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Backfiring
by: rcq92130 - Jan 7, 2015 15:01:18 GMT -5
Post by rcq92130 on Jan 7, 2015 15:01:18 GMT -5
Probably oil, but maybe a way over-rich condition.
Go to O'Reilly, hand them a CC or debit care to secure a comp. tester. I don;t thin any charge is actually run into the system, and several hours later when you return the thing it's all simply erased.
Just trying to help, dude. Getting a reading on the condition of the piston, rings, valves, valve timing is the first step.
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Post by lain on Jan 7, 2015 17:20:26 GMT -5
I installed my new Keihin carb, the starting issue went away (and surprised me at how well it started in 15 degrees). I put a brand new #  main jet on the keihin carb, I'm not sure what the pilot jet size is but I haven't touched it. I have no idea at all what I'm doing here with this mixture screw on the side. Here is a video of it running and you can hear the popping. You can also see/hear how easy it starts after putting the keihin carb in. It pops during low rpms, and sometimes during accel. I tried going down a jet to #  and it popped horribly on accel more than during idle that's for sure so I went back to # and this video is of right after going back to # main jet. Skip to 2:18 to see closeup of exhaust pipe and hear the popping sound more clearly. Sorry this camera isn't that great. rcq92130 Sorry for being difficult, I just don't have money or a credit card or anything. All the parts I recently bought, I bought with a gift card I received for ebay. |
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Backfiring
by: rcq92130 - Jan 7, 2015 18:37:26 GMT -5
Post by rcq92130 on Jan 7, 2015 18:37:26 GMT -5
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Post by lain on Jan 7, 2015 18:58:31 GMT -5
The sounds thing doesn't help a lot with this situation. The popping is constant, less at higher speeds but still there. Is it possible to be too rich at idle and too lean on the main?
Adjusting the fuel mixture screw doesn't help to make the popping go away. It seems to make the whole scooter shake everytime it pops. When the autochoke fully engages the popping seems to be on time with the engine, but it still seems like a problem that is only getting worse and I can't seem to track down the cause.
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Backfiring
by: jerseyboy - Jan 7, 2015 19:36:17 GMT -5
Post by jerseyboy on Jan 7, 2015 19:36:17 GMT -5
Noisy little bugger,,almost sounded like it was missing to me..idle is a little too high also..Ive seen and heard worse..
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Backfiring
by: JerryScript - Jan 7, 2015 20:11:21 GMT -5
Post by JerryScript on Jan 7, 2015 20:11:21 GMT -5
It almost sounds like one or more of the muffler baffles has broken down. The valves may be a little loose, but they don't sound clackity so that's ok, they usually tighten up over time after each adjustment. What you describe as popping sounds to me like the muffler not doing it's full job, but it doesn't sound bad. I'll wait for other opinions, but I think you are doing good.
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Post by lain on Jan 7, 2015 21:27:19 GMT -5
Could a gasket leak cause this? I haven't used new gaskets the last couple times I opened up the engine to tinker with it. I'm also wondering why the smoke only happens when I let it sit overnight or longer than a few hours and why it is thicker when sitting for a day or two. Also wondering why it consumes so much oil... Could all of these be caused by a leaking gasket letting oil slip by somewhere and into the combustion chamber? It's starting to feel like it might be possible because now it does seem like it has lost compression. I tried to start it up after about a couple hours of sitting and it sounded like it was cranking faster than normal. I tried a few times to start it and the 3rd or 4th time it sounded like it slowed down because the compression was higher and it started right up at that point.
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Freshman Rider
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Posts: 65 
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Backfiring
by: bashan - Jan 7, 2015 22:45:28 GMT -5
Post by bashan on Jan 7, 2015 22:45:28 GMT -5
If it smokes a lot after it sits it's the valve stem seals. The oil on top of the head seeps down into the combustion chamber when the bike is off and causes a lot of bluish smoke on startup.
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Backfiring
by: geh3333 - Jan 7, 2015 22:52:10 GMT -5
via mobile
Post by geh3333 on Jan 7, 2015 22:52:10 GMT -5
Im i the only one who didnt notice any popping ? Maybe its just the recording or maybe its just because im litening to it on my phone ? I heard the noise and I think jerry may be right about the bafles . mine smokes a good bit if I leave it sit for a few months " over the cold months " and sometimes if it sets for a few days without running. Where are u located lain ?
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Backfiring
by: geh3333 - Jan 7, 2015 22:57:12 GMT -5
via mobile
Post by geh3333 on Jan 7, 2015 22:57:12 GMT -5
If it smokes a lot after it sits it's the valve stem seals. The oil on top of the head seeps down into the combustion chamber when the bike is off and causes a lot of bluish smoke on startup. I would expect it to constantly smoke if that were the case, especially if it does it after only sitting for a little while . also he has a new head and had this problem with the old one also. That's not saying the new valve seals could be leakin but its not that likely. |
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Post by lain on Jan 7, 2015 23:03:12 GMT -5
Im i the only one who didnt notice any popping ? Maybe its just the recording or maybe its just because im litening to it on my phone ? I heard the noise and I think jerry may be right about the bafles . mine smokes a good bit if I leave it sit for a few months " over the cold months " and sometimes if it sets for a few days without running. Where are u located lain ? It's definitely the recording. The sound is as loud as the engine is but it sounds like nothing in the recording because the camera does not pickup bass filled sounds. Imagine the popping you hear at 2:18 deeper and louder. The sound is loudest from the tailpipe but in person can be heard from as far as across the yard about 10 feet away so it has got to be the camera not picking up the sound. I am in Boston, MA. |
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Backfiring
by: alleyoop - Jan 7, 2015 23:07:28 GMT -5
Post by alleyoop on Jan 7, 2015 23:07:28 GMT -5
Bashen is correct you have to be a motorhead to know this stuff it is the valves leaking by the seals after you shut it down and the metals cool. Then It will smoke at start up until some expansion occurs as the parts heat up and stop the sippish and will keep on doing this until you fix it. So if you don't fix it always check you oil level otherwise you may be running with low oil level and will do real damage.
Yes I heard the popping, also you have idling way to high the idle should only be 1500-1800 after it warms up. Also after you start it cold does the idle ever drop or does it always idle that high and never drop?
Also the rear wheel should not be spinning after say 5 minutes if it is Lower the idle so that the rear wheel Barely Wants to turn or not turn at all.
Alleyoop
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Post by lain on Jan 7, 2015 23:19:28 GMT -5
Bashen is correct you have to be a motorhead to know this stuff it is the valves leaking by the seals after you shut it down and the metals cool. Then It will smoke at start up until some expansion occurs as the parts heat up and stop the sippish and will keep on doing this until you fix it. So if you don't fix it always check you oil level otherwise you may be running with low oil level and will do real damage. Yes I heard the popping, also you have idling way to high the idle should only be 1500-1800 after it warms up. Also after you start it cold does the idle ever drop or does it always idle that high and never drop? Also the rear wheel should not be spinning after say 5 minutes if it is Lower the idle so that the rear wheel Barely Wants to turn or not turn at all. Alleyoop That makes sense. What about leaky gaskets? Would they cause the issue I am having with the popping and/or smoke on startup after long periods of sitting? I haven't changed to new gaskets the last couple times I cracked everything open down to the piston. Last time I saw the head gasket it looked like there was shavings of it coming off. Also noticing lower compression as of lately but not sure if it's just due to the extremely cold weather causing parts to not be sealed entirely until they warm up or something along those lines. Yes it drops, usually around 4-5 minutes in this weather. The autoenricher is brand new with the carb I just installed today. The video did not go far enough to see it slow down. It was about 15 degrees during the video. I imagine it is hard for the needle to heat up when freezing cold gas is pumping by it. The wheel does not spin at all during the idle or startup. If I lower the idle the engine cannot stay alive after the autoenricher kicks in until after a ride when it is this cold out. I am trying to avoid riding it until I can figure out this issue so I do not keep damaging things. |
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Backfiring
by: geh3333 - Jan 7, 2015 23:24:49 GMT -5
via mobile
Post by geh3333 on Jan 7, 2015 23:24:49 GMT -5
For as much oil he is losing it would have to be leaking after warm up also. ma ybe it is ? Also that means his new and old head has the same issue .possible but unlikely.
I was hopping u were closer to western pa. Would have been nice to be able to help in person.
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Backfiring
by: alleyoop - Jan 7, 2015 23:28:16 GMT -5
Post by alleyoop on Jan 7, 2015 23:28:16 GMT -5
Yes oil can be getting in by the gasket area, it would naturally be between the head gasket and not the bottom one by the motor case and jug. Oil passes through one of the Studs to the top so you should see leakish if you take the head off.
But normally the way it happens it points more toward the valve stem seals because once you shut it off there is no pressure to push it past the gasket into the chamber. Actually it is a very common thing and you see this in older cars at lot.
Alleyoop
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main jet on the keihin carb, I'm not sure what the pilot jet size is but I haven't touched it. I have no idea at all what I'm doing here with this mixture screw on the side.
and it popped horribly on accel more than during idle that's for sure so I went back to #
..BAD TO THE BONE..