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fighter transplant in NC
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14,319 Posts
Discussion Starter · #1 ·
ok, so this will be my first engine rebuild. I'm pretty sure that I need to replace the piston rings. but how do I know if I need to replace the pistons as well. and such? I assume that I will need to hone my cylinders if I need to replace the rings.

cylinder 1 is running cool (about 30 degrees). I thought it was just a sticking valve but when I took the headers off there is a pretty nasty oily buildup in the header pipe of cylinder 1. but its not blowing blues smoke


and if I need to replace the pistons, where do I get them? where do I get rings?

thanks for your help
 

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The Soft Serve Enigma
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16,719 Posts
It's all about the measurements. In your manual, it should have specs and service limits for the bore (taper and out of round), the piston (usually measured about 10mm up on the skirt) and the piston/cylinder clearance. Measure with a dial bore gauge and micrometer. If any of those are out of spec or even very close to being so, a rebore/big bore kit may be an option. If they are good, a good ball hone to put the crosshatch back in your cylinder and a new set of rings and you should be good to go. One IMPORTANT thing to remember, is if you remove the piston, REPLACE the circlip (or circlips if you take them both out) and install them in the correct position. I'd check with Wiseco for a piston kit and even possibly Yamaha.
 

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Fresh outta Fighter camp!
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357 Posts
If you replace rings, might as well go ahead and replace pistons. Good for a piece of mind if not anything else.

One tip when using a ball hone, make no more than 8-10 passes up and down the cylinders. Anymore could actually hurt more than it will do good.

I have rebuilt many outboard engines, 2 stroke and four stroke alike. And like Endo said- make sure you have a manual. I wouldnt even attempt a rebuild without a complete manual.
 

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fighter transplant in NC
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14,319 Posts
Discussion Starter · #5 ·
well, the engine has 26,000 miles on it, so I won't be supprised if the whole damn thing is worn out.
 

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All star !!!
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6,714 Posts
A properly maintained engine can easily see 100K miles...a guy on the SV board had over 125K on his.

And like Sev said, its the rings that get worn out, and can be replaced. If the pistons are still in spec, I would leave them in as well. The things that need to be replaced, in a full engine build, besides the piston rings, both the compression and oil rings, are all the bearings, and timing components, chain and guides....there may some other things that I am forgetting. If it were me, I also go one step further, since you are in there anyway, and replace all the rubber seals..not just the normal gaskets.

I am also really particular when I do a motor rebuild....I make sure I number everything that came out of a particular cylinder, and make sure the same components go back in the exact cylinder...like piston, connecting rod and cap, wrist pin, etc.

Good luck.
 

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The Soft Serve Enigma
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16,719 Posts
26K miles? That's it? lol. Sev has close to that on his '04 Hornet. My last bike was sold with almost 60,000kms on it and the engine had never been apart for anything more than valve adjustments.
 
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