Running lean - apparently

[Messie]

Help me out here wise ones

Put the SV on a dyno on Sunday for a laugh but ended up a bit worried.
The reading showed it was running very lean pretty much across the rev range. Several people looked at it and said to get it sorted or my engine/pistons would go bang..
Phoned my local tuning place (Setons - excellent - got a team sponsored on the BSB circuit) but they say they can't do it for ages and it's going to cost £170!!!

What should I do? It's got a power commander fitted when the new exhaust was put on. Is it really that critical? Can any old bod with a bit of knowhow and a laptop fix it?

Ignorance is not bliss

[the_lone_wolf]

lean running will burn a hole in your piston after time, far worse than running a bit rich, i'd get it sorted asap if i were you...

Originally Posted by Messie

Can any old bod with a bit of knowhow and a laptop fix it?

Kinda.

You'd be able to change the map for another one with just a laptop, but without paying said ?170 you won't get it mapped properly.

That said, you can download maps off the internet, and the software will allow you to view the maps. As long as the one going on gives more fuel than the one at the moment it would be better. Might not run the best but at least it won't melt.

Did they map it when the new can and Power Commander was fitted? If not it's either running a downloaded power commander map, or the power commander's not doing anything at all. Depending on your setup you may get some joy in finding a map that closer to your set-up and installing that (anyone with a laptop and the right software can do that bit). But for the best result you're better off getting a custom map done on a dyno.

[Messie]

I bought it like this 4 months ago. The guy I bought it from had the stuff fitted and I don't know how it was done

My bike runs a bit lean. Do you have the Dyno read out? Ill tell you if its too lean or if its acceptable. But tbh if you have a PCIII already then it shouldnt be an issue sorting the fueling out. All you need to do is get someone with a dynojet system to set up the fuel. It shouldnt cost £170 though im sure!

[Messie]

Originally Posted by ThEGr33k

My bike runs a bit lean. Do you have the Dyno read out? Ill tell you if its too lean or if its acceptable. But tbh if you have a PCIII already then it shouldnt be an issue sorting the fueling out. All you need to do is get someone with a dynojet system to set up the fuel. It shouldnt cost £170 though im sure!

I do but can't scan it at home. It reads 13.4 A/F Ratio at 4000, drops steadily after 4500 revs to 12.2 until 5800 revs, then hovers around 12.6 until nearly 10,000 revs


Crikey that almost sounds like I know what I'm talking about! Could be in Russian for all I know tho

[Skip]

I had a custom map done at BSD in Peterborough and they told me it would be no more than £145 - ended up at £95 - worth every penny too as the bike feels great now - well worth it.

www.bsdmotorcycledevelopments.co.uk

Originally Posted by Messie

I do but can't scan it at home. It reads 13.4 A/F Ratio at 4000, drops steadily after 4500 revs to 12.2 until 5800 revs, then hovers around 12.6 until nearly 10,000 revs


Crikey that almost sounds like I know what I'm talking about! Could be in Russian for all I know tho

Erm that dont make sense. 13 is the perfect ratio according to the fella that dyno'd my falco (look at the link in my sig) and mine is about 14 over all so mine is a little lean. He said its a little leaner than is good but not bad enough to worry overly. Though im going to get a new Eprom soon (new chip) to try and sort it. maybe get a PCIII later if I need one.

So from what I mentioned yours sounds to be running a tiny bit lean low down and becomes a little Rich. So either they are trying to screw you or they ain got a clue!

Oh and take a picture of it with the camera... that will do

Originally Posted by wikipedia

AFR

The Air fuel ratio is the most common reference term used for mixtures in internal combustion engines. It is the ratio between the mass of air and the mass of fuel in the fuel-air mix at any given moment.

In Naturally Aspirated engines powered by octane, maximum power is frequently reached at AFRs ranging from 12.5 - 13.3:1.

[Messie]

Ok will do. hadn't thought of that!
Doesn't it matter that yours is a different bike?