kglazer
Scoot Enthusiast
Posts: 198
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Post by kglazer on Sept 20, 2011 17:30:18 GMT -5
i think i found the problem a faulty pet cock becasue when i opened the drain for the carb bowl a ton of gas cme out more then what would be in the carb bowl so im assuming the petcock is bad and is constantly open so gas is constantly going into the engine and flodding the engine consistantly. what do you guys think
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Post by rabidnz on Sept 20, 2011 20:35:07 GMT -5
you need to check the condition of you float needle and seat and adjust your float height first, though it is likely that your petcock is stuck open as well if it is the vacuum type, though this shouldnt automatically cause the float bowls to fill more than the float valve is set to allow. On many bikes i can leave the manual fuel petcock flowing for weeks without issue. Have you done a leakdown test of the crankcase?
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Post by jmkjr72 on Sept 20, 2011 21:14:32 GMT -5
yeah even if your petcock is staying open the float needle and seat should stop the flow of fuel i never use the shut off on my tractos and it ahs a gravity tank and updraft carb and only use it on the stella when the scoot is parked for several days
and yes have you done a leak down test and i didnt notice if you have done a compresion test on the new build
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kglazer
Scoot Enthusiast
Posts: 198
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Post by kglazer on Sept 20, 2011 21:41:10 GMT -5
what is a leakdown test?
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Post by speedy1125 on Sept 20, 2011 22:03:42 GMT -5
From Wikipedia: A leak-down tester is a measuring instrument used to determine the condition of internal combustion engines by introducing compressed air into the cylinder and measuring the rate at which it leaks out.
Compression testing is a crude form of leak-down testing which also includes effects due to compression ratio, starter/battery condition and other factors. Leak-down testing confines the results to cylinder leakage alone.
Testing is done on an engine which is not running, and normally with the tested cylinder at top dead center, although testing can be done at other points in the compression and power stroke. Pressure is fed into a cylinder via the spark plug hole and the flow, which represents any leakage from the cylinder, is measured.
Leakage is given in wholly arbitrary percentages but these “percentages” do not relate to any actual quantity or real dimension. The meaning of the readings is only relative to other tests done with the same design of tester. Leak-down readings of up to 20% are usually acceptable while greater than that requires a repair. Racing engines would be in the 1-10% range for top performance.
In the United States, FAA specifications[1] state that engines up to 1,000 cu in (16 L) engine displacement require an 0.040 in (1.0 mm) orifice diameter, 0.250 in (6.4 mm) long, 60-degree approach angle. The input pressure is set for 80 psi (550 kPa), and 60 psi (410 kPa) minimum cylinder pressure is the accepted standard.
While the leak-down tester pressurizes the cylinder, the mechanic can listen to various parts to determine where any leak may originate. For example, a leaking exhaust valve will make a hissing noise in the exhaust pipe while a head gasket may cause bubbling in the cooling system.
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kglazer
Scoot Enthusiast
Posts: 198
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Post by kglazer on Sept 20, 2011 22:35:20 GMT -5
so its the same as a compresion test. i dont have one and havent performed one becasue all of the ones i found at my local auto parts store i have looked up and ahve been know to be off by quite alot since they are kinda cheap....
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tango
Scoot Enthusiast
Ad agendum semper parati
Posts: 389
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Post by tango on Sept 21, 2011 0:48:58 GMT -5
so its the same as a compresion test. i dont have one and havent performed one becasue all of the ones i found at my local auto parts store i have looked up and ahve been know to be off by quite alot since they are kinda cheap.... Not quite. A leakdown test entails first putting compressed air into the cylinder and then follows with a measurement of how much leaks out. A compression test basically measures how much pressure the piston exerts on the combustion chamber as it reaches top dead centre. There is no gas of any sort that is added during a compression test. During a wet compression test a little oil is added to the combustion chamber. This isolates worn rings as the cause of low compression if the reading goes up after oil is added.
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kglazer
Scoot Enthusiast
Posts: 198
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Post by kglazer on Oct 7, 2011 8:39:28 GMT -5
took it to the dealership and found out the piston broke. i guess it was due to a hard break in and running 2 stroke synthetic oil through it from the get go:( does anyone know where i can get a new malossi piston the rod and jug are still in good condition. what oil should be run through break in period i thought it was synthetic?
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Post by 90GTVert on Oct 7, 2011 9:47:23 GMT -5
I run synthetic in all my fresh builds for my 2Ts these days and I always go for a hard break in. I've had exactly 0 trouble with it. If that were going to do anything, it would make it harder for the piston rings to form a good seal. For 4Ts I prefer petroleum based oil for break-in, but the 2T is a more harsh environment and I just don't like ever using anything other than synthetic in mine. It may not be the right way according to some, but I can't see how it would break a piston. Have you seen the old piston and how it broke? To break and not melt or damage a piston, something pretty bad should have to happen and I'd think there was a problem other than just the piston. For a replacement, you might try Malossi themselves. If you don't see it listed, contact them. www.malossiusaonline.com/Here's a list of US dealers too. www.malossiusa.com/dealers.htm
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Post by Thebatman on Oct 7, 2011 12:58:40 GMT -5
I would avoid malossiusa.... There were several of us that were "gotten" by them. They have went down the tubes over the last 2yrs very badly.. It took me 13 WEEKS for 1 pk of rollers and they were wrong, then 9 more behind that. They even still owe me money. There is a thread on another forum that discusses it. They are terrible all around anymore... I try to shop at provoscooter.com for malossi parts or scootercraft.com
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kglazer
Scoot Enthusiast
Posts: 198
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Post by kglazer on Oct 7, 2011 17:51:01 GMT -5
yeah ive decided to not look into fixing it and am going to part it out. and starting fresh next summer. if anyone needs any parts for the sf10 kymco engine let me know i have many performance parts such as clutch springs,torque springs, 16x13 rollers in size 6-7.5 grams , gasket kit and Malossi carbon fiber reeds. PM me for more details and ofers
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