A piston ring compressor NEVER slides into the cylinder. They only compress the rings to the same diameter or just slightly smaller than the cylinder bore, providing a smooth transition between the ring compressor and the cylinder bore. One thing to be sure of is that, as you push the cylinder over the piston be sure that the ring compressor remains in contact with the bottom of the cylinder. If it does not, the rings have the opportunity to squeeze out between them and you have to start over. Use a fair amount of engine oil on the inside of the ring compressor to help the piston/rings slide out of the compressor and into the cylinder bore.
It's all about the proper technique. Once you learn how to properly use the tool, the process becomes much easier!
Thanks, yea, in a heated moment I posted the wrong thing.I know the compressor isn't supposed to fit into the cylinder. Its stupid hot and humid around here so I wasn't thinking clear. I am going to try again tomorrow. I think another set of hands will help out.
always adviseable. walk away from it, regain your composure, get a friend to help, and re-try. just tap lightly around top circumference of cylinder with friend helping and it should guide itself right past the rings. lube up everything well with either motor oil or assembly lube. do NOT pound on the top of the cylinder when you do this as you'll either break 1 or more rings or damage the piston ring lands. either one is expensive.I am going to try again tomorrow. I think another set of hands will help out
So I know this thread is from a while ago, but it's the most relevant to the situation I have currently.
I've got over 60k miles on my xb12r, long story short, the exhaust stud broke, and I had to pull the head off to get it machined out. No big deal really, the engine needed freshened up anyways. So I got the heads done, with valve guide seals, ect, and a service over bore.
I got the parts back with new pistons and rings from Harley themselves. I was measuring the gap on the rings, and the second ring is already out of specs stated in the Buell repair manual, although it doesn't say anything about service over bores or anything. Has anyone else run into this, or is there a company making better rings? after measuring the bore, I've found Hastings has a set that is 0.002" larger than the bore of the cylinder I have. Has anyone used their rings before?
For reference, the 2nd ring measures a gap of 0.023" and the book calls for 0.007-0.020"
I would call the company performed the work and asked them to clarify the situation and replace the rings or fix the issue. But check all the rings first. I do not know if they adjusted rings gaps or sent you new rings so you have to check and adjust the rings gap by yourself, but if they preadjusted the rings gaps it means each ring should go in the particular cylinder, not in the random cylinder. If they preadjusted the rings and some of the rings do not fit properly it also might mean they made a mistake and removed too much material from the ring tip, but it means you can buy or request from them same rings and fix it.
Last edited by TPEHAK; 01-20-2018 at 04:47 PM.
I'm not familiar with the term "service overbore"? A cylinder hone job would not need new pistons or different rings, but a cylinder bore job would.
Most ring sets need to be gapped to spec in the cylinder. I'm with TPEHAK on this one, seems like someone got happy with the ring grinder.
They called it a service overbore, essentially just increasing the bore size by 0.010" to refresh the cylinder walls and such harley makes a 0.010" oversized piston and ring set, but the ring gaps on the second compression ring that came with that set are already too large. It's weird because it's only that one ring, the rest measure out fine, actually nearly exactly in the middle of the tolerance on the gap. I did call the company, they don't gap the rings before they send them out, and both sets measured about the same in each cylinder.
I intended on gaping the rings to specs, which is why I measured them in the first place, but there's not much I can do to add material if the gaps already too large. I asked some guys at Harley, and they know essentially nothing about Buell, and aren't really keen on helping me much because I'm not paying them to do the work. at this point I'm just gonna pick up a new set of rings from a different company, and hopefully I can gap them myself.
So now the question is: Is there a preferred company for aftermarket piston rings, and how do I know I'm getting the right thing, because the second ring in this set has a bevel on one inside edge, I think it's supposed to be oriented up, but I'll have to look back in the manual. Do all compression rings come in this style?
No, they have different styles, different materials and different purposes. Some of them is better for fresh bore, some of them is better for old bore with fresh hone. Google for details.
Thanks TPEHAK, I didn't know that but I'll look into it now.
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