Too many people tune bikes solely to A/F ratio... the NC30 generally 'feels' better slightly richer than the stochiemetric 14.1.
Have a word with kevprojex, he's dyno's lots of 30's and 35's so should be able to advise you what their A/F ratios are.
I believe his own 35 which is now making 65hp at the rear wheel runs around 12.5:1 overall. Which is what makes the best curve and power delivery after lots of runs.. the NC30 he owned was the same. My NC24 and ZXR400 all rode nicer when slightly richer. Just felt a bit more crisp.
The only change between the 89 and the 90+ bikes besides the 110's all around to 115/118's is that the front emulsion tubes are slightly different... rear emulsion tubes are the same, as is the exhaust, so Honda basically upped the size from 110 -> 118.
While the jets you have are probably flowing different I don't think your A/F is too bad, maybe slightly leaner.. but between 12.5 - 13.5 at WOT seems to yield best overal results.
To do a proper plug chop you need to do some high speed running at WOT (when your on full mains) and kill the engine with the switch / clutch in and then inspect the plugs. Even then this isn't perfectly reliable.As far as power is concerned, I'll say only this: Every vehicle is different. If one wants to find the best air/fuel ratio for generating power, one should put the vehicle on a dyno and test it. Many believe that a particular ratio will result in the most power under any circumstances, and that belief is just too narrow-minded. There are far too many factors involved to make such blanket statements
Back to back dyno's with the 110's and the RO jets will give you an idea of how your bike is performing on both setups... besides AF ratio though look at the torque and power curves too.As far as power is concerned, I'll say only this: Every vehicle is different. If one wants to find the best air/fuel ratio for generating power, one should put the vehicle on a dyno and test it. Many believe that a particular ratio will result in the most power under any circumstances, and that belief is just too narrow-minded. There are far too many factors involved to make such blanket statements
The bikes are frugal enough to run without making them super lean... my 115/118 setup (stock silencer) i generally get around 270km from a tank, which is 167miles, based on 13 litres of fuel (Approx) this is 58mpg!When performing dyno testing and tuning, one must ask oneself "what am I trying to achieve?" If maximum power is the goal, then just look at the power curve first and make adjustments accordingly. The fuel curve is only used as an aid. Many NA race car owners tune in this manner, and by the time they are done the air/fuel ratio is sometimes between 14:1 and 15:1. This is usually not considered "safe" by anyone, but most race car teams accept the fact that they usually change the engine at least once during a typical season. Most street car owners are willing to sacrifice the 3 - 5 hp that they might get by running so lean and instead opt for an air/fuel ratio that will help their engine last for many years
I think amorti might be fairly on the mark as usual, maybe 1 size down from your current jets.
PS: Do you have the emulsion tubes in the correct carbs and are your float heights all good?
Oh and the super-lean at the start might be your bike not being able to clear all the gas from the silencer causing a 'false' lean reading.. quite common on smaller cylindered bikes.
