Registered User
New to the board
Rebuilding my atc90 engine. Put new valve guides in, reamed to 5.50mm and new valves are on the way. Went to check piston and cylinder and measured 52.2mm.. I saw online they were suppose to be 50mm bore. The cylinder is stamped 89cc. Maybe a aftermarket piston?
Will post photos below.
Roostin' Away
Arm chair racerRoostin Away
Yep, someone bored it 2mm over and uses a factory Honda piston it looks like. Not uncommon at all for these motors
90 nickolson Bored and Stroked "The Good"
Big Bore 110 Pauter frame "The Bad"
90 Bored and Stroked “vey’s frame” "The Ugly"
110 JSC frame Bored and Stroked
flat track build. “Shop trike”
1974 original 90 X 2
1974 Original 70.
Power User
Got the holeshot
so that's a stock 110 piston? jim
81 185s
82 185s with 85 200s motor
suspended 185s
85 atc70
1984 200s
85 350x 3rd owner
and a 72 ct70
projects coming along
85 200s
81 suspended 185s (can't believe I came across 2)
1982? 185s
Registered User
New to the board
From the research ive done, it looks to be a piston out of a CB175/CL175 etc. They are the only pistons i see with a tall dome and 52mm. This piston has been modified for spark plug clearance as well by the looks of it.Originally Posted by Jim mac
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