Exhaust sounds

[mixongw]

At one point, I had my mixture set a little on the rich side (I think). The exhaust would make very pleasant popping and burbling sounds when decelerating. Is this harmful? After resetting the mixture screws for best idle, the sounds are gone. I miss them...

[Steve]

Only harmful to the atmosphere.

Actually, if it is rich enough to make those kinds of noises, it is not running as well as it can, so overall, you are better off having made the adjustment.


.

[my425E1979]

fellas... i currently have the same popping and burbling coming from my left pipe.. i don't harbor any fondness for these noises and would like to fix, if possible... i posted my problem today under "exhaust popping".. anyway, i got some feedback to the tune that my mixture might be too lean in this cylinder.. but i think you guys are saying that a rich mixture is causing these noises.. is there a way of getting to the bottom of this debate??? i'm not even sure which way does what as far as adjusting the air screws.. anybody?

[chef1366]

Plug readings will tell the tale.

[ruddy]

You could have an exhaust leak.

[my425E1979]

umm, just out of curiosity... what's a plug reading?

[Pharkmeh]

You could have an exhaust leak.

i have a tiny exhaust leak and running a lil lean....


I know I know - Im doin damage.....


but it sounds soooo freakin kooool.....\\/

[b1ackd3ath]

umm, just out of curiosity... what's a plug reading?

They mean run the engine to the point of interest (where the popping occurs), kill it and then pull the spark plugs. Take a "read" of the plugs by looking at them. White means lean and black is rich. Wet black is oil fouled and clear wet could mean gas fouled. The should be chocolate brown colored.

I was having popping on decel on my 1100G and it was running lean. As far as I know with all the reading I have done, popping/backfiring = gas starvation which could be caused by a bunch of different issues.

The mechanism for backfiring as I understand it is that too little gas goes into the cylinder so that sometimes it fires and sometimes it doesn't. When it doesn't, that gas actually goes out into the super hot tail pipe where it is then ignited giving the pop or backfire.

You can also check the tailpipes. Right after a cold start you can check to see if the pipes heat up evenly. You can either spray a non flamable liquid (water) on each pipe and look to see how fast it evaporates or can touch each with a glove. If you find one that is far colder than the others, it may be firing inconsistently. Also, the tail pipe color can indicate a lean condition. Pipes will turn a metallic blue.

Tony

[patrick1]

what does blacjk and wet mean on a plug. I have gs850 1979 and it seems not to be running on cylinder nos1. I am a complete novice on mechanics even at my age but want to know how to fix it. I ahve checked each spark against the head and all are firing. Pipe nos 1 remains cool so am pretty sure its not firing. Howa\ever the bike runs ok otherwise. I think it may cut in when I get a bit of speed up but not sure. any help would be geratful. BTW I do not understand anything about carbs at the moment.

[Road_Clam]

At one point, I had my mixture set a little on the rich side (I think). The exhaust would make very pleasant popping and burbling sounds when decelerating. Is this harmful? After resetting the mixture screws for best idle, the sounds are gone. I miss them...

Popping on decelleration means your pilot jets are slightly lean.

[Dink]

what does blacjk and wet mean on a plug. I have gs850 1979 and it seems not to be running on cylinder nos1. I am a complete novice on mechanics even at my age but want to know how to fix it. I ahve checked each spark against the head and all are firing. Pipe nos 1 remains cool so am pretty sure its not firing. Howa\ever the bike runs ok otherwise. I think it may cut in when I get a bit of speed up but not sure. any help would be geratful. BTW I do not understand anything about carbs at the moment.

Could be many things, black and wet normally means oil in the cylinder; which can come past the rings in a worn motor as well as via the valve stem seals.
When seated on the bike which cylinder are you calling no 1?? the one on the left? do you park it on the sidestand?
Cold pipe at idle, is likely a blocked idle circuit, so you are correct it may be running with a few revs on, as it starts to draw fuel through the progression holes and onto the main jet.
To sum it all up get your carbs cleaned out, and then synched.
If no1 cylinder is on the left when seated, your sooty plug is caused by oil passing the valve stem seals, park it on the centrestand.

Dink

[patrick1]

yes its is parked on side stand

thank you for your response. i do park it on is stand and cylinder 1 is on that side. I would get it up on the centre stand but do not seem to have the right technique. As for the carbs i have the cycman book but it is hard to follow and the description on the carb rebuild on the forum is for the newer type mine are vm type and were only on the 1979 bike. 2 questions are the tuned n the bike or off and if on the bike how do you do them and have the fuel going from the tank. I know these may sound redicilious questions but i am a **** when it comes to this, but can learn fast.

Cheers Patrick

[Dink]

Buy a couple of feet of extra hose, then go to an auto parts store and get "double ended barbs" to fit the hoses(trust me on this) I put my tank on the seat and use the extension hoses to run fuel to the carbs.
Centre stand is easy, STOP trying to lift the bike onto it!!! hold the bike and push on the stand; BTW try removing the stand and lubing the pivots first.

Dink

[patrick1]

i will give it a try

I will try and get it on the center stand tomorrow its been raining all day here. BTW where is it you live I know its Australia but never heard of the place. Should Ii take out the crabs and clean them first, then try them them sync? This sound logical to me. Or can they be cleaned in position.

Cheers Patrick

Its great to be able to find help here.

[Pharkmeh]

I will try and get it on the center stand tomorrow its been raining all day here. BTW where is it you live I know its Australia but never heard of the place. Should Ii take out the crabs and clean them first, then try them them sync? This sound logical to me. Or can they be cleaned in position.

Cheers Patrick

Its great to be able to find help here.

:shock: 8-[