Help with strange fuel line spark?

[Guest]

Hello guys and gals, having a strange problem with my Chinese 125 (I know I know ) for all intents and purposes it's a Honda cg engine ( albeit a copy ) my problem is that a few days ago it started to run a little rough and was very boggy I stripped the fairings and seat and tank off to get to the engine and carb and found a line had become unattached to a small non threaded pin with a hole in one side ( pin? Was brass ) I've no idea what this is for but it seems reattaching has solved the roughness, while testing the engine to make sure it was good I noticed a spark or a flash in a clear fuel line running from the tank to a small plastic piece connecting the carb to the engine now I'm no genius but I realised that a spark in a fuel line is a dangerous thing to have, does anybody here have any idea what migh cause this and how to remedy as I'm reluctant to take it to my local bike garage as he charges quite a lot and I'm currently unemployed and the bike was an easy and cheap way for me to be able to look for work in a larger area as I live in an isolated village any help and/or suggestions would be very welcome.

[eastanglianbiker]

if there was a spark or flashin the fuel line it would of gone bang are you sure it wasnt a reflection off something ????

[Guest]

Yeah I'm sure it's accompanied by a small popping sound and a small dip in engine revs, it's as it the engine is firing before the inlet valve is fully closed its visible within the line itself, I thought at first I'd pulled a cable loose and it was arcing off the carb by then looked again and it's definitely contained within the line itself

[Guest]

And just noticed your in Chatteris I lived there for almost two years it's a nice place

[rennie]

take a picture of the pin and put it up here!

If there really is a spark in the fuel line I'd run away! fast!

[Guest]

Can I add pictures here using iPhone? And I know it sounds strange but there are two lines from the tank one from the tank to the carb and one from the tank to the plastic piece just after the carb but before the engine itself. The pin is far too small to show on a picture but it's just behind the choke mechanism on the carb is about 25 mm long by 5 mm in diameter and has a small hole in the side that lets fuel escape if the pipe is disconnected, other end of the pipe leads to the bottom of the carb if that helps

[eastanglianbiker]

sounds like one of them is a vacuum hose from the rubber infront of the carb that would go to the fuel tap if that wasnt connected then the fuel tap wont open to allow petrol into the carbs

[Guest]

Have sorted now, was a vacuum pipe and not a fuel line and the sparking was caused due to really bad valve clearances allowing fuel to ignite within the rubber connecting piece adjusted valves to correct gaps and all is well once again thanks for all the replies anyway

[oslin06]

Well having read the post it is still very odd ??? I would of thought the flash would of gone to the air box but maybe it was and because it is a clear pipe it is acting like a fiber optic and reflecting it.

Keith