I've been digging deep and finding some specialist websites....no, not that type; ones about Weber carbs.
We all know that the engine tickover needs to be fairly slow when adjusting the mixture, but I read somewhere, on a much more sophisticated carb, that the throttle butterfly should be adjusted so that it is barely open; ie. the screw is just touching the stop. This is to avoid exposing any of the tiny progression holes, which would affect the mixture adjustment.
I don't think that's possible on the 26IMB but using that principle and having first got the timing spot-on, I adjusted the mixture the usual way after achieving a really minimal tickover and found it much more obvious when I had achieved that "sweet spot".
Subsequently also found that it was much easier to get a steady, but fairly slow idle. I know that there are advantages in having a fairly fast idle, but I think that upwards gearchanging with the non-synchro gearbox is easier when the tickover is slow.
A useful discovery that came out of this is that when the tickover has been slowed down, it creates a slight amount of slack in the throttle cable. If not adjusted you may not be able to achieve maximum throttle opening. The situation is simulated in the photo.
MAL_1785 by Peter Thompson, on Flickr
We all know that the engine tickover needs to be fairly slow when adjusting the mixture, but I read somewhere, on a much more sophisticated carb, that the throttle butterfly should be adjusted so that it is barely open; ie. the screw is just touching the stop. This is to avoid exposing any of the tiny progression holes, which would affect the mixture adjustment.
I don't think that's possible on the 26IMB but using that principle and having first got the timing spot-on, I adjusted the mixture the usual way after achieving a really minimal tickover and found it much more obvious when I had achieved that "sweet spot".
Subsequently also found that it was much easier to get a steady, but fairly slow idle. I know that there are advantages in having a fairly fast idle, but I think that upwards gearchanging with the non-synchro gearbox is easier when the tickover is slow.
A useful discovery that came out of this is that when the tickover has been slowed down, it creates a slight amount of slack in the throttle cable. If not adjusted you may not be able to achieve maximum throttle opening. The situation is simulated in the photo.
MAL_1785 by Peter Thompson, on Flickr