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
Honda MX & Off-Road Dirt Bikes
97 CR250 Air Leaks Driving Me Crazy
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="mylesc, post: 771937, member: 30514"] I've been chasing my tail trying to track down an air leak for a while now on my 97 CR250. My bike would surge and knock at low throttle openings and closed throttle deceleration. I tried to richen up the pilot circuit and went all the way up to a 65 pilot. The low, 1/8, throttle opening knocking went away but the bike was running way way rich. The closed throttle decelaration surge was still there. I tried richer needles and clip positions but couldn't get rid of the surging under deceleration. I built the leakdown tester found here: [url]http://www.dirtrider.net/forums3/showthread.php?t=87952[/url] and I was losing about 1.5 psi per minute. The cylinder base,head, and intake showed no leaks using windex to show any air bubbles. My left side crank seal was leaking so I replaced that. I did another leakdown test and it was a little better but I was still losing 1.25 psi per minute. I pressurized the tester again and stuck the tranny breather hose in some soapy water and it immediately started bubbling. I 'm not losing any tranny oil so I didn't think that my right side crank seal was bad. I removed the right crank case cover and sprayed some windex on the right crank seal and no bubbles. I coud hear the leak and tracked it down to the pinion shaft that's driven off the crank to control the exhaust valve. So air is traveling from the top end exhaust valve drive shaft down to the tranny. The shafts look to be in good shape with some looseness in the bushings. I ordered new bushings and will compare their tolerances to the old ones. While the RH crankcase cover is off I'll go ahead and replace the right crank seal since it's cheap and easy to replace. Has any one else ever experienced this weird source of an air leak before? Is there any other possible source for an air leak that I haven't checked for yet? I'm waiting for parts right now so it will be a week before I can get it back together for another leak down test. [/QUOTE]
Verification
Which ocean is California closest to?
Post reply
Forums
Dirt Bike Discussions By Brand
Honda MX & Off-Road Dirt Bikes
97 CR250 Air Leaks Driving Me Crazy
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