So in talking to a buddy who's a long time wrench on old metric bikes,......I told him about my front cylinder plug fouling. He asked if it was a blocked exhaust pipe.

So I looked. Is this normal? It looks factory to clear the motor but is it?!?

Is it actually damaged from bottoming out on something by the previous owner?


Pipe from front cylinder.

 

Normal. FWIW one of the automotive TV shows did dyno pulls to determine if smashing an exhaust pipe for clearance affected power and concluded it didn't! So maybe your problem lies elsewhere?

 

Here`s an unused "squish" pipe from an OHV big twin

 

The vintage Harleys ran a front flat header pipe. It went between the engine and lower frame.

 

Thanks. I just this morning re-installed the M88. The float was set too low and was leaking gas all over. I will play with it this week. If the front cylinder keeps fouling, off to Hillside Cycles for some problem solving. Which means $$$$$.

 

I`d suggest determining if it fouls due to fuel or oil before sending it out

 

Yes. But I can't wrap my head around one plug fouling with soot and one clean as a whistle being the carb. But I'm not that experienced.

As if it's oil, which it doesn't look like because it ain't wet, that would still necessitate a trip to Hillside. Same if a sticky valve. I'm lucky in that he's only about 45-mins to an hour away.

 

I struggled with a Pan doing that, chased the carb for several days, No bueno
It was weak spark due to a plug wire

 

Timing? Run a hotter plug in the front? Just a guess.

 

You can your check plug wires in a darkened garage or at night, start bike and use a spray bottle and mist your plug wires and coil and see if they light up like a Christmas tree (they shouldn't of course). It also could be an intake leak on the clean running side.