My Honda ATV is Making a Knocking Noise: What's Going On?

What does it mean when a Honda ATV's engine is making strange noises like knocking or ticking? Usually it means it's time to do a valve clearance adjustment. 

Our resident powersports pro John Talley does live Q&As on our YouTube channel every Friday at 3pm Eastern. In this edition, John answers a question from one of our viewers about a Honda Rancher 400 ATV making a hard knocking noise.

Honda ATV knocking noise valve adjustment

Honda ATV Knocking Noise

I have a 2007 Honda Rancher 400 and when I start it up and go to take off, it gives a hard knock, almost like the rocker arms are hitting the valve cover. Any thoughts? 

John Talley: Wow. That scares me. It sounds like it’s coming from the top of the engine. I think it’s time to go ahead and pull that valve cover and take a peek. If you’re hearing something that dramatic, that may be the case. Something may be broken in there causing it to hit that hard. I can’t remember if that one’s got a compression release on it or not. I don’t think it does though, so it sounds like we need to open it up and take a peek. Worst case, I’m sure it needs to have the valves adjusted.

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Strange noises coming from a Honda ATV's engine can often be attributed to the need for a valve clearance adjustment. In the video below, John shows you how to adjust the valves on a Honda TRX 400EX ATV using a feeler gauge. The walkthrough covers intake valve clearance adjustment and exhaust valve adjustment. John shows you how to take off the TRX 400's plastic side covers, remove the fuel tank, pull the access plugs on the side of the crankcase to get to the crankcase bolt, and remove crankcase caps to expose adjustment bolts. Ticking from the top end is usually an indication of the valve adjustment being off, and the feeler gauge will tell you whether they need to be tightened or loosened. 

Watch the video above to learn how to do a valve clearance adjustment on a Honda TRX400 ATV.

Want to see more live repair questions answered? See more motorcycle and ATV questions answered here.  



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