Honing cylinder

[bexabarr]

So I have my entire engine apart. Here is why:

http://www.thegsresources.com/_forum/showthread.php?p=722200#post722200

So I was just going to replace the head gasket and be off with it. But since I have a complete gasket set, I figure I might as well replace the lower head gasket as well, it seems perfectly fine but who knows if I've disturbed it while removing the head.

There is very little carbon build up on the pistons, and the piston shafts look like mirrors (not a single scratch). I also noticed that there is no ridge on the top of any of the cylinder shafts if that's what you call them.

I didn't do a compression test because I was told that it was worthless doing so with a blown head gasket was pointless.

The piston looks like it sits tightly, but should I replace the rings now that I'm in there? If so, I plan to hone it with a drill and ball hones. The inner diameter of the cylinders is around 2.6 inches.

Does the ball hone have to be exactly that size, or can it be a bit smaller? Where can I find these that fit my engine (gs 750)?

Thanks!

[Nessism]

How many miles on the engine? Rings wouldn't hurt but they may be a waste as well, hard to tell. Of course, taking some cylinder measurements would be a good idea - it will tip you off to any possible wear.

Regarding the hone, I'm not sure where to find one other than searching on-line.

Good luck.

[Dave8338]

That's the nice thing about the ball hones, they have a greater degree of flexibility as they rely on rotational speed to adjust their expanse. You should be able to pick one up at any good auto parts supplier. Make sure that you keep the drill moving up and down at all times as there is a higher possibility of "gouging" a cylinder wall using a ball hone. The older "bar" type is almost fool proof. Good luck and send in some pictures when you have her polished out.

You're looking for a finished wall texture, as seen in the photo below.

[bexabarr]

it has around 22,000 miles. Any easy way of figuring out if I need new rings?

[bexabarr]

awesome pic! Thanks. That helps a lot.

[Dave8338]

If you're going to the bother of pulling it down to the point of honeing it, I wouldn't waste your time with used rings...my .02 cents.

[waterman]

I am looking at something like this:

http://item.express.ebay.com/2-5-8-Engine-Cylinder-FlexHone-Flex-Hone-180-grit-69mm_W0QQitemZ250185651385QQihZ015QQcmdZExpressItem

My question is what grit is recommended? This is 180 grit, I would think this is fairly aggressive. Any comments from those that know?

[tkent02]

At 22,000 miles the rings and cylinders should be almost new, unless something bad happened along the way. Like severe overheating, over revving or running with no air filter, or running too lean. How did it run before it had headgasket troubles? If it ran fine then it will again. You can get in there and measure everything, then you will know for sure.
If the pistons still fit tightly, new rings and honing the cylinder should make it good as new in that area. Some guys will hone and reinstall old rings. That seems a false economy to me, but you would probably get away with it just fine.

[Dave8338]

At 22,000 miles the rings and cylinders should be almost new, unless something bad happened along the way. Like severe overheating, over revving or running with no air filter, or running too lean. You can measure everything and know for sure.

My thoughts also but without seeing it, I can only assume it must need it.

[Dave8338]

I am looking at something like this:

http://item.express.ebay.com/2-5-8-Engine-Cylinder-FlexHone-Flex-Hone-180-grit-69mm_W0QQitemZ250185651385QQihZ015QQcmdZExpressItem

My question is what grit is recommended? This is 180 grit, I would think this is fairly aggressive. Any comments from those that know?

Unless you spend all day in the hole (yeh...I know) 180 won't cut that hard. You need to have a good score pattern to "marry" the rings the the cylinders.

[bexabarr]

Well I was planning to change the rings also. The bike ran great, it started right up every time (unless it was really cold). The bike was leaning towards rich not lean. Again I never checked compression because the head gasket was blown. Tomorrow I'll have some pictures to post to get your opinions. Thanks again.

[Casino Joe]

New rings

If you are going to hone the cylinders you must use new rings. (ask any machine shop) Rings break-in according to the crosshatch pattern of the hone, change the crosshatch on old rings and they're toast.
I would recomend you have a shop do the hone. Rings require a spcific crosshatch based on thier composition. (steel vs.chromoly)
The pattern is determined by the speed of the plunge and return stroke while honing the cylinders. A good shop will ask what kind of rings you are using before starting work.


Sent from my iPhone

[bexabarr]

here is a pic of one of my cylinders to give you an idea of the condition:

[SPARKSS]

it has around 22,000 miles. Any easy way of figuring out if I need new rings?

The best way to know that it might need rings, would have been part of the reason you knew your head gasket was "blown" to start with.......a compression test! Symptoms that would lead a mechanic to start thinking about rings would be: 1. excessive crankcase blow by (the rings aren't sealing against compression)....2. excessive oil smoke on acceleration (compression and/or oil ring sealing.....might be piston ring land problems as well here)......3. compression lower than normal in one or more cylinders with low and/or uneven running complaint.

I'm guessing by the way you've described your components and the bore as being "around 2.6" that you've never done any engine work so I'd recommend studying some basics with respect to engine operation and machining first.....it's probably easier to find good general automotive books on the subject than bike-specific ones but start there first.....I often refer to "Automotive Engines" (Mitchell) but there's many others.......or a factory shop manual (MUCH better than the usual C or H aftermarket books).

And just to get you started......The piston rides in the cylinder, pivoting on it's piston pin, which transmits reciprocating force from the connecting rod, attached to a crankpin - which is of course, part of the crankshaft. You have compression rings (often 2 but sometimes less and more) and typically 1 oil ring set (which may consist of up to 3 or more pieces - top and bottom rings and an expander). Critical to good compression and engine longevity is piston to bore clearance (read up on ridge, taper and concentricity as well) and ring sealing (cylinder wall finish for type of rings and ring positioning during assembly!). On the top side of course your head gasket has to seal that compression to the head providing the valves close tightly (springs....retainers...locks) with good sealing (see valve and seat grinding or replacement). Oil from the top has to be kept out of the valve seat area by the valve seals. The valves will do this with good longetivity if their stems and guides are round, concentric and have correct clearance - allowing the added valve seals to work.

Hope this doesn't seem too simplistic but helps set you on the right course (unless I'm mistaken!).

Have fun by gosh :-D

[DaveDanger]

Disassembling the engine that far and not re-honing and re-ringing is the equivalent of taking a shower and not washing between your toes.
You're there. Do the job right.