Does any one know whether or not the 1972 cmf frames are heavier or lighter than the High-Breather frames of 1973-4?
peter klinck
No idea, but I bet there is very little difference. The big difference is the sharper steering geometry of the '72s.
Brian
Brian,
1.) What do you mean by a different steering geometry?
2.) I think there is a difference in weight, but it would be nice if someone knows. The slotted channel for the high breather I would imagine is different than the tube??? Secondly, I think they were continuously improving the CMF fourmula while I heard that maybe the "72' cmf is lighter since the channeling weights more (???).
peter klinck
I always heard the '72 had a sharper steering angle, I dont know how much though.
Brian
Brian,
Were the 72 and 73' penton 125s (cmfs both non and high breather)with the same wheel base and how that plays into the sharper steering angle?
peter klinck
Some years back I found that the first year CMF frames with a 71 # had thinner mounting tabs and flat metal and the motor sits higher in the back mounts and is just over three pounds lighter than the HB frame. The CMF 72-73 non HB has thicker tabs and flat metal is just under three ponds lighter, and rear motor mounts sit lower. GEO is the SAME based on the frame ; all depends on the triples and forks used . First year used 6.25 inch travel forks with smaller triples. The 72-73 used 7 inch travel with a beefer triples with slight more offset . And then the you have the 35 mm set up and the ACERS triples with a bit more offset
Larry,
Thanks for the info just above about the weight of different year cmf frames non-breather and high-breather.
peter klinck
Brian,
1.) What do you mean by a different steering geometry?
2.) I think there is a difference in weight, but it would be nice if someone knows. The slotted channel for the high breather I would imagine is different than the tube??? Secondly, I think they were continuously improving the CMF fourmula while I heard that maybe the "72' cmf is lighter since the channeling weights more (???).
peter klinck
I always heard the '72 had a sharper steering angle, I dont know how much though.
Brian
Brian,
Were the 72 and 73' penton 125s (cmfs both non and high breather)with the same wheel base and how that plays into the sharper steering angle?
peter klinck
Some years back I found that the first year CMF frames with a 71 # had thinner mounting tabs and flat metal and the motor sits higher in the back mounts and is just over three pounds lighter than the HB frame. The CMF 72-73 non HB has thicker tabs and flat metal is just under three ponds lighter, and rear motor mounts sit lower. GEO is the SAME based on the frame ; all depends on the triples and forks used . First year used 6.25 inch travel forks with smaller triples. The 72-73 used 7 inch travel with a beefer triples with slight more offset . And then the you have the 35 mm set up and the ACERS triples with a bit more offset
Larry,
Thanks for the info just above about the weight of different year cmf frames non-breather and high-breather.
peter klinck
I built my "rocket ship" Mint 400 using a 1972 non HB Piner frame to save weight. Never weighed the frame, just always heard they were lighter. Of course the JP Morgen reed valve job and the 1981 495 "snake pipe" and the bored out to 40mm Mikuni carb probably made more difference in making it a hole shot wizard than the weight of the frame. Wanna drag???? Teddy