Low speed fuelling

[black-k1]

Yeah the stock fuelling when you're at the very edge of on/off like around town/traffic riding is driving me insane.


I'm really thinking of looking into a flash or remap if that does fix it but it's an area I have zero knowledge about

I've not had an issue with mine, either on the original flash or the one I had done by Hilltop. It do an across London commute so would notice it, but haven't. I do run my bike on 99RON fuel though and I think that may make a big difference.

I usualy use the good stuff too unless I'm doing a 100+mile motorway run where cheap stuff as it's just cruise control.


Put of curiosity at say 30mph what gear do you use?

… hmm … all of them! ;)

It all depends on why I'm doing 30mph and what I think will be happening next. On standard gearing my bike will happily pull top at 30mph (and a little lower), pulling away cleanly and without snatch.

[Racer-X]

I was running in 5th or 6th gear @ 50kmh (30mph) which seems like a very high gear but the bike seems to be fine with it. I've started using lower gears at low speed and keeping rpm > 2500 which alleviates the snatchiness a lot.

I know its probably better to use low gear .. none of my other bikes (incl a zx12) would allow top gear at such low speed but the behaviour is odd. Its like the engine starts hunting and combined with the chain slack sets off this jerky harmonic which is horrible.

Anyway .. lower gear ... flash ECU ... should all be fine ... its a minor complaint about a brilliant bike

(edit - to correct kph to mph - thanks black-k1 )

[black-k1]

48kmh = 30mph

I checked last night on the way home from work and, even with 19/42 gearing, my bike will pull 6th gear from 30mph, cleanly and without snatch, on a level surface. Acceleration from 30mph in top is unimpressive initially, requires a steady roll on of the throttle, but is clean and without complaint.

[Champ87]

I tested low speed behavior of my SE after I changed gearing. I was concerned how it would feel in traffic with the new 19/42 sprockets. As reported in this post, I found an empty back road where I could I let the bike run down to a minimum speed in first gear. With zero throttle and without touching the clutch, the bike settled at an indicated 9 mph and continued that way with no snatching, jerking or any bad behavior.

Out of curiosity, I tried the same in top gear - it settled at an indicated 19 mph. Again, there was no misbehavior and it felt like it would run that way all day – although I can’t imagine why anyone would do that. Impressive low speed manners, especially when you consider that the new gearing is high enough for a potential top speed of 212 mph at 12,500 rpm. My bike has a vcyclenut flash with idle reduced to 1,050 rpm so my experimentation shows that low speed issues caused by OEM fuelling can be fixed with a flash.

[Switch18]

ooh this thread has come to life again ... thanks for the links DeRox and HaraldB I'll check them out ... really want to get it flashed soon.

I have never turned on KEBC ... I ride with TC off, KEBC off, KQS off ...

That's seems like a waste of a good bike.

[Racer-X]

Interesting findings Champ87 ... looks like there's hope for me yet!

@Switch18 ... well ...

TC - aka wheelie police
KEBC - nope ... this is not a two stroke ... I expect it to slow down when I shut off the throttle.
KQS - I find it really harsh on the street ... I can clutchless shift smoother than the QS anyway
Power Mode - always full ... I didn't buy a supercharged bike to ride it in neutered mode.

I had a ZX12 that was equally brutal and I did just fine without the whizzbangery. This is just my preference ... each to their own

[JustinP]

I had a ZX12 that was equally brutal and I did just fine without the whizzbangery. This is just my preference ... each to their own

I'll taker anything I can get to protect me from.. well... me.

[Champ87]

Power Mode - always full ... I didn't buy a supercharged bike to ride it in neutered mode.

Well, if you haven't flashed the ECU yet then you are riding it in neutered mode. I'm not arguing with your choice, just restating a fact that in Full power mode, 6th gear @12,500 rpm, twisting the grip 100% gives 49.8% throttle opening with stock ETV mapping.

[Racer-X]

Yeah I know Champ ... I intend on having it derestricted soon (I'm in Europe so posting the ECU to the US is a little daunting). You say in 6th gear ... does the map give full throttle in the lower gears?

[Champ87]

... does the map give full throttle in the lower gears?

In Full power mode, with the grip wound open, you get 100% throttle opening in all gears at 9,000 rpm. As rpm increases the ECU gradually closes the throttles. How much depends on which gear you're in. In lower gears it's softened much more so, for example, in any of the first three gears the throttle will gradually close as you pass 9,000 rpm until it's only 13.3% open. Here's a chart of the stock ETV values for 100% throttle in full power mode in each of the gears:

That might seem like big brother messing with us but don't get too disheartened by that. The result is a bike that (in my opinion) is more pleasant to ride. I have a vcyclenut flash and I rarely use the Full power mode. For that he set the ETV values at 100% so when you twist the grip 50% you get 50% throttle opening, 100% when you ask for 100%. I find it too aggressive. It's quick, it's responsive, it's fun, but I really prefer his Medium power and Low power modes. They still give full power at higher rpm but for general riding the softer response translates into better road manners. That's my opinion, and that's what counts in my world.