Are you 2 stroke guys really that scared of Honda xl125 fourstrokes? Just kidding!! Does anyone here know why the later XL125 Hondas with the 2 piece heads and I believe 1mm bigger valves are banned by AHRMA? Good one piece heads where the cam surface isn't worn out are hard to find compared to the slightly later 2 piece design which don't wear out. Heads fit interchangeably on the 1971-1973 motors. No other performance difference except valves. Just wondering.
The only SL/XL fourstroke that I would be concerned about is the one which is belching blue smoke every time it is downshifted. In the day, it indicated that the engine was punched out to around 150cc. I saw many examples of this at Ascot in the 100cc class. Biggest offender was Sig Erson's (of camshaft fame) son's bike.
The 2 piece heads didn't come out till 1975 or 76 which makes them POST VINTAGE. Same reason you are not supposed to use a XR200R Crank although I know of at least one rider that does. His SL125 is over 220cc. LOL
I understand the year thing but i believe a SL125 made 6HP and a XL made a whopping 7HP. Still had 5 speeds etc... I think AHRMA is eliminating a TRUE like design bike/engine. Can't you 2 strokers take the 8HP + advantage and still be happy?
I really dont understand this rule, and I have no idea why its in there. I also dont know why they allow modern ignitions like the PVL on Classic 125 two strokes, but they say the SL125 must stay with points?
FYI, most of the guys running SL125s seriously in AHRMA are using some brand of Chinese copy one piece Honda head that has valves the size of the two piece head. They are brand new an go on those new scooters/bikes you see all the time.
Brian