tyrefryer Posted September 7, 2014 Report Share Posted September 7, 2014 I hadn't used my Sherco for nearly a year until a week ago when it started up fine and I ran it at our club practice ground for about half an hour. Then after my son dropped it, it started missing when opening the throttle and wouldn't idle so I packed up and went home to sort it out. I emptied the tank and found about an egg cup worth of water in the fuel tank, this I cleaned out. I removed the (Delorto) carburetor and found the plastic link pipe between the float bowl sides had a big hole in it, I guess where it had been rubbing on the intake manifold. I stripped the carb, cleaned it in my ultrasonic tank, blew it out with compresses air, dried the metal parts at 50 degrees C in the oven, replaced the plastic pipe, fitted a new fuel pipe and inline filter, new spark plug changed the gearbox oil and put it all back together with fresh fuel and 2 stroke. It started second kick, ran for a minute or so but wouldn't idle and then stalled. I couldn't get it started again and on investigation have found that it's flooding badly. There is a spark at the plug but the plug is saturated and the air filter box has a cupful of fuel in it. With the tank removed I have got it started by kicking it over half a dozen times with the throttle fully open but it won't keep running. I've taken the carb off and checked that I've put it all back together properly and that the rubber end of the choke mechanism is intact. When I stripped the carb I counted how many turns from fully in the gas and idle screw were and have set them back as they were. The idle screw was 4.25 turns out from fully in and the mixture screw was 3.5 turns out from fully in. I'm stumped as to what to look at next, can anyone advise? Thanks for any help, Martin. Quote Link to comment Share on other sites More sharing options...
tyrefryer Posted September 7, 2014 Author Report Share Posted September 7, 2014 I've just noticed that with the fuel tap left on for half an hour the tank has emptied it's fuel into the airbox which I guess would indicate that the floats aren't shutting the fuel off yet there doesn't appear to be anything wrong with them or the shut off valve? Quote Link to comment Share on other sites More sharing options...
breagh Posted September 7, 2014 Report Share Posted September 7, 2014 Don't think this is your problem but the link pipe as you call it is a breather pipe and will need a hole in it. Often they are 2 completely separate pipes. Maybe you replacing it with a sealed pipe has caused a vacuum. Long shot. Quote Link to comment Share on other sites More sharing options...
copemech Posted September 8, 2014 Report Share Posted September 8, 2014 Urgh, yea the tubes on either side are vents to the bowl. Many run without, but I like to make mine about 2 inches long just to diflect crap. Longer than that has its own issues, and a closed loop simply will not work! Fix that and re inspect the needle/ seat if needed. Ck your cans for water too! It came from somewhere! Quote Link to comment Share on other sites More sharing options...
tyrefryer Posted September 8, 2014 Author Report Share Posted September 8, 2014 Doh! Thanks for that guys, I'll rectify the breather pipes and give it another go. Cheers. Quote Link to comment Share on other sites More sharing options...
thats_a_five Posted September 9, 2014 Report Share Posted September 9, 2014 (edited) If you were riding easy lines, there could have been water in the tank all along. Because water is heavier than gas, it drops to the bottom and may have been low enough that the main tap did not pick it up. When the bike got dropped, the water mixed with the gas and then went into the tap and to the carb. This would cause the poor running after the fall. As others have mentioned, the vent pipe needs to have a hole otherwise there is no vent. That loop of hose from the factory has fooled many people because they think the hose has rubbed through. It probably saves the factory a couple pennies of vent hose. The non-vented bowl may have caused the floats to not work properly. Some of the old Delorto's had problems with floats getting saturated and not floating properly. Also, some of the floats can be assembled upside down which doesn't work either. Pull the bowl off, give things a good clean, make sure the floats do in fact float and reassemble it. Drain all the gas to get rid of all the water. Add an in-line fuel filter if there isn't one there already. Let us know how you get on. Cheers Edited September 9, 2014 by thats_a_five Quote Link to comment Share on other sites More sharing options...
copemech Posted September 10, 2014 Report Share Posted September 10, 2014 Actually, the Dellorto has its own inline filter built in under the round housing of the fuel hose inlet to the carb. Known as the BANJO screen or filter, it is very effective, making an inline filter redundant. Just be sure to ck it on occasion. Any large particles in the bowl restricting jets and such probable did not enter through that screen! Yet the vents must breath, and are subject to water from riding and washes and such. Which is why I use short deflector tubes. 1 Quote Link to comment Share on other sites More sharing options...
tyrefryer Posted September 10, 2014 Author Report Share Posted September 10, 2014 Well thanks for all the input, the problem was in fact down to me using one tube with no hole connecting the float bowl vents. After cutting this into two seperate tubes it started and ran and after adjusting the mixture and idle screws it seemd to be running fine though I have yet to test ride it. Hopefuly cleaning and stripping the carb, cleaning the tank, installing new fuel pipe, filter and fuel have cured what was the problem in the first place. Quote Link to comment Share on other sites More sharing options...
thats_a_five Posted September 10, 2014 Report Share Posted September 10, 2014 Yes Cope, DelOrto's do have a screen. And an external filter is indeed redundant. I prefer to add an extra disposable one, preferably clear plastic so I can easily see if there is fuel and if there is any debris or water settling out. My preference. Quote Link to comment Share on other sites More sharing options...
copemech Posted September 11, 2014 Report Share Posted September 11, 2014 Yes Cope, DelOrto's do have a screen. And an external filter is indeed redundant. I prefer to add an extra disposable one, preferably clear plastic so I can easily see if there is fuel and if there is any debris or water settling out. My preference. Sorry, not trying to discount your advise, I have run them as well as it will not hurt, and you may indeed see something. Yet point being the necessary venting and crap entry points! Crap does not enter the bowl and jet area through the air filter or intake of the carb per se, all that is fed directly to the poor motor! Specially after a wash when the water takes the dirt right through the filter and beyond!! Thoughts for a few! And ck your cans! EMPTY them on occasion to remove all water and condensation! Quote Link to comment Share on other sites More sharing options...
thats_a_five Posted September 12, 2014 Report Share Posted September 12, 2014 No apology needed Cope. Always good inputs from you. Quote Link to comment Share on other sites More sharing options...
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