bike rev'd alot and made alot of noise but that's about it.

If anyone was ever at Ascot Park motocross, they would have seen Bruce Baron on a factory 4 stroke 125 get beat very badly week after week by Chuck Bower and Bruce McDougall on their Mettco Pentons.

Don't like, the Honda SL100/125 engine was always a dog no matter how much you put into it. I remember putting a SL100 in a Rickman frame and how it never was right.

Don't use a rim strap since they can break and are a pain to work with. I have always used multiple wrappings of black plastic electrical tape on my rims.

Back in the day Uncle Donny milled my head .060 as part of his porting process.

Those yellow fenders are called Preston Petty (s). In my neck of the woods, the stock fenders were removed and tossed away as soon as the bike got home.