Running rough below 8k rpm

[VFRkieran]

So i took the 30 in for its MOT today and on the way through town it feels like its running out of fuel but otherwise riding ok.

After the test (which i passed) i brimmed the tank and went down one of the quiet backlanes to see if i could sus the problem, and it seems that the bike is runing like shite up to 8-9k hits a big flatspot and once that clears it takes off and runs fine right up to the red line.

I got home had a feel of the pipes to see if one was cold and cylinder no1 was only luke warm whilst the others where as hot as they should be.

So my thinking is one of the pilots has been blocked up and is causing the bike to only run on 3 untill it hits 9k, moves onto the main jet and then kicks in again, does this sound correct or does anyone have another suggestion?

Also bit of info, plugs are allmost brand new, carbs are running 122f/124r everything else set up to Cammo's guide including drilled slides and 1mm under the needles, running a JHA sp1 style exhaust.


Cheers guys,
Kieran.

[CMSMJ1]

easiest test is to put a working plug in that cylinder for a starters.

going to be a proper doozy this bike. I do hope that we get some head to head action at the track..lol - want to see how much harder yours pulls!

Unless I get motivated and clean up my spare heads...but to be fair, my days of being arsed with no9 and the fettling thereof are just about gone..

carbs wise - what is your airbox setup? what did it used to feel like? Have you tried it with smaller jets? Air screws set right?

[VFRkieran]

Took the bike for a 100odd KM ride and it seems to have cleared, weather was lovely and all seems well! Was running a little rough up high too for the first 20k or so but after that i didnt have any problems even low down, forgot how well these bikes handle!

Mark, me too mate i think i will struggle to keep up with you on track though lol, im going to take 3 sets of carbs to the dyno sometime before cadders so i can get it set up properly and try out a few setups.

Airbox is standard with brand new filter, if im honest there was less of a flatspot with my old system on so i think i will try and go down a size on the mains to see if that cures it, airscrews i have forgotten what they are set at but i stuck religiously to Cam's guide when i did them in august last year.

You get my PM btw Mark?

[Cammo]

Airbox is standard with brand new filter, if im honest there was less of a flatspot with my old system on so i think i will try and go down a size on the mains to see if that cures it

I think those main jet sizes (122/124) will be a bit rich for that system, but yes best to get it on a dyno to check properly.

[VFRkieran]

Thanks Cam, i did think they might be a little too rich when i put them in but i wanted to be on the safe side, also wasnt sure if the RVF cams would have affected anything fueling wise.

May get out for another ride in the next few days to see if cylinder no1 is still ok, will update here when i do.