Lean... Rich...???

[gl_s_r]

I have to ask as it is all dark mystery to me and after reading lloydie's comment in the modding airbox thread it makes it worse..

But how do you know by the "seat of the pants dyno" if your bike is running lean, rich or whatever and wherever and the symptoms that tell you such?

[agentpineapple]

i believe one tell tale sign is how sooty the outlet on your exhausts are, iirc that means its running rich and theres unburnt fuel. get yourself up to east london on saturday morning for a £10 dyno/power run. i'll even buy the food n drinks....

[popkat]

Lean could mean more popping on overrun (could also be an air leak or pair system) blueing of exhaust downpipes is an indication too, feel loss of power at higher revs.
Rich, it may feel sluggish smell of fuel at the exhaust exit, flat spot in rev range.

A good old fashion plug chop will tell you if it's running lean or rich at max revs. For cruise (steady throttle) hold it for a while then crack the throttle, if it bogs down before picking up it could be rich.

pilot circuit, upto quarter throttle, rev bike up from tickover, if revs hold up before settling it's lean, if idle drops low then recovers of engine stalls then it's rich.

This is Just a rough guide to some possible symptoms.

[lloydie]

I have no idea anymore :-(
Get it on a dyno to be sure .

When I test road the no lid air box the bike felt very strong but a little fluffy in the middle and I thought it was running a tad rich .
But on the dyno it was running dangerously lean !

[gl_s_r]

It was your response about the thoughts it was running rich but the total opposite that made me ask... I just rely on the bike to be right and have no idea how to gauge if any changes I make are making things rich or lean?

Thanks for the pilot symptoms and it is a nice and easy one to see and do with how the idle recovers.. but it concerns me a little now as I have changed a few things in the airbox.. erm.. stack wise (it was dynojetted previous to this) and it is a little poppy (not loud poppy but kind of muffly popping) on the over run but not sure if this could be the pipes or the new stacks now as the exhaust is only held together with springs so presume this could have a little air leak?

Bike appears to pull cleanly in my eyes though and doesn't seem to have any hesitations so just not sure.. me thinks a dyno is in order then if AgentP is dishing out the biscuits as it may be the only way to know?

[agentpineapple]

the dyno's the only true way to know, and yes the tea and biccies are on me(normally in me )
the guys across the road from me on the highway do the special price on saturdays, £10 a run. they've dyno'd several of my friends bikes. they seem to know what they're doing...
they run the same dyno machine as the guy in birmingham.
maybe we could get a few people together for this one...
i know me and carl will be up for it. kev was talking about some dyno time aswell?
then theres tony, he always loves a bit of dyno....

[Gazfirestormowner]

Where in London is it

[mik_str]

popping on over-run is usually caused by a lean pilot circuit, Try easing off your fuel screws by one-quarter turn and see how it runs......

[8541Hawk]

Well for me when the bike is lean it "coughs" under steady throttle.

When rich it "farts" when you get on the throttle.

It is a feel thing but if you get slow acceleration and it is not "crisp" then you are usually rich.

If you get a bang from the carbs, it is usually lean.

[lumpyv]

i thought a good guide was to take the plugs out and check the colour?

[BigVeeGrin]

I've often wondered this. I get a hell of a lot of popping and crackling with the new cans, but no idea if this is excessive relative to 'normal', and the standard cans had a lot of carbon at the butt end, while the plug colour looks pretty normal . Never done a dyno so may have to take the plunge into the dark art it seems

[popkat]

I've often wondered this. I get a hell of a lot of popping and crackling with the new cans, but no idea if this is excessive relative to 'normal', and the standard cans had a lot of carbon at the butt end, while the plug colour looks pretty normal . Never done a dyno so may have to take the plunge into the dark art it seems

Which model have you got ?, if it's an F2/3/4 with 19 litre tank then you have the "pair" system, you'd need to blank it off to stop the popping.

[AMCQ46]

Marty, Lots of popping could mean you have an air leak in the pipe jots

[agentpineapple]

I've often wondered this. I get a hell of a lot of popping and crackling with the new cans, but no idea if this is excessive relative to 'normal', and the standard cans had a lot of carbon at the butt end, while the plug colour looks pretty normal . Never done a dyno so may have to take the plunge into the dark art it seems

make sure theres no air leaks on the exhaust....

[agentpineapple]

Where in London is it

the highway east london, the place is called ploe position. its just down the road from tower bridge........