Advice on Set up for the new 100 class

[john durrill]

Folks,
Tom B. , Marc B. , have sent me a couple  things via email that may help everyone with the New AHRMA class. Combined with Ron C's and Larry P,s
posts they should be good suggestions to follow and help everyone.
 I can post them if you would like.
 The first one is listed below. This one is for the really aggressive
POGers that can hold the hammer down all the way chuckle chuckle! If you have had the pleasure of watching Tom ride you will understand the
above qualifier .
 
Tom B. wrote,

After reading your mail I went on the POG and read all I could concerning every
100cc post. I actually do have a unique set-up for baby cerianis that make them
feel like my favorite fork. I am not so sure it would be a set-up that would
gain wide praises so i have not posted. The set-up is more designed for my hard
landing, berm it off an oak tree style.

I cut the std. Ceriani springs in half, then I took a pair of std. CR125 Honda
springs and added 3 inches of spring to the overall standard height. This
concept goes after a simple philosophy I have.
 (If I only get 6 inches of fork travel, why would I want to lose 2-3 inches of
travel just because I sat on the bike)?

For oil I used ATF and fill each leg 4 inches from the top when the legs are
fully compressed with out the springs inside.

My Ceriani forks were awesome and I would put them on any V bike. My CR 125 Elsinore forks suck by comparison.

If you need forks like this for your riding style then send bentrims a note and get the specifics on how much to cut and which end to use on the stock spring. They are progressive wound and that would be a good thing to know[8D]
John D.

[brian kirby]

That is how I set up all of my Vintage 7" or less forks, no matter what brand or size. I set them up with enough preload to get minimal sag, relatively stiff spring rate, and very light oil like ATF which is 5wt. It is not the best for slow technical riding, but for MX or fast CC its ideal.

Brian

'72 Six Day (on loan from Ernie P.)

[john durrill]

Brian,
Could you go into more detail and use a specific set of forks as an example please. How much preload and what type of material you used for preloaing . Too much preload and you can coil bind the fork springs.
There is an air gap between each coil in the spring. If we preload too much for a specific set of forks ( like the 32 mm ) The spring coils come in contact with each other under full compression and bind.  We limit the travel of the front wheel and will damage the spring. You already know this but for folks that don't its a good thing to take into account.
 If you do the mod Tom B sent us then use the same materials. I would not sub out the Oil as an example. Use ATF not something else unless you don't mind doing R&D at the track chuckle chuckle!
 That setup was tested and worked with the 32 mm forks.
John D.

[brian kirby]

I can use the Betor 35mm forks on my Canned-Ham 175 as a current example, but I have done similar setups to everything from XR75 forks to early 80s long travel motocross forks.

The stock spring in the Betor was very soft, so I tried to preload them some and I used 20wt fork oil. This stopped the sag, but the rate was still bottomed too much for anything but tight trail riding. I ordered stiffer "MX" springs, which turned out to be just the right preload without any spacers. It seems counterintuitive but in addition to better bottoming resistance, a stiffer rate spring with zero or low preload has better small bump compliance than a softer rate spring with too much preload. Only use as little preload as you can to get the sag you want, which I want essentially zero sag like Tom's setup. The Betor forks recommended oil weight is 30wt, so the 20wt I am using is lighter, but I am going to try ATF soon as they seem a little over damped.

I know Tom's spring setup works, but I have to think that there is a spring out there that you could use instead of cutting the originals. What Tom is doing is adding 3" to the overall spring length to build in preload, but if you find the right spring, it will be only a bit longer and a higher rate which will get you the same sag with less preload. If you can find the right spring, it would just be a matter of installing the stiffer spring, measuring the ATF level and go riding.

Anybody know what the stock Ceriani spring rate is for the 32mm forks? If someone knows I'll see if I can do some research and find a suitable spring.

Brian

'72 Six Day (on loan from Ernie P.)

[john durrill]

This  cut and past is from Marc B. He has some personal knowledge of how the Mettco Pentons were maintained an prepared. The approach of 2 different rider's to shifting is interesting. Marc confirms what Ron C. and Larry P. have already said about Gearing. It makes a lot of sense and with different tracks it might be a wise idea to have some spare chain , master links , 2 counter shaft sprockets of different sizes and 3 rear sprockets 1 tooth off .
 

Hi John,

Back to the Mettco bikes....First off, they did not run any 100cc bikes out
of their shop so I really do not have any more info other than what would
also apply to the 125 Pentons. As you know, rider is 90% and bike is 10%. I
believe the 2 best 125 MX riders during the 1971-1973 era were aboard Penton
motorcycles riding under the Mettco banner. More than anything their bikes
were meticulously prepared for every event, and owner/team manager Fred Hayes
was a 'hands on' type guy. I know Chuck Bowers liked the 'Koba' shift kit
while Bruce McDougal stayed with the standard set up. The absolute key to
the
trans shifting correctly was keeping it in adjustment, keeping a fresh
selector in it, not rushing your shifts and using the clutch. Even today
when Bruce rides a vintage race on his Penton he is in no hurry to get to
the next gear. You can see him using the clutch, and he is a good enough
rider to keep his speed through turns allowing him to use a higher gear than the average rider. Gearing was a high priority for
Team Mettco. The same principal still applies; you want to gear
to hit the maximum RPM at the end of the longest straight in the highest
gear, and work on taking your turn in a higher gear than
normal. Less shifting, less missed shifts! I wish I could tell you about the
Mettco porting specs and head work, but they really kept that info under their
hat. I can only tell you that in 1975, Fred ported my CR 125 Honda and that thing
flew! During that period he was consulting American Honda's MX
125 team with regards to cylinder porting, head work, etc. Super intelligent man and very knowledgeable on 2 stroke technology.
Mettco like using a modified 175 rod in the smaller
bore models, and the larger Bing carb off a Jackpiner. In 1973 I had a
125 Six Days, and Fred modified the pipe for me. Basically he cut the rear
section off and added a built in silencer. Again, I do not have any specs on
this mod. It did however make a noticeable improvement over the stock pipe. Just a little more noise emanating from it. See the pictures attached of my bike for pipe mod. Black and White pictures taken in 1973 at Irwindale Raceway MX track in Irwindale, Ca.. Color picture taken in 1973 at Claude Osteens Riding Park in Pomona, Ca.

John D.
 

[Marc Biro]

Hey Guys,

If your really serious about fork springs you need to contact Progressive Shocks in Hesperia, Ca. I believe thay can supply or make whatever you need.

Marc Biro  

[john durrill]

This  cut and past is from Marc B. He has some personal knowledge of how the Mettco Pentons were maintained an prepared. The approach of 2 different rider's to shifting is interesting. Marc confirms what Ron C. and Larry P. have already said about Gearing. It makes a lot of sense and with different tracks it might be a wise idea to have some spare chain , master links , 2 counter shaft sprockets of different sizes and 3 rear sprockets 1 tooth off .
 

Hi John,

Back to the Mettco bikes....First off, they did not run any 100cc bikes out
of their shop so I really do not have any more info other than what would
also apply to the 125 Pentons. As you know, rider is 90% and bike is 10%. I
believe the 2 best 125 MX riders during the 1971-1973 era were aboard Penton
motorcycles riding under the Mettco banner. More than anything their bikes
were meticulously prepared for every event, and owner/team manager Fred Hayes
was a 'hands on' type guy. I know Chuck Bowers liked the 'Koba' shift kit
while Bruce McDougal stayed with the standard set up. The absolute key to
the
trans shifting correctly was keeping it in adjustment, keeping a fresh
selector in it, not rushing your shifts and using the clutch. Even today
when Bruce rides a vintage race on his Penton he is in no hurry to get to
the next gear. You can see him using the clutch, and he is a good enough
rider to keep his speed through turns allowing him to use a higher gear than the average rider. Gearing was a high priority for
Team Mettco. The same principal still applies; you want to gear
to hit the maximum RPM at the end of the longest straight in the highest
gear, and work on taking your turn in a higher gear than
normal. Less shifting, less missed shifts! I wish I could tell you about the
Mettco porting specs and head work, but they really kept that info under their
hat. I can only tell you that in 1975, Fred ported my CR 125 Honda and that thing
flew! During that period he was consulting American Honda's MX
125 team with regards to cylinder porting, head work, etc. Super intelligent man and very knowledgeable on 2 stroke technology.
Mettco like using a modified 175 rod in the smaller
bore models, and the larger Bing carb off a Jackpiner. In 1973 I had a
125 Six Days, and Fred modified the pipe for me. Basically he cut the rear
section off and added a built in silencer. Again, I do not have any specs on
this mod. It did however make a noticeable improvement over the stock pipe. Just a little more noise emanating from it. See the pictures attached of my bike for pipe mod. Black and White pictures taken in 1973 at Irwindale Raceway MX track in Irwindale, Ca.. Color picture taken in 1973 at Claude Osteens Riding Park in Pomona, Ca.

John D.
 

[Marc Biro]

Hey Guys,

If your really serious about fork springs you need to contact Progressive Shocks in Hesperia, Ca. I believe thay can supply or make whatever you need.

Marc Biro  

[socalmx]

The trick was to cut off the outer muffler housing and stinger then weld on a soundmaster silencer/stinger it it's place. If you look at the Mid-Ohio pictures from 2005, that is the setup I ran on my bike.

[john durrill]

Marc,
 The 32 mm use a progressive wound spring. I dont know how to find out spring rates properly or i would test a set and post the measurements.
 We tried a bathroom scale on my 35 mm springs. We did get a measurement on the springs but it was off 5 lbs on what is listed for stock. I must be missing something with our setup.
 Any one that knows how to do this right please respond.
John D.

[john durrill]

socalmx,
 Can you give is the diameter and length on the stinger that setup used?
That would be helpful.
John D.

[Paul Danik]

Hi,

   My comments are geared toward the newer rider who is starting out in racing, and is looking to possibly brake into racing in the new 100cc class, and might possibly be overwhelmed with all of the technical information that is being presented by the more advanced riders and tuners.
   The quote below is from a post listed above, to me this is the most important thing for the newer rider to remember,

 " As you know, rider is 90% and bike is 10%. "  

   You can argue the percentages forever, but the fact is that the guy who wins usually can win on most of the bikes in the class, I said usually because sometimes when everything else is equel the bike will obviously make a difference. For the newer rider the name of the game is good basic machine preperation and as much practice time as you can get. Concentrate on making your bike as reliable as possible, check your engine bolts, swingarm bolt,every nut and bolt, have your cables working perfectly, oil them up to reduce any resistance and besure they are in good condition.  Run newer tires, don't buy porting if you can't afford newer tires. Get your carb dialed in perfect, don't show up with a bike that wants to load up. Before you get porting get some good shocks and possibly install 35mm forks if your bike has the 32mm forks on it. Besure your brake cams are not rusted up in the backing plates, take them out and wire wheel them and put a dab of never sieze or grease on them so that they turn easily.  Make sure your brake shoes are in good condition and not adjusted to the point of wanting to go over center.
  Ride your bike as much as possible, all the porting in the world is not of any use if you are not "one with your machine". When you ride try to keep your feet up as much as possible and try to be smooth. If you don't have much trail to ride, ride it in both directions, try to ride till you are tired, this will help to prepare you for your races. Try to gear you Sachs engine so that you can start out in second gear, possibly 13 X 60 gearing, as this will eliminate the worst shift in the Sachs and will put your remaining gears in a nice sequence.
   The name of the game in small bore racing is keeping your momentum up, in the turns and really everywhere as much as possible, try to run the turns without as much breaking.
   Besure that your bike will push without any rolling resistance, this can be caused by improper brake adjustment or your rear tire rubbing the chain guard or swingarm, rolling resistance will rob you of horsepower.  Make sure that your wheel bearings and sprocket carrier bearings are in great condition as well as your chain and sprockets.
   Check that your piston isn't wore out or that your rings aren't wore out, sometimes the rings can be worn and the piston is still good, a new ring job can really make a difference.  
   As I said before, I am only trying to help the newer rider who might be overwhelmed by all of the great information that is being presented, you have to finish the races before you can win them.
   If others have different views or more things that may help the new rider, please post them.

Good luck to all of you racers.
Paul

[rd400pi]

Paul,
  Great post.  I think it really applies to all classes!  Cheers.

  Mike H.
  Tulsa POG

[Ernie Phillips]

Paul,  Thanks for all the great tips.  Additionally, I'd add Ron C's "You don't breed race horses at the race track," meaning do you work at home and be ready to race when you hit the track.  Another overlooked area is physical conditioning.  You can step up your performance by simple body-weight exercises or hit the gym.  Either way, just showing up is not enough.  But, the best training is riding your bike.


Kid Christopher with his fresh "Doug Wilford" 100-6B

http://pictures.aol.com/ap/singleImage.do?pid=c060XSuUTqrrxPgwkZuYlTOlDe16qOaxv8XOv4xQp5Fd3Ig%3D


Ernie P.
Chattanooga, TN

[john durrill]

Paul,
 Thank you. Something that would help also i think is bringing along  spare tire tubes ,a way to air tires up, cables and a chain. The older guys already know this . I was at the 2005 ride at Gatorback and watched a man miss the race he had driven all the way from RI to ride. A flat and no tubes were the reason. We looked for an hour and we not able to find a tube for him.
 Like Paul said to finish first you first have to finish chuckle chuckle!
 I hope more folks will add to this post.
John D.