by ian » Tue Jan 09, 2018 8:05 pm
I think the differences for the 43 can be explained by the completely different and much less restrictive airbox. Other than the apparently massive difference in the pilot jet, the differences between the 41 and 42 seem quite minor and the main jet would have no effect on the pilots anyway. It would be interesting to have some more info come to light. But at this stage I am unconvinced that the 41 has a 0.15mm pilot jet. Or if it does, maybe the jet or the metering orifice is somehow different so that it allows more fuel through?
I bought the Funduro carbs a little while back when I had the opportunity and intended to just use them for spares. But I am currently having issues with the original carbs. The bike stood for a while and when I started it, it would not idle, so I suspected the pilot jets were blocked. When I opened up the carbs I found some light deposits of very fine powder like rust in the carb bowls which I suspect came from the tank. I cleaned the tank out and have now completely stripped and cleaned the carbs numerous times, using all methods known to man, but with the same result. The bike starts instantly once carbs are installed, but after a few starts it will only start again with full throttle. I suspect there is dirt or rust trapped in the passageways of the pilot circuit. A clean and blowing with compressed air clears the jet but because the jet is pressed in it is impossible to clear the debris from the passageway. So the bike fires up the first time but shortly thereafter the pilot jet gets blocked again. Anyway that's my theory! We will see tomorrow if I get the Funduro carbs set up.
Another question though. The Mikuni pilot jets available at the local bike shop look identical to the originals but they all have 6 bleed holes which the originals don't have. Are they correct or are they for a different carb?