Author Topic: cylinder porosity  (Read 1628 times)

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Offline Foxx4Beaver

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cylinder porosity
« on: March 08, 2012, 01:21:10 PM »
My buddy that I ride with regularly purchased a 97 KX5 about a month ago.It's in pretty decent shape and came with a few extras....one being an extra cylinder that was freshly replated to STD bore.We don't know who did the plating,but there were ALOT of pits in it,some fairly large.There is also a number stamped on it,not something the factory would've stamped(so we think). So he sent it out to PowerSeal for it to get re-replated.They called him and told him they would need to go to 86.5mm to clean it up..."ok no problem,do whatever you have to,to make it right" my buddy says.
He gets the jug back with a new Wossner...piston/cylinder clearance is 3.5thou.Gets it running the other day,only to find the head nuts leaking.Pull it apart after 10 mins running time,and 1st thing he noticed was two scrapes on either side of the exhaust ports...possibly from being too tight,or getting too hot from the bad head gasket.After lapping the the cylinder today,he found ALOT of pits/porosity on the surface....ALOT,not big pits,but a severe amount of tiny ones...like the size of a pen tip.
So we started wondering if that number stamped on the jug is some sort of REJECT/DEFECT #.

If the porosity is really severe enough in the casting....could it cause some crazy expanding of the cylinder itself,as it heats up?...we believe it could.Has anyone ever seen or heard of defective cylinders due to porosity/casting defects? 

Would love to hear some thoughts on this.
Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline Polar-Bus

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Re: cylinder porosity
« Reply #1 on: March 09, 2012, 07:17:32 AM »
I've had a few cyl's  replated by US Chrome with excellent results, and never heard of post process "porosity" . Why would any reputable replating service complete a resurface on a questionable surface ? Post up pics of the surface.
01' KX500
'84 GPz1100
'87 GSX-R  750
'06 HD Fatboy
'73 Kawi H1
'03 CRG KX500 Shifter kart

Motorrad

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Re: cylinder porosity
« Reply #2 on: March 09, 2012, 07:24:07 AM »
I believe we had a thread on platers around here somewhere..


My CYL that USchrome did... turned out awesome..   even after 300+ miles... and overheating.. it still looked awesome...


Oh.. and I have never heard of ANY Motorcycle company letting any "rejects' loose..   
« Last Edit: March 09, 2012, 07:29:20 AM by Motorrad »

Offline Foxx4Beaver

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Re: cylinder porosity
« Reply #3 on: March 09, 2012, 07:36:26 AM »
I think you guys misunderstood,so I'll be more clear....it's not the plating in question,but the casting of the cylinder as a whole.If there's a casting flaw in the walls of the cylinder(meaning air pockets/cavities)...then would it cause the cylinder to expand awkwardly.
Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ