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
Dirt Bike Discussions By Brand
Yamaha MX & Off-Road Dirt Bikes
Too much Compression on a YZ250
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="adam728, post: 1165282, member: 55463"] Blindly milling or stacking gaskets to try and get a cranking PSI you want is not the way to go. I would measure your squish (lead solder through the spark plug hole, roll the engine and measure it where it gets flattened in the squish band). Then pull the head and find the volume, but don't forget about the volume added or taken away by the piston height at top dead center. Now if all that looks good, just run it! Like 1BAD250 said, lots of oil can give false numbers, run it a little and then test. Compression numbers vary from engine to engine and gauge to gauge. I had an old Toyota with a rebuilt engine that put up almost 200 psi on each cylinder, about 60 psi more than the manual called for (if I remember right). I was told the head was milled too far, the block was over decked, all sorts of things. Truck ran great for the 30,000 miles I owned it, all on 87 octane gas. Point is, cranking compression is great for monitoring engine condition when checked fairly regularly. It's not great for determining how the engine is put together. [/QUOTE]
Verification
Which ocean is California closest to?
Post reply
Forums
Dirt Bike Discussions By Brand
Yamaha MX & Off-Road Dirt Bikes
Too much Compression on a YZ250
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