Had the bike dyno'd on Saturday AM.

Background info is the bike rides fine, idles like a swiss watch and pulls cleanly upto the redline in all gears with not noticeable flat spots.

Specs are stock 1989 K model, cleaned and balanced carbs, air-screws set to 2.25 turns out, slides drilled but no shim and 115/118 jets (later size jets).

Bike is running a Yamamoto half-system with matching can and stock airbox setup.

Max power on the day was 57.3bhp.

Fuel / Air is straight as an arrow through the rev-range.

The bike feels great to ride but as you can see from the graph the curve is a litle dippey around 8krpm (but I cannot feel this)

I'm tempted not to mess too much as i'm happy with the way it's performing but would like to see what those in the know suggest (I have a few ideas myself, but i'm always keen to hear other opinions)

Many thanks.

I'm assuming thats Wide Open throttle through the range.
I can't quite see all of the top graph, but does thae AFR scale read from 10:1 to 18:1?
Although the AFR looks quite level which is good, it does look quite lean for wide Open Throttle, for best power, you should be looking for around 12.5:1. The dip in the middle could be because of the standard ignition system.
115/118 does sound a bit lean for a full race system though

Neo.

Is it running a standard airbox with snorkel, oem filter and the rubber flap?

If so I thought the jetting is on the small side but your in Japan aren't you? If it feels good leave it mate

If it aint broke dont fix it .

17.5:1 is quite lean, safer to run richer than leaner, and if you richen it up at peak, you may get a little more power

Thanks for the replies!

The 17.5:1 is at idle so it's probably not getting enough gas to give a good reading.

The line is between 14 and 15 on the graph throughout the rev-rang.

Yep, as in the first post, stock airbox setup (standard filter) and snorkel etc.

The little dip at around 8k I was going to shim the needles, you can't feel it when riding but it should richen up that area a little so maybe smooth the curve out.

I thought that peak power would be slightly richer than the stochiometirc 14.7:1 which my bike seems to run at, I already upped the jets to the later size from the 110's when I serviced it (got rid of the flat spots)

Was considering a 118/120 setup and seeing how that goes.

Since I already have 118's I only need 2 x 120's and 4 shims so the outlay isn't great.

Worth giving a try and seeing how it feels?

Aye, as they said - a sniff lean but nice and steady eh!