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Started a top end rebuild

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Don't you just love a 2-stroke that looks like on the inside it was actually cared for and jetted properly :)

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My new piston should be in by the weekend, I also noticed someone went in and tried to clean up the ports.. I may have to go in and clean up there clean up. I also have a quick question, Should I run a hone through the cylinder to get the cross hatching back?

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You can't hone it but you can use a Wiseco cylinder brush, mihylo33 knows all about it. I have never used one.

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I decided to go with a green scotchbrite and WD40 to clean off the glazing, The cylinder was in much better condition than I had thought. Also who makes this crank or is it stock? (I'm guessing not the later)

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Since I'm new to two strokes is it normal to have a little bit of discoloration on the bottom side of the piston?

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Looks like a hotrods crank/rod but not sure. As long as the big end of the rod is not turning black and blue with a hint of gray then it should be fine. Grab the rod at TDC and see if you can lift it at all. Side to side is okay but radial or up and down movement is a no no. But it looks fine. Scotchbrite and WD will take care of the glaze on the cylinder wall.:thumbsup:

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There is a bit of side to side movement but no up and down and no discoloration so I think were good. The carb has a 430 main in it right now and I think I might replace that with a 440 because the 430 seems a touch lean.

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Thanks, there was no reason just that the bike was used... And none of that dirt will get down there... the rag was taken out for a quick picture.

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There is a spec for lateral movement in the connecting rod. To much movement up & down or back & forth isn't good.

I was looking in my manuel for a service spec. I was unable to find one. Nevermind on the lateral movement. I'm a moron! :thumbsup:

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haha, thats ok. Like I said there is no up and down only some side to side so I think we're in the clear. Just waiting on my piston to come in.

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So, my piston should be in by tommorow hopefully...... And on the other side of the crank it has 36e written on it.

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So, the parts place took forever to get my piston in but everything is back together and the bike sounds so crisp. I just ran it through a heat cycle and tomorrow or Wednesday I'm going to go for a quick little ride.

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so you just replaced the piston and ring without boring over the cyl head?

how did the cyl head looked like before installing the piston?

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Boring over the cylinder head? I don't understand. Theres a picture of the cylinder head before I cleaned off the carbon. The cylinder looked fine aswell I just scuffed it up and installed the new piston.

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oh so you just used the same size/diameter type of piston/ring and did some light cleaning on the cyl wall (ops i meant cyl wall on my previous post)

what type of piston is the newer one? how much did it cost for everything? and also did it increase your compression ratio?

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Yup, thats basically what I did in a nutshell. The new piston is an oem piston, I'm not sure of the cost because it was my birthday present but I presume about 150$ for the piston and 40 ish for all the gaskets. But thats Canadian prices. Since its stock the compression is the same.

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Sorry to hi-jack, but since were on the Top end rebuild thing, I just rebuilt my 06' RM125. Compression before breakdown was 138 psi and compression after rebuild is 155psi. Do those numbers seem right?

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