Hello all,
My name is Raul, I'm from Europe.
I posted a while back about this problem, but now I have some more details, maybe someone has a clue here.
The bike is a 1996 1500 Vulcan Classic single carb.
Problem is that the bike is popping in the exhaust on deceleration, only in one cylinder/exhaust, the rear one.
After that at idle I noticed that the front cylinder has a sound like bop-bop-bop-bop, and the rear sounds
like bop-bop-pff-bop-bop-pff. So it sounds like popping is present also at idle but almost not noticeable.
Also the spark plugs are different.Front are white/gray indicating a lean condition, while the rear ones are sooth black, no oil but most likely carbon. I replaced them with new ones, but no improvement.Air intake is stock air filter, only exhaust is custom one.Front exhaust pipe is longer than rear one, it is a bagger style. Carb is re jetted(I bought it like that, and it had a 155 main jet).I played around and went down until 120, but not an improvement.I checked compression with a mechanic and I do not know the value but he said it was fine.I also put high flow air intake for testing, but popping was still there.
I am totally lost here.Could it be and ignition problem?Coil?or something else?
Problem short:
-popping on deceleration only on rear cylinder
-almost unnoticeable popping on rear cylinder at idle
-black sooth plugs on rear cylinder, and white/gray on front
Trials short:
-changed the plugs, no improvement
-re jetted carb from 160 to 120 main, no improvement
-tested with stock and high flow air intake, no improvement
-compression check , ok
-valves are hydraulic, as far as I know they auto adjust
-marbled reed valve hose, no improvement
I added some plug pictures.This is how front and rear look like.
And also a bike picture.
I am loosing it guys, please help.
My name is Raul, I'm from Europe.
I posted a while back about this problem, but now I have some more details, maybe someone has a clue here.
The bike is a 1996 1500 Vulcan Classic single carb.
Problem is that the bike is popping in the exhaust on deceleration, only in one cylinder/exhaust, the rear one.
After that at idle I noticed that the front cylinder has a sound like bop-bop-bop-bop, and the rear sounds
like bop-bop-pff-bop-bop-pff. So it sounds like popping is present also at idle but almost not noticeable.
Also the spark plugs are different.Front are white/gray indicating a lean condition, while the rear ones are sooth black, no oil but most likely carbon. I replaced them with new ones, but no improvement.Air intake is stock air filter, only exhaust is custom one.Front exhaust pipe is longer than rear one, it is a bagger style. Carb is re jetted(I bought it like that, and it had a 155 main jet).I played around and went down until 120, but not an improvement.I checked compression with a mechanic and I do not know the value but he said it was fine.I also put high flow air intake for testing, but popping was still there.
I am totally lost here.Could it be and ignition problem?Coil?or something else?
Problem short:
-popping on deceleration only on rear cylinder
-almost unnoticeable popping on rear cylinder at idle
-black sooth plugs on rear cylinder, and white/gray on front
Trials short:
-changed the plugs, no improvement
-re jetted carb from 160 to 120 main, no improvement
-tested with stock and high flow air intake, no improvement
-compression check , ok
-valves are hydraulic, as far as I know they auto adjust
-marbled reed valve hose, no improvement
I added some plug pictures.This is how front and rear look like.
And also a bike picture.
I am loosing it guys, please help.