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Post by 'O'Verse on Jul 31, 2016 19:22:13 GMT -5
I meant to ask, what does TDC look like? Is it above or below deck? Edge of piston is Below. But, the crown on the piston is above. Measured the solder and it's 2mm. Like spaz said could the piston be to tall? |
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Post by 'O'Verse on Jul 31, 2016 19:25:58 GMT -5
That's the thread I was gonna go in and look for earlier. I remember you making your own gaskets. And with the metal base gasket that was bent I could just outline and cut a new one. The guy said the cylinder was for his Yamaha. Don't know..... |
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Post by tsimi on Jul 31, 2016 19:32:28 GMT -5
I currently have a 47mm piston somewhere and could measure it once so that we can compare. Here we have 9:30 am and I'm at work but as soon I get home I could do it.
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Post by 'O'Verse on Jul 31, 2016 19:45:26 GMT -5
I currently have a 47mm piston somewhere and could measure it once so that we can compare. Here we have 9:30 am and I'm at work but as soon I get home I could do it. Thanks Tsimi. It's probably the only choice left. To find a shorter piston. |
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Post by 'O'Verse on Jul 31, 2016 19:54:23 GMT -5
Got the intake, reed, and carb on. Bearings and tube for the engine mount was a P.I.T.A since my tube was so scratched. Just need that rear axle seal to finish up the motor.
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Post by ryan_ott on Jul 31, 2016 20:17:59 GMT -5
If you get your timings in check you can get the deck machined to adjust squish. Raise the cylinder with spacer or gaskets to get the piston to clear at bdc. I think my kit (elite) was around 185/128 ?? I'll pull my covers and measure my cylinder height to see if you have a kymco/ Honda corsa or the minarelli if you want. Not until tomorrow though.
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Post by tsimi on Aug 1, 2016 8:16:10 GMT -5
I just measured the piston and got a height of 47.5mm. Width is logically 47mm.
It is a 10mm piston that I was running in my MHR Rep cylinder before going to a 12mm piston.
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Post by ryan_ott on Aug 1, 2016 8:41:18 GMT -5
I just measured the piston and got a height of 50mm. Width is logically 47mm (46.8mm). It is a 10mm piston that I was running in my MHR Rep cylinder before going to a 12mm piston. What is pin center to piston top measurement? I think that is the important one here. |
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Post by tsimi on Aug 1, 2016 10:10:38 GMT -5
Don't take the following measurements as 100% accurate but this is what I get.
From pin center to the top of the piston side wall 24.5mm. From the pin center to the top of the crown 27mm.
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Post by ryan_ott on Aug 1, 2016 10:19:55 GMT -5
That should be helpful, I'll check my cylinder when I get home.
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Post by ryan_ott on Aug 1, 2016 18:02:56 GMT -5
Here are some measurements for comparison, this is elite/kymco corsa Piston height 46.9mm Piston pin center to top 24.8mm Cylinder height, gasket to gasket 59.3mm Deck to exhaust port bottom 42.2mm One thing to mention if the plug angles to the rear wheel it's not h minarelli        |
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Post by tsimi on Aug 1, 2016 19:04:57 GMT -5
Is it possible that something got mixed up? Kymco cylinder with Yamaha piston?
Is your measurement of 24.5mm to the top of the crown or piston side wall? If it is top of the crown that would be 1.5mm difference.
I think he would be able to use more thik gaskets and remove a tiny bit of the cylinder top to get better squish. It would be difficult to grind down the head because of that O-ring gasket.
I am not very familiar with that whole squish stuff so not sure how important that is. I never checked squish for my Polini sport and it runs strong. I did check squish for my MHR Rep and Malossi recommends a 0.8-0.9mm but best I could get was 1.10mm and the cyliner runs like a beast.
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Post by ryan_ott on Aug 1, 2016 19:10:35 GMT -5
All of the measurements are to piston edge.
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Post by tsimi on Aug 1, 2016 19:11:42 GMT -5
I see, then not big of a difference there then.
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Post by 'O'Verse on Aug 1, 2016 22:03:54 GMT -5
Thanks fellas. If I were to quote you all one at a time we might get lost. I appreciate all the advice and recommendations.. Let's see here. I haven't degreed anything yet. Haven't even made a wheel. I'm out of town till friday so I can't get the measurements till then. Ryan the plug is straight foward like a minarelli. No angle. Definetly have to consider milling the head. Sorry for the long response time. But like I said I won't be able to touch anything till this weekend. Sorry...
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