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Honda 20hp rattle

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ogreman72

New member
I have a 20hp I just got running again and it's making a rattling noise that seems to be coming from the head/camshaft area is that normal?
 
No, I don't think that's normal. It would definitely make me nervous.

As to what it might be, I don't know but I can tell you that, very recently, there have been two instances here of people reporting cam pulley failure on BF 20 D's that resulted in the timing belt coming off. Item 3 in the link below. That pulley is plastic and can crack.


If the noise has a "ring-ah-ding-ding" sound to it, the retaining nut (item 5) for the crankshaft timing pulley (item 1) may have backed off. I've seen that happen a couple of times before on Honda twins. The "bell ringing" is caused by the big flange washer (item 2) bouncing around loose.

I would also suggest pulling the rocker cover and look to see if all is good with the valve train.

The oil pump is in that area and the fuel pump too.

You can make an excellent stethoscope style listening device from a piece of car heater hose and a 1 gallon plastic jug with the bottom cut out to help pinpoint the location.

Just a couple of ideas.

Good luck and please keep us updated.
 
Ok so I pulled the rocket cover, everything seems to be ok. There does seem to be some play on the valves but more concerning there is a "click" coming from the camshaft. It's not all the time but I can feel it on the cam gear.
 
Are you working with a shop manual?

It is normal....even necessary.... for the valves to have some play. Just not too much play.

If you have a manual and maybe some experience working on engines, you could check the timing and the valve clearances.

I agree that, in the video, the engine sounds noisy but I can't make out what might be the cause.

As to the click you feel on the cam pulley, the camshaft drives both the oil pump and fuel pump. The oil pump is a rotary pump and shouldn't cause any clicking.

But the fuel pump is a plunger/diaphragm type that is pushed by a rocker arm running on a camshaft eccentric lobe.

Could the click you feel be the rocker pushing the fuel pump plunger? That might be normal but I suppose if the plunger were binding it could cause what you're feeling. I just don't know. Sorry.
 
The fuel pump is brand new and I also pulled it off to see if maybe that was it but the noise is still there. The thing that gets me is how inconsistent the noise is, sometimes it feels like every compression stroke it clicks and other times it just won't make any noise.
 
Well, I don't know but I would still be suspicious of a possible valve train issue. If you haven't checked the clearances with feeler gauges, I would urge you to do so. And, while in there, look very carefully at the valve springs. They can break, usually at the very top or bottom, and it can be hard to see.

As far as the pump being new....
N.E.W. stands for:
Never
Ever
Worked

Any chance this clicking started right after installing said new pump?
 
When it's running it sounds like a rattle, when I pull it slowly it sounds like a click but I'm not sure if it made this noise when I initially bought it. Between having a kid and moving it's been over a year since I've heard it run. I replaced the fuel pump when I got it running again. I'm gonna get some feeler gauges this weekend and check the valves and springs.
 
Did you save the old fuel pump? Maybe you could put it back on and see if the click goes away?

I would still check valve adjustment regardless.
 
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