darmah - leaky 36mm dell'orto carb (and headlight reflector repair?)
Posted: Sun Oct 24, 2021 7:44 pm
hi all!
well, i was doing some headlight work the other day - replacing the bulb with one of those new-fangled led types, (this one works like a charm, btw), and deciding whether or not to replace the bosch headlight reflector, which has about a 2"x2" area at the bottom that no longer reflects, thanks to the shield that was broken and rattling around before i realized it. i tried chrome paint, which was better than nothing, but not much. before i bite the bullet and get another reflector, i'm gonna try silver duck mirror crafting tape; it looks like it just might do the trick, at a fraction of the cost.
anyway, when i was done, i moved the bike back to its spot and was putting stuff away. a bit later, i noticed a puddle underneath the darmah, which at first looked like oil, but closer examination (and smell) clearly indicated it was gas. i could see it dribbling down from the front carb onto the intake to the cylinder, down the side of the sump and onto the floor. yes, the petcocks were open, but it wasn't leaking prior. i shut off both petcocks, and immediately i could see that the gas that was dribbling from the carb/intake area immediately stopped. i opened up the petcock again, and could see gas starting to slowly accumulate again; turned it back off. so then, i tried to crank it over, and nothing - indicating the cylinder was full of gas. so, i pulled the front plug and held a pot over the hole and tried again. sure enough, it turned over, and gas shot into the pot; i should have pushed the kill switch first, because it ignited, and i was fortunate enough to toss the pot out into the drive before i had a catastrophe on my hands. and a rag to put out the flames caused by the gas that wasn't caught in the pot.
anyway, when i put the plug back in, opened the petcocks and cranked it again, it fired right up, and ran fine. i let it idle a bit, and then shut it down and turned off the petcocks. today, i wanted to take it for a ride, so i opened up the petcocks, and it fired up immediately. i went for about a 10 mile ride to a local pizza joint, and everything was fine; it idled fine, was a bit rough running for the first half mile or so, and then everything smoothed out as normal. petcocks shut off at the pizza place, turned back on for the ride home, and everything was perfect. turned off the petcocks when i returned home.
so, my question is - what's inside the carb that may be causing this? i don't think it's leaking when the petcock is off, or it wouldn't have immediately fired up after sitting for 10 days or so, as gas would have leaked out the carb into the cylinder when the petcock was off - it only leaks when under the gravitational pressure from the gas in the tank. i'd like to fix it, but i don't want to be buying parts i don't need. or maybe, some debris was causing the leak, and riding it flushed the offending debris out? would it be worth it to open the petcock and keep an eye on it, to see if it starts leaking again?
any/all suggestions and/or advice is appreciated.
thanks!
doug s.
well, i was doing some headlight work the other day - replacing the bulb with one of those new-fangled led types, (this one works like a charm, btw), and deciding whether or not to replace the bosch headlight reflector, which has about a 2"x2" area at the bottom that no longer reflects, thanks to the shield that was broken and rattling around before i realized it. i tried chrome paint, which was better than nothing, but not much. before i bite the bullet and get another reflector, i'm gonna try silver duck mirror crafting tape; it looks like it just might do the trick, at a fraction of the cost.
anyway, when i was done, i moved the bike back to its spot and was putting stuff away. a bit later, i noticed a puddle underneath the darmah, which at first looked like oil, but closer examination (and smell) clearly indicated it was gas. i could see it dribbling down from the front carb onto the intake to the cylinder, down the side of the sump and onto the floor. yes, the petcocks were open, but it wasn't leaking prior. i shut off both petcocks, and immediately i could see that the gas that was dribbling from the carb/intake area immediately stopped. i opened up the petcock again, and could see gas starting to slowly accumulate again; turned it back off. so then, i tried to crank it over, and nothing - indicating the cylinder was full of gas. so, i pulled the front plug and held a pot over the hole and tried again. sure enough, it turned over, and gas shot into the pot; i should have pushed the kill switch first, because it ignited, and i was fortunate enough to toss the pot out into the drive before i had a catastrophe on my hands. and a rag to put out the flames caused by the gas that wasn't caught in the pot.
anyway, when i put the plug back in, opened the petcocks and cranked it again, it fired right up, and ran fine. i let it idle a bit, and then shut it down and turned off the petcocks. today, i wanted to take it for a ride, so i opened up the petcocks, and it fired up immediately. i went for about a 10 mile ride to a local pizza joint, and everything was fine; it idled fine, was a bit rough running for the first half mile or so, and then everything smoothed out as normal. petcocks shut off at the pizza place, turned back on for the ride home, and everything was perfect. turned off the petcocks when i returned home.
so, my question is - what's inside the carb that may be causing this? i don't think it's leaking when the petcock is off, or it wouldn't have immediately fired up after sitting for 10 days or so, as gas would have leaked out the carb into the cylinder when the petcock was off - it only leaks when under the gravitational pressure from the gas in the tank. i'd like to fix it, but i don't want to be buying parts i don't need. or maybe, some debris was causing the leak, and riding it flushed the offending debris out? would it be worth it to open the petcock and keep an eye on it, to see if it starts leaking again?
any/all suggestions and/or advice is appreciated.
thanks!
doug s.