Hi guys, I've been trying to find out if someones been messing with my NC30's petrol tap. When I took the tank off there was some petrol left in the tank, so I turned the tank to reserve and drained it. I did a little reading this shouldn't have happened by the sounds of things as the diaphragm should have been closing the feed off.

I had a look at the carbs today and there's a black hose with a red stripe coming off the bottom of the rear right hand carb rubber. It was stuffed down the side of the frame and was quite difficult to get out, so must have been put there deliberately. I think this may indicate the tap has had the HRC mod done to it and that that hose was the vacuum pipe for the tap.

My question to those in the know is IF my tap has had the HRC mod, will it cause problems for me if I reconnect the hose?

Are you referring to the vaccumn hose?

If it has had the tap modded (i.e. fuel will flow when it is set to on / reserver without the engine running or sucking on the smaller vaccumn pipe) then there is no need to connect the pipe.

Yeah, the tiny one (maybe 2mm i/d?) that comes off the bottom of the rear right carb rubber. I got the petrol out with the tank completely free of the engine, but the tank cap was open (not sure if that would make a difference?)

It hasn't been blocked up, so will be making that carb go lean, thats the main reason I want to block the hose off with the tap where it should go.

Tank open / closed makes no difference, tap has been modded.

When the engines running can you feel the pipe sucking in air? If so the pipe hasn't been blocked off and will make that cylinder a little leaner.

I usually push a tight fitting bolt into the pipe and put a little zip-tie aroud it rather than re-connect up the pipe. Helps to let people know that the bike hasn't got a vaccumn tap on it too :)

it hasn't got a bung in it, so i'll get that sorted before i put it on the road (i'm not sure how much, if any damage it can do, but if it MIGHT cause damage, it needs doing)

cheers, while the tanks dry, i might whip the tap apart to make sure its been done properly, i seem to remember there being a large, silver spring in there, but on the knob side of the diaphragm (so pushing it out of the way of the fuel feed?)

oh the joys of working on other peoples half arsed jobs

cheers for the advice Neo