Ribbed forked 1975 AHRMA legal!!!

[wildman]

I got an answer from AHRMA tech inspector Dave Janiec concerning vintage class eligibility of my 1975  250 Cross Country. Letter as follows,:
"Dan, sorry for the delay in answering. I've been on the road for nearly three weeks between my job and AHRMA commitments (just got back from Sandia today- great event).
Your question does not have a absolutely clear answer as the rules exist today, but I'll give you a path to be legal until we clarify this. The '75 250 and 400 pentons have been somewhat controversial as to the "like design" criteria of the bikes based on exactly when (and in what configuration) the later '74s were (the basis of like design). As a practical matter, we have accepted them, with modifications below.
I spoke with the eligibility committee chairman on this today to be sure we have this right (they make the rules, not me or James Smith) and here is what is acceptable currently.
The '75s are considered "like design" if: A) Rear wheel travel is limited to 4" and, B) the ribbed front forks are limited t 7" inches of travel (can be done a couple ways, nome quick unless you are a mechanic, but not really hard).
Hope this helps you, I've info'ed my east coast Tech lead counterpart (James Smith) here so that we re all on the same sheet of music.
See you at the track!
Dave Janiec
AHRMA Tech"

Yessss!!! To answer some questions I've rear on this subject, I've shortened travel on lots of forks, all I do is replace the stock top-out spring on the damper rod with a longer spring (by the amount wanted shorter) made by cutting down an old fork spring and grinding the ends flat.Simple and easily reversible. I've heard of metal spacers also used but I like the little extra give in the spring. After this mod there is almost exactly 7" between the lower triple clamp and the wiper boot, easy to check travel for inspectors, the fork can't travel any more than that!
Man, am I happy. I had set my bike all up for AHRMA, and then didn"t think it was legal(heavy sigh). I always thought it would be OK,but read about Lew Meyer's bike and wasn"t sure. Thank you Dave, AHRMA,POG,Lew, everyone. Wildman Dan Pagel  

1975 250 Cross Country, 1974 175 Jackpiner, 1975 125

[firstturn]

Dan,
  Your input is excellent in my opinion.  You have choosen the best and safest way to trim down the length of suspention.  The other methods I worry about a part moving or braking and stopping one fork.  If you think your life has past in front of you in a bad dream try one fork seizing at above 60 MPH[].  I speaking from personal experience, complements of someone elses handy work.
  Now lets look at my custom two piece 1973 Penton homemade long travel swing arm.  But that was complments of Ron Carbaugh Engineering[].  I did go back and read that chapter on Physics 101 after that weekend race.

Ron Carbaugh

[Gavin Housh]

I had the same forks on my 75 250. Raced it in AHRMA races for two years with no problems. I did add 1 inch of rebound spring to comply with the seven inch rule. I used a 1 inch rebound spring from a pre 75 Maico rebound spring. It does have to be ground a bit on the outside of the spring to fit into the bottom of the stantion tube. I also found it helpfull to cut 1 inch off the main fork springs. If you don't do this it is very hard to get the fork caps on. Enjoy!

[lobo6y]

Dan,

I'm glad that you and our fellow POGers are happy with this. We (AHRMA) really strive to keep the MX period technology  represented properly (so that as many of the bikes of the period are competitive and will be seen on the track), but  we also like to be as "friendly" as possible.

Your solution is one of the better ones, and you correctly identified our primary method for determining if you have limited the forks to 7".

Look forward to seeing you on the track, having fun!
Dave