Author Topic: This ever happen to your B4? (Read 2841 times)

Vidrazor · « **on:** November 12, 2006, 01:43:52 AM »

I've been having problems the last week with my B4 not wanting to start. It turns and turns for an indefinite period of time before it finally decides to kick in. It's not really cold right now so I can't attribute ot to weather. I'm thinking my carbs are getting crudded up. Time for some SeaFoam, I guess.

The weird thing that happened to today, however, is that after trying to start it a couple of times, I shut it off to give the battery a break. As I'm walking away from the bike, the thing BACKFIRES BIG TIME, out of the blue! A big-ass blast of soot comes flying out of the exhust. Scared the shit out of me.

Has that ever happened to anyone? What the hell was that about?

Banditmax · « **Reply #1 on:** November 12, 2006, 02:10:36 PM »

All that is is unburnt fuel in the exhaust combusting. And the reason you had unburnt fuel is cause the bike wasnt starting.

speedwaymaniac · « **Reply #2 on:** November 12, 2006, 02:32:36 PM »

Take out your Plugs and check them! I had this recently and the plug on the 4th Cylinder was screwed! All the ceramic insulator was cracked and damaged, thus wasn't firing and if it was, was far too weak to start!

Could also just be there's some fouling on the plugs! If this isn't the case, your Carbs may well need stripping to clean them out

bigbadmad · « **Reply #3 on:** November 13, 2006, 11:26:44 AM »

Lol I've had that happen to me a couple of times too, quite made me jump!

Vidrazor · « **Reply #4 on:** November 13, 2006, 03:04:57 PM »

>>All that is is unburnt fuel in the exhaust combusting. And the reason you had unburnt fuel is cause the bike wasnt starting.<<

Didn't know there was a spark plug in the exhust pipe.

Welcome aboard BanditAlley.

Bartjan · « **Reply #5 on:** November 13, 2006, 06:42:30 PM »

Quote from: "Vidrazor"

>>All that is is unburnt fuel in the exhaust combusting. And the reason you had unburnt fuel is cause the bike wasnt starting.<<

Didn't know there was a spark plug in the exhust pipe.

didn't know you need a spark plug to ignite fuel.
how about a lighter or a warm valve or other hot spot?

speedwaymaniac · « **Reply #6 on:** November 14, 2006, 08:31:36 AM »

It is scary when it does it the first time and your not expecting it! Was very well described in the original post! Made me jump like crazy.

Worse thing is when it happens 2 -3 times, your ears start whistling and hurt like mad. Horrible sensation.

Hope you get it sorted though, nothing worse then a bike that wont start.

Vidrazor · « **Reply #7 on:** November 14, 2006, 11:23:03 AM »

>>how about a lighter or a warm valve or other hot spot?<<

Yeah, the bike was completely cold, that's what's weird. I wouldn't have any idea what could've lit that up.

speedwaymaniac · « **Reply #8 on:** November 15, 2006, 07:27:07 AM »

More than likely just a build up of compression, hence back fire including soot, rather than an actual explosion. (Even though it really does sound like one)