Vintage Dirt Bike Q & A

Hey guys I ran a quick search on the topic with no result. Does anyone know if running a Mossbarger reed on my 74' Elsinore is legal for AMA vintage days at mid-ohio?
Thanks

2015 AHRMA handbook (rules) page 70 b),1 Reed valves may be used only on Sportsman machines.
Classic machines it is a no no.

Hope you modded your piston intake skirt to let the reed work properly.

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1994 AHRMA National Champion Sportsman 125 Intermediate.
1996 AHRMA National Champion Classic 125 Expert.

For the AMA Vintage days, just about anything goes regarding engine mods, including Reed valves. Here is part of an email I sent to the AMA. "I am building up Honda MR 175's for next year's races and have many questions about what is allowed based upon the rulebooks. Firstly I have seen that 1975-77 MR's can race in Vintage Cross Country so I assume they are eligible for MX and Trials? Can I run the swingarm off of a later 125 CR Honda? Do I need to move the shock mounts back to mimic the MR setup or can I leave them moved up but limit the shock so there is only 4" of travel? The MR has a mighty pair of 31MM forks, can I use forks off of something like a 1982 Honda XL 185 which look similar but are bigger and use MR damping rods to limit travel? I plan on creating a 195cc MR with V-Force or Boyesen reed and wondered if there are any transmission or centercase requirements?

David L. Patton, Jr."

David,



Thank you for the questions. We purposely structured the classes to eliminate these type of questions in Motocross. We are simply focused on Suspension travel, water/air cooled, power-value and disc brakes. Anything more than that, we don’t worry about.



Vintage Motocross Class Breakdowns:

a. Vintage – Vintage classes will include machines originally sold as pre-1975 (and like design) models. Vintage classes will include bikes with 7 inches or less front wheel travel and 4 inches or less rear travel

b. Evolution 1 – Evolution 1 classes will include machines originally sold as pre-1978 (and like design) models. Evolution 1 Classes will include bikes with a max of 9 inches of travel for the front and rear. No water cooling.

c. Evolution 2 – Evolution 2 classes will include bikes with no linkage type rear suspension, no water cooling and no disc brakes. There are no travel limitations.

d. Evolution 3 – Evolution 3 classes may have been produced with water cooling and have linkage type rear suspension, but they cannot have disc brakes or any power valve type mechanism built directly into the engine. Yamaha’s YZ 1982-1984 are the only eligible motorcycles allowed to use a power valve mechanism.

e. Non-Current – Non-Current class will include motorcycles originally sold as 1998 and older (and like design) models.





Alex Hunter

Motocross Operational Coordinator

American Motorcyclist Association

13515 Yarmouth Dr.

Pickerington, OH 43147

Phone: (614) 856-1900, ext. 1239

Fax: (614) 856-1935