| Author | Message | ||
     Towjam |
It seems that lately there have been a number of discussions about the "proper" starting procedure and recommendations not to do short rides, etc. in an effort to prevent plug fouling. This is not something I've found to be a problem with other bikes (although I never blip the throttle before or immediately after starting a bike.) So I have to wonder... what makes Buells so easily foul plugs? Apologies if this is a stupid question - I'm not a wrencher. thanks! | ||
| Damnut |
I was wondering the same thing, this has been brought up a lot on the board lately. I am wondering why people are having problems with fouling plugs? I haven't fouled a plug on my XBR yet and I have ~22K on my bike. I don't always warm my bike up and have gone on plenty of very short rides. | ||
| Badlionsfan |
guys are having problems because they're starting bikes in 20 degree weather and think they have to rev them to keep them running. the fuel injection already rich-ens the fuel mixture to compensate for the temps, so blipping the throttle is not needed and can foul plugs. when you start it, if it wants to stall the first time let it. mine does even on cool mornings in the summer. just let the fuel pump cycle and restart it and you'll be fine. | ||
| Damnut |
Didn't think of the cold temps, I always let my bike warm up in the winter months. It's the summer months that I don't always warm the bike. | ||
| Old_man |
I never fouled a plug on my Buell. I NEVER turn the throttle while starting the bike. If it dies the first time. I try again, it usually starts and runs fine. I let it warm up on it's own, without messing with the throttle. | ||
| Pwnzor |
I never fouled a plug on my Buell. I NEVER turn the throttle while starting the bike. If it dies the first time. I try again, it usually starts and runs fine. I let it warm up on it's own, without messing with the throttle. +1, almost 45k miles on the ticker and only my second set of plugs. Still have the first set as spares. | ||
| Blazinc5 |
In cold weather (30Deg.) one of cyl. likes to skip a little so once it is running I'll raise the rps to 2k and let it clear its self out and let it go back to idle... never totaly fouled out though. then it will run smooth and don't have to worry bout it dying. | ||
| Beachbuell |
I've never fouled a plug on my 2004 XB12R. Maybe rider error? | ||
| Poppinsexz |
Big cylinder bore in a buell as compared with the metric bikes. This gives more cold surface area. The fuel hits these areas and can't vaporize as well, this will cause a build up of liquid fuel which doesn't burn and if to much becomes liquid and gets to the plug it will then "foul out" More fuel in the cylinder -ie using the throttle- doesn't necessarily create more heat which is what is needed to vaporize any liquid fuel so that it will burn. revving the engine just adds more fuel to a cold cylinder that could liquify and exasperate the problem. | ||
| Spatten1 |
It's 100% because of Buell's proprietary DDFI fuel injection. It gets great fuel mileage but has numerous quirks. Touching the throttle on startup will flood the front cylinder. Don't do it. | ||
| Id073897 |
Big cylinder bore in a buell as compared with the metric bikes. This gives more cold surface area. Your calculator is broken. XB9: displ. 984 cm^3 / stroke 79.4 mm / bore 88.9 mm / cylinders 2 Piston+cylinder+head area app. 70,000 mm^2 YZF-R1: displ. 998 cm^3 / stroke 53.6 mm / bore 77 mm / cylinders 4 Piston+cylinder+head area app. 90,000 mm^2 It's 100% because of Buell's proprietary DDFI fuel injection. 100% bollox. None of the DDFI features is active during startup/warmup enrichment. Regards, Gunter | ||
| Spatten1 |
If none of the DDFI "features" are active, then fuel will not flow into the cylinders. DDFI is the name of the entire fuel injection system. If the FI is not flooding the engine, what is? | ||
| Poppinsexz |
XB9: displ. 984 cm^3 / stroke 79.4 mm / bore 88.9 mm / cylinders 2 Piston+cylinder+head area app. 70,000 mm^2 YZF-R1: displ. 998 cm^3 / stroke 53.6 mm / bore 77 mm / cylinders 4 Piston+cylinder+head area app. 90,000 mm^2 As I said it has a bigger bore per cylinder. Sorry maybe I wasn't clear about the per cylinder. | ||
| Id073897 |
If none of the DDFI "features" are active, then fuel will not flow into the cylinders. DDFI is the name of the entire fuel injection system. If want to see it that way ... But, please, tell me more about those "numerous quirks" which make the engine flood. Regards, Gunter (Message edited by id073897 on February 24, 2008) | ||
| Clutchless |
I think its just cause and effect happening here. The gas lines bleed in a little air (mainly when below 20 degrees) when the bike is at rest. Once you go to start it again it will die because its moving air out of the system into the intake and such making it stall the first time or so. You could just cycle the ignition twice and then start the bike allowing the fuel pump to purge the lines of air. But if you start it and it dies, dont rev. Thats why plugs foul. Cold dense air=computer dumping loads of gas in. For some reason people think that hitting the throttle is going to make it warm up faster or "clear out" or I dunno what just dont rev it, its Fuel Injection. If a candle starts to go, out do you spray it with gas and blow on it? You cover it and choke the flame. dont rev on startup, and dont rev on startup. Mostly I see this problem when you rev your motor at stand still. so dont rev on startup. Revving the motor on ANYTHING that I have had that is internal combustion did not fix the prob or aid warm up enrichment. Why do people do it? sry, one of my pet peeves  Im not pointing fingers because I dont know any of you guys, but the people I know it real life are ridiculious with chopping the throttle on ANY startup, ANY bike, ANY gender. | ||
| Teeps |
Why do Buells foul plugs so easily? I'm not sure (mine has never done that) but; Buell uses extreme(?) ignition advance (and I suppose extra fuel) during cold starts, to keep the engine running. Why this is, I suspect, is because there is no Idle Air Control or Idle Air Bypass, for cold starts. The ignition timing, on my Uly, is 61 degs(advanced)after cold starting. As the engine warms up, the timing retards back to near zero degs. The startup sequence seems to be a delicate balance that, I suppose, gets upset by blipping the throttle. | ||
| Id073897 |
As I said it has a bigger bore per cylinder. Yes, I agree in that. But, OTOH, the R1 has the worse displacement/surface ratio compared to the XB9 and will therefore most probably need a higher startup enrichment. If fuel drops hit the surface, they generally tend to stick there and thus just lean out the mixture, but not "wander around" in the combustion chamber. For the same reason, it's more probable that the plug itself has to "catch" it's amount of fuel which then leads to fouling. So, in my oppinion, neither the bore size nore the surface ratio provides a really sufficient explanation. Regards, Gunter | ||
| Id073897 |
The ignition timing, on my Uly, is 61 degs(advanced)after cold starting. Too much for an IB310 ECM. Standard advance from the timing table is zero degrees, up to 1350 rpm and 20 TPS 8bit (app. 8%). Idle additional spark advance at 0 degC/32 degF head temperature is 30 deg crankshaft, this is the value also shown in ecmspy monitoring. Besides that there's no additional advance. Regards, Gunter | ||
| Teeps |
I will recheck the timing at cold start with ECM Spy But, I am sure that VDSTS reported 61. My bike is '06 Ulysses with '07 flash, if that makes a difference. | ||
| Spike |
I keep reading about plug fouling, but I'm not sure what these guys are doing. I've put ~34k miles on my own XBs and another ~2k miles other XBs and I've yet to experience a fouled plug. | ||
| Poppinsexz |
If fuel drops hit the surface, they generally tend to stick there and thus just lean out the mixture, but not "wander around" in the combustion chamber. For the same reason, it's more probable that the plug itself has to "catch" it's amount of fuel which then leads to fouling The fuel and air mix enters the combustion chamber in a high speed swirl. As the XB has a larger volume per cylinder it will get a larger air fuel charge. Due to the larger surface area of the XB's cylinder, incomplete combustion caused by temperature would leave a greater volume of unburned fuel in the XB's cylinder. The amount of unburned fuel could be increased by applying throttle on a cold engine. This of course is affected by many things- timing advance, plug heat range, compression ratio, intake design, valve size, air filter restriction, extra fuel at cold start-up, ect... This could also just be the nature of the beast. Sacrifices sometimes have to be made when you high-preformance an engine. Now on to more pressing matters. Where is a good Buell shop near the airport as I will be in Frankfort next month for vacation? | ||
| Id073897 |
The fuel and air mix enters the combustion chamber in a high speed swirl My assumption is that it's just the way the gas flows into the cylinder what causes the problem. Where is a good Buell shop near the airport as I will be in Frankfort next month for vacation? There is none near the airport. Buell Frankfurt is in Frankfurt East, Wächtersbacher Str. 83., and their homepage is http://www.harley-davidson-frankfurt.de Regards, Gunter | ||
| Poppinsexz |
Danke Schoen Lass den gummi auf der strasse  und weizenbier im magen. but not at the same time!!!!  | ||
| Metalstorm |
Doesn't FI kinda work opposite of carbs? I mean a carb will feed air followed by fuel where as FI will feed fuel followed by air before it is atomized. Upon cold start I imagine very little air is injected to keep the mix rich. Blipping the throttle would be just like spraying straight fuel onto the plug. Not a good thing to do until the engine reaches running temps. I am unedgeamacated in all things mechanical so this is just my uneducated guess. (Message edited by metalstorm on February 24, 2008) | ||
| Reepicheep |
20k miles on stock plugs on a stock 9sx, and they were running fine (though pretty ugly looking) when I pulled them. | ||
| Spatten1 |
Metalstorm: You've got it right. DDFI is doing the equivilent of squirting an accelerator pump when not much air is moving and atomization is at it's worst, in a cold engine. The formula is very simple: Too much fuel for a cold engine at low rpm will foul a plug. | ||
| Id073897 |
I mean a carb will feed air followed by fuel where as FI will feed fuel followed by air before it is atomized. Talking about accel enrichment, this is effectively delayed by not using the actual throttle position but a -what they call it- filtered value. This is more or less the same as setting up a trend curve, as will be shown in stock quotes. In my oppinion these problems are related to letting the engine idle when getting ready to drive. Regards, Gunter | ||
| Bombardier |
The O2 sensor does not get hot enough to control fuel mixture for quite a while from startup. Takes about 3 minutes from first start to get hot enough to send a signal/voltage to regulate fuel mixture on my 07 XB12 Bolt. Bike is now waiting for a new rear tyre so in will go the 4 wire heated narrowband sensor to see if it makes a difference. Will let you all know how it goes. | ||
| Id073897 |
Takes about 3 minutes from first start to get hot enough to send a signal/voltage to regulate fuel mixture on my 07 XB12 Bolt. Closed loop will not get active as long as warmup enrichment is running. I don't know exactly, which value limits this, but you might perhaps check against hot start condition (offs. 0x009C for IB310). If this is the limiting factor, a heated sensor wouldn't be of real help. Regards, Gunter | ||
| Bombardier |
If the ecm sees voltage from the o2 sensor perhaps this will stop the warmup enrichment. |
