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I bought a bunch of performance parts for my 50cc scoot, and this cylinder head came with some poo poo machining on one of the cam bearings: Now this is a lovely Chinese scoot and I don't care if this thing only lasts a few thousand miles as I'll just throw a new head on (parts are ridiculously dirt cheap for these things, this is probably a $15 head), but if it's going to blow up right away then I'll send it back. I can just catch a fingernail on it, but it's pretty mild overall. Is this cause for concern or should I just slap it together and see what happens?
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Oct 12, 2016 15:30
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| # ? Apr 25, 2024 17:32 |
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polish it out and run it. check your clearances.
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Oct 12, 2016 18:20
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It looks like the machining on the cam journal next to it isn't very nice either so I bet you need to clean them all up. Looks expensive to do it right: https://www.youtube.com/watch?v=VM49MMvn6PA Seat Safety Switch fucked around with this message at 18:25 on Oct 12, 2016 |
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Oct 12, 2016 18:23
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Got the engine torn down. Apparently these cams have integrated ball bearings. Those aren't actually bearings, they're seats for the bearings to sit on. So I doubt the machining matters at all. I think they're polished/machined so that the cams are properly located, rather than as an actual bearing surface.
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Oct 12, 2016 20:06
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Also look at this cute lil piston: And I have to give the Chinese credit, this engine has 1500 miles on it (imho that's a lot for a 50cc) and the internals look absolutely spotless.
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Oct 12, 2016 20:07
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Speaking as someone sitting in the (American based) R&D arm for a company that builds their engines in China... no, you don't have to give the Chinese credit. 
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Oct 12, 2016 20:18
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That's like the tiniest pistons I've ever seen outside of an AC compressor.
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Oct 12, 2016 21:18
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I thought that was your 'herb' grinder, what with the lighter and all. I use the piston from my 80cc honda elite as the shifter handle in my jeep 
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Oct 12, 2016 22:39
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mekilljoydammit posted:Speaking as someone sitting in the (American based) R&D arm for a company that builds their engines in China... no, you don't have to give the Chinese credit. I may have spoke too soon. There was only one circlip holding in the wrist pin lol
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Oct 12, 2016 22:49
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| # ? Apr 25, 2024 17:32 |
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Seat Safety Switch posted:That's like the tiniest pistons I've ever seen outside of an AC compressor. That's the BBK piston btw. UPDATE: The scoot runs. The kickstarter now tries to break your ankle. Maybe I should rethink the battery/starter delete... revmoo fucked around with this message at 01:05 on Oct 13, 2016 |
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Oct 12, 2016 22:50
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