Snatchy throttles

[A_morti]

In scenario 2, the rpm will only be high if I'm giving the TPS a signal of >0. Then it should match that, but at the same time I want it to give *at least* enough to keep the engine at idle. Which is what I believe it's doing.

The bike must think hands are off the clutch rn, as it won't start in gear. Past that, IDK how the switch works. After riding the bike through town to work today, I'm not in a hurry to plug it back in.

[Mr. Dazzle]

The rpm will be high just 'cause the engine is spinning? it's got an engine speed sensor so it knows which part of the map it's on.

[Screwdriver]

I had a long saga with my former "best bike ever" the original SuperdukeR. I tried everything including throttle cam swap, blah blah. There was a massive thread on TRC (which I still have) but the fix for this FI problem was a comprehensive dyno remap.

Chris at XBikes did an excellent job under very difficult circumstances (me!) and I can throughly recommend their services. It is in my opinion, the ONLY way you will ever fix fuelling issues. Well worth the time, money etc.

http://www.xbikes.cc/services/index.html

[A_morti]

@Screwdriver I suspect it's a different case on that bike than on mine, as I assume that won't have been a Euro 4 bike, so it wouldn't have been a problem specific to deceleration fuel cut?

[A_morti]

@Mr. Dazzle I think I'm picking up what you're putting down, now. I may have it backwards. It won't start in gear so it must think clutch is engaged. I want it to think clutch is disengaged.

Either way I'd swear it's riding better.

I'll try a direct back to back test this afternoon.

[Mr. Dazzle]

Stick a wire in the plug to short it and try again

[KungFooBob]

Stick a wire in the plug to short it and try again

Or unbolt the switch.

[A_morti]

Stick a wire in the plug to short it and try again

Or unbolt the switch.

Unbolting is kind of a swine, you have to remove the lever and get all greasy pulling the switch through.
Putting a bit of paper clip in there is easy though

[Mr. Dazzle]

Unbolting also won't help, you want it to be permanently on.

[A_morti]

Do you suppose rather than just being 0/1 it's clever enough to be aware that the switch is unplugged? Maybe it has a resistor in there and sees it or not? That way if it saw no switch, it could default to the safest option.

Idk... Will have a look later.

[Screwdriver]

@Screwdriver I suspect it's a different case on that bike than on mine, as I assume that won't have been a Euro 4 bike, so it wouldn't have been a problem specific to deceleration fuel cut?

Don't know. 2011 machine iirc. Problem was with getting back on the throttle after rolling off.

Personally, I am not convinced the issue is necessarily related to emissions strangling gubbins but more about FI generally on these big 2cyl motors.

[Mr. Dazzle]

There's always the 'problem' that EFI is able to respond much more quickly than carbs. When you open the throttle on a carb bike (assuming you're got CV carbs) there's an inherent delay and 'softening' of the power because it takes a finite amount of time for the vacuum to build up and hence lift the needles. In fact, if you consider how snappy slide carbs can feel, you'll see what I mean. Yamaha actually fitted carb style vacuum operated slides to the early EFI R1s, did they not?

EFI on the other hand goes "you wanna open the throttle? Let's open the throttle! - here have some petrol!!!". It's doubly difficult on a bike (vs. a car) because bikes often don't have an air flow meter (in fact, I don't think I've even seen a bike with one?) so the ECU only has the rpm and throttle position to go on.

Part of the advantage / point of FBW is that when you come off/one the throttle the ECU is able to regulate what the butterflies are doing in a less on/off fashion.

[Screwdriver]

Here's one @weeksy will remember. Took the bike to a meet up (forget the name, one of them famous biker ones). I came down the hill towards the car park sounding like the god of thunder, that Superduke + Akras = awesome.

Arrived in carpark, blipped throttle, stalled (pre XBikes) and am hopping on one leg trying not to fall over in front of hundreds of bikers...

[Gregor]

There's always the 'problem' that EFI is able to respond much more quickly than carbs. When you open the throttle on a carb bike (assuming you're got CV carbs) there's an inherent delay and 'softening' of the power because it takes a finite amount of time for the vacuum to build up and hence lift the needles. In fact, if you consider how snappy slide carbs can feel, you'll see what I mean. Yamaha actually fitted carb style vacuum operated slides to the early EFI R1s, did they not?

EFI on the other hand goes "you wanna open the throttle? Let's open the throttle! - here have some petrol!!!". It's doubly difficult on a bike (vs. a car) because bikes often don't have an air flow meter (in fact, I don't think I've even seen a bike with one?) so the ECU only has the rpm and throttle position to go on.

Part of the advantage / point of FBW is that when you come off/one the throttle the ECU is able to regulate what the butterflies are doing in a less on/off fashion.

Early BMW K100s have an air flow meter.

[Mr. Dazzle]

Trust BMW to do it the textbook way.

[dern]

The 1150gs was the worst throttle response of any bike I've ridden. It made the superduke feel like a superdream.

[Count Steer]

The 1150gs was the worst throttle response of any bike I've ridden. It made the superduke feel like a superdream.

Did you ever ride someone else's? Never noticed anything snatchy on mine or heard anyone complain about theirs. Sounds like something had either been 'tweaked' or was out of whack. R1200 was slightly smoother generally but not a world away..

[dern]

The 1150gs was the worst throttle response of any bike I've ridden. It made the superduke feel like a superdream.

Did you ever ride someone else's? Never noticed anything snatchy on mine or heard anyone complain about theirs. Sounds like something had either been 'tweaked' or was out of whack. R1200 was slightly smoother generally but not a world away..

No but putting a booster plug or getting a remap was common talk on the forums for those bikes. It was a shocking bike in terms of reliability but the fueling was the worst experience.

[dern]

I fitted the throttle spacers to the 1190 adv and did a couple of hundred miles on it over the weekend. It wasn't as snatchy as the 1290 sd but was still not brilliant. It's made more of a difference to the 1190 and I wish I'd done it when I bought it. It felt a lot more predictable in the wet leaves and rain. Best ten quid spent.

[Bustaspoke]

@Mr. Dazzle I think I'm picking up what you're putting down, now. I may have it backwards. It won't start in gear so it must think clutch is engaged. I want it to think clutch is disengaged.

Either way I'd swear it's riding better.

I'll try a direct back to back test this afternoon.

On my Gen II SV650 you can short the clutch switch to get you home,( I've done it myself) but it affects the fueling. It comes up often on the forums as a lot of SV's get used on track & modify the looms.
Not sure how it affects Honda's.
Here's something from one of the SV forums;

Default Re: Clutch switch start
Dont bypass the clutch switches on the injected SV or any other injected Suzuki. Even if bypassed the bike will run in a neutral ignition and gear map loosing performance and in some cases like the GSXR1000, revs. The GSXR600 is particulary one that reacts badly to it making circa 80-90bhp with it bypassed.