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Post by urbanmadness on Apr 16, 2015 11:09:02 GMT -5
Yes, too loud= too loose.
The process you have read about is lapping the valves .
With the head torn down, you take the valve, put some lapping compound on it, and use it to grind the seat. This mates the valve to the seat and makes it seal. It's not always necessary when you buy a new head as they should be lapped by whoever build the head in the first place. The way to check is to put the head upside down with the valves and springs installed (without the cam) and fill the combustion chamber with gasoline and see if it leaks out thru the valve seats.
Yes, to take the valves out, you need a valve compressor. You can rig something up, but it's much easier to deal with if you have a valve spring compressor.
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Post by urbanmadness on Apr 16, 2015 9:46:01 GMT -5
What style feeler gauges are you using?
I use "go no go" type gauges. Each leaf has a step in it so the tip, where you take the measurement is say .004" and the rest of the feeler "leaf" is .006". They really help to get it right. especially if you are working in a difficult to get to place, Like when you adjust valves on a scooter. You make it to where it just slides in the measurement portion on the leaf, and stops when it hits the step.
Of course I've adjusted so many valves that I do it by feel, then confirm it with the gauge. When I had my 150, I set both valves at .004" and it seemed to happy. It's where I set most 150's when I was working on them. Before they left my shop, I'd run them up to operating temp and if I thought it was too quiet, or too loud, I'd set looser or tighter accordingly.
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Post by urbanmadness on Apr 16, 2015 9:28:46 GMT -5
You know.... we were talking about metal in the oil.... Pull the cam and take a good hard look at the valve springs. Maybe it broke one.
Any nasty noises?
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Post by urbanmadness on Apr 16, 2015 9:20:25 GMT -5
It's what they call a outlet on a tank or barrel. Or an outlet/inlet on the side of a pipe, like what you screw in an Oxygen Sensor in on a car.. In this case, it is the part the petcock would thread into... "Screw the Petcock into the Bung".... Now that sounds dirty. It is the technical names for them tho... Makes me wonder about the person who came up with the terminology.
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Post by urbanmadness on Apr 16, 2015 9:13:44 GMT -5
I can't see the pics at work and I won't have time to look at them until Saturday evening.
Does it look like the spring from a ball point pen? If so, it's the lip spring from an oil seal.
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Post by urbanmadness on Apr 15, 2015 17:48:46 GMT -5
this isn't mine but it is the same. i removed the hose  then i used a bolt and gasket maker to attempt to seal the hole. i'm guessing it will work but probably won't know until tomorrow. anyone have some fool proof advice to seal that hole so i don't have to do it again tomorrow.  You know, I've thought about getting the sizes for that, and the EGR port on the heads of these bikes, and then sell block off plates. Just a nice little stainless steel plate done on a cnc plasma cutter with a couple of hex cap machine screws... Kind of a kit. |
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Post by urbanmadness on Apr 15, 2015 17:44:46 GMT -5
Are you overfilling the fuel tank when you get gas? If you overfill, the tank, and it get's into the emissions canister, it can end up in the air box.
You can get traces of oil in the air box on a worn engine (you said it was consuming oil before you rebuilt it, so it might be residue from before the rebuild. If you were getting a lot of blow by on the old motor, it would be oil that smells like gas). It may also be residue from break-in. Clean it up and see if that clears it.
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Post by urbanmadness on Apr 15, 2015 17:35:16 GMT -5
spam
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Post by urbanmadness on Apr 15, 2015 17:33:10 GMT -5
I'm guessing here, and a picture will tell us a lot.... it might be a spring from one of the seals.... or part of a bearing cage? Have you had the valve cover off recently? Maybe something got thru the cam chain cavity?
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Post by urbanmadness on Apr 15, 2015 17:28:15 GMT -5
Prepare for RAMMING SPEED!
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fuel pump
by: urbanmadness - Apr 15, 2015 17:27:10 GMT -5
Post by urbanmadness on Apr 15, 2015 17:27:10 GMT -5
It would work if you had a bung on the tank (like a motorcycle).... Most of these scoots don't. You need a stand alone petcock. Just a ball valve with hose barbs for the inflow and outflow. then just plug it in, and cap off the vacuum line. You'll be golden. It will flow more then enough fuel.
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Post by urbanmadness on Apr 15, 2015 17:18:28 GMT -5
It differs a little from bike to bike. Loose valves are better then tight valves. Just know that if they are set too loose, they are more likely to break valves if run hard and they don't make is much power. You might end up with a little more low end, but you will be lacking on the high end.
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Post by urbanmadness on Apr 14, 2015 16:10:48 GMT -5
I was trying to remember if valve clearance on the exhaust valve would cause over pressure of the crank case. In any event, it's something else for him to try.
It would also mean it would be harder to start, and I know when I had my 150, as that valve tightened up, it didn't like to idle as well when it was cold.
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fuel pump
by: urbanmadness - Apr 14, 2015 15:59:38 GMT -5
Post by urbanmadness on Apr 14, 2015 15:59:38 GMT -5
Be carefull with this. Some have Vacuum pet cocks, some have vacuum fuel pumps. It depends on where you tank is. If the tank is below the carb, you have a pump of some sort. Most scoots use a vacuum driven fuel pump. If the tank is above the carb, then you will just have a vacuum petcock.
The big problem with the vac fuel pumps and vac petcocks is when you run at wide open throttle. At wide open throttle, the bike is not making enough vacuum to keep the petcock open or run the pump..
A manual petcock will fix this problem on scooters with the tank above the carb. A low pressure electric fuel pump will fix the problem on scooters with the tank below the carb. Upgrading the fuel pumps on those scooters with better vacuum fuel pump will not always fix the problem because at full throttle, they just don't have enough vacuum to run it.
Back to the original post.
If you overfill the tank, sometimes the excess fuel will get into the vent lines (emissions system equipped bikes) and it will try to pull raw fuel thru the vapor recovery system making them run rich. especially if the carbon canister is above the carb.
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Post by urbanmadness on Apr 14, 2015 14:58:36 GMT -5
What I did on one, is cut the tube off the stock air box and then use it to couple the uni and the carb. Yeah that bar on 150's is a real pain.
Don't for get to re-jet that carb!
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