compression test spec for 06 yz125

[mxrider227]

I'm having trouble finding a spec for compression readings for an 06 yz125. Does anybody know what yamaha's spec is for min compression reading is.

[Urps]

Its probably on their website, it will take you to the 07 model but there should be a tab for the 06 model....just check out specs....it have a high number for low speed and then a smaller one for when its on the pipe...

[mxrider227]

Its probably on their website, it will take you to the 07 model but there should be a tab for the 06 model....just check out specs....it have a high number for low speed and then a smaller one for when its on the pipe...

Thanks but unfortunately those are comp ratios listed on the yamaha site i'm looking for compression pressure specs. I have done a compression pressure test and just want to know what yamaha specs are.

[adrunkgerbil]

Have a service manual?

[UpAllNight]

Its gotta be high enough to ping like hell, because my wifes 06 YZ125 pings like hell on 40/60% Race/Pump mixture. But only when I ride it and put a load on it that she is not fast enough to. If I shift hard and fast "bunk" and "ping". Good sign though is any bike that pings means it will perform better once it has the correct octane to stabilize the combustion.

I think it would need 100% race feal to run 100% correctly.

[FFRacing79]

Its gotta be high enough to ping like hell, because my wifes 06 YZ125 pings like hell on 40/60% Race/Pump mixture. But only when I ride it and put a load on it that she is not fast enough to. If I shift hard and fast "bunk" and "ping". Good sign though is any bike that pings means it will perform better once it has the correct octane to stabilize the combustion.

I think it would need 100% race feal to run 100% correctly.

?

[Baron Von Beard]

I'd hate to see what the piston looks like in UpAllNight's wife's bike! ?

Eventually the piston will get so pitted that the compression will come back down and the pinging will cure itself, right?

[UpAllNight]

Hmm... maybe not.

I had a 91 Honda CR125 back in the day that had the same pinging problem under heavy upshifting loads as this YZ125 has. Back then I didnt know that higher octane would cure it so I ran it the way it was. That bikes pistons lasted longer than any bike I owned ever since.

ModMotoMan can back me up on that one.

Every YZ125 from 05 to 06 I have rode (about 5 so far) has pinged under heavy loads of hard upshifting (all on pump gas). Yet we dont hear about them blowing pistons too often do we?

Now if it was pinging throughout the RPM range then it would kill a piston, but this is just a short split second unstable combustion I am talking about. Not enough to destroy an engine, just enough to catch your attention.

If it was mine I would run 100% race, but because my wife never brings it to the point of pinging.... screw it

[Modmotoman]

Yeah to melt a piston you usually need a really lean condition plus a lower then needed octane fuel. The stock YZ jetting is not a lean condition but pump fuel is a little short on octane for these motors.

[Motocross26]

Is this with 91 octane premium or 93? No pinging here on 93 octane.

[UpAllNight]

93... It wont ping unless you are riding the piss out of it. Not saying your not.... But if you are slower or gentle on the upshifts then it will be just fine. Of course altitude plays a role too, I'm at sea level.

[redrider91]

YEA!!! make e'r lean and run it hot!!!! LOL Jk