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what to look for in a v7

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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep 2019 at 16:28
The Lamda sensors are there to get the mixture more accurately set. Disconnecting it/them makes the ECU run on its preset base map.
Brian.

Better 5 minutes late in this world than years early in the next.
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motopete View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote motopete Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep 2019 at 17:07
Originally posted by Ben. Ben. wrote:

PS. Must remember to plug the sensors back in when I MOT the bike next time.

No need, emission control components aren't checked in the MOT for Euro 3 bikes.

BTW, as an added refinement to running without lambda sensors: Get yourself the GuzziDiag tool and reset the ECU learning parameters, that will restore the map to ex-factory and fix any over-lean parameters it's learnt from the lambda sensors.
You can also check/reset (auto learn) the throttle position.

Also, if you have a lambda correction device (that fools the ECU into reading the lambda sensors at a higher voltage), then I found that temporarily connecting the lambdas and correction device then running the engine at idle for a few minutes, made the ECU learn a slightly richer setting low down in the rev range.  Don't open the throttle, just run at idle. Stop the engine and disconnect the lambdas then it'll run off the base map with a slightly enriched bottom end.

Performance wise I've found the bike feels more powerful without the lambdas because it runs so much cleaner at low revs/low throttle, top end should be completely unaffected because the ECU doesn't read the lambda sensors above 4kRPM or thereabouts, or at wide throttle openings.

Economy wise, my bike is far better without the lambdas, easily getting mid 60's MPG commuting and 72MPG on a recent trip to Cornwall (measured, not guessed).




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Ben. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ben. Quote  Post ReplyReply Direct Link To This Post Posted: 14 Sep 2019 at 18:12
Many thanks Motopete, a wealth of information there, stored away in my notes.

I'm just back from a test ride, having a celebratory Scotch, rather than drowning my sorrows.
Both Lambdas disconnected, and the drive and tyres cleared of figs, I set off down the mountain out of gear as always, and thought the tickover sounded nice and even. 
Reaching the village and flat ground, everything was much smoother at low rpm and negotiating the narrow streets was a more relaxed affair. Throughout the ride the performance was much smoother at low speed, and pickup was also faultless.

I headed west up the valley where the roads are straighter and more level,  through old Beznar edging round Durcal and up to Padul, looking for a connection to another road I use, which I eventually found.
Returning through Beznar, I spotted a Mk111 Stone outside a bar, and stopped to have a look. A chat with the owner, an Italian gentleman now in Orgiva then ensued, we compared models and found we have a mutual friend in Los Cigarrones, small world.

Heading back, I stopped by the bridge over the river Torrente, where anyone looking for water would be sorely disappointed, to have a smoke and consider.
Sometimes I sits and thinks, and sometimes I just sits.
I'd noticed that the plug caps were a loose fit, so having assessed the effects of the Lambda's absence, 
I made a couple of tinfoil hats for the plugs, and wedged the caps on firmly.
Perhaps my imagination, but I think that made a slight further improvement, and I think new plugs are probably due.
A very satisfactory afternoon, thanks again to all who contributed information.




 
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Andyb View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Andyb Quote  Post ReplyReply Direct Link To This Post Posted: 15 Sep 2019 at 20:44
Not new plugs.  New plug caps.  A known problem
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Ben. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ben. Quote  Post ReplyReply Direct Link To This Post Posted: 15 Sep 2019 at 21:03
That's very interesting Andyb, thank you. 
I like the extended rubber covers on the original caps, but the fit does leave much to be desired.
I'm also wondering if the leads are copper or that funny graphited string whateveritis.
I've had 4,000 miles out of these plugs, and was interested to see that the top ferrules were blackened, I suspect with heat rather than the vagaries of fashion, so I'm thinking a change might be in order to start from a known position, but I will change the caps at the same time and make sure the fit is satisfactory.
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Andyb View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Andyb Quote  Post ReplyReply Direct Link To This Post Posted: 15 Sep 2019 at 21:22
The blackening is probably due to a bad fit between plug and cap. The normal mod is to replace the caps with NGK ones which fit to plugs which do not have the solid end - ie the plug top has a screwed thread and the cap is the type that fits to that.  Not explaining very well but I hope you understand - there are quite a few threads on here about this problem.
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Ben. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ben. Quote  Post ReplyReply Direct Link To This Post Posted: 15 Sep 2019 at 22:08
Got it!
I've used those in the distant past because I remember the feeling of pushing the plug cap on and feeling it clicking down on the threads, also of having a little stash of useless threaded ferrules.
Now to find some in deepest darkest Spain...
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Andyb View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Andyb Quote  Post ReplyReply Direct Link To This Post Posted: 15 Sep 2019 at 22:38
Try NGK CPR 8EA-9 plugs set to 0.025” and XB05F (stock 8062) caps
On ebay no doubt
Andyb
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 16 Sep 2019 at 00:47
Originally posted by Andyb Andyb wrote:

Exactly right Mike.  The map unadjusted by the lambdas will be richer.
The real question is whether or not this ‘unadjusted’ map is actually the ‘correct’ map so that the adjustments made by the lambdas make it over weak.

And I guess only Guzzi know the answer to that!

AndyB


No the ECU (a computer) uses the Lambda to measure how much oxygen is in the exhaust, why should there be, because, it backs off the fuel a bit until oxygen starts appearing in the exhaust gas, then it knows how much to increase it (the fuel) by so that the stoicometric ratio is correct. Or at least, more correct. If, on the other hand, there is (momentarily) excess unburnt fuel instead (too much for the available oxygen), that's burnt up by the cat(s). It's quite flexible so that it can compensate for temperature and altitude differences. It's a level of fine control that's way beyond carburettors.

What's fecked it up now tho is the environmentalists who believe that reducing the amount of fuel in the mix a bit will save the planet. But they are not motor engineers (who know better).


"Chicken nuggets don't dance on a Tuesday."
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Ben. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ben. Quote  Post ReplyReply Direct Link To This Post Posted: 16 Sep 2019 at 07:17
NGK CPR 8EA-9 plugs set to 0.025” and XB05F (stock 8062) caps ...

Will do, thanks again.
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