98 Wide Glide
-- 34k miles
-- 133 pounds compressing front cyl, 130 pounds rear
-- "mild" cam
-- stock carb (don't know jetting)

I just read my plugs today, and the rear cylidner is reading leaning than the front. Since the rear cylinder runs a bit hotter than the front, is this common or do you think I've got trouble somewhere. If you think trouble, then what do you suggest the trouble might be?

Thanks,

Chuck

 

Rear cylinder should be slightly richer than the front.

You might have an intake leak on that head.

 

Normal.....

It is not leaner in the sense of Less Fuel....

As you have already pointed out, it is HOTTER, and therefore burns off more fuel than the front....

Burns it off, less carboning up of the plug...

 

I read in one of the DIY threads that the rear plug will read richer than the front.

Am I confused???

 

There is no rhyme or reason for plugs to be different....

There are far too many variables that have to be taken into consideration....

Single or dual plenum......

Coil / Plug wire / Plug function and transmission of voltage / Plug Indexing.....

Valve / Guide / Seating.....

Carb'd bikes (Where does the Acc Pump nozzle point ? Rear of center, Why?..... It is easier for fuel air mix to travel to the rear cylinder because of the construct of the modern V-Twin...), Hence the Rear cylinder is theoretically richer...

With the additional heat generated by LACK OF CIRCULATING AIR, the fuel will disipate as it cools down the combustion chamber... Leaning it out.... But the fuel is still there, just in another form... It is vaporized to the point of a better gasseous mass, that burns off better, and leaves less residue...

 

Thanks Bob! Your answer is reassuring. BTW, I saw a pic of a shovel Wide Glide and damn, what a gorgeous bike. I've decided that some day I'll own a shovel. I've even thought that when my evo dies, I'll drop in a modern shovel... kick-start mandatory.