Just acquired a Montesa Cota 123 ( see here ) and need to powder coat the frame. As far as I can tell, 1972 bikes have a silver frame (and my frame is 72 i think); can anyone confirm this and that the frame's went black from 1974. The bike has 21/18" wheels retro fitted, as far as I know the early Cota 123's has 20" / 17" wheels

My dad picked up a 123 recently. The frame is white. The paint is pretty rough but I can't vouch for the originality.

Putting the bigger wheels and even forks from the 247 seems like it would be the way to go, at least for competition. The bike is very twitchy with the bigger wheels/tires.

I have heard the shifter is the weak link on these bikes.

The shifter's not really a sore point, unless you throw the bike down on rocks repeatedly, then maybe a little but it's easy to work on.

The frame should be a kind of dove gray, almost silver, if the bike is pre-'74. I guessing the serial number around the cutoff point would be around 28m3000, but that's just a guess. I'm probably within a couple hundred or so.

When I converted my first 123 to 18/21 wheels, I compared the circumferences of the rear tires and lowered the gear ratio by the same percentage. It works like a charm. If memory serves correctly, I went from a 12 front to an 11 and a 54 rear to a 60 tooth sprocket.

When I bought my Cota new in 1974 the frame was black. 1973 had silver frames. The tire for the 20/17 wheels were some kind of Pirelli and they was a disaster. I guess that the 21/18 Dunlop Trials Universal had been a better choice.

Carl

thanks a lot for the replies;the frame number is 28 M 833, so silver it is :-)

will keep you updated on progress, though as i am current 6000 miles away from shed (and bike), progress will slow in the short term :-(

Hey Malc where are you 6000 miles away? Curious?? Brian W who has the Ulf K replica may know a thing or two about Mont colour shades.

Hey Malc where are you 6000 miles away? Curious?? Brian W who has the Ulf K replica may know a thing or two about Mont colour shades.

Johannesburg (and there are no trials this weekend in Gauteng AFAIK). Yes, will speak to Brian. Funnily enough, looking the production numbers, there were over 4000 Ulf Karlsson reps made by Montesa.