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Re: Brown soot...

Posted: 28 Apr 2019, 10:54
by Blade
Good suggestion by Deegee. I was thinking similar if it persists after 200 miles of regular use.

Go and get a dyno run for £20 and it will give you an AFR graph as well as BHP and Torque.

Re: Brown soot...

Posted: 28 Apr 2019, 10:54
by Rossgo
Blade...you are right I defo don't want to be concentrating on issues that aren't there! I'll do as you suggest, wipe it down and monitor

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Re: Brown soot...

Posted: 28 Apr 2019, 11:01
by Rossgo
Deegee

Yes everything is standard, cat is still oresent, the tailpipe is aftermarket.

Didn't realise a biscuit colour was normal and clean. I know usually the tips go black due to manufacturers tuning slightly rich but it's wired that it's gone from pretty standard to this biscuit colour. Pictures don't show the true colour to be honest it's pretty bright inside.

I'll keep my eye on this

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Re: Brown soot...

Posted: 28 Apr 2019, 11:02
by Rossgo
Cav yea sorry it was the only pic I could find online lol

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Re: Brown soot...

Posted: 28 Apr 2019, 11:02
by Rossgo
Duke could be right there!!

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Re: Brown soot...

Posted: 28 Apr 2019, 11:06
by Rossgo
Deegee and Blade

Great suggestions

I may very well do that.

However i dont think I ever get tested for emissions so don't think I have the test results for that!

Does a Dyno tell you if you are running out of spec?

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Re: Brown soot...

Posted: 28 Apr 2019, 11:09
by Cav
In terms of AFR, everything N/A should be as close to 14.5 as possible with a total tolerance of 1.0

Re: Brown soot...

Posted: 28 Apr 2019, 11:11
by Rossgo
Ok thats good. Just one question
What is AFR?!!

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Re: Brown soot...

Posted: 28 Apr 2019, 11:18
by Stonesie
Air/Fuel Ratio.

Re: Brown soot...

Posted: 28 Apr 2019, 11:29
by Deegee
The probe in the exhaust when you have a Dyno run shows the result of your air to fuel ratio, if you up the fuel too much when they tune your bike for more power the probe shows it up, so a 10:1 will give you a black tailpipe and a 15:1 would show a white-ish tailpipe.

It should take barometric pressure and air temp into account to calculate oxygen available in the air, one of the dodges tuning houses use when dynoing a bike is to move the booth air temp probe close to the bike, it senses a higher than normal air temp and makes the power curve higher than it should.

Re: Brown soot...

Posted: 28 Apr 2019, 11:58
by Blade
One well know cure for Brown soot is take it on the local bypass and hold it wide open in every gear to clear it's throat (happy)


Repeat 3 times or until you see blue flashing lights which are commonly used to signal end of diagnostic testing for the day (giggle)

Re: Brown soot...

Posted: 28 Apr 2019, 13:44
by Rossgo
Thanks Fellas didn't know that

Deegee once again your explanation is grade A. Absolutely perfect. Thank you for your post. I know we have a local Dyno in town may go them up tomorrow and have a talk to them

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Re: Brown soot...

Posted: 28 Apr 2019, 13:45
by Rossgo
Blade. Now this sounds fun!! I hope though no flashing blue lights!

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Re: Brown soot...

Posted: 28 Apr 2019, 13:53
by kiwikrasher
Deegee wrote:Iirc from back when I was an apprentice:

Black - too rich (carbons up engine & exhaust)
Biscuit brown - Correct mixture (running clean)
Light grey/white - too lean (can burn out valve seats and spark plugs)

I’d guess your bike has the usual exhaust sensor and catalytic converter Rossgo, if your engine management light isn’t on, the chances are there’s not much wrong with your bike and it’s just a side effect of the Redex.
I’m sure you’re of a similar vintage to me Deegee and remember a nice grey pipe was an indication of a perfectly tuned engine in the leaded days (nod)

I remember in NZ when they stopped leaded fuel but in the airforce the AvGas was still leaded. The CO of the training Sqn (the only piston aircraft on base) called a parade and explained if he witnessed any more airmen with grey exhaust pipes on their cars in the Sqn car park they’d be charged with theft. From then on in it was only our race bikes and lawnmowers that burnt grey pipes (lol)

Re: Brown soot...

Posted: 28 Apr 2019, 13:58
by Rossgo
charged with theft, that was clearly an easy open shut case!!

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Re: Brown soot...

Posted: 29 Apr 2019, 21:14
by Rossgo
So i popped by our local Dyno place and although the main guy isn't there someone said he could probably fit it in one afternoon and the guy just suggested £50 for a Dyno. To be honest I don't think that's too bad. He gave me a card and said for me to call the main fella and have a chat. Wouldn't mind knowing how much BHP my bike makes anyway plus to get to know the FAR.

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Re: Brown soot...

Posted: 30 Apr 2019, 13:51
by Cav
I suppose that's £50 to find out if anything is way out of sorts.

Because the power and AFR curves run along the same X-axis (time) you can also spot if the fuelling is causing any blips or spikes in the power curve. I would expect it to run lean near redline and for there to be a drop in midrange where the exup valve moves

Re: Brown soot...

Posted: 30 Apr 2019, 14:14
by Rossgo
I'll take that on board Cav thanks for your comment. Yea wouldn't mind knowing how the bike is anyway, and also gives it a proper good spanking!

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Re: Brown soot...

Posted: 30 Apr 2019, 14:19
by Cav
I should've had mine mapped years ago when I decatted the header and popped the racefit on.. oh well, it's black sooty which is better than white sooty!! The plugs last ages too so I know it isn't burning too hot.

Re: Brown soot...

Posted: 30 Apr 2019, 16:29
by Rossgo
We love and learn I think lol!!

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