Slight misfire right side black plug WITH PICTURES

[Ketis]

Hi all!

Well i got my chop on the road and have about 450 miles on her.

The engine runs really good in the high rpm range and pulls really hard and no stumbling or anything and when i let off at a higher rpm i get no backfiring and the decel is really smooth. I am getting around 42-47mpg (should be a bit better, i am not constantly beating on it either)

I am creating this thread because the right side plug is BLACK. I have replaced the plugs. I went from the NGKs to the autolite 63s and i get the same issue. Plugs are gapped to .040 and i have set the valves to .002(inlet) and .006(exhaust) and have also set the cam chain.

I have a 77xs650d with the bs38s the jets are 27.5(pilot) and 135(mains) and the needled lowered a step. Both carbs are the same and i have jew JBM boots.

I also have a brand new pamco with e-advance and mikes monster coil.

Here are the pics

Right side float setting

Right side plug

Left side float

Left side plug


Any help would be appreciated.

 

[TwoManyXS1Bs]

Yep, I set my floats just like your left side. The right is too high...

 

[5twins]

Yes, I would lower the fuel level in the right carb. Spec is 25mm for those carbs. I would also open the intake valves up to .003" and reduce the plug gaps a little, maybe down to .035".

 

[Ketis]

ok, i put in a new plug on that side gapped to .035 and i set the fuel level identical to the side that is working.

I also put a new spark plug boot.

On the new plug it has oil on it.

So are my plugs getting oil fouled? What causes this? could it be that my valves are too tight?

 

[5twins]

Well, oil on the plug usually gets there in one of 3 ways - down through the valve guides, up past the piston rings, or through the head gasket from the cam chain tunnel between the cylinders. The 1st two would require a top end tear down to remedy. The 3rd may be cured by a head re-torque.

 

[FB71]

is the black on the plug dry and sooty, or sticky?

Dry and sooty indicates a fuel/air concern, sticky is an oil concern.

edit; duh, I just reread your last post. Sorry.

 

[5twins]

The sad fact is that being 30+ years old, a simple tune-up isn't enough sometimes. They need some inside work.

 

[Ketis]

Allright, well to bring this thread back from the dead!

I did a leakdown test last night (20psi) and air did not seem to be coming out of the valves.

I could hear a bit of air and when i covered the oil fill hole the sound changed. So im assuming the air is leaking past the rings?

The funny thing is i get around 150psi for both cylinders when doing a compression test

 

[oldbiker]

Allright, well to bring this thread back from the dead!

I did a leakdown test last night (20psi) and air did not seem to be coming out of the valves.

I could hear a bit of air and when i covered the oil fill hole the sound changed. So im assuming the air is leaking past the rings?

The funny thing is i get around 150psi for both cylinders when doing a compression test

................hi with air leakage in cyclinders ,,, you could use a castrol 20-50 oil for motorcycles,,,,, or a shell sx4 20-50 oil ,,,,i,ve used the sx4 and its brilliant for bikes hope this helps you regards oldbiker

 

[FB71]

Allright, well to bring this thread back from the dead!

I did a leakdown test last night (20psi) and air did not seem to be coming out of the valves.

I could hear a bit of air and when i covered the oil fill hole the sound changed. So im assuming the air is leaking past the rings?

The funny thing is i get around 150psi for both cylinders when doing a compression test

When you did the leakdown, you lost 20psi, or you charged it with 20psi? Are you using a leakdown gauge (preferable a dual gauge), or just putting air in the cylinder and listening for leaks?

When doing a leakdown at 100psi, you should only loose 10psi, 20psi absolute max
With the regulator set to 100psi, 1psi then = 1%

It is normal to loose 10% past the rings, especially on a cold engine

 

[Ketis]

I just made a spark plug adapter to my compressor and put 20 psi In the cylinder and listened

 

[Ketis]

Going to try some sea foam. Really don't want to tear the motor apart when it's so close to running well

 

[xs650dreamer]

hey man whered you get those fitting for the bowls so you can use a hose for the fuel level. mine just have a nut