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Post by spaz12 on Dec 9, 2015 18:41:53 GMT -5
Yeah, just got told that I get to sit on my butt for another month  190mech, what about the windows in the piston for the boost ports? That's what they there for, correct? Anyway, don't they need to be pretty specific? |
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Post by oldgeek on Dec 9, 2015 18:57:40 GMT -5
Is that piston a 10 or 12 pin?
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Post by 190mech on Dec 9, 2015 19:19:09 GMT -5
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Post by spaz12 on Dec 9, 2015 19:24:11 GMT -5
Is that piston a 10 or 12 pin? It can be either. |
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Post by spaz12 on Dec 9, 2015 19:28:56 GMT -5
I thought I had one of the old pistons, but apparently I've thrown them all away. Anyway, I'm giving the cylinder away (I couldn't justify selling it not knowing for sure that it works) and I'll let them decide what they want to buy. I'll email Autotch355 though to see what he has. Thank you for the link John. P.s. it is a 47mm bore: www.drowsports.com/malossi-yamaha-zuma-70cc-piston-12mm-mhr-replica/ |
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Post by 190mech on Dec 9, 2015 19:49:19 GMT -5
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Post by spaz12 on Dec 9, 2015 19:59:53 GMT -5
Very cool. I shall look at them straight away. Thank you again.
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Post by spaz12 on Dec 9, 2015 21:06:12 GMT -5
I can't hold my phone and the cylinder and get it to focus by myself. I'll try to get better pics when my son gets home. There are slight ridges that I can feel with my finger when I rub it sideways around the bore. I think that all the aluminum is gone so these must be minute scratches? What is acceptable? I wouldn't think any?   From this angle it looks terrible, but it's mostly discoloration I believe, though there are definitely small scratches.   Well, what ya'll think? |
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Post by FrankenMech on Dec 10, 2015 0:44:03 GMT -5
frank,,, there is just something wrong with cleaning your coffee pot with toilet::: cleaner, sorry  The guys at work thought so too. A couple of them spit up their coffee. They all wanted to know how the coffee pot got so clean looking and nice, -so I told them. I washed the pot and it was still dirty so I found the toilet bowl cleanser and used it. It was cleaned by washing and rinsed like normal after the chemical cleaning. They told me to never touch their coffee pot again but they kept drinking. I didn't drink coffee myself at that time. I have never been adverse to using chemistry. I stopped coming in to work early too. |
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Post by 190mech on Dec 10, 2015 5:04:29 GMT -5
You might try a hand hone job with some fine wet or dry paper to get that residue off,as long as the plating is intact and the bore is round,it should seal and run fine..
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Post by Corrosion on Dec 10, 2015 9:46:26 GMT -5
Extra-Fine Gray scotch bright on a old 3 shoe hone will polish off aluminum, and leave the hard Nikasil.
Use plenty of flushing fluid,kerosene,solvent, Mineral spirits, with a bit of ATF works great, to keep it well flushed. I use a battery powered drill. Cylinder submerged in solvent & a bit of ATF.
Hone slowly, cylinder submerged the in a large plastic coffee container and hone them with a wrap of scotchbrite, over the shoes. it slowly removes the softer aluminum.
If if it is rubbed through in anywhere, you have a problem. Around the exhaust port area is usually where it rubbed thin.
When finished wash the cylinder in boiling soapy water, then flush with hot water to remove any grit from remaining trapped in the transfers. (this last step is where people often shortcut. and the job will suffer)
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Post by Lucass2T on Dec 10, 2015 9:56:57 GMT -5
I wouldn't sand a nicasyl liner. It's soo thin that if you want to remove any material...you'll go though immediatly. Won't happen too quickly since its rock hard....I think you only want to remove the material that came off the piston and do a hone job afterwards to remove all the material thats protruding the 47,6mm mark (do you understand what im trying to point out?). Material sticking out inwards that can cause a seize due to rubbing and maybe the tolerances getting too small.
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Post by frank50e on Dec 10, 2015 13:08:24 GMT -5
I am with 190 on the finish.Hand hone with 300 grit has worked for me in the past.IMO a power tool with fixed stones has a much higher likelyhood of removing the coating IMO.From the pics if that were a standard cast bore that looked like that I'd recommend a bore.But nikisal is a coating and blemishes much easier than cast.A comment 190 made as an aside which is typical of a pro is to check bore for roundness.If you don't have an internal caliper this can be done with a ring in a pinch.Place ring in bore just below where you might have a land and measure end gap in several places down the bore using the piston to make sure it's straight.Don't be concerned with a slight taper.Hope that makes sense.
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Post by spaz12 on Dec 10, 2015 18:52:57 GMT -5
I don't have a hone that will fit this so I'll try wet sanding it out with some fine grit. I've heard that your not supposed to hone them, but at this point I would have tried the scotch brite on the shoes had I had one that fit, just to see what would happen. I'd written this cylinder off a long time ago but when I saw a thread talking about fixing them, I figured that I'd give it a try. So, if it doesn't work I won't cry  I do appreciate the help and suggestions guys |
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Post by frank50e on Dec 10, 2015 19:48:10 GMT -5
Good man Spaz stick with it well fix it and you sir can be the pioneer.
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