Six Days gearing

[Rick Bennett]

What gearing is anyone running on a 125 set up for the woods. Mine has 14/54 and it would make a good road racer. Just looking for a place to start.
Rick bennett

[Paul Danik]

Hi Rick,

  "Back in the day" 14/54 was the gearing that I most always preferred for woods riding, and especially for enduros, while riding the 125 Sachs powered Penton. Don't want to bore you, but here is the thinking behind my absolute love of that gearing.

   Many of the more nasty, hilly or muddy sections of a run can be classified by what gear can be used to conquer them, such as a 3rd gear hill, or a really nasty and muddy 2nd gear swamp section, reason being that with the small bore engine a shift into the next gear was not an option. By running the 14/54 gearing you can still run those sections in the same gear, but you can carry more speed, and more speed also gives you more momentum.

   For example, in a long section of nasty swampy trail with a few logs thrown in occasionally, a guy with 14/60 gearing is going as fast as he can in 2nd with no option to hit third, then you come along with 14/54 gearing and overtake him with relative ease, just then you come across a log right after a quick corner, or a steep creek bank, the momentum/speed you have will carry you past the obstacle much easier than the guy with 14/60 in most every case. many times you can shut the throttle for an instant if needed and your momentum will get the job done. The same logic applies whether it is a 2nd or 3rd gear section, the fun factor also goes up with that gearing....at least in my opinion....

    Another real gem of that gearing is for road work as it is a real joy to run those small bore engines thru the gears and occasionally overtaking much larger machines that were essentially gear bound as far as 6th gear top speed goes, but that mostly applies to enduros and such, and really comes into play only if you are running late.

   But to answer your original question, 14/57 is nice woods gearing, vs 14/60. I might add that really dialed in carburation is also critical to enjoyable woods riding, crisp and clean low and midrange makes riding those machines on woods trails a real joy.

   Before you change that gearing, maybe give it another chance and feel the smooth pull you get with it. I believe you will need less shifts, have better hook up, carry more momentum/speed, and will in the end be smoother, which usually translates into being faster

Just my 2 cents worth, hope it helps.
Paul

[Koen Cuypers]

For offroad (enduro) usually 14/54.
Only MC types have rear 65 teeth, the transmission inside is different
Sachs 1251/5C MC motor:
Motocross: 14/65
Sachs 1251/6D GS motor:
Enduro: 14/54
Sachs 1251/5A GS motor:
Enduro: 13/54
Koen

[Rick Bennett]

Right now I know my jetting is off. The bike came with a Mikuni carb with 165 main and 45 idle jet. I have ordered others to try out. The woods cross country racing we are doing in central Pa is VERY tight single tracks with LOTS of switch backs and hills with rocks. We hardly ever get out of 2nd gear in the tight sections. I will rejet the carb and try the gearing I have now before making a change. I just hate being in 1st gear. Thanks for the thoughts.
Here is one more question. Several bikes last weekend were running trials instead of knobby tires. Did you ever do this back in the day?

[Paul Danik]

I have never used trails tires except for when riding observed trials, and don't recall anyone using them in the woods events we rode.  

The jetting/carburation is paramount in getting your Penton to work properly. I always had a low to mid range that was very, very crisp and clean, with the fuller throttle jetting  set up to provide plenty of fuel/oil mix to allow for fuller throttle abuse with little concern for proper lubrication. There are times when higher rpm running for longer periods of time in 3rd. or 4th. are needed to set good times in longer woods rhythm sections, before we had access to larger main jets for the Bing we actually would drill the 140 main to the 150 size and run the needle in a lower position, this would provide plenty of fuel/oil mix at fuller throttle running for longer periods of time. Getting everything dialed in perfectly took a little bit of time and testing initially, but it was well worth it.

 All of what I have stated is what really kept my personal interest in the small bore forever peaked, the challenges in the set up, as well as in making it all come together on the trail was never ending as well as rewarding.

I know exactly what you mean by the tight sections. Your example of 2nd. gear sections is exactly what I was referring to in my earlier post. The trick is to be the fastest guy in 2nd. gear, hence my absolute love of the 14/54 gearing. If someone is going 12 mph and you pass him at a whopping 14 mph he will be wondering what he is doing wrong....and what you are doing right...

I would love to bash the Mikuni and tell you to pitch it and get a Bing as I love the Bing carb, but the verbal abuse that I would be showered with isn't worth it..  

Paul

[brian kirby]

I run 12/57. With that I can do a 2nd gear start in MX and I have never run out of top speed in 6th during hare scrambles/ISDT races.

Brian