Rec'd. my 3rd try at a front fender today for my 1971 CB750K1 - none fit
Yep,
Bought 3 used ones.. none fit.
It seems that the later models, (1972 - on ) have mounting holes that are 1 7/8" on center.
Earlier than 71 : right side, center to center is 2 3/8"on center, left side 3 3/8 on center , higher and offset and are threaded instead of holes with rubber grommets, one of the fender braces also has a bend in it ?!?.
1971 appears to be 2 3/8" on center left and right with grommets. That's what I need.
Where am I going to find one for my 71??... and anyone looking for a fender? 
I have what I am calling the Earlier than 71 with the odd brace on it, 2nd brace is normal, (no bend), it had acrwease and a ding..(I wasn't happy to see that either. Chrome is very nice... I paid 90.00 plus shipping for it..
The other 2 , what I called 72 on, are the same. One with some pitting, with braces, the other has very nice chrome no dents, with braces. I think I paid 70.00 for the good one and 30.00 for the pitted one..
Thanks-
Bob
Bob:
There were 4 distinct front fenders in the K0-K6 bikes. They were:
1. The K0 early fender, which fits only those sandcast bikes that had the asymmetric front forks (i.e., could not mount a caliper to the right side). These are rare.
2. The 1970-style K0 fender, which has the shorter fork brace and would not allow for a larger tire than the 3.25x19 to be fit, but would match up to the fork legs that we all know (which allow the right side to have a caliper).
3. The K1 style, which has the longer fork brace to allow up to a 3.50x19 (or 4.10x19 TT style) front tire. These braces have smaller holes where they bolt to the legs, and there are no grommets or rubber fittings in those holes: like the earlier ones, these are a true fork brace, in addition to being the fender mount.
4. The K4 style, which has larger fork brace mounting holes and also larger holes in the fender stays. These holes usually contain rubber grommets so the fender "floats". The left sides of the stays on these fenders are shorter to pull the fender toward the fork on that side and reduce the appearance of the misaligned front wheels.
If you want, you should be able to use either of the K1 or K4 styles, as the holes should line up OK. If using the K4 type, I recommend using the metal grommets on the mounting bolts (and washers), shown in the (second) K4 picture below. These won't stiffen up the front as much as the earlier fenders, though.
When shopping for a fender, watch the shape of the fork brace, which can be seen clearly in the pictures below. The K1 style has a dished look to the left brace, which wraps closely around the fork leg.
I've also seen a lot of incorrect listings on Craigslist and eBotch where "F" and K7/8 fenders are being sold as "750K" fenders. They won't fit, as the holes are spaced differently.
