Spark Plugs Woes! Please Help

[mjamusic]

Greetings,
I'm having an issue with my right plug becoming charred black within a couple minutes of riding the bike...here are the details of the engine:
1980 xs650 SG
Pamco e-advance ignition
HHB PMA
2 into 1 Gordon Scott exhaust w/ cone muffler
UNI pod filters
Mike Morse jet kit ( 145 main, 45 pilot, needle in 3rd position from top)

The engine is timed, the carbs synced, valve clearances adjusted and this is my initial thought that I have too big a clearance on the right side but I would like some other view points...all constructive comments welcomed I want to ride!!!! Thanks,

-Matt

 

[xjwmx]

Does the left look kind of bad too? One thing it might easily be is a weak coil. The coil will pass the ohmmeter test but not give a good enough spark to get good enough combustion to clean the plug. Test by substition, but if I'm wrong it's still good to have a spare coil handy. It doesn't have anything to do with valve clearances. There's an order of things to check, starting with compression.

 

[mjamusic]

The left side plug is actually great I think, but I'll give a check of the coil (suggestions for a new/ better one? I got the one that came with the basic pamco kit from mikes) and compression and post results, thanks!

 

[xjwmx]

^If the other side plug is great then it's less likely to be the coil. If it's a dual coil that is. Not sure what coil your setup uses, but you'll find lots of suggestions and warnings about coils here with the search function. Let's see how the compression test goes.

 

[TwoManyXS1Bs]

That plug looks shiny, not sooty. 2 into 1 exhaust makes it harder to tell, but you could feel the inside of the muffler outlet and see if it feels slimy...

 

[mjamusic]

The plug is definitely on the wet side...thoughts on which direction to go in that case...? I have to go out of town for a few, but I have a compression tester that will be here when I get back and I will definitely test, but other thoughts? I'm a bit perplexed on what may be causing this? Thanks

 

[gggGary]

Well I'll guess oil. How long have you been running the engine? History? If it's recently back from the dead run it. If it's oil and the motor hasn't been run much try riding it for awhile see what happens, sometimes seals soften, rings reseat and oil consumption goes down. It's happened to me... Other times it gets worse and you are looking at a top end job. Carry an extra plug and wrench. A BP6ES is one hotter than a standard BP7ES that can reduce oil fouling.

 

[mjamusic]

I've put about 600 miles since I've made the changes listed above this past winter. The engine only has 5500 miles on it and the PO had it sitting for several years. I got the bike at the end of last summer.

 

[5twins]

Did you change to plastic floats and if so, use the proper setting for them?

 

[mjamusic]

I'm still using the stock brass floats. Is it common to switch to plastic ones?

 

[retiredgentleman]

Could be a passing head gasket, drawing oil in from the camchain tunnel. Does the engine use a lot of oil? Have you noticed any puffs of black smoke out the exhaust?

Check the head nuts for the correct torque. 30 ft-lbs for the large ones.

 

[mjamusic]

I do get an oil leak on the left side coming from the head gasket area, I have checked the torque on all the head nuts...the results of my compression test: left=112, right=115. This is the status of my plugs, both less than a week old NGK BP7ES.

 

[mjamusic]

Thought this might help...this is how she sounds right now...

Thanks for all the help!

 

[cobrasneverdie]

you know what, I am having the same problem, last year when I got it running, I used a dual coil and one plug was charred. So I'm going to sit here and hopefully someone sheds light. gggGary my bike hasn't been ridden in a long time so I am going to see how it runs soon. Sorry Id on't mean to hijack this thread, but I'm rockin the same boat.

 

[retiredgentleman]

mjamusic;

Your engine is never going to run well with that low compression.

I think Gary summed it up very well in post #7. It might improve, but then again it may not.

The engine may have low miles, but its not good for engines to sit for years. Valve stem seals are likely hardened, and its sucking oil in on that one cylinder. I see a top end re-build in your future.

 

[mjamusic]

Are there any other tests I can do to confirm, before I jump into a rebuild?

 

[5twins]

How did you do the compression test? Was it on a warm engine and with the throttle held wide open? If the answer to either of those is no then you didn't get the best results possible. Do another test in the manner I outlined.

 

[TwoManyXS1Bs]

That idle doesn't sound right to me, too much popping, perhaps not synchronized? The plug bases, to me, read rich idle. My 2 cents...

 

[mjamusic]

5twins: I did the test exactly as you describe, my only thought is that I only let the bike idle for a few minutes...maybe let it warm up more?

Twomany: I just synced the carbs using vacuum gauges. Both read the same...I've heard some groans on the vacuum gauges around here...is there a better way to sync?

Lastly: should I just ride for a while and see if things get better, or face the facts and hunker down for a top end rebuild? Thanks all

 

[jchen]

i got the exact same problem but im smoking out of the right exhaust. My guess would be valve stem seal or head gasket. You could try a hotter spark plug to compensate for the potentially weak coil. Try B5ES's dont go on the highway with those tho, just around the city putting.