Hitchcocks Forum

Took the 2011 500 EFI out after the monsoons had eased yesterday. I haven't used it for several days due to the weather. It started OK and I pottered up the road to visit my wife. Came out and it started OK again so I set of for a bit of a run.
Altogether I covered about a half a mile when I noticed a bit of hesitation as I accelerated. This developed into a misfire and started to get quite bad. I turned round and started nursing it back to the stable and the misfire gradually began to ease.
Once home I pulled the plug and it was sooty black. Cleaned it up and put it back and everything seems OK but I'll have to test it properly today.

Anyway, it occurred to me that I might just have a sick plug and it's one of the twin electrode Bosch plugs. What is the best plug to use in the EFI and what should the gap be (in proper measure please (thous) I refuse to go metric )?

According to our hosts bible it`s the NGK BP6ES 20thou gap or half a millimeter if you accept.

Thanks Jaffa

Took the bike out again. It started OK and ran for a few hundred yards but it wasn't happy. I stopped the engine and checked the fuel level but it wouldn't start again.
Swapped the plug for a BP8 that I had lying around and it started and ran a bit better but not quite as it should. So, I've ordered a brace of BP6's and I'll see how they go.

Surely your bike is under warranty? It sounds like a weak spark or fuel injection too rich because of a faulty sensor.

Jim, got some other news for you , lot of metric stuff on the UCE

Hi Jim,

One question. How cold was it? My 2011 500 EFI was delivered late 2011 and I did not have it on the road until late January 2012. In Switzerland we usually have freezing temperatures then and whilst the engine would start readily in my unheated garage, if I took it straight out on the road, after about 1km it would start to badly misfire. Dealer changed the ECU but this did not help. Finally re read the instructions which tells you to let the engine tick over for a few minutes from cold start. Followed the instructions and no problem since then, but winter is approaching, so I am sure I will have to revert back to winter start procedure. It seems the engine sensors need to warm up somewhat, before they can achieve correct cold weather mixture control. Never happens on my 2012 sophisticated scooter, so guess it is just a Bullet quirk. Regards Trevor

Jim , your right dont use metric cause our universe is made of fractions like music .

Gentlemen (and others) thanks for your replies. The bike is still under warranty and will be going back if a new BP6 doesn't cure the problem.

Trevorch, it wasn't too cold when the problem surfaced but it had been raining on and off for several days. I always follow the same starting procedure i.e. turn the engine over on the kick start several times with the ignition off. Pull the clutch and kick again to free the plates off. Then I start the engine and leave it idling while I put my helmet and gloves on. This procedure has worked well all year despite the weather.

Trouble is, there was a time when you'd put a brew on, roll your sleeves up, get the tools out and get stuck in and logically isolate and then cure the fault. Now that every damned thing is computer controlled and plastered with sensors, you're very limited in what you can do. Mind you, pushing 70 years old and without a man cave to work on the bike in doesn't help either.

Trevorch - your symptoms are identical to 'carb icing', where the combination of damp cold air rushing over cold surfaces forms minute ice particles. If the bike starts and runs fine after a short time stopped, the ice will have warmed and melted into water vapour again. Cured by either insulating the air inlet routing, or warming the area. Kawasaki fours used to suffer terribly from this until water cooling came on the scene, where they routed warmed water around the inlet areas. Steve