KX Riders

Maintenance & Technical => KX500 Original => Topic started by: AV8 on July 28, 2009, 01:07:30 AM

Title: Compression Issue
Post by: AV8 on July 28, 2009, 01:07:30 AM

When I slowly kick my K5 it seems to have low compression. When kicking to start it, it has high compression (enough to stop my stroke at times) and it starts easily.  It is an 86 with the single ring piston. Is this normal, or does it need rings?

Thanks

Phil

Title: Re: Compression Issue
Post by: oic0 on July 28, 2009, 01:36:43 AM

How slowly? I can move mine through its stroke with my bare hand if I go slow enough but it has around 165 lbs compression.

Title: Re: Compression Issue
Post by: toomany on July 28, 2009, 08:13:15 AM

As said by oic0, how slowly are you kicking it? Mine has great compression and when going super slow (finding TDC) it is very easy to move. It's normal for the presure to bleed off past the rings. When I go to jump on it....I can stand on the kickstarter and have it barley move (I weigh 155lbs). There have been times when the pistion is comming back up (midway through kick) and I wasn't completly "commited" to kicking it....it has stop me dead in my kick.

Title: Re: Compression Issue
Post by: AV8 on July 28, 2009, 02:23:38 PM

How slowly?  When I am easing it thru to get TDC prior to the starting kick it feels weak although it will stop me mid kick if I dont kick like I mean it. I need to put the compression gauge on it and see where I am. 

Phil

Title: Re: Compression Issue
Post by: doordie on July 29, 2009, 07:27:47 AM

Maybe it?s KIPS-funktion,it should bleed a bit of compression when kicking thru "mouse-ear",but if it?s no slack in actuator-arm,it will close exhaust chamber (front of barell) and sub-exhaustports (mouse-ear) when kicking faster.
I don?t remember if 86-barell have the same funktion as 89-on.. :|

This is a longshoot.... :roll:

Title: Re: Compression Issue
Post by: AV8 on July 29, 2009, 01:06:40 PM

Doordie,

Great call, I will check into the KIPS tomorrow.

Thanks

Title: Re: Compression Issue
Post by: oic0 on July 30, 2009, 02:16:18 AM

Just do a real compression test. If it runs well and scores good on a real compression test, you are probably ok :D I would think with just one ring your bike would bleed down even faster than our two ring bikes. Rings aren't a perfect seal but at a few thousand RPMs there isn't enough time for anything substantial to get by them or through the end gaps.