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So i know people have been curious and i personally havnt read or seen anyone hook up a wideband to see what the stock AFRs the ecu is running for the grom so i decided to pull my standalone off and plug the stock ecu in to find out and give everyone a general idea.
First off and first test, my groms mods are, a stock header with a bung welded on (before cat), no muffler with a 45 degree adapter at the end,1 step colder plug, 14t sprock and intake mod.
Idle and cruising afrs are what to be expected running off the o2 sensor at stoich (14.7) and the ecu does a pretty good job of it no matter what rpm ur at and below the 70-80% throttle. One thing I dont like is that at certain rpms and throttle (50-80%) it stays at 14.7 since the bike has no map sensor so it doesnt know load, i'd like to see that "load" be more around 14.0's 13.8's. . .
Now for the fun stuff, at Wide Open Throttle the afrs are pretty good down low at 12.5 afrs up to 13.5 around 7,500 rpms.
***Than after 7500 rpms it gets lean at 13.9 afrs to fuel cut.
My second test i removed the intake cover so the filter was exposed and the afrs stayed the same for the most part until agian 7500rpms, except i was seeing around 14.1 afrs which is way too lean for those rpms and WOT.
When i got home i checked the spark plug and one thing i have discovered is that the factory timing on this bike is very aggressive, and i mean way too aggressive. I purposley installed 1 step colder plug due to reading the factory plug and there was too much heat going up the threads. With the 1 step colder plug the heat range is perfect but finding the timing marks that excessive surprised me a little. Now every bike is differnt and im not sure if it had something to do with the colder weather or whatnot but knowing this i'd definantly advise everyone to run a colder plug and use atleast 89 octane fuel to prevent any internal problems (stock motor, basic boltons, no tuning). I will double check with a new spark plug on a nicer day and confirm on the timing.
Sorry if some of this doesnt make much sense im kind of in a hurry and just typed this up quickly. :blackgrom::blackgrom::blackgrom:
 

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So i know people have been curious and i personally havnt read or seen anyone hook up a wideband to see what the stock AFRs the ecu is running for the grom so i decided to pull my standalone off and plug the stock ecu in to find out and give everyone a general idea.
First off and first test, my groms mods are, a stock header with a bung welded on (before cat), no muffler with a 45 degree adapter at the end,1 step colder plug, 14t sprock and intake mod.
Idle and cruising afrs are what to be expected running off the o2 sensor at stoich (14.7) and the ecu does a pretty good job of it no matter what rpm ur at and below the 70-80% throttle. One thing I dont like is that at certain rpms and throttle (50-80%) it stays at 14.7 since the bike has no map sensor so it doesnt know load, i'd like to see that "load" be more around 14.0's 13.8's. . .
Now for the fun stuff, at Wide Open Throttle the afrs are pretty good down low at 12.5 afrs up to 13.5 around 7,500 rpms.
***Than after 7500 rpms it gets lean at 13.9 afrs to fuel cut.
My second test i removed the intake cover so the filter was exposed and the afrs stayed the same for the most part until agian 7500rpms, except i was seeing around 14.1 afrs which is way too lean for those rpms and WOT.
When i got home i checked the spark plug and one thing i have discovered is that the factory timing on this bike is very aggressive, and i mean way too aggressive. I purposley installed 1 step colder plug due to reading the factory plug and there was too much heat going up the threads. With the 1 step colder plug the heat range is perfect but finding the timing marks that excessive surprised me a little. Now every bike is differnt and im not sure if it had something to do with the colder weather or whatnot but knowing this i'd definantly advise everyone to run a colder plug and use atleast 89 octane fuel to prevent any internal problems (stock motor, basic boltons, no tuning). I will double check with a new spark plug on a nicer day and confirm on the timing.
Sorry if some of this doesnt make much sense im kind of in a hurry and just typed this up quickly. :blackgrom::blackgrom::blackgrom:

what are you meaning with aggressive timing ?
ignition timing ?
how did you measure pre ignition angles at load ?
 

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What altitude were these tests done? I noticed my bone stock Grom at sea level at wot seemed very lean. It was bogging bad and if I let off the throttle by about 25% the bike would actually gain speed. Once I noticed that I bought a pcv and it feels great now.

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total timing. Yes. Muscle car guys have been doing it for ages. The spark plug is like the blood to s human. If u know what to look for u can find everything u need to know. ;)
So what's the short and sweet way to know? I'm running the Fi Con2 controller and I'm not sure if it changes spark timing or just adjusts fuel.
 

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Good info, and thanks for posting. Would be great to see a proof of all the scenario's together; stock vs exhaust mod only vs exhaust & intake mod vs the basic mod combo (full exhaust, intake, and EC tuner). This would put all these threads to rest.
 
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