[dlslick]

My CB450 runs and idles great. The problem is from idle if you twist the throttle just slightly the bike starts to die. But if you blip the throttle it responds fine. It is almost not noticeable while riding it because you almost never open the throttle as small of a movement that this will happen at.
I have gone over synching the carbs a couple of times thinking that has to be it.
I am now suspecting carb pistons that might not be responding quick enough. I was going to try cleaning them up or maybe even polishing them some and their bores.
I suspect that I dont want to get too aggressive in polishing to keep the fit correct but what have others done with these to make sure that they are sliding smoothly, and do you think that I might be on the right track?
Don

 

[66Sprint]

Don, ....Yes, ...Even the slightest amount of dirt or grime will cause hesitation in a 450 Kei-Hin carb....They MUST be scrupulously clean.... Believe it or not, I have seen this caused by either a "wet" cardboard cushion under the slide, or forgetting to put one in the assembly........
Go back to Bill's posts, and try the "straw test"........Steve

 

[dlslick]

I forgot about the straw test and those posts. I will read those again and do the work possibly tonight.
Thanks,
Don

 

[tbpmusic]

Normally when a 450 has troubles like that, it is indeed a problem with the synch-up.
It's an aquired technique, not easy to master at first.

Vacuum taps on the manifolds take care of that crap completely.
I'm piecing together some now, I'll post some photos and a procedure of how to use them.......

 

[dlslick]

Seems like I got it.
Not sure what it was because I cleaned the pistons ( they didnt seem dirty ) synchronized the carbs again ( think maybe that I did improve that just a bit ) and didnt like the looks of the air filters so I put some pods on that I had laying around. I am not really a fan of the pods, I would rather have the stock filters but these are the originals and although they dont look plugged I just dont see much light through them.
The response to the smallest amount of throttle brings the revs up now without stalling and it seems to have better driveabilty during shifts and running at a crusing speed.
Thanks for the help.
Don