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Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
Just a hint for what it's worth. You can quote it just to read and back out without saving. On a phone, you can press and select it and it will reverse color so it's visible.
Originally Posted by davidlyons37
.........snip <<<<<<<
Of course, to first poster David, guess you realize now, when you copy and past, and it does that reverse, select it, hit the A font color and the black and save it.
When I hit this, double click plays photo. Odd format.
David, you need a two ear stethoscope to determine what you are hearing and problem area on Harley's in most cases. Sound travel all over but a two ear mechanic's stethoscope will pin point it close
Think you have a little excess piston to cylinder clearance. That little scuff at the bottom is when piston reaches the bottom of stroke and crank starts up, rod angles other way.
That tapping is the other skirt hitting the other side of cylinder in a rocking motion.
Most refer to it as piston slap.
Last edited by Jackie Paper; Jun 24, 2024 at 06:26 AM.
Just a hint for what it's worth. You can quote it just to read and back out without saving. On a phone, you can press and select it and it will reverse color so it's visible.
Of course, to first poster David, guess you realize now, when you copy and past, and it does that reverse, select it, hit the A font color and the black and save it.
When I hit this, double click plays photo. Odd format.
David, you need a two ear stethoscope to determine what you are hearing and problem area on Harley's in most cases. Sound travel all over but a two ear mechanic's stethoscope will pin point it close
Think you have a little excess piston to cylinder clearance. That little scuff at the bottom is when piston reaches the bottom of stroke and crank starts up, rod angles other way.
That tapping is the other skirt hitting the other side of cylinder in a rocking motion.
Most refer to it as piston slap.
Hi Jackie Paper, thanks for your Input.
Didn't even cross my mind on the copy and paste. Definitely something I will keep in mind moving forward.
I measured the clearance a few days ago and posted the results here. The measurements fall right into S&S specs.
I rode the bike 42 miles from p the coast yesterday. I rode it hard as.S&S tech support actually say that what's printed in there instructions is old news. told me just don't bog it but use a heartbreaking method. so pretty much the speed was 100 to 120 mph. getting there quick. throttle super responsive and Power unhindered. It performed spectacularly in every area except for the noise. actually when I reached the destination noise had gotten so loud that I decided to call the tow truck and have them return it back to my house. here's a video of the way that it sounds right now:
the video doesn't give it 100% justice. but I would say that it is at least three or four times worse than it was before I left. again the power and everything else is unaffected. Doubt it will remain that way if I continue to use it and let it get worse. Is piston slap possible even when the clearances are good?
I'm about to do a complete teardown all the way down to splitting the case starting in a few minutes from now actually. Gotta do it. S&S said that it looks like they were overheated when they looked at the photos that I posted here. They've never been overheated and they actually exchanged a different set for me that the clearance was not correct and cylinders looked basically identical. it seems like that they are trying to get away from having to warranty it a second time. If by some chance they actually do not warranty it then I am considering getting the skirts coated. AreThere any other methods to fix piston slap with out changing any of the parts?
It's totally amazing how close for a air cooled motor Harley builds their motors. A 04 TCb 88 runs 0.0006 to 0.0017. Plus I am sure that Teflon coating helps.
At .0035, motors are noisy.
Normal driving does the same thing as what you described as far as speed. May take a little longer.
If things are correct , it doesn't take long to seat rings. Probably less then 100 mile.
I don't drive like that. Slow down. Keep in mind, a bike can hurt you more then just getting you killed.
Just some advice from a 76 year old. I apologize if that was too much.
It's totally amazing how close for a air cooled motor Harley builds their motors. A 04 TCb 88 runs 0.0006 to 0.0017. Plus I am sure that Teflon coating helps.
At .0035, motors are noisy.
Normal driving does the same thing as what you described as far as speed. May take a little longer.
If things are correct , it doesn't take long to seat rings. Probably less then 100 mile.
I don't drive like that. Slow down. Keep in mind, a bike can hurt you more then just getting you killed.
Just some advice from a 76 year old. I apologize if that was too much.
No problem at all. I appreciate any advice you can give!
At 52 years old, I'm definitely surprised that I still have this need for speed in me. when I was in my twenties, i definitely though I would grow out of it, but no, it's only grown stronger. I guess it's in my DNA. Definitely matured, though. No more 150 plus through Bay Area traffic close enough to kiss bumpers all the way from San Jose to San Francisco. Only empty roads with like minded individuals. I do miss the bridges, though.
Have you built many custom bikes? Done a lot of engine tear downs?
I have the top end disassembled. Here's some photos and videos with each cylinder a separate folder:
I honestly thought there would be much more mayhem and carnage based on the sound but it doesn't look that bad. The skirts are basically untouched. For this reason I'm splitting the case. Might not be slap after all. Here's some pics of a skirt and cylinder of one they replaced under warranty:
On the 110 drop on cylinders, if the piston skirt extends out of the spigot at the bottom, there could be interference with the case.
I had to clearance my cases when using the KB915C std pistons.
By the way, those std pistons are made a couple thousands oversize, so you can hone to correct minor flaws or out of round or taper on the thin drop on 110 cylinders.
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