these are for Olly but anyone is welcome to inform, i think he nailed it that i have a valve adjustment issue but the cover must come off and inspect the adjustment first. here are all 4 cylinders

---

Hi Joel, Looks like we are getting somewhere with this one.
I had a look at your captures, I'm not familiar at all with in cylinder pressure wave forms but having had a look through i think we can identify that its defiantly  a valve issue, please correct me if i am wrong here anyone. [smiley=scratch-head02.gif]

I have reference wave formed the files to see all cylinders on one screen and have labelled them in the notes. Cyl numbering is 1,2,3,4 from left to Right as you are sitting on the bike.

I suspect, looking at the dips in the waveform at the end of the compression cycle the 2 problem cylinders seem to dip further into negative pressure and hold there for longer after TDC which i would say indicates not a clean valve closing event.

I also labelled in the notes some approximate values for where i think the valve closes/cylinder seals after the tdc event, which i did using the degree cursers and rulers. This shows that the 2 problem cylinders both have more crankshaft degrees before the cylinder pressure equalizes, also the closing event is not as clean a shut of as can be found in the 2 good cylinders.

If anyone with more experience can add anything to this please do as this is my first time with this type of waveform.

Good work Joel, [smiley=thumbsup.gif] some nice captures. I look forward to hearing what you find when you pull the top off and have a look.

---

I'm definitely not a pro at WPS captures, but I think your on the right track Olly.  Valve lash adjustment is probably a huge factor, but I believe there is something more sinister going on.  The vacuum pocket is deeper because the mass of air in the cylinder is less due to the leak of air in the cylinder during the compression stroke.  Since there is less air mass in the cylinder as the piston travels down on the power stroke, the vacuum pocket goes deeper.  You can also kind of see the compression towers leaning which suggest the cylinders aren't sealed that well.

Question:  Would excessive exhaust valve lash or an exhaust valve opening problem cause lower than normal compression peaks?  What other things could cause leaning compression towers other than cylinder sealing issues?   ::)

---

This post is old, so probably fixed.  Noted signatures of 2 good jugs 119 after TDC and the soft ones skewed. 

Would like to have seen this with compression wave form as cannot do on a lot of bikes if single cylinder and a twin lopes so bad signal if questionable, but here is a 4.