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Post by pmatulew on Jun 10, 2013 12:10:09 GMT -5
Any port between the cylinder head and the butterfly valve in the carburetor (the circle plate attached to the throttle cable) will be a vacuum port. They should all be at the same negative fluctuating pressure so it doesn't much matter if you have multiple hoses going to multiple ports or if they are all connected to one port with T's and Y's. So long as none of the vacuum ports are venting directly to outside air pressure.
When you say it's not drawing gas into the carb, do really mean IN? As in no fuel in the carburetor bowl? Or not sucking atomized fuel out of the carb into the intake? Could this still be a fuel delivery problem? Petcock screen? Petcock vacuum? Fuel pump? Fuel pump vacuum?
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Post by pmatulew on Jun 8, 2013 13:37:19 GMT -5
Those squeeze bulb siphon tubes meant for kerosene heater re-fills actually work great for quickly draining a scooter fuel tank. Less mess that way when you take the petcock off the bottom.
Do a quick search on "kerosene heater siphon hand pump" and you'll see exactly what I'm talking about.
Old gas in a 50cc? Oh yeah, The smaller the motor, the more fussy they are about fuel quality. You probably sucked up some gunk or dirt and plugged one of the carb jets. Out with the old, in with the new. DX
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Post by pmatulew on Jun 8, 2013 13:22:54 GMT -5
Sounds like you did everything right. Shouldn't matter which way up the valve springs go. Let us know what you find out.
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Post by pmatulew on Jun 8, 2013 7:20:24 GMT -5
The head gasket experiences high pressure and needs specific metal or metal lined gasket material.
The valve cover gasket just needs to be sealed against oil leaks. Most anything will do. I use Ultra Gray for everything.
Quotes I stole from elsewhere...
Ultra Grey is rated for sealing two surfaces that are under torsion/ twisting and is not degraded by exposure to petroleum products.
Ultra Black is more efficient at sealing in petroleum based lubricants, but doesn't deal with vibration/ twisting as well. Good for oil pans and transmissions.
Ultra Red is meant for surfaces that see higher temperatures (near exhaust piping for example).
Ultra Blue is meant for general use sealing (coolant flanges, intake manifolds, etc.)
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Post by pmatulew on Jun 8, 2013 6:53:27 GMT -5
180 degress? Actually yes it's possible, but doesn't matter. Most modern distributor-less electronic ignition systems fire on every stroke. The trigger coil is attached to the crank via the rotor and doesn't know one rotation from the next. The piston goes up, the piston goes down, it just sends the signal every time. I know it seems odd but firing the spark on the exhaust stroke doesn't bother anything. It's just simpler to build it that way. My Subaru is the same way.  The cam shaft is geared via the chain so that two turns of the crankshaft equals one turn of the cam shaft. That's what determines the which stroke you're on. If the cam timing is off one tooth either way it should still run, just maybe not as well as it should. The timing marks could be off just a hair due to manufacturing tolerances. (You could try slipping the gear a tooth either way to see if it lines up better or worse.) Get the timing really wrong and the valves will be down when the piston comes up and bad thngs start to happen. (I am making the bold assumption that you are lining up the "T" mark on the crankshaft rotor with the index mark on the case while you are checking the cam gear alignment.) Valve adjustment could also be a factor. The valve clearance will ultimately affect when the valve comes in contact with the cam lobe and the height and duraton of the valve lift. Too little clearance and the valves won't close completely and or don't rest on the head long enough to dissipate the heat build up. Too much clearance and they bang around and are noisy. You did check that the new parts were same dimensions as the old? Have you done any sort of compression test to see that the new valves are seating correctly? i suppose I have to ask; Did you change anything else or take anything else apart during this valve change? Coincidentally I have my Lance Milan (same as the Evo V9) in pieces on the bench at the moment (waiting for parts) So I have reference material  |
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Post by pmatulew on Jun 6, 2013 18:20:55 GMT -5
Just another add to the knowledge base, since I had to find this information out for myself. What the kick start gears should look like when they're properly aligned. --> |
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Post by pmatulew on Jun 6, 2013 17:51:08 GMT -5
I recently purchased an abused Lance Milan, and in the process of researching it and making it road ready I came across this post on the old forum about the front suspension and the nuts that are loose and shouldn't be --> scootdawg.proboards.com/index.cgi?board=talk&action=display&thread=21243I think I have the answer to the question and just wanted to add in my two and a half cents so I made a video of what's going on. --> |
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