Bike Popping through exhaust

[crazy_ss75]

My 79 xs1100 special pops through the left exhaust when I have it on main tank, but not on reserve. I have K&N filter pods and 4-2 exhaust with Harley mufflers. I have thoroughly cleaned and synced carbs. New plugs but #2 is fouled out after 50 miles of riding. Any advice on what I could check or fix would be appreciated.

[donebysunday]

Any way you could link to a picture ? All I can think of is a plugged or blocked air jet but then why not on reserve too ? ? ?

[crazy_ss75]

What are you wanting a picture of, the whole bike? If you let me know what you want to see, i can get a pic posted

[motoman]

My 79 xs1100 special pops through the left exhaust when I have it on main tank, but not on reserve. I have K&N filter pods and 4-2 exhaust with Harley mufflers. I have thoroughly cleaned and synced carbs. New plugs but #2 is fouled out after 50 miles of riding. Any advice on what I could check or fix would be appreciated.

May have a mal-functioning 'octy' if that valve and hoses are still intact on that special.

[donebysunday]

What are you wanting a picture of, the whole bike? If you let me know what you want to see, i can get a pic posted

PLUGS to see what your dealing with ?

[Rasputin]

I have to ask which way the handle of the petcock is pointing when you are on reserve?

[Gallaecus]

if your plug is fouled, youre getting too much gas or not enough air.
doesnt seem like it would be related to your petcock position.
maybe float level ? maybe worn rings ? maybe valve adjustment.
or if it works good riding on reserve, screw it, ride that way.

[Rasputin]

if your plug is fouled, youre getting too much gas or not enough air.
doesnt seem like it would be related to your petcock position.
maybe float level ? maybe worn rings ? maybe valve adjustment.
or if it works good riding on reserve, screw it, ride that way.

I rode for many years thinking that the prime position was the off position on my 79SF petcock's. It was not until I joined this site that I found out differently. There are many things that can be wrong due to that simple mis-understanding including the symptoms he is mentioning.

[crazy_ss75]

Reserve is straight up on my petcock. There's no octy on it, I removed it because it leaked.

[crazy_ss75]

Top is #2, bottom is #1, #3 and #4 look like #1.

[jjz28]

cant see pic.

[crazy_ss75]

Retrying Picture of Spark Plugs



Ok, this time left is #1 and right is #2. #3 & 4 look like one on left.

[CaptonZap]

Run a compression check on #2. If it checks OK, then put the plug from #3 into #2, and #2 into #3, and go for a long ride. When you get back, look at the plugs again. If #2 looks like it did before, and #3 looks better, exchange the plug boots on 3 and 2.
Go for another ride. When you get back, look at the plugs again. If the problem went to #3, it is the plug boot that is faulty.
If it still is #2, look at the plug wire, making sure that it does not get close to any metal portions of the bike. Tie it up with pastic tywraps if necessary. If that doesn't help, we'll think of something else.
Compression check first. Don't think you can skip it, it is the most important check at this point.
CZ

[crazy_ss75]

I'll try that tomorrow. Have to rent a compression tester. I'll post results.

[CaptonZap]

I'll try that tomorrow. Have to rent a compression tester. I'll post results.

Check with Checkers or Autozone, they may loan you one. Be sure that you hold the throttle open when you crank, and make sure that all plugs are out and laying on the head, wires attached, so that you don't burn out the coils. Or pull the big plug on the TCI.
Oh and yeah, get that car battery rigged up.

CZ