Home
Basic Dirt Bike How-To's - Video
Dirt Bike How-To's - Video
Living The Moto Life - Video
Bike Tests | Shoot-Outs - Video
Forums
What's new
Latest activity
Log-In
Join
What's new
Menu
Log-In
Join
Navigation
Install the app
Install
More options
Close Menu
Forums
MX, SX & Off-Road Discussions
Dirt Bike Mods & Maintenance
Scored cylinder
Reply to thread
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
[QUOTE="76GMC1500, post: 1202566, member: 73139"] Piston to cylinder wall clearances should be greater than .0015" measured at the tightest point. .004" is the maximum clearance most manufacturers allow. The piston needs to be smaller than the cylinder. Your measurements are weird. Generally speaking, on a worn cylinder the largest diameter will be somewhere in the middle, measured fore and aft (orientation of cylinder as installed in the bike). There will be a thin band at the very top of the cylinder which will match the original bore diameter. Near the very bottom is usually fairly close to the original bore diameter, especially when measured left to right. Generally speaking, the difference between the widest portion of the cylinder and the narrowest shouldn't be more than .002" (this measurement is referred to as taper). The cylinder shouldn't be more than .002" out of round. Because your measurements don't follow the standard convention for cylinder wear, I would be suspicious of operator error or the accuracy of the measuring instrument. However, if your measurements are correct and your cylinder is indeed smaller than most aftermarket pistons, this is good news. You can buy any aftermarket piston and have the cylinder bored to match (usually $60 or so). If this is the case, you can start fresh and you won't have to worry about the scoring or the crazy measurements. Don't forget about chamferring those ports. Here is a pic looking through the intake port of my cylinder at the exhaust ports. I wasn't trying to show the port chamferring, but it's the only pic I've got. See the band around the ports, that's where it has been ground back at an angle. All ports, intake and exhaust need to be chamferred. The important thing is that there is a smooth transition that doesn't catch the piston rings. [IMG]http://i24.photobucket.com/albums/c8/76GMC1500/DSCF1911.jpg[/IMG] [/QUOTE]
Verification
Which ocean is California closest to?
Post reply
Forums
MX, SX & Off-Road Discussions
Dirt Bike Mods & Maintenance
Scored cylinder
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top
Bottom