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[djkak]

I can just about guarantee that every 110 that is leaking at rear of rear cylinder would look exactly like that on the inside. Makes you want to stay close to home doesn't it   Thanks soooo much for the pics.

I’ll go a little farther than that and say that any OEM EVO or Twin Cam engine with more that a few thousand miles will have vertical discoloration of the cylinders similar to Scott’s. The vertical discoloration results from a temperature variation of the cylinder liner at each point where the cylinder studs and oil passages pass between the liner and the cast aluminum heat sink.

Attached are a couple of photos comparing Scott’s cylinder with an EVO cylinder and a 113 cylinder with an EVO cylinder. The vertical discoloration is a lot like Hoist’s personality; you may not like it, but you can’t get away from it; it’s the nature of the beast.

djkak

[djkak]

113 vs EVO

[Fired00d]

I’ll go a little farther than that and say that any OEM EVO or Twin Cam engine with more that a few thousand miles will have vertical discoloration of the cylinders similar to Scott’s. The vertical discoloration results from a temperature variation of the cylinder liner at each point where the cylinder studs and oil passages pass between the liner and the cast aluminum heat sink.

Attached are a couple of photos comparing Scott’s cylinder with an EVO cylinder and a 113 cylinder with an EVO cylinder. The vertical discoloration is a lot like Hoist’s personality; you may not like it, but you can’t get away from it; it’s the nature of the beast.

djkak

Are the ones you are displaying rear jugs also, and is this seen more in the rear then front in the instances you've seen?

 
Ride Safe,
Fired00d
 

[SBB]

The vertical discoloration is a lot like Hoist’s personality; you may not like it, but you can’t get away from it; it’s the nature of the beast.

djkak

Now djkak!

That is the most profound statement I have heard today!
You nailed it!
Good job!

 

S
  /
    B

[djkak]

Are the ones you are displaying rear jugs also, and is this seen more in the rear then front in the instances you've seen?

 
Ride Safe,
Fired00d
 

The 113 cylinder is a front; I don't know which cylinder the EVO example is from. This kind of vertical discoloration has been around since the first EVO's rolled off the line in mid 1983. It’s a safe bet that the rear cylinder runs hotter than the front, therefore discoloring earlier and possibly to a greater degree, but the bottom line is that relative to the cylinder’s design and function, it’s a non-issue.

Cylinders showing damage from overheating typically have pistons with severe skirt damage and sometimes the crown area is damaged as well.

djkak

[sadunbar]

The 113 cylinder is a front; I don't know which cylinder the EVO example is from. This kind of vertical discoloration has been around since the first EVO's rolled off the line in mid 1983. It’s a safe bet that the rear cylinder runs hotter than the front, therefore discoloring earlier and possibly to a greater degree, but the bottom line is that relative to the cylinder’s design and function, it’s a non-issue.

Cylinders showing damage from overheating typically have pistons with severe skirt damage and sometimes the crown area is damaged as well.

djkak

Djak,

That is interesting to learn...  Like I said, I am no V Twin expert...however...  When I saw the very distinct vertical discoloration on rear cylinder and virtually no vertical discoloration on the front cylinder, it caused me to believe it was due to abnormal hign temperature in the rear cylinder.  I still have to believe that to some extent, the significant discoloration rear vs. very minimal front is due to higher rear cylinder temperature.  But, thanks for the great input.  Every piece of information will be valuable to me...  I'd love to take advantage of your experience and knowledge as I work thru the rebuild.

Scott

[sadunbar]

So, today she starts going back togther.  I have almost everything, just a couple of loose ends...here are some rebuild pictures from today...

[sadunbar]

So, today she starts going back togther.  I have almost everything, just a couple of loose ends...here are some rebuild pictures from today...

[sadunbar]

So, today she starts going back togther.  I have almost everything, just a couple of loose ends...here are some rebuild pictures from today...

[sadunbar]

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62 mm HPI throttle body mounting....