TOPIC:

purchased a set of rebuilt 28's this winter..they were completely tore down, cleaned, and rebuilt, then tested on a bike and aynched..now the question..was running 26's with a stage three dynajet kit..140 mains..when i received the 28's i took off the fuel bowls and noticed it had 122.5 mains..no given the larger size of the coarbs doesn't this seem a bit small..these new carbs willo be feeding a freshly bored 1075 mill..accel coils, pod filters, 4-1 meg. open can..any opinions appreciated..

I would start off by putting the stage 3 stuff out of the 26's into the 28's and then go from there.
Sorry, I cant be more precise, there are probably others who can chime in with more accurate advice,
Fish

I think the jet design is different. It is between my 26's and 28's. I'd ask wiredgeorge, he seems to know more about carbs than the people that made them I do recall reading somewhere the jet selection for the 28's was not as diverse as what you can get for the 26's, not sure how much truth there is to that. I havent even gotten mine on the bike yet so I havent really looked into those things yet. It does seem like a pretty big difference in size for you though, you might need bigger jets... I suppose you could try them and see what the plugs look like, how it runs etc.
I want to say the stock jet size on the 28's was probably 120 for comparisson. That's what came in mine when I got them. My 26's had 102.5's.

Ron

brianrae33 wrote:

purchased a set of rebuilt 28's this winter..they were completely tore down, cleaned, and rebuilt, then tested on a bike and aynched..now the question..was running 26's with a stage three dynajet kit..140 mains..when i received the 28's i took off the fuel bowls and noticed it had 122.5 mains..no given the larger size of the coarbs doesn't this seem a bit small..these new carbs willo be feeding a freshly bored 1075 mill..accel coils, pod filters, 4-1 meg. open can..any opinions appreciated..

my 900 has a 1075 kit, pods and an open 4 into 1 exhaust. all i ever ran was 120 mains...with early style vm28's. i got vm26's on there now with 112.5 mains for the fuel economy and so far they seem to work o.k.