Barber Race Report - VMX Sportsman 100

[tonupchad]

For those who missed out on Barber this year, you missed a great one.  I've been to every one now and can't remember having better weather. 80's and breezy during the day 60's at night and not one drop of rain.

VXC

I raced the BSA 441 in VXC so I won't bore you with the details of riding that bulldozer through the woods.  I really wish I took the Penton out on the trail.  Except for a rocky case smashing downhill I thought the 3 miles course was amazing.  Not too tight but technical and fun. I managed to break the 9 lb airbox off the bike after the first lap and my race ended after the 3rd lap.

VMX: Moto 1

After consulting some Penton brethren we concluded that the engine numbers on my Penton may be telling the truth and I really do have a 100cc bike.  This doesn't make me very happy as the seller swore up and down it was a 125.  Nevertheless, I signed up for 100 Sportsman Int and lined up on the second gate behind the 125's or 175's and next to 18y/o Trey A. on a Hodaka.  The only thing I did to the bike before riding was change the gearbox oil out with 700cc of ATF.  After a terrible start I managed to catch up and pass Trey on the first lap.  He caught me on the second or third lap after I missed a shift down to second.  We traded the lead a couple of times and he fished me off on the last lap and I ended up in 2nd/last. I was quite proud I only missed 2-3 shifts and was amazed by the power the bike put out.  It was much faster than the Hodaka in a straight line.

VMX: Moto 2

I got off to a much better start in the second Moto and was probably in 2nd overall till I missed my shift into second and scrambled to find any gear that would get me to the first turn.  After that it was a comedy of shifting errors.  Trey and Hodaka were nearly a lap ahead of me by the end of the race. I missed nearly a dozen shifts and was just trying to survive till the checkered.

A mixed weekend overall but had a ton of fun and looking forward to next season.

Huge thanks Randy, Sean, Bill, Dale and many others for all the Penton pointers.

[seanguthrie]

Man I'm sorry I missed your first outing on the Penton.  Trey is one fast little dude. I'll let you take my 250 for a spin when we meet up in the spring and you can feel the difference.  
If it truley is a 100cc looks like you are due a 25cc refund!
 
Don't feel bad about the missed shifts.  It took me a whole race season to learn how to shift a Penton!


74 250 Hare scramble
2 68 Six Day (projects)

[brian kirby]

Why not just take the cylinder head off and see what size the bore is? It will take all of about 15 minutes to do. If it was that much faster than Trey's bike then its probably a 125.

Brian

[tonupchad]

You are correct sir.  125cc

I picked up a spare head and barrel in the swap meet just in case.

[brian kirby]

Thats what I figured. Real 100s are actually pretty rare, since the only difference is the top end, a lot of 100s got converted to 125s. And very few Sachs engines have their original mag cover that the tag is attached to. If the chain derails it usually takes out that cover and the ignition. Luckily, with good modern chains that doesnt happen very often like it did back then.

Brian

[checkcrew]

Brian,

you are absolutly correct about the mag covers with the "ID" plates,

i have 2 of the Sachs GS bikes that have 1001/5A covers on them and upon removing the heads found out that they are 125's :-((

you made another good comment about the modern 428 chains, little to no failures !!!
what make chain are you running and do you run the 428 O-ring ??

these answers will help everybody that runs these 100's and 125's :-)))

quote:Originally posted by brian kirby

Thats what I figured. Real 100s are actually pretty rare, since the only difference is the top end, a lot of 100s got converted to 125s. And very few Sachs engines have their original mag cover that the tag is attached to. If the chain derails it usually takes out that cover and the ignition. Luckily, with good modern chains that doesnt happen very often like it did back then.

Brian

Mike Gallagher, NJ.
[email protected]

[seanguthrie]

I can't wait to check my 125 out whenever it makes its way into my possession!

74 250 Hare scramble
2 68 Six Day (projects)

[joe novak]

No need to remove the head.   If you remove the exhaust pipe, you can slide a piece of thin cardboard strip inside the exhaust port, rotate the crank until the piston pinches the cardboard on the top of the exhaust port.   This will give you the diameter of the cylinder bore.   Of course, pulling the head will definitely give you the exact bore....     joe

[OUCWBOY]

I don't know Joe, it's almost easier to remove the head than the exhaust.... lol

Donny Smith
Paragould, AR

[gooddirt]

Early 100s where the fins are cut for the pipe two or three of the fins were not rounded at the front of the head edge like the 125 head.