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GS wrote:IC,
In the spirit of enlightenment, what does blow-by look like in your experience? Reason I ask is that Ive seen similar "brownish" coloring on seriously worn cylinder walls and I may have mistakenly credited it to just that.

After taking a fresh look, it does appear to have the "look" of light corrosion.

I should have clearly stated that blow-by would first show up and be most evident on the piston. The cylinder could have some glazing on the lower cylinder walls and which could have occured sometime ago (pre-current piston install).

Cylinder glazing, if sever enough, can prevent the rings from sealing to the cylinder wall and which doesn't allow a good seal and set the piston up blowby. However this piston doesn't show any evidence of serious blowby (unless it has been cleaned off which I'm assuming it has not.)

I've never seen a case where piston blow-by shows up first on the cylinder or prior to the piston on a 2-cycle engine. Piston just runs too hot compared to the cylinder, so the oils get cooked onto it first when the rings are not transfering the heat and allowing fuel mixture to past.

When I looked at the cylinder in the picture I thought most of the dark coloring was due to the lighting coming through the ports and shadowing within the cylinder. I certainly could be wrong!!

It really does appear to me the engine got moisture into it somehow and was not throughly dryed prior to be parked for awhile. That is my best guess

IC
Thanks for sharing your experience. Makes sense to me!

Greg

Here is one post-ScotchBrite pic. The photo is over-exposed quite a bit.

The shop is concerned with the whitish strip at the 2 O'Clock position -- as if it doesn't have plating. They also are concerned that the finish on top is so dull, while that in the bottom is still shiny. They're wondering if Kawasaki did a bad job of OEM chroming.



BTW, Jeff Fredette chimed in before I was able to send him the pic above. This is his comment from the initial pic I posted here:

It looks like to me it is from moisture above the piston. if it is not pitted then it will be ok. the photo i can not see well. just run a ball hone through it and go. if it is pitted replating would be the thing to do.

jeff

I'm still tempted to have it re-chromed, but I fear the potential cruddy chrome job (and metal damage) even if I don't go with U.S. Chrome.

I'm being quite a pain, aren't I?

Rick

I'm being quite a pain, aren't I?

Nope, just cautious as I would be if I were in your position.

I had the bore measured.

69.08 mm on average. A small portion of the upper bore was 69.10mm while a portion of the lower bore was 69.06mm.

What are the in-spec tolerances?

Rick

Re: being a pain....That's why we are here and not over "there" (If you get my meaning).

That white spot is above where the rings would travel, so I wouldn't worry about it. The area that the rings come in contact with the barrel is the only important part. Even though they plate the entire bore, the part where the rings travel is why they plate it. Areas above and below the ring travel area aren't too important for plating. Well, unless it's flaking off and then it could cause some trouble.

It's your call. I would remind you that a replated barrel will most likely require a new piston and rings as well to get the right match.

Also, I would not be riding 20 miles away from anywhere, especially the desert, without company. It wouldn't matter what shape the bike was in. Heck, I've fallen down in my own backyard and wished I had told my wife. Laid there for 20 minutes before I was sure I wasn't gonna pass out due to a good whack to the knee.

I think I would run it....

Ride that puppy!

I'm going to say the opposite of the comments so far (SORRY).

Looking at your picture I think you do have small pits all over the place and since the coating is very dull even after scotchbrite pad work (compromised coating IMO) by the time it gets mated to the new rings you may not get much life out of the new top end. Typical factory coatings are very, very thin to begin. A new coating should fix your cylinder up for extended use and you will not be worrying about that area at 2 o'clock which is getting blasted by combustion gases at each engine cycle starting to flake off.

If it were mine - I'd be sending it off for new plating and only buying a new piston and rings once.

P.S. I know about CC's experience with his cylinder and U.S. Chrome but there are a lot of places out there performing quality plating and it is my believe he was just unfortunate. I've had excellent results from U.S. Chrome and Langcourt although none of the cylinders have been KAW cylinders.

never time to do it right, but always time to do it again

In class so I'll be quick.

Piston and gasket kit was ordered last week.

We ride in packs here in the desert.

My calculus on this issue is based on the odd look of the plating in general. No warm fuzzies there.

I'm sure if I were to bolt it up as is, it would run just fine. But after a year I'd be in the same boat, and opting for the re-plate.

I'm keeping the bike for another two years, I might as well treat it nicely now.

I told MunchyButt to ship the cylinder head ASAP before I weenied out and changed my mind.

I'll give an update in three or so weeks when it's all buttoned up.

I'm looking for an extra 1.5 HP when this is all done.

Rick

I wish my cylinder looked that good when I did the topend 2 - 2 1/2 years ago

Wib, you LOVE to stir the pot, now don't you?!

Must...resist...calling...MunchyButt...to...cancel...re-plate...

skipro3 wrote:Wib, you LOVE to stir the pot, now don't you?!

Fookinay!

Specially on my B-Day!

Happy Birthday Wibs !!

So how much is a replate cost anyway?

Happy Birthday Wibbens, you 'ol pot stirrer you

Greg

Happy Birthday Wibbens dude

I think it's like $180 or so. They pay the shipping back.

Rick