Spark Plugs
#11
Intake Leak
Did you try snugging all the carb mounting bolts and intake bolts? Really sounds like an intake leak on front cylinder. The extra air coming in leans out the mixture ( radically in your case) causing the symptoms you have; preignition, overheating,and plug failure. I would not ride it until it was fixed or you'll burn a hole in that front piston.
On a normally running Twin ( with carb) the rear cylinder plug will always look hotter as that cylinder has a harder time getting air to cool it.
On a normally running Twin ( with carb) the rear cylinder plug will always look hotter as that cylinder has a harder time getting air to cool it.
If it is not an Intake leak then could it be that my coil or wires are bad. I am at a loss?
Thanks for the input, I will tighten the bolts as you said.
Could it be the VOES?
#12
Spark Plugs Update
So I have tried everything that you guys have mentioned, with zero results.
By adjusting the idle mixture screw, now both cylinders are running the same, very lean.
Idle is rough and won’t stay at idle, once the engine is hot.
I spoke to someone else who has the same engine and carburetor, and they stated that I should have the carburetor re-jetted, what are your thoughts?
By adjusting the idle mixture screw, now both cylinders are running the same, very lean.
Idle is rough and won’t stay at idle, once the engine is hot.
I spoke to someone else who has the same engine and carburetor, and they stated that I should have the carburetor re-jetted, what are your thoughts?
#13
Still sounds like you compensated for an intake leak by tweaking the carb out of adjustment. VOES will only be apparent when accelerating under a load ( pings if switch not operating) or your top end speed is sluggish ( VOES not advancing the timing properly).
Next thing I would do is take the carb and intake tubes off and check those gaskets and parts for cracks, breaks, etc.
I wouldn't run it much at all until it's figured out or serious engine damage could occur.
Have you considered a good Indy to have it looked at? For a few hundred bucks it's well worth it to me anyways to have it done right.
Good luck, bro, and thanks for keeping us informed on your progress.
Next thing I would do is take the carb and intake tubes off and check those gaskets and parts for cracks, breaks, etc.
I wouldn't run it much at all until it's figured out or serious engine damage could occur.
Have you considered a good Indy to have it looked at? For a few hundred bucks it's well worth it to me anyways to have it done right.
Good luck, bro, and thanks for keeping us informed on your progress.
#14
Joe,
Your original post said the front plug was burnt(lean) and the rear was "sooty"(rich), also you had detonations and I think from only the front cylinder.
What is happening now that you messed with the mixture and idle? Are the plugs burning even and how are you checking them-(how long a ride-etc.). Any more detonations?
You did not mention making any changes to the engine before this started happening and we have to assume it was running good-(correct??). If so then it likely does not need to be jetted at this time, re-jetting is done after someone makes a change, air cleaner-exhaust-cam, that sort of thing. Jets don't go bad or change, if they were good before this issue then they are good now.
The voes is like the vacumn advance on engines with distributors and as Tacticle said it will ping and bog down if it's in-op. The vacumn line to it is prone to cracking and I've seen the wire come off.
Do you have a manual for this bike? It's very hard to diagnose these things without seeing, touching and knowing the bike's maintenance history. From where I sit, based on your first post, you probably have an air leak, especially when you consider how old the engine is. If you sprayed or used proplane all around the intake flanges and carb with no change in the way the bike was idling then I guess you don't have a leak and I'll be surprised. The fact that you adjusted the carb and the symptoms seemed to change tells me that I would take the carb off and apart, give it a thorough cleaning and make sure the diaphram has no holes. While it's off I'd change the intake gaskets, carb donut and voes line, cheap insurance (10-15 bucks or so). If I found a bunch of crap in the float bowl of the carb then I'd clean the petcock screen and flush the tanks if it's not been done in awhile. A compression test would also be a nice idea to eliminate something serious with one of your cylinders, you can borrow a guage from Autozone for free. This is all just good basic maintenance and even if it doesn't fix this issue it will probably eliminate a future one.
D
Your original post said the front plug was burnt(lean) and the rear was "sooty"(rich), also you had detonations and I think from only the front cylinder.
What is happening now that you messed with the mixture and idle? Are the plugs burning even and how are you checking them-(how long a ride-etc.). Any more detonations?
You did not mention making any changes to the engine before this started happening and we have to assume it was running good-(correct??). If so then it likely does not need to be jetted at this time, re-jetting is done after someone makes a change, air cleaner-exhaust-cam, that sort of thing. Jets don't go bad or change, if they were good before this issue then they are good now.
The voes is like the vacumn advance on engines with distributors and as Tacticle said it will ping and bog down if it's in-op. The vacumn line to it is prone to cracking and I've seen the wire come off.
Do you have a manual for this bike? It's very hard to diagnose these things without seeing, touching and knowing the bike's maintenance history. From where I sit, based on your first post, you probably have an air leak, especially when you consider how old the engine is. If you sprayed or used proplane all around the intake flanges and carb with no change in the way the bike was idling then I guess you don't have a leak and I'll be surprised. The fact that you adjusted the carb and the symptoms seemed to change tells me that I would take the carb off and apart, give it a thorough cleaning and make sure the diaphram has no holes. While it's off I'd change the intake gaskets, carb donut and voes line, cheap insurance (10-15 bucks or so). If I found a bunch of crap in the float bowl of the carb then I'd clean the petcock screen and flush the tanks if it's not been done in awhile. A compression test would also be a nice idea to eliminate something serious with one of your cylinders, you can borrow a guage from Autozone for free. This is all just good basic maintenance and even if it doesn't fix this issue it will probably eliminate a future one.
D
#15
#16
One thing on the VOES. If it looses vacuum it puts the module in the retarded mode. If a wire breaks or comes off of the VOES, it also puts the module in the retard mode. That way if you loose your vacuum or break a wire it will not ping from being advanced. It will just run slugish. It could have the contacts stick which would put it in the advanced mode, but this is really rare.
#17
Update
Wow, lots of great advice....
To answer a few questions:
1. I changed nothing other than the plugs.
2. After I adjusted the Idle mixture, the plugs are burning even but lean, so I adjusted the idle mixture screw again, to richen it up a bit.
3. The bike was bought used, with no maintenance history.
4. The bike has an S&S Super E Carb, with a hypercharger intake and Vance & Hines Short Shots.
5. When I let off the throttle there is a popping noise in the exhaust.
6. I did use a fuel additive from Harley for cold weather about the time this all started.
7. Now the idle is off, it does not have that normal Evo sound.
Next steps, I plan on doing everything Doug said to do.
Thanks for all the info guys you have been great.
To answer a few questions:
1. I changed nothing other than the plugs.
2. After I adjusted the Idle mixture, the plugs are burning even but lean, so I adjusted the idle mixture screw again, to richen it up a bit.
3. The bike was bought used, with no maintenance history.
4. The bike has an S&S Super E Carb, with a hypercharger intake and Vance & Hines Short Shots.
5. When I let off the throttle there is a popping noise in the exhaust.
6. I did use a fuel additive from Harley for cold weather about the time this all started.
7. Now the idle is off, it does not have that normal Evo sound.
Next steps, I plan on doing everything Doug said to do.
Thanks for all the info guys you have been great.
Last edited by RodeoHard; 04-12-2011 at 10:22 AM.
#18
We are not making much progress here! When you bought your bike was it running fine? Or has it always had issues?
From what you describe the two cylinders are running differently. Changing anything in the carb or if there is anything wrong with the VOES, will affect both cylinders. So it seems you have something wrong with one cylinder, or it is possible each cylinder is suffering from something wrong, but they have different problems.
My advice is find yourself a local indy and get this diagnosed properly. There are limits to what we can do for you on a forum.
From what you describe the two cylinders are running differently. Changing anything in the carb or if there is anything wrong with the VOES, will affect both cylinders. So it seems you have something wrong with one cylinder, or it is possible each cylinder is suffering from something wrong, but they have different problems.
My advice is find yourself a local indy and get this diagnosed properly. There are limits to what we can do for you on a forum.
#19
please by all means DO NOT use brake parts cleaner. once it's burned via combustion or however, it creates a very deadly gas. i'm surprised that this isn't reason for a cautionary label on the can of brake parts cleaner. i've read about guys who've cleaned parts with brake cleaner and then welded on them. brake parts cleaner can be quite deadly with just a few whiffs of it when it's burned. please guys, let your friends know this, those who fabricate and weld, etc.
#20
I'm not sure if you already did this, but I changed the two intake manifold gaskets that go to the cylinder heads and that seemed to fix my lean/ rich condition. The gaskets were in terrible shape, shrunken, with some tears too. The gasket to the carb was fine, like new. Changed the plugs and wires too.