Been having some trouble of late getting the bike to start and run on all four cylinders. Over the past couple of weeks it’s been a triple and a twin at various points. It’s also been a bit incontinent if the fuel tap was left on, leaving puddles and trails of fuel about which is not really very safe or economical.
I had my suspicions about the state of the engine and wondered if the black oily crap on the plugs was oil or just petrol and soot. So I did a cold compression test to get a feel for the state of the cylinders, valves etc. I know compression tests should be done warm but I couldn’t get the bugger to run long enough to get warm. Results weren’t fantastic but it did show enough compression to rule out this as the cause of the problems.
So I took the carbs off and stripped the float bowls down to blow the muck out of em. Inside there was a fair bit of fine brown dirt and after refitting the carbs it started ok. A quick blat up the road was a revelation; opening the throttle in 1st had me hanging on for grim death with my ass sliding towards the rear of the seat ! WOW I though what a difference, then the speedo broke 😦 but that’s an other story.
Good job it was quick because little did I know it was leaving a trail of fuel behind it and should some have dropped a fag in the road I’d be trying to out run the flames 😐
I noticed the fuel pissing out as I pulled back on the drive and quickly knocked the fuel tap off and stopped the bike; retreating to a safe distance !
Identified the 2nd carb as the source of the leak so took the float bowl off and adjusted the float height a bit. This had the opposite effect of stopping any fuel getting to the jet and again the bike ran on 3 cylinders. Pulling the plug lead of no. 2 cylinder made no odds to the running of the bike so obviously this was the culprit. Took the float bowl off again and readjusted it, this time checking the fuel height afterwards with a piece of clear tube connected to the drain on the base of the float bowl.
This seems to have done the trick, now starting and running OK again