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Engine light on a few rides post decat pipe fitted

Data said:
Hitchcock's are brilliant. But sometimes things don't quite go to plan. Do you have an air leak anywhere on the induction side?
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I'm sorry I have no idea where one might be, never mind if I have one.
I have only a relatively basic knowledge of motorcycle mechanics.
Maybe I should just go back to stock :oops:
 
Back when I was doing things to engines not covered by any organized rule set, I played a lot with the math of harmonics and pulse control. Fascinating stuff, blending fluid dynamics with sonic theory to make the thing do the thing when you want the thing done. 112% of the (before harmonic tuning) theoretic maximum flow was observed in practice on one of my (harmonic tuned) designs.

I know nothing about thumpers though. I'm sure it's the same math, but we depended a lot on a constant which I'm not so sure still is right with so few charges per second. I was working mostly with 2, 3, and 4 cylinder banks with power bands starting somewhere around the redline of the J series motor, so the chances of a direct translation is minimal even if I still remembered the formula.
 
disposalist said:
I'm sorry I have no idea where one might be, never mind if I have one.
I have only a relatively basic knowledge of motorcycle mechanics.
Maybe I should just go back to stock :oops:
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No, I'm sure you don't need to do that. But I think someone should check your bike over properly to make sure everything is ok. You don't want to damage your engine.
 
disposalist said:
Yes. Let it idle with no input for 10-15 minutes.

Not sure what you mean by "thrown the Air-Fuel Ratio at full throttle".
I didn't go full throttle on the ride - was quite gentle, though I had a pillion, she isn't big.
Do you mean the no-throttle post-decat routine might have made the bike unprepared for the couple of hours with a pillion?
I do wonder why the usual suggestion to let an ECU re-map is to have it idle. What can it learn at idle apart from how to idle?
I suppose it is important to have it idle well, though, so it doesn't stall at every junction. Also I suppose it's best for the ECU to do some adjustment before you are shooting down a road. But 10+ mins at idle?
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I thought you mentioned a brief Full throttle going under the Bridge.
The 10 mins bit is not really correct as it has more to do with temperature then the off for 30 seconds before restart bit.
How the ECU learns is out of my pay grade.
That your MIL has gone away must be a good sign.
 
Dool2 you are right about the temperature thing. The lambda needs to read the oxygen content of the exhaust gases but it cannot do that until the engine reaches working temperature. Idling for 15mins is the best way to do that. You must not touch the throttle at anytime during the process. 10 mins isn't long enough. The lambda sends that information it collects to the ECU which then makes base fuelling adjustments to the fuelling map to ensure the 'range' of fuelling over the entire 75% of it's operating mode is correct. Remember, the lambda only operates to control fuel mixture during the first 75% of engine revs. After that fuelling (AFR) is fixed by the throttle body & doesn't change.

It doesn't end there though. During the next usually 250 miles the ECU continues to learn as the lambda sends information to it. The ECU then trims the fuelling map at the top & bottom of it's fuelling operating curves to enable the engine to fuel efficiently with minimum pollution & best power. This is done by using averages for any given throttle & engine speed setting. It works though! That's the simplified version...I could go on & on. I'm good at that!! 😄
 
It sounds likely that my exuberant throttle blip upset the ECU that was still learning to remap, then?

I didn't pull it wide open, but may have exceeded 3/4 and made her cough.

Since the light is now out I'll just keep an eye on it for the next few rides - next couple hundred miles.

I'm getting hold of an OBD scanner just in case.

I emailed Hitchcock's for any related advice and it included "just to put your mind at rest, we have sold over 1000 of the decat pipes for the 350 J platform bikes" and that does, to a certain extent, put my mind at rest about the decat anyway. I'm sure we would have heard a lot more about it if it were something that is likely to cause ECU issues.

They also suggested checking the fitment, checking for disturbed sensors and using a scanner, as you'd expect.

Thanks for everyone's input! All very interesting and useful.
 
One other related issue I'd love opinions on, if I may?

Insurance and warranty. It seems that a decat (and even a DNA air filter) may be considered a 'performance upgrade' as far as insurance and warranty are concerned.

Is this the sort of thing that may be best left until a bike is beyond warranty? Is this something people would advise telling insurance companies about?
 
disposalist said:
One other related issue I'd love opinions on, if I may?

Insurance and warranty. It seems that a decat (and even a DNA air filter) may be considered a 'performance upgrade' as far as insurance and warranty are concerned.

Is this the sort of thing that may be best left until a bike is beyond warranty? Is this something people would advise telling insurance companies about?
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I spoke to my insurers about these very things. Yes it will invalidate your insurance if you don't tell them about it when you take the policy out. Your warranty is also officially invalidated with RE. I had that too in writing from RE HQ. The reasons are of course that you are changing the bike specification from what they sold you.
 
I've put it back as stock hehe

I'll leave it a few hundred miles and see if she settles and then think about it again.

To be honest, I didn't notice a whole lot of difference (apart from the sound, which was nice, but loud) and one of the things I love about this bike is the carefree riding style and I don't want the worry of potential errors, warranty issues and insurance issues overshadowing my riding joy :)

Thanks again, though, for all your comments. It's fantastic to have a knowledgeable community so willing to share. It's very much appreciated!

P.S. The OBD2 device I got reported no codes stored. Is that normal for if the light goes out? I thought they were held in memory? Or does the light out mean the memory is cleared?
 
LIGuy said:
Get a cheap code reader, clear the code and ride on :)
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(y) I got one. No code to clear though.

It seems the trick of cycling the kill switch multiple times turns off the MIL and clears the code (as long as the fault is no longer 'current', I presume).

I thought there would be a 'history' of old codes, but no.
 
smilespergallon said:
The light itself is a 'I have a code in memory' light.

When you have an active fault it flashes because that is recurring instances of the code entering memory.
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To be clear, does this mean that when a solid light turns up on a ride, that means "something happened, but it's not happening now" so it's _probably_ not serious? Or at least not as serious as a flashing light that means "something happened and is still happening so you better stop"?

So 'clearing' a code is only really useful once you've identified it and you want to be sure you know if more turn up (because otherwise you wouldn't know if you'd had one or twenty codes from a solid light being on)
 
Yes, you've got it exactly.

At least to my understanding. I tried to keep myself on the pre-1990 side of the shop as much as I could, being forced to work on 2000s cars is what convinced me that I no longer wanted to be a mechanic for a living.
 
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