I'm wondering if anyone with experience of doing valve clearance measuring could give me some help. I know using a feeler gauge is a lot about feel and getting the right amount of resistance to measure the gap correctly.

I am in the middle of checking my valve clearences and all seemed normal for the first few. I checked one of the intakes on my forth cylinder and it seemed that I could pretty much get any size guage under if I gave it a bit of a push. (gap should be 0.13-0.19 mm but I can push 0.5mm under if I try)

In my limited experience I have found that once I get to a feeler size greater than the gap size, it's pretty clear it's not going to go in and applying a small amount of pressure to the gauge is just met with resistance.

The problem with this valve is that I can feel there is resistance to the guage but a small amount of pressure gets it under there. Is this telling me something? Maybe that the valve spring is weak and easily moved by the pressure from the gauge? I've never experienced this so am wondering how to proceed.

Thanks for any tips.

 

update......so I managed to get a measurement on the troublesome valve that I was happy with and it was 0.43mm. That is more than double the acceptable upper limit of tolerance.

I realised that there may be carbon build up on the valve that is stopping it from closing properly so I looked down the intake port and sure enough it looked like the valve was actually being held open a fraction by a number of black deposits. I removed the spark plug, shone a light inside the chamber and I could see a thin ring of light around that valve but not the other one. I should mention the cam is off at this point so all valves should be closed.

My first thought is to remove the cylinder head and get the vlaves cleaned up profesionally. Anyone know of any other options for cleaning the valves without removing the head?

 

I have heard that a "fine"mist of water not the water hose LOL while running will clear the carbon out well it has been done on cars not sure about motorcycles YMMV

 

I had the same problem with one of my valves on NR 1, could force a thicker
gauge in there but I tried to put the right gauge in there carefully still without using any force and went for that.