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Post by magoconnor on May 22, 2019 10:35:36 GMT -5
Okay so far I have cheked the vacuum line, and no fuel seems come from there.
I checked that the intake valve is not sticking, by removing the manifold. I have checked the manifold for leaks.
All seems to be in good shape.
No instruction came with cylinder kit, so I assumed the arrow meant in. Im still not sure If thats the right way, but could this be the problem? installing the piston up side down?
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Post by SMALL CC TEK on May 22, 2019 16:51:40 GMT -5
IMO - that black smoke is RICH. Way too rich. It honestly sounds like fuel is spilling down the vacuum line from the petcock into the intake... that would be my next inspection if you say everything else is in order (timing, valve lash, etc) dexameth is right all that black smoke is just way rich at idle flooding the motor ! So unplug the Vacuum line and see if it is wet or fuel running out of it. If it is get a fuel pump, if it's not suck on the line pulse for a second like your siphoning a car don't drink it ! lol .
then see if it drips fuel . If no drip then just plug the manifold port and start the motor see if it runs ,sometimes you can not make the save vacuum pull and they wont leak . If that is not it your float is right at the tipping point of fuel dump rest floats then try it again whe you lean the bike over does it leak fuel ? You should be able to go 45 degree or way more over be for fuel comes out the carb ...
Looks and sounds like fuel dumping in the manifold from carb or fuel pump . Good call Dex ... I for got to say close the port on the manifold or you will have a vacuum leak with the fuel dump issue , and one more thing smell your oil if it smells like gas change it when you get it running . Cause if you can smell fuel in the oil a lot of fuel the oil is done you don't want to wash all the oil off your cylinder and rings you will have a engine failure because of that wash down ... One last thing jumping your motor like that right infront of the carb will get you on You-tube in the worst way and a lot of likes from the fire ! lol AHahahhh lol
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Post by GrumpyUnk on May 22, 2019 17:50:56 GMT -5
If it won't idle, all I can suggest is opening the idle mixture screw 1/4 turn at a time to see if you can get it to fire off. The only effect of having it backwards would be 1)thrust angle if the wrist pin is off center(by design) and 2) heat capacity of the 'exaust' side of the piston vs that of the intake side. Exhaust side would have hot gas passing out that 'side' vs the cooling effect of incoming fuel:air mixture. It might run hotter on the exhaust side, and on 2T I understand that there may be more mass of metal, i.e., thicker on the exhaust vs the intake side.
IOW, it should have no problem running, but longevity might be affected in the long term. tom
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Post by magoconnor on May 22, 2019 18:35:00 GMT -5
I will try to use a vacuum pump and see if I see any fuel. I have changed tha manifold just to be sure along with the spacer.
I pulled the motor today to turn the piston, so that the arrow points towards the exhaust. There dosen't appear to be any damage to the piston or the valves.
I have tried starting the engine about 30-50 times with short burst of "idle" Should I replace the piston rings ? so that I get the best compression when broken in. Or are they still good and not "worn" and get still bedded in
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Post by dexameth on May 22, 2019 18:54:52 GMT -5
If you are worried about burning oil, the smoke would be blueish if it were oil burning. So, your rings are fine. I'm happy to hear the piston is good. This must be too-rich from something.
Try the 24mm carb and matching intake. I run 102/35 in mine but I am slightly rich at idle, runs fine. Little velocity stack, no filter element.
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Post by magoconnor on May 22, 2019 19:03:04 GMT -5
Im definitely gonna give that 24mm a try soon.
I've just heard that you have a narrow window for the rings to bed in. I'm just worried that I have used some of that roughness while trying to get it started.
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Post by dexameth on May 22, 2019 19:15:08 GMT -5
Im definitely gonna give that 24mm a try soon. I've just heard that you have a narrow window for the rings to bed in. I'm just worried that I have used some of that roughness while trying to get it started. You need some good cylinder pressure to bed the rings in. The first couple times you start after the build is really for tempering the metals, only idling for a few minutes. Then you ride it, but not past half throttle while fluctuating the rpms while riding. Do that for 10 minutes, on 2 separate rides. Then go back out for the third ride and do the same thing. Only this time after 5 minutes i want you to go wide open, let the rpms scream for a second then completely back off the throttle, repeat every 20 seconds or so while fluctuating the throttle in between. That high rpm forces more cylinder pressure and this literally forces gasses between the rings and the piston, this bedding the rings to the cylinder. Then, the quick release of the throttle is thought to allow the oil up into the cylinder because of the crankcase pressure fluctuating, helping lube up the cylinder walls. This is how I break in every 4 stroke.
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Post by magoconnor on May 22, 2019 20:06:37 GMT -5
So you think that the rings still are in good shape?
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Post by magoconnor on May 23, 2019 1:42:51 GMT -5
If you are worried about burning oil, the smoke would be blueish if it were oil burning. So, your rings are fine. I'm happy to hear the piston is good. This must be too-rich from something. Try the 24mm carb and matching intake. I run 102/35 in mine but I am slightly rich at idle, runs fine. Little velocity stack, no filter element. Do you see a big increase in fuel comsumption going from a 20mm to a 24mm?
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Post by dexameth on May 23, 2019 8:41:11 GMT -5
If you are worried about burning oil, the smoke would be blueish if it were oil burning. So, your rings are fine. I'm happy to hear the piston is good. This must be too-rich from something. Try the 24mm carb and matching intake. I run 102/35 in mine but I am slightly rich at idle, runs fine. Little velocity stack, no filter element. Do you see a big increase in fuel comsumption going from a 20mm to a 24mm? Yeah, kinda. Not a whole lot more, and I can't give ya an exact number but my guess would be around 60mpg. I did only jump from a 95 main in the 20 to a 102 main in the 24...
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Post by GrumpyUnk on May 27, 2019 12:07:04 GMT -5
As the piston goes up and down in the cylinder, the rings move. Yes, up and down, but also rotate within the groove. There is a precession of motion so as long as the rings are put back pointing the same direction(this side up) they should seat after they are re-installed. I tried to figure out how, and decided that is was like a hula-hoop doing its last few turns after you spin it around. One point will touch before the rest, and cause some slight bit of rotation by the hoop, and I think the same thing happens with piston rings. Maybe. perhaps. tom
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Post by magoconnor on May 28, 2019 22:41:08 GMT -5
Okay so today I tried hooking up a vacuum pump to the vacuum hose that goes to the manifold, to see if its dumping fuel there. But I saw no signe of fuel, so I think the pump is good The oil did not smell of fuel either. I took of the carb bowl to check the floats here are some pictures of that:
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Post by magoconnor on May 28, 2019 22:42:26 GMT -5
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Post by magoconnor on May 30, 2019 13:36:34 GMT -5
The carburetor is standing level when I took the picture.
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Post by GrumpyUnk on May 30, 2019 14:15:01 GMT -5
Looks good to me...
Did you pick up and drop the floats with the carburetor inverted? The float should be easy to pick up, and should drop freely to close the needle valve. There should be no binding, and the needle should be free to seat, move off the seat, and return. If there is any feeling of binding, make sure to clean the needle and the bore of the needle valve seat(the walls). tom
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