The top seven symptoms of poor ATV valve adjustment, include:

It needs about a 1/2″ of play with the rider seated on the bike. That should allow the chain enough slack to not break.

Out-of-adjustment valves usually make it easy for you to notice them because:

1. You’ll hear a distinct clatter from the valve area – this points to lose valves.
2. At times you might hear a click sound while idling.
3. You may notice a subtle loss of power (compression).
4. The bike could start overheating.

1. ATV won’t start.
2. Engine noisy.
3. Engine misfires.
4. Bike lacks power.
5. Engine runs rough.
6. Erratic idle.
7. Hard on gas.

Tight valves can easily make your bike hard to start, it can even prevent it from starting at all. Make sure that the feeler gauge fits easily between the tappet and valve. When you torque the nut down, it usually tightens a bit more than what you measure with the nut at finger tightness.

Low compression can be caused by several issues. Most of these problems stem from wear and tear and improper maintenance where low compression results from one of the following: Bad or Broken Valves. Worn Piston Rings.

ATV Low Compression: The Signs

1. Low engine power.
2. Noisy sounds coming from the engine.
3. Problems when trying to start up your ATV.
4. The engine might have intake valve leaks.
5. The spark plugs might have oil residue – they should be completely dry.

The overall compression should be between 210 and 250 psi per cylinder.

What Outboard Compression Test Results Mean. Results vary depending on whether the outboard is a Four-Stroke or a Two-Stroke. Good results for Four-Strokes should be 180-210 PSI, and Two-Strokes should be around 110-130 PSI. Here is everything that you need to know about outboard compression tests.