Penton 100 Berkshire

[Oldebonz]

I recently acquired a 100 Berkshire 1974 "Bitsa  bike" ISDT Replica built by Doug Wilford.I love this little bike!Has Sun rims,ss spokes,28mm Bing and runs like a bat out of hell at2/3-full throttle and still will not fall on it's face at low revs.It has Doug's stickers on each side of the engine and DOUG W stamped on the center case below and behind the carb.My only question,did Doug prefer the 5 speed,heavier crank A lower end and B big fin top end for woods riding?I thought the 6 speed transmission would be better with the small engine but it does perform admirably! Are the 6 speeds less reliable?just have a good 5 speed lower end and decided to use it??I had hoped to talk to Doug but was very sorry to hear that he is not able respond as he once could.We all get old but love our old bikes!  Thank you all for any insights,information!

[brian kirby]

I dont know what Doug thought, but I see no advantage to the 5 speed over the 6. The extra ratio is (I think) between 2nd and 3rd, not on the top, which tightens up the gaps between each gear. I also prefer as low a rotating mass in the crankshaft as possible on small bores, so I prefer the small crank and an internal rotor ignition. Others will probable prefer a little more flywheel weight than I do.

Brian

[Oldebonz]

Anybody have a good 6 speed bottom end??? cases,trans,crank and rod???

[brian kirby]

OK, I misunderstood, I thought you already had a 6 speed and were asking if a 5 speed was better. If you have a good running 5 speed I would not bother too much looking for a 6 speed. The 6 speed is better but the difference is not large and unless you are going to race it at the expert level it wont make much difference.

Brian

[Paul Danik]

Oldebonz,

   In reading how you evaluated the engines performance I failed to see the misgivings of the current configuration, or is there none for your intended use?

   As far as advantages / disadvantages of the 5 speed "A" verses the 6 speed "B", much would depend on your intended use and riding style.

   Obviously I can not speak for Doug, but I can easily envision the logic in wanting more mass to create some inertia allowing him to smoothly ride a trail without constantly needing to shift.

    Doug could ride a difficult trail as smoothly as water cascades down a stream, much of that smoothness was of course Doug's abilities. But he also understood the Sachs engine like few others and used that knowledge to combine components to give him the performance characteristics he wanted. Keep in mind that trail riding is certainly different that all out racing, so as I stated earlier, a lot depends on your intended use and riding style.

    There are other variables in setting up a Sachs powered Penton to suit your needs as well, a major one is sprocket size. Possibly I have missed something in your post, but I do hope my comments are of some help to you.

   You are a lucky guy to have a " Doug Wilford Penton ".

Paul

PS  Have you confirmed that it is indeed a 100cc machine by pulling the head? Not doubting your word, just curious.

[firstturn]

Thanks Paul as you stated Doug's ability was so  wonderful on the Sachs engines.


Ron Carbaugh

[Oldebonz]

Thank you for your ideas! I have a spare 6 speed,small crank lower end in great condition but I am going to leave it alone as Doug built it.It really runs and works beyond my expectations,so thankful for his expertise!