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Discussion Starter · #2 ·


So it turns out that 3 circlips had either broken or become loose, allowing the pins to slide up and down against the cylinder walls. The grooves are pretty deep. I think i'll be looking into a Wiseco 3mm overbore kit. My pistons wouldn't mind being replaced as well, and a new head gasket is a must, so that kit wouldn't be to expensive if I can get it under $550

I'm glad I took my motor apart. I was considering just cleaning the outside, painting it and throwing it back in. But I've been going through everything with such detail that deep down inside, I would have always known I could have done a better job on this bike.

Opinions on what to do with my cylinders would be greatly appreciated!
 

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I love the attention to detail. Keep in mind that your 3mm overbore is just 1.5mm radially. It would be a bummer to get all that machine work done and still have grooves in the cylinder wall. That holds doubly true when this can be found for much less. 1mm over bore with pistons.

http://bit.ly/1wgamZU


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Discussion Starter · #4 ·
You're right about the 1.5mm. I was thinking that maybe they could machine it off-center, shaving 2mm off one side and 1mm off the other. The pistons do slide side to side on the pins.

I saw that link you posted last night. Would the 90 fit into my 89 (long vs short stroke)

I'll have to speak with the machine shop when they're open. They were closed today.
 

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I don't know enough about the 750s to say with certainty what years will work with others. Picking that cylinder block was more an example of my point than showing you what parts to buy.

I don't think machining the barrels on different centers than what they're at is necessarily a good idea. Sure there are tolerances in play anyway, but to reduce stress on the wrist pin you want to keep the rod as close to the center of the piston as possible.


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I agree that machining the cylinder offcenter is a bad idea. It's also difficult to do, and is likely more expensive. Instead, consider getting the cylinders relined, or replacing the block.
 

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Discussion Starter · #7 ·
So I was on the gsxr zone site looking at the kits, and noticed that they list it for the 88-89 GSXR750 and the 88-97 GSX750F Katana.

More research turned this up

GSX750F Specifications 1988—1997

Engine Type: 4-Stroke, 4-Cylinder, Air Cooled with SACS, DOHC, TSCC
Piston Displacement: 748 cc (45.6 cu.in)
Bore/Stroke: 73.0 mm x 44.72 mm
Compression Ratio: 10.7:1

That's the same as my bike! And there are a LOT more jugs on ebay under "katana" than "GSXR"


Now the question is, should I buy one and still go with the bore kit? hmmmmmmmmmmm
 

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The answer to a big bore is ALWAYS yes. I did a 660 on my FZR600 and it was night and day after I threw it together. It was quick and dirty too. Nothing like what you're doing here.


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Discussion Starter · #9 ·
















Some paint striper to loosen the carbon and a light touch on the wire wheel :)

Going to do some valve lapping later today. That way my head will be ready for reinstallation.

I also just bought a some 92 Katana Jugs for to replace mine. Should be a direct fit. Both are 748cc and have the same bore and sleeve length.
 

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good jon, great attention to details
 

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Discussion Starter · #12 ·
Thanks for the compliments! Nice headlight mightlife! I'm looking at getting a big 7" light on the front, but I can't find any decent fork clamps. Everything I've seen looks cheapish.

Tore down the engine a bit, and I found those circlips that fell out of the pistons!











On a side note, my oil pan was missing an oil plunger (16442-34301) that goes behind a spring and one of those bolts on the side of the oil pan. I'm going to order the oil pan gasket, the oil pump gasket and that part.

Now my OCD self is telling me to split the case and give everything a once over, but I really think i'll just throw in the jugs I bought and use the same pistons. I'll do an overbore next year, or in the winter. This is my first bike, so I kinda want to get out and ride before winter comes!
 

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Discussion Starter · #13 ·
So I forgot to mention that there was this copper "dust" in the bottom of the pan and around the heads. It had a consistency of copper anti-seize. My clutch basket has some wobble in it as well. Not sure if that's normal. Do you think it's got something to do with bearings?
 

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Thanks for the compliments! Nice headlight mightlife! I'm looking at getting a big 7" light on the front, but I can't find any decent fork clamps. Everything I've seen looks cheapish.
Thanks man, I'd prefer a 7" light as well, but need to take a break from spending ;).
Well done for delving into the engine, I wouldn't know my way around.
More photos please!
 

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Much props to you for digging into that engine and doing work. I decided to take ampeak in the build threads for motivation to work on my slingshot or my SV and I think I found a good chunk of I aspiration here. You're making me want to tear mine down to the bare frame to thoroughly clean and polish it. Kudos my Brother, keep up the great work.
 
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