bikemonkey wrote:I see you mentioned you don't have the rubber flap, maybe that's causing turbulent air in the airbox not allowing enough to flow through properly?/hot air from the rad getting into the airbox?

I installed one in the meantime.

krisztian_andre wrote:

pip wrote:A plugged exhaust???
That is too rich plain & simple, what mains have you got - assuming the air filter is good, try smaller mains for starters.

The bike is as standard as it gets, air filter is new. I can see it's too rich, the question is why is it rich, why are the power and A/F curves so rough adn why does the A/F ratio decrease at the end?

Getting richer at the top end; too large main jets.

Pip

krisztian_andre wrote:I'm wondering what causes the rich condition with a standard setup and I don't think it is the climate since other vfrs around here have no such problems.

Incorrect carb float settings can cause exactly these symptoms. You say it's standard, but what sized jets are in it? Are they genuine keihin brand?

I'm no dyno expert but judging from the initial power graph you posted I would suspect that spark is breaking down at high revs. If so it will show as being rich on the a/f chart because fuel is being unburnt.

It would be worthwhile checking the plug leads and coils with a multimeter (specs are in the haynes), checking system voltage at 10k rpm and also getting hold of a spare cdi to see if it makes an improvement. Poor plugs (or oil on plugs...) could also be responsible.

Cammo wrote:

krisztian_andre wrote:I'm wondering what causes the rich condition with a standard setup and I don't think it is the climate since other vfrs around here have no such problems.

Incorrect carb float settings can cause exactly these symptoms. You say it's standard, but what sized jets are in it? Are they genuine keihin brand?

I'm no dyno expert but judging from the initial power graph you posted I would suspect that spark is breaking down at high revs. If so it will show as being rich on the a/f chart because fuel is being unburnt.

This seems likely to me. What about the pulse generator, how does it look when it fails?

Leads and caps are new. I measured the resistances of the coils and they are in spec (didn't measure when hot or under vibration). I have no peak voltage adapter so I'll try to borrow a set of coils and a CDI.

Floats are set to 6.8+-0.1mm. Jets are jap standard keihins 115/118. I'll swap them to 112s as an experiment but I doubt it would cure the misfires.

krisztian_andre wrote:Jets are jap standard keihins 115/118. I'll swap them to 112s as an experiment but I doubt it would cure the misfires.

I wouldn't bother swapping to smaller jets, I reckon something else is up. As you say, standard sized jets should run fine. 112 would hardly make a difference, you'd be wanting something a lot smaller to lean that out.

Trying a replacement cdi is the easiest way to know if yours is dud. Make sure that your cdi is plugged into both plugs securely also, seen that come up on the forum a few times which has led to running issues.

Is all the system voltage in spec?

Cammo wrote:

krisztian_andre wrote:Jets are jap standard keihins 115/118. I'll swap them to 112s as an experiment but I doubt it would cure the misfires.

I wouldn't bother swapping to smaller jets, I reckon something else is up. As you say, standard sized jets should run fine. 112 would hardly make a difference, you'd be wanting something a lot smaller to lean that out.

Trying a replacement cdi is the easiest way to know if yours is dud. Make sure that your cdi is plugged into both plugs securely also, seen that come up on the forum a few times which has led to running issues.

Is all the system voltage in spec?

The chrging voltage at 5000rpm is within spec since I sorted the wiring. Battery is new and the alternator output voltages are good. Earth upgrade kit was installed.

I'll pull the sparkplug when the bike is hot and running like shit and will take a photo to see if it's that but they looked fine last time. It did run much better when they were installed new but only for about 20kms so I guess the ignition voltage is down,

Rough idle is now fixed, carbs were balanced. http://youtu.be/pv4zGmiI9gk

krisztian_andre wrote:Rough idle is now fixed, carbs were balanced. http://youtu.be/pv4zGmiI9gk

the idle speed is a bit low.. 1300 is book spec (when warmed up like in your video of course)

Neosophist wrote:

krisztian_andre wrote:Rough idle is now fixed, carbs were balanced. http://youtu.be/pv4zGmiI9gk

the idle speed is a bit low.. 1300 is book spec (when warmed up like in your video of course)

Because of the lower oil pressure?

krisztian_andre wrote:

Neosophist wrote:

krisztian_andre wrote:Rough idle is now fixed, carbs were balanced. http://youtu.be/pv4zGmiI9gk

the idle speed is a bit low.. 1300 is book spec (when warmed up like in your video of course)

Because of the lower oil pressure?

you can adjust it with the idle adjuster.

When its cold the bike will not idle well, set the idle with a warm engine to 1300rpm.

It can idle lower, like yours does, but when cold the idle will be lower so wont idle well at all if it is that low warmed up...