Too Rich or Too Lean - Honda Shadow Forums : Shadow Motorcycle Forum

Stretch9301 · 11-05-2012, 02:59 PM

How do you tell?

I (finally) got my VT500 running again (thx for the replies, BTW), but now theres this weird popping noise coming from the exhaust.

It's random from 3-5k rpms and sporadic, but anywhere 6k and up its like someones making popcorn, very steady and rhythmic. They are much louder on deceleration, where they're noticeable at ANY rpms...

These pops are NOT loud at all, but they still bother me. Something isn't right.

I looked at the spark plugs and they're kinda black, defiantly not white.

What causes this? BTW the bike still has its stock exhaust, although I drilled some small holes in the baffles.

Extra-special bonus information:
The last owner wallowed out the jets in an attempt to get more power, then sold the bike to me cheap because it wouldn't run right. I replaced the jets and it ran 100x better. Is it possible there are still more bad repairs in the carb or elsewhere in the engine that need to be fixed?

Any thoughts appreciated...

nanewt02 · 11-05-2012, 04:37 PM

i would check the compression in both cylinders and the exhaust system to make sure the guy hasnt screwed with it. i would say its too lean, but without knowing the other factors its hard to tell. the reason i mention compression is not because of the noise, but if you retune the carbs, some people use the compression differences to influence the tuning of each carb if the difference is alot., first i would check the exhaust system, i smell a lack of back pressure, and have you retuned your fixed carbs from factory settings, theres a tiny chance it could be a rod bearing going bad.
here to help
nick

Stretch9301 · 11-06-2012, 10:18 AM

The exuast system *looks* fine, like I said I drilled some holes in the baffles but that was a while ago and this is a new problem... What am I checking for? I think its lean, but I really want a second opinion...

jpr1968 · 11-06-2012, 10:29 AM

Black plugs indicate a rich condition. Are they new plugs?

Stretch9301 · 11-06-2012, 11:49 AM

Yes, well, they're newish lol. I changed them when I first got the bike and ive only put a few hundred miles on it. IDK what to think :/

Stretch9301 · 11-06-2012, 12:18 PM

So this morning I decided to go for a ride and the stupid bike wouldn't start...

The engine would spin, and it made this "popping" noise like it wanted to start, but it wouldnt actually start.

What a PITA. Im thinking this is some kind of electrical problem, weak spark or something. IDK what to think...

What could cause that?

nanewt02 · 11-06-2012, 06:56 PM

is this popping noise the same unusual popping noise the bike made when it it ran, it could be the fuel pump depending on the year. what year is it??
sorry to here about the bike not starting. ive decided when stuff like this happens to me, it is caused by "the world just hates you" phenomenon

Stretch9301 · 11-06-2012, 07:22 PM

Thanks...

Nope, its not the fuel pump, this bike is a 1983 and there is no fuel pump. Its gravity fed to the petcock, then straight across into the carbs...

Hmmmm, its always something :/

nanewt02 · 11-07-2012, 08:32 AM

im restorin an 83, its a 750 though, how many miles are on the engine?

nanewt02 · 11-07-2012, 08:35 AM

ive got it, have you tried adjusting your idle screws?

11-05-2012, 02:59 PM	#1 (permalink)
Stretch9301 Member Join Date: Aug 2012 Posts: 46	Too Rich or Too Lean How do you tell? I (finally) got my VT500 running again (thx for the replies, BTW), but now theres this weird popping noise coming from the exhaust. It's random from 3-5k rpms and sporadic, but anywhere 6k and up its like someones making popcorn, very steady and rhythmic. They are much louder on deceleration, where they're noticeable at ANY rpms... These pops are NOT loud at all, but they still bother me. Something isn't right. I looked at the spark plugs and they're kinda black, defiantly not white. What causes this? BTW the bike still has its stock exhaust, although I drilled some small holes in the baffles. Extra-special bonus information: The last owner wallowed out the jets in an attempt to get more power, then sold the bike to me cheap because it wouldn't run right. I replaced the jets and it ran 100x better. Is it possible there are still more bad repairs in the carb or elsewhere in the engine that need to be fixed? Any thoughts appreciated...

11-05-2012, 04:37 PM	#2 (permalink)
nanewt02 Junior Member Join Date: Oct 2012 Posts: 19	i would check the compression in both cylinders and the exhaust system to make sure the guy hasnt screwed with it. i would say its too lean, but without knowing the other factors its hard to tell. the reason i mention compression is not because of the noise, but if you retune the carbs, some people use the compression differences to influence the tuning of each carb if the difference is alot., first i would check the exhaust system, i smell a lack of back pressure, and have you retuned your fixed carbs from factory settings, theres a tiny chance it could be a rod bearing going bad. here to help nick Last edited by nanewt02; 11-05-2012 at 04:44 PM.

11-06-2012, 10:18 AM	#3 (permalink)
Stretch9301 Member Join Date: Aug 2012 Posts: 46	The exuast system looks fine, like I said I drilled some holes in the baffles but that was a while ago and this is a new problem... What am I checking for? I think its lean, but I really want a second opinion...

11-06-2012, 10:29 AM	#4 (permalink)
jpr1968 Senior Member Join Date: Apr 2008 Location: Palatine, IL Posts: 4,556	Black plugs indicate a rich condition. Are they new plugs?

11-06-2012, 11:49 AM	#5 (permalink)
Stretch9301 Member Join Date: Aug 2012 Posts: 46	Yes, well, they're newish lol. I changed them when I first got the bike and ive only put a few hundred miles on it. IDK what to think :/

11-06-2012, 12:18 PM	#6 (permalink)
Stretch9301 Member Join Date: Aug 2012 Posts: 46	So this morning I decided to go for a ride and the stupid bike wouldn't start... The engine would spin, and it made this "popping" noise like it wanted to start, but it wouldnt actually start. What a PITA. Im thinking this is some kind of electrical problem, weak spark or something. IDK what to think... What could cause that?

11-06-2012, 06:56 PM	#7 (permalink)
nanewt02 Junior Member Join Date: Oct 2012 Posts: 19	is this popping noise the same unusual popping noise the bike made when it it ran, it could be the fuel pump depending on the year. what year is it?? sorry to here about the bike not starting. ive decided when stuff like this happens to me, it is caused by "the world just hates you" phenomenon

11-06-2012, 07:22 PM	#8 (permalink)
Stretch9301 Member Join Date: Aug 2012 Posts: 46	Thanks... Nope, its not the fuel pump, this bike is a 1983 and there is no fuel pump. Its gravity fed to the petcock, then straight across into the carbs... Hmmmm, its always something :/

11-07-2012, 08:32 AM	#9 (permalink)
nanewt02 Junior Member Join Date: Oct 2012 Posts: 19	im restorin an 83, its a 750 though, how many miles are on the engine?

11-07-2012, 08:35 AM	#10 (permalink)
nanewt02 Junior Member Join Date: Oct 2012 Posts: 19	ive got it, have you tried adjusting your idle screws?

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