Topic: # 3 pipe not as hot as others ? 72 CB500

[78 k550]

Hey All,
 My # 3 pipe doesnt get nearly as hot as my other's. I don't think this is normal. I'll be pulling the plug's tomorrow and change them out with new one's. That would be the easiest. Would low compression cause this also? Seem's to run real smooth. I can ride it alot longer now I have the charging sytem fixed. Was only getting 7.6 volt's at the battery. Cleaned up the point's with a file, wiped them and sytem is charging at 12.5 volt's.   I was hopeing it was the no charging that was keeping the # 3 pipe from getting as hot as the others. It is the same.
 Are platinum plugs good to run in these old bike's?

Thank's
 Paul

[LeoLegendATL]

Sounds like you got a carb and an air fuel mixture problem.  Check and make sure your idle screws and carbs are working properly, ie floats and jets not clogged.

[DammitDan]

When you pull the plugs make sure you're getting good spark on #3.  If it's fine, then it's the cylinder running too lean.  If there's no spark/weak spark, check the plug caps and coils for damage or grounding.

[TwoTired]

In addition to spark and compression issues would be carburation; cleanliness, settings, and syncronization.
Time to start an isolative process that confirms or exposes each item needed for even combustion across the cylinders.
Wouldn't hurt to do a complete tuneup procedure as a starting basis.
Cheers,