Cylinder boring
#1
11-19-2009, 08:43 PM
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Cylinder boring
I need to bore the cylendars of my XL1200 +.010. I am going to do this my self because I work at a machine shop. Is there anything I need to look out for with this??? Also what size do I make the cylinder? I will have the piston and rings when I do the bore job but how much clearance? Any input is helpful thanks
Keith
Keith
#2
11-19-2009, 08:47 PM
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11-19-2009, 08:58 PM
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11-19-2009, 09:04 PM
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11-19-2009, 09:15 PM
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#6
11-20-2009, 05:00 AM
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#7
11-20-2009, 05:15 AM
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bore size
You said you will have the rings and pistons. I would measure the out side of the piston, you know it has to be at least that big, a starting point. Then, in your service manual you will find a spec for ring end gap. The ring has to be "square" in the bore for this. The ring end gap (just using these figures) will be- .025" to .035" -. Bore accordingly. Remember if you have to take .020" out, you only cut .010". (.010" on each side equals .020")(just using these figures) When you get something you like, hone it to get your crosshatch (or what ever you call it) ( you need those lines for oil lube) Your are done. Hope this helps. Ride safe.
Last edited by 1200efi; 11-20-2009 at 05:21 AM.
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#8
11-20-2009, 05:27 AM
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Due to the stress applied by the cylinder head bolts, the bore gets out of round when torqued down. That is why you need the torque plates when boring your cylinders out. If not, your bore will be round when you take it off the mill and out of round when torqued to spec on your bike. Use the torque plates.
As far as piston clearance goes, your pistons should come with setup instructions...follow them as each different alloy has different thermodynamic properties and will grow at different rates as they heat. The JE pistons I put in my 95" build recommended .002" bore clearance; but I've seen recommendations ranging from .001"-.0035". I believe it was the KB hypereutectic pistons that could be set up as tight as .001"
As far as piston clearance goes, your pistons should come with setup instructions...follow them as each different alloy has different thermodynamic properties and will grow at different rates as they heat. The JE pistons I put in my 95" build recommended .002" bore clearance; but I've seen recommendations ranging from .001"-.0035". I believe it was the KB hypereutectic pistons that could be set up as tight as .001"
#9
11-20-2009, 06:36 AM
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what are you planning on boring theses with?(what type of machine,lathe`s & mill`s are not correct for cylinder boring,bore them on a cylinder boring machine))no offense,but by your questions asked,i dont know if its a real good idea for you to do the boring,take them to a properly equip shop that has done the job a many times (buying or making torque plates will be more than just having a shop do them)but if you feel you can do it,measure the piston at the thrust surface(90 degree`s from pin).500 from bottom of skirt,piston manufacture will have specs,but it should be around .002,bore to .001 under desired size,leave .001 for final honing,gap rings at .010 (or whatever manufacture calls for)
kirby
kirby
Last edited by prodrag1320; 11-20-2009 at 06:48 AM.
