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ART
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I pulled the piston on the RM tonight to see if I could figure out
who it was manufactured by. One the kick-start side it has the letters
"ART" embossed. I didn't know what that meant, so I searched the web for it:
****
'ART' is Japan 's largest piston manufacturer and is the supplier of
the original equipment piston assemblies in nearly all Japanese
motorcycles, ATVs and watercraft. 'ART' Piston Kits from Sudco are
available up to 1.50mm oversize, 2 oversized larger than what is
normally availalble from the Japanese motorcycle manufacturers,
allowing extended service life and additional displacement performance
gains. All 'ART' Piston Kits come complete with rings, wrist pins and
pin clips. For quality, precision and reliability there are no better
pistons in the world.
****
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Excellent quality piston kits. Sold in the US as Art-Sudco.
As far as I know, they are only available in the US for atv
applications.
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Interesting.
I have some other questions for you experts:
1) Is "side-to-side" play okay on the crank rod?
2) Is "side-to-side" play okay on the piston-to-upper rod?
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No. another test for "up and down" play is to "twist" the connecting
rod. It shouldn't twist on the crank pin. This sort of play means the
crank pin/con rod kit needs to be installed (crank rebuilt).
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There are limits for both. Most factory service manuals tell you what the
limits are.
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I couldn't observe any "up-down" play at either, but there's
definitely side-to-side play in both. I think, from previous threads
here, that that's okay though, right?
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Some is normal. Too much is not.
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I removed the cylinder head studs to replace them with new ones...
should I use Loctite when I install the new ones? Red or blue?
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Blue. or use NeverSeize on them. Don't lock them in for a potential
future problem.
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Different manufacturers/models have different specs on this. For instance,
Harley says insert them dry. Check your service manual.
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And one last thing... after removing the cylinder and wiping down
the inside real well, I notice that I can see the cross-hatch pattern
(from boring/honing) only on the lower sections at the front and rear
of the cylinder. Everywhere else the cylinder walls have distinct (but
light) vertical scoring from the piston and/or piston ring. Does this
mean that my cylinder is out of round? I guess I should just take the
cylinder into a shop and see what they say. I may have to go to the
next overbore size.
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Sounds like a bore job is getting eminent. Check your ring gap. (off
the piston)
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Only a portion of the cylinder wall is actually swept (the area that is in
contact with the piston rings). The thrust face of this contact is always
greater at the front of the cylinder because the angle of the conn rod and
downward force of combustion forces more pressure on the piston in this
area. If it's real shiny then at the least another honing is in order if not
a full overbore. All pistons are out of round. They are actually egg-shaped.
The bore will eventually wear to this shape with prolonged usage. I think an
overbore is a definite consideration.
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Fred Bradford - CrashTestDummy
f.j.bradfordREMOVE@verizon.net
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You're welcome.
Wudsracer/Jim Cook
Smackover Racing
'06 Gas Gas DE300
'82 Husqvarna XC250
Team LAGNAF
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