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AnsweredBriggs 625 series

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mower1
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2018/10/21 22:48:43 (permalink)
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Briggs 625 series

I'm rebuilding my 625 series Briggs 190 CC.
 The cylinder had some scoring, and like a dummy i first honed it. (Cant hang a fingernail on  any of the score lines)
 BUT (Im kicking myself upways downways sideways and any other way)  It's an ALUMINUM cylinder.
I only honed for about 10 seconds and stopped to check. and the gouges are still there.
 question is: can i bore it  .020 over after honing it?  I know some have a coating that if you break it, it's junk.
 I know there are a lot of different opinions on honing aluminum.
thanks for helping this dummy out.
 
AVB
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Re: Briggs 625 series 2018/10/22 01:54:09 (permalink) ☼ Best Answerby mower1 2018/10/24 17:58:37
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You hone not bore an aluminum cylinder when over sizing.
 
You would need a ridge hone with 280 grit stones and honing oil. This is so you remove both the taper and ovaling of the cylinder as you work you way to .020 over. A flex or ball hone will only make things worse. You also will need a low speed drill as if you go too faster you will gall the cylinder. On that size cylinder you will need no faster than 200 rpms.
 
A piece of advice if this is something you rarely do and due to cost of the tools it better just to replace the engine. This is because you are looking about $175 for the tools plus shipping.
mower1
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Re: Briggs 625 series 2018/10/22 09:43:12 (permalink)
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Thanks for your reply!!
I called the machine shop after reading your post. Said they would do it for $25.
Thanks again!
mower1
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Re: Briggs 625 series 2018/10/22 09:43:45 (permalink)
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At least I know what to do with an aluminum cylinder now.
 
AVB
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Re: Briggs 625 series 2018/10/22 10:51:30 (permalink) ☄ Helpfulby mower1 2018/10/24 17:58:33
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Just be careful of the machine shop as all don't know how to hone a small engine cylinder to spec. The first and last time I had one done outside my shop the machine bored the cylinder and ruined the engine. They went to .020 over and didn't even finish hone to the spec so when I finish hone it to remove the boring marks it was .030 over with no piston or rings available.
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Re: Briggs 625 series 2018/10/24 17:59:03 (permalink)
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Im pretty confindent  with Ted's doing it. They've been in business 50+ years.
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