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Discussion Starter · #1 ·
I plan on swapping to SE heads next month. The opinion here seems to be that if the tops are off I should replace the cyl base gaskets to prevent any leak. Is this a simple pull off and replace or do I need to replace rings during that operation. Motor has only 15K miles on it. Will old rings seat properly on reassembly? What's the best technique here? Thanks to all.
 

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I would say definitely replace the cylinder base gaskets. Pulling the cylinders off after the heads are removed is very simple. Rings? I recently did this to my bike (16K miles) and I decided to replace the rings. Some will say that it's not necessary. Me, I had the cylinders honed at the same time, discovering a slight ovality forming on one of them from wear. Had them honed true, and replaced the rings. I would have replaced the rings anyway, since I was there. Just seems like a cheap, obvious thing to do.

My philosophy is to weigh the cost of labor, or effort to replace a part against the cost of the part and decide if replacement is justified. I'd hate to have to tear the motor down again if the old rings refused to re-seat, even if I hadn't honed the cylinders.
 

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Ideally, lift the cylinders until the piston pins are accessible but do not lift the cylinders past the rings. Then remove the piston pin and leave the piston in the cylinder. Now remove the cylinder with the piston still in it and this won't disturb the rings.

This will require someone to help. And be slow and deliberate in your actions to avoid mistakes.

Of course, the reverse applies when assembling it again. The object here is to never actually remove the pistons from the cylinders.
 

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springer- said:
Ideally, lift the cylinders until the piston pins are accessible but do not lift the cylinders past the rings. Then remove the piston pin and leave the piston in the cylinder. Now remove the cylinder with the piston still in it and this won't disturb the rings.

From all the posts of yours I've read in the past, I'm sure you're the pro here, but I'm just asking: Why not just go ahead and replace the rings and clean up the cylinders while you've got it all taken apart anyway. This just seems rather fiddly to save some old parts that don't cost that much to replace. Like I said, I'm just asking.
 

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FXR2 said:
From all the posts of yours I've read in the past, I'm sure you're the pro here, but I'm just asking: Why not just go ahead and replace the rings and clean up the cylinders while you've got it all taken apart anyway. This just seems rather fiddly to save some old parts that don't cost that much to replace. Like I said, I'm just asking.
It is not a right or wrong type question. There are many ways to do this. You can even pull the cylinders, change the gaskets and slap it back together and it would probably be OK.

The method you mentioned is perfectly acceptable also.

There are only 15K on the rings and cylinders and are just broken in. They should go for a 100,000+ more miles without a problem. If you pull the cylinders and Rigid Hone them and find a slightly out of round situation, you may have to bore to the next piston size to clean them up properly for new rings. That would also include a new set of pistons.

If the rings and pistons are left undisturbed, they should continue to wear as if never taken apart. Sort of like putting blinders on. Cost wasn't a consideration on my suggestion.

BTW, we were both typing at the same time (note post times), I was not contridicting what you had said, in fact I didn't even read it until I had posted.
 

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If I were doing the same job, I would take it a bit farther and deck the cylinders since it is apart for performance upgrades. Here is a thread that talks about it in detail.
http://www.v-twinforum.com/forums/showthread.php?t=70065

Along with that, I would bore and hone the cylinders and replace the pistons at .005" to have everything new. But that doesn't address the original question.
 

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springer- said:
If you pull the cylinders and Rigid Hone them and find a slightly out of round situation, you may have to bore to the next piston size to clean them up properly for new rings. That would also include a new set of pistons.
We talked about this very possibility when working on my bike. Turns out that only one of my cylinders indicated any out-of-roundness, and it was only a small area at the very base, so we didn't get into any overbore/new pistons situation. Thank goodness, from a budget perspective.
 

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Discussion Starter · #8 ·
Thanks for the tip Springer.
Assuming I go all the way and pull the jugs can you eye ball if it needs a bore job? Can't think I would after only 15K mi. Assuming all looks good with no obvious strange wear marks can I just use a ball hone to break the glaze by hand and re-ring? If not who can I send em to to get it done without costing me a arm and leg? I don't want to cut corners here on stuff that has a history with others as being a source of pain. At the same time I don't want to go over board to satisify every "just in case" either. What say you?

Thanks again.
 

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rclines said:
Thanks for the tip Springer.
Assuming I go all the way and pull the jugs can you eye ball if it needs a bore job? Can't think I would after only 15K mi. Assuming all looks good with no obvious strange wear marks can I just use a ball hone to break the glaze by hand and re-ring? If not who can I send em to to get it done without costing me a arm and leg? I don't want to cut corners here on stuff that has a history with others as being a source of pain. At the same time I don't want to go over board to satisify every "just in case" either. What say you?

Thanks again.
It depends on how much you want to know. Yes you can ball hone it to break the glaze. No you can't typically eye ball it and see the wear. It would require a rigid hone to see the low spots. Then you need to measure and determine if it needs to be bored. With only 15K I don't suspect much wear.

As I mentioned, I would deck the cylinders, rigid hone and see where I am at, then either rering or bore depending on the results from the rigid hone.

All the options mentioned are acceptable. IMO
 

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this may be a little off topic, but i had my top end apart 92 flstf early last year. 50 thousand miles, no visual wear on pistons or rings but 4 verticle rub marks on each bore almost mirroring the stud location, quite shiney with the hone marks still visible between the high spots. bike has no evidence of overheating and uses no oil between changes. have you seen this before springer, and if so , what is it
btw, bought the bike new, so not done and half repaired by any one else
 

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bonnie john said:
this may be a little off topic, but i had my top end apart 92 flstf early last year. 50 thousand miles, no visual wear on pistons or rings but 4 verticle rub marks on each bore almost mirroring the stud location, quite shiney with the hone marks still visible between the high spots. bike has no evidence of overheating and uses no oil between changes. have you seen this before springer, and if so , what is it
btw, bought the bike new, so not done and half repaired by any one else

If I can jump in,... I have seen the marks on almost every one of the hundreds of Evo cylinders I have seen. Not to mention Twin Cam. I consider it normal as they all are the same. I rigid hone and they will still appear miles later.

Bean
 

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bonnie john said:
this may be a little off topic, but i had my top end apart 92 flstf early last year. 50 thousand miles, no visual wear on pistons or rings but 4 verticle rub marks on each bore almost mirroring the stud location, quite shiney with the hone marks still visible between the high spots. bike has no evidence of overheating and uses no oil between changes. have you seen this before springer, and if so , what is it
btw, bought the bike new, so not done and half repaired by any one else
Yes, Many times at Big Boyz Cycles with Bean .... See above :D
 

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springer- said:
Ideally, lift the cylinders until the piston pins are accessible but do not lift the cylinders past the rings. Then remove the piston pin and leave the piston in the cylinder. Now remove the cylinder with the piston still in it and this won't disturb the rings.

This will require someone to help. And be slow and deliberate in your actions to avoid mistakes.

Of course, the reverse applies when assembling it again. The object here is to never actually remove the pistons from the cylinders.
That's a great idea, springer! I never thought of that... gonna have to try it out! :)
 
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