Well not so early but it's damn cold!!!!!!!!!!!!!!!!!!
It's 25° this morning and it takes a while for me to get moving when it's this cold!!!!!LOL

 

Wow it's actually warmer up here this morning.. 36* almost felt like a heat wave.. Lol...

 

Yup, cylinder head, thermocouple under the spark plug. Also, that's just the front cylinder since it's always hotter than the rear. My speculation for this is more oil is flung at the rear cylinder than the front. With the lack of oil squirters on the Evo engine, oiling the bottoms of the pistons relies on oil being flung up from the crankshaft.

 

Sooooooooooooooooo................................ ............................. she popped again. (FYI, this is gonna be a long, technical post)

A couple weekends ago I wanted to head out on the interstate for a few miles. Mind you I'm at 220 miles so far on the build and have already put short interstate jaunts of about 25 miles on the bike with success. This time it was 40 out and 40 back. Temps were nice, low 80's. Keeping a constant cruise of between 70 and 75, RPM's never over 3000, AFR's never went over 14:1, CHT's never above 260F (I had a tail wind for the ride north, they dropped under 240 on the way back), and EGT's around 1450F. The whole way up only one weird thing happened. The bike had a quick hesitation, like a missed spark, then back to normal. The way back seemed fine as well but when I went to pass a semi I noticed the bike sounded weird as I accelerated to go around. It sounded as if I could hear excessive blow by going out the breather tube. When I got to the first stop light that's when the knocking started. Clear as crystal, KNOCK KNOCK KNOCK at idle only like there's a little guy with a hammer in the cylinder trying to get out.



First thing I did was have a chat with the wife. Without going down that road in this thread, I'm buying a 19 EGS soon after we close on our house in April. I need something reliable. I like going with my dad on rides and I've missed so many rides last fall and this spring it's starting to really bum me out. He's getting old and I want to spend as much time with him as I can.

The next thing I did was really think about the issue and what's causing this. The only thing I can think of, since it's commonly the front cylinder with the most damage, it lack of oil being slung onto the bottom of the piston from the crankshaft. If you think about it, as the crank is spinning it collects oil at the bottom of the case, then whips oil into the cylinders as it makes the pass around. The bulk of the oil hits the rear cylinder. This would explain three things:

1. Why the large bore S&S motors come with piston oil squirters
2. Why the Twin Cam comes with piston oil squirters
3. Why the rear cylinder is always running cooler than the front.

This piston oil squirter thing has been at the back of my mind for some time now, although it doesn't explain how S&S was capable of marketing the 96" (which is tightly based on my build only smaller with aluminum cylinders). It could also shed light as to why S&S stopped at 96". Maybe they tried the 106" but kept scuffing pistons like I am. Ultimately, someone from S&S would have to answer that question.

In my research I discovered someone on the XL forum who was having the exact same issue on his S&S 100" Sportster build only he was on his 6th set of pistons/cylinders. At the end of his thread he shows a pic of piston oil jets he's had machined into his crankcase with notches in the cylinder skirts:



Also within that thread is a person who has a LOT of Big Bore Shovel head experience with the same experience both of us have, as well as the same root cause analysis as to why it's happening (lack of oil hitting piston to cool crown). If anyone wants to read that thread:

http://xlforum.net/forums/showthread.php?t=1487546

Read post #24 for an elaborate theory as to why this happens.

Anyway, I've done a lot of research into this modification and I'm going to pursue it. Piston oilers are available from S&S for about $50, and I've recently purchased a Grizzly mill that's a bit larger than that shitty Harbor Freight one I used on my heads. The only difference I'll make is mine will point into the bottom of the piston domes. The ones in the pic above may help but the oil jet will be hitting the wrist pin the way it's currently pointed. Once we move into the new house I'll dive into the motor and start making chips. I'll also be sourcing new pistons/cylinders but I think I'm going back to the original build thesis of 30 degree domed pistons with the S&S 585 cam. There's just something about the satisfaction of meeting my intended goal, I'm hell bent on attaining it.

Thanks for listening, whoever still is.

 

I love reading your post it’s very informative wishing you all the best of luck

 

You're not running it hard enough.
According to an S&S tech the rings are very hard and you need to run it harder to get them to seat.
I was told to regularly run it up to 4.5k then shift ( I missed the then shift part when talking to the tech the first time) or you would get smoke out the tail pipe.
When I say regularly they meant to do it in 3rd and 4th gear every 10 miles or so.

Needless to say I know what my bike will do at 4.5k in 5th and it ain't a legal speed!!!!!!

 

Always enjoy reading about your experiences with your machines. Always interesting.
Are you really buying an M8 tourer?
Oh, and sorry she pooped again. Can’t believe it happened.

 

Thanks man. Yes, either an M8 or Twinkie. Like I said, I need something reliable that I can just swing a leg over and ride. I suppose eventually I'll have this bike in such running order but for now it's back to the drawing board.

I must admit, as frustrating as this is I kinda like the challenge.

 

LOL! THC.
That would make a great excuse fir talking your way out of being arrested. But officer!

 

Sorry to hear... Can you post a video of the sound?