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Post by lain on Apr 22, 2015 8:55:22 GMT -5
Took everything off, it does not make any sounds except the gurgling noise from the oil vent hose from the valve cover. I am guessing the clanking was the variator. When I compared them side by side, variator A (the one that was in there during issues) has what looks like little pieces of metal to limit how far out the plate can go, while variator B (a spare I have) has nothing on the ends of the slide posts to limit how far out the plate can go. Other than that they look very similar. I decided to put the spare variator back in (variator B) with all 8g weights of the same set and the clanking went away. I also put in a new clutch (I suspect has 1k springs as it is stock 50cc clutch) while I was down in there. I am now going to go test it out on the road, but it seemed to idle fine.
For some reason I cannot get my carb to adjust under 2k though, once I get down to 2k the screw comes out and it still idles there at 2k without issues. I put the screw in just to where it started to have some resistance because I do not want it falling out on the road.
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Post by lain on Apr 22, 2015 9:51:42 GMT -5
It rides smooth again, still smells like burning and I had someone tell me I was smoking every time I took off. The spark plug looks like mocha so I believe the mix is good. I can smell oil from the valve oil vent hose when running.
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Post by urbanmadness on Apr 22, 2015 10:10:22 GMT -5
I re-read your post and my first response wasn't relevant.
Is this bike a 2 stroke? (you said your mix is right)
On the carb, are you talking about the idle speed or the mixture screw?
Thanks,
Ray
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Post by lain on Apr 22, 2015 10:54:37 GMT -5
This is a 4 stroke 139qmb with "100cc" BBK. I was talking about the idle speed screw, sorry forgot to specify.
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Post by lain on Apr 22, 2015 11:12:56 GMT -5
I've had this oil issue with this engine ever since I first tried to install a BBK. I first thought it was a gasket issue, and at this point I have used 3 different heads for my 50mm BBK, 2 different sets of cylinders and pistons, and they all have had the same issue where I am somehow losing oil through my valve oil drain hose like all the time, and my oil keeps getting black and dirty fast and constantly needs changing or additional oil every couple weeks or so. I have been unable to figure that out for months but it has not effected performance, just has been costing me a lot to keep getting oil...
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Post by urbanmadness on Apr 22, 2015 11:16:29 GMT -5
did you rejet the carb when you went to a bbk?
is this a new problem (with the carb). Is your throttle cable too tight?
The other problem is blow by. I think the rings didn't seat correctly.
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Post by lain on Apr 22, 2015 11:27:05 GMT -5
did you rejet the carb when you went to a bbk? is this a new problem (with the carb). Is your throttle cable too tight? The other problem is blow by. I think the rings didn't seat correctly. No there's still slack on the throttle. It has always idled around 2k, in the winter at the same point where the screw is it would idle at about 1800. I am using #  jet with one of those foam filters as you can see in the beginning of the video on the previous page, along with the gurgling noise I hear from the valve oil vent hose. I do not have my friend over today and do not have a good camera of my own, but it makes the gurgling noise on what seems to be the exhaust stroke. I can hear the intake stroke pull air in from the carb (I had my fuel and spark turned off while doing this) and it builds up pressure like it should making it harder to turn by hand, then on the exhaust stroke as it gets easier to move by hand I can hear the gurgling from the valve oil vent hose. |
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Post by urbanmadness on Apr 22, 2015 11:44:05 GMT -5
Did you clock the rings when you installed them? (all ring gaps should be  degrees from each other so that they don't line up)... And you have probably posted this, but what's your valve gap? I still think the rings didn't seat. How many miles has the BBK been on it? How did you break it in, etc. Symptoms of worn or not seated rings.... higher crank case pressures (your valve cover vent hose), combustion by products contaminating the oil, and of course, low compression. Is the plug oily? On the carb issue, I'd pull it and clean it and check for vacuum leaks. |
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Post by lain on Apr 22, 2015 12:06:25 GMT -5
Did you clock the rings when you installed them? (all ring gaps should be degrees from each other so that they don't line up)... And you have probably posted this, but what's your valve gap? I still think the rings didn't seat. How many miles has the BBK been on it? How did you break it in, etc. Symptoms of worn or not seated rings.... higher crank case pressures (your valve cover vent hose), combustion by products contaminating the oil, and of course, low compression. Is the plug oily? On the carb issue, I'd pull it and clean it and check for vacuum leaks. I followed the guides on how to install the rings and BBK to the dot. I installed the ring gaps by marking the piston with a marker and installing them so the gaps all lined up even while I slide it into the cylinder. The first BBK I tried I did not install the rings properly and so back then it was spouting oil out the exhaust all the time. But the second complete kit after trying a second head (so my third head but second complete kit) I followed directions from people on the forum and marked it up and everything. The plug is not oily, but I removed some carbon deposit from the electrodes (I have a 3 electrode spark plug) by just chipping it off with my fingernail. The plug seems really good, mocha brown, no wetness, no oil. I feel like on the exhaust stroke maybe gas is getting into the oil in the valve cover through the exhaust valve, but oil is not being sucked into the chamber. Usually when I change my oil the oil level does not go down until after the oil has blackened. |
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Post by rcq92130 on Apr 22, 2015 12:29:35 GMT -5
Did you clock the rings when you installed them? (all ring gaps should be degrees from each other so that they don't line up)... And you have probably posted this, but what's your valve gap? I still think the rings didn't seat. How many miles has the BBK been on it? How did you break it in, etc. Symptoms of worn or not seated rings.... higher crank case pressures (your valve cover vent hose), combustion by products contaminating the oil, and of course, low compression. Is the plug oily? On the carb issue, I'd pull it and clean it and check for vacuum leaks. I followed the guides on how to install the rings and BBK to the dot. I installed the ring gaps by marking the piston with a marker and installing them so the gaps all lined up even while I slide it into the cylinder. The first BBK I tried I did not install the rings properly and so back then it was spouting oil out the exhaust all the time. But the second complete kit after trying a second head (so my third head but second complete kit) I followed directions from people on the forum and marked it up and everything. The plug is not oily, but I removed some carbon deposit from the electrodes (I have a 3 electrode spark plug) by just chipping it off with my fingernail. The plug seems really good, mocha brown, no wetness, no oil. I feel like on the exhaust stroke maybe gas is getting into the oil in the valve cover through the exhaust valve, but oil is not being sucked into the chamber. Usually when I change my oil the oil level does not go down until after the oil has blackened. Hopefully this is just a misread - but you said you had the gaps in the rings all lined up. If so, that's your problem right there because that is guaranteed to cause blowby. The gap on every ring should be rotated 120 to 180 degrees from where the gap of the next lower ring is (some say 1/3 of the way around, others say 1/2 the way). You NEVER should have ring gaps right above each other. |
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Post by lain on Apr 22, 2015 12:42:35 GMT -5
I followed the guides on how to install the rings and BBK to the dot. I installed the ring gaps by marking the piston with a marker and installing them so the gaps all lined up even while I slide it into the cylinder. The first BBK I tried I did not install the rings properly and so back then it was spouting oil out the exhaust all the time. But the second complete kit after trying a second head (so my third head but second complete kit) I followed directions from people on the forum and marked it up and everything. The plug is not oily, but I removed some carbon deposit from the electrodes (I have a 3 electrode spark plug) by just chipping it off with my fingernail. The plug seems really good, mocha brown, no wetness, no oil. I feel like on the exhaust stroke maybe gas is getting into the oil in the valve cover through the exhaust valve, but oil is not being sucked into the chamber. Usually when I change my oil the oil level does not go down until after the oil has blackened. Hopefully this is just a misread - but you said you had the gaps in the rings all lined up. If so, that's your problem right there because that is guaranteed to cause blowby. The gap on every ring should be rotated 120 to 180 degrees from where the gap of the next lower ring is (some say 1/3 of the way around, others say 1/2 the way). You NEVER should have ring gaps right above each other. No, I meant all lined up to the marks I made with the marker... |
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Post by urbanmadness on Apr 22, 2015 15:22:49 GMT -5
Ok a couple of more questions....
Are the kits you have used from the same supplier? Is it a quality kit?
Did you install the rings upside up?
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I feel like on the exhaust stroke maybe gas is getting into the oil in the valve cover through the exhaust valve, but oil is not being sucked into the chamber. Usually when I change my oil the oil level does not go down until after the oil has blackened.
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The head doesn't really open into the top of the head like that, unless you have a leaky exhaust valve (doughtful, but possible).. Maybe if you had a leaky valve, it could get to the top of the head thru the valve guide. I think It's getting thru the rings.
What has your break in process been? How many miles on the kit?
what are your valve clearances?
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Post by lain on Apr 22, 2015 15:43:32 GMT -5
Ok a couple of more questions.... Are the kits you have used from the same supplier? Is it a quality kit? Did you install the rings upside up? . ---------------------------------------- I feel like on the exhaust stroke maybe gas is getting into the oil in the valve cover through the exhaust valve, but oil is not being sucked into the chamber. Usually when I change my oil the oil level does not go down until after the oil has blackened. ------------------------------------------ The head doesn't really open into the top of the head like that, unless you have a leaky exhaust valve (doughtful, but possible).. Maybe if you had a leaky valve, it could get to the top of the head thru the valve guide. I think It's getting thru the rings. What has your break in process been? How many miles on the kit? what are your valve clearances? All the kits have been from the same supplier, a seller on ebay. I installed the rings text side up. I broke it in mostly by going about half throttle, and not sure about the miles, I have had the newest bbk for about 4 months, the other kit I had in october. I started with 0.004 and 0.005, recently moved to 0.006 both valves to see if it would help with the oil issue which it didn't, it actually got worse with bigger clearances. |
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Post by urbanmadness on Apr 22, 2015 15:57:05 GMT -5
go to .004 on both valves. I used to run my at .003 but it was a 150.
This will be counter intuitive... but it will hold the exhaust valve open a little longer and it will open a little earlier and close a little later. It will actually lower the crank case pressure.
What kind of oil are you using during break in? you might not of run it hard enough.to seat the rings.
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Post by lain on Apr 22, 2015 16:03:31 GMT -5
I'm beyond break-in at this point man, it's been months since I installed it and I ride it everyday. I used SAE 5w-40 for breakin, then I was using synthetic 0w-40 for a while during the winter and now I'm back to using SAE 5w-40 or 5w-30 depending on what is available where I am at the time.
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jet with one of those foam filters as you can see in the beginning of the video on the previous page, along with the gurgling noise I hear from the valve oil vent hose. 
degrees from each other so that they don't line up)... And you have probably posted this, but what's your valve gap?
