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Post by kliff on Nov 2, 2009 16:38:39 GMT -5
Seee....now whatcha need to think about is a lil fidddy. Yup, a 50cc scoot.... join us at the NASRA, and start building a RACE scoot for the 1b Class.
Much cheaper than the 150's trust me! I'm building one! Keep your main ride(s) reasonably stock and reliable, and we'll beat hell outta the 50cc scoots on the track. BTW....Drags right now, but we're heading toward road racing too. Hell, I can afford both forms of racing, with race specific scooters, than 1 150, and all the BBK parts and maintenance...
Check out the NASRA kid(under 40, you're a kid), we are growing fast.
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numbski
Non-Com
Sargeant, Ist Bt, 2nd Brigade, Mechanics Apprentice, BRONZE STAR 11/01/09, for having continued, when others would have QUIT!
Posts: 91
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Post by numbski on Nov 2, 2009 21:16:56 GMT -5
It got home just fine. Still some smoke coming out of the breather and oil coming out the breather. Seems to do just fine so long as I don't want to open it up all the way.
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numbski
Non-Com
Sargeant, Ist Bt, 2nd Brigade, Mechanics Apprentice, BRONZE STAR 11/01/09, for having continued, when others would have QUIT!
Posts: 91
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Post by numbski on Nov 3, 2009 12:00:43 GMT -5
Well this morning was odd. I had a conversation with Brent about the bike. It really does idle just fine, the knocking is gone - it was just the blow-by that's left. Not to say that there's no damage in the crankcase unseen, but at this point it's either damaged or it's not. Not much in-between, so I'm riding it slow and hoping that the rings seat. I have extra rings, and so far I'm a little over 100 miles since I got it towed over the weekend, checking oil level often and topping off as needed.
Anyway, left the house the morning, went about 1 mile to the nearest gas station to fill up. As expected, had some oil drainage out the breather hose. I had topped the oil level off before I left, and what was coming out the breather had me befuddled. It looked like fresh motor oil that was milky/gray. Now this isn't the first time I've seen this - on Sat when i got it towed, we filled the bike with oil, emptied my oil catch, and it was filling with milky/gray oil then. Brent told me then that is what oil looks like when water gets into it, but he wasn't sure that the little filter in that catch wasn't doing it, since it's original design is as a water separator. I didn't have a good answer then either.
So - given that I had just filled up with gas, and that I have a manual petcock and filled the tank pretty much "to the brim", I wrote it off as maybe having somehow gotten some gas mixed in. When I got to work, it was coming out black again.
Hrm. I know I'm playing with fire since Kliff told me "don't do that" and I'm doing it. I'm asking for humor here though - it's not like gas is flowing back through a vacuum line since there's no vacuum hose hooked to the petcock. Am I running so rich (110) that now not only am I blowing oil by, but too much gas is getting into the combustion chamber, and therefore the oil it's spitting out it discolored by gasoline?
I can't believe I'm saying this, but I really hope it's just the rings. I want so much for some of this to start making sense. It's like a chain reaction of things breaking that just don't ever seem to add up in the end.
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Post by Rebel on Nov 3, 2009 12:15:20 GMT -5
I've never heard of gas getting into the oil in the way you are asking about. The fact that the noise has gone is a positive sign to me. Not wanting to insult you, but do you screw the dip stick all the way down when you check the oil level? The oil may also be coming out if the rings were not properly lined up when the motor was assembled. The gaps need to be about a third of a rotation off from the next one, so that it decreases the loss of compression and wipes the oil back down the cylinder wall.
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numbski
Non-Com
Sargeant, Ist Bt, 2nd Brigade, Mechanics Apprentice, BRONZE STAR 11/01/09, for having continued, when others would have QUIT!
Posts: 91
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Post by numbski on Nov 3, 2009 13:37:15 GMT -5
Yeah, I do screw it all the way down. The real question is "cold or hot"? I've taken the cold measurement as the valid one - although I'll feel really dumb if it's spewing oil because I'm overfilling based on the dipstick. I'll have to look at the Haynes manual when I get home - I installed the rings exactly the way it stated, however I never measured the cylinder wall to ring gap. To be honest, I kinda trusted the shop to do it right when I dropped the piston, rings, and cylinder off with them. Probably my mistake - apparently "trust no one" has to be my motto with shops. Seriously though - I was still down in bed sick when I put them on. Was literally reading the Haynes manual in bed. I just straight up don't remember if I did that rotational bit or not. Sounds vaguely familiar, but I'll look.
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numbski
Non-Com
Sargeant, Ist Bt, 2nd Brigade, Mechanics Apprentice, BRONZE STAR 11/01/09, for having continued, when others would have QUIT!
Posts: 91
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Post by numbski on Nov 4, 2009 9:26:43 GMT -5
Switched back to my oil catch for the ride in this morning to see if I could quantify how much oil is coming out the breather. I cleaned and dried the catch container last night to make sure that any oil in there was from the commute this morning. 20 miles of "easy" riding, only once did I creep anywhere near WOT. Speed never exceeded 50 mph (real) and in most cases stayed around 40-45mph as my "top" speed. Stop and go riding most of the way, many traffic lights, etc. First off, that's not all of it. Some of it still made it through the check valve and drained out the back. I don't know how much, but the last 2 lights I stopped at the hose was dripping, so that oil catch is hardly perfect. Maybe for guys who tie it back into the oil pan somehow it's good, but in that case, why use the catch at all? Second, the one time I wandered near WOT I wasn't paying as close of attention as I had - it was running pretty good. I noticed because rather suddenly I felt a loss of power. This is what happened when I "broke down" on Saturday, and when it was smoking really bad the day I started this thread. It was still running, but felt rougher. I was close to work by that point, so I just took it easy coming the rest of the way in. Throttle response was still okay - but it was almost as though the range of power I had available suddenly shifted on me. I don't know how else to explain it. When I go out at lunch, I'll check the oil in the pan so that it's had a chance to cool off, but I don't know what to make of it. So far as the oil in the catch, it occurs to me that if I had the stock airbox, I'd probably not even notice it. That would go up into the airbox, and drain back into the pan when I parked it. Maybe I'm just creating the problem myself?
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Post by Rebel on Nov 5, 2009 14:39:20 GMT -5
I kind of doubt you are creating the problem, motors just should not be blowing that much oil out. I would be tempted to find a way to have it go back into the crank case, unless there was some kind of contaminate in it. But eventually the problem should be fixed.
The only thing I've ever had blow a lot of oil like that was an old truck. The truck had a "breather" for the crank case ventilation that got plugged with carbon deposits, it would build pressure up in the crank case and cause oil to just run out of the front seal on the timing chain cover.
Is there any chance that someplace you have any obstruction in the ventilation of the crank case?
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Post by Rebel on Nov 5, 2009 22:35:12 GMT -5
Numbski,
Performance scoot posted this on another thread, does it sound familiar??? Check it out
"Anyway, the reason I torn it down after the first build is becuase I was having trouble keeping the oil in it. I had a balance tube between the oil fill tube and valve cover connected to an oil catch with a breather attached to that and it would pump half the oil out on a high rpm run and was blowing oil everywhere out the breather and valve cover gasket. It worked perfectly on my last engine so I had no idea why it was doing this. I couldn't figure out the problem, so I dumped the oil stick tube and just ran a tube to a catch can and then a breather. Still did the same thing, so I torn it down figuring something must be wrong inside with the oil pump or passages. So I resealed everything, and low and behold, still pushing oil out the beather.
I ended up fixing this problem by installing a PCV valve. It goes from a hose on the valve cover tube to an oil catch, another hose out the catch to an inline PCV valve to a hose connected to the vacuum port on the intake. I was a little freaked out on my first couple of rides thinking I was going to dump oil into the engine via the intake, but it turns out that negitive crankcase pressure is the ticket to these engines! I've got about 75 miles so far with this set up and this engine does not leak a drop of oil, oil vapor is non-exsistant and it hauls ass!"
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numbski
Non-Com
Sargeant, Ist Bt, 2nd Brigade, Mechanics Apprentice, BRONZE STAR 11/01/09, for having continued, when others would have QUIT!
Posts: 91
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Post by numbski on Nov 6, 2009 10:32:54 GMT -5
Heh, as luck would have it, we hit the same man up at the same time. scootdawg.proboards.com/index.cgi?action=display&board=talk&thread=15245&page=1Anyway, I found a *great* article on the topic: www.absoluteastronomy.com/topics/PCV_valveExplains it point blank. All I need is confirmation that a check valve as I have on there is functionally identical to an automotive PCV valve. If so, the only thing I'm doing wrong is leaving the check valve running no where rather than to the vacuum lines. Do that and I should be good to go! So yeah, his description is 100% identical to what I'm doing wrong! If so, then I need to get jumping on my own personal version of the PDI that is catered to people like me that are learning, and dang it - tell them to install a PCV valve on the thing! It's not that expensive, and if they ever go to a big bore, problem averted.
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