Topic: 750 Cam Chain

[jcarthel]

I haven't owed my bike that long so here is a good newbie question:  Is there any cam chain noise at all on a k2 either at idle or freeway speeds in top gear when the chain is properly adjusted?  What is the nature of these engines; is there supposed to be some cam chain noise or not even a hint of noise such as a slight whir?  I have adjusted the tension at the proper mileage intervals and followed the owner's manual directions.  My tensioner may be frozen or could be working fine.  I just don't know what if any noise a properly tensioned cam chain makes.

Justin in Texas

[HondaMan]

It makes a bit of a swishing noise, unless the rubber on the idler roller is old enough to have chunked out bits of it. Then it rattles a little as the chain passes over the bends.

You can test the cam chain tensioner's action: with the crankshaft set in the proper position (15 degrees past TDC on #1 compression), remove the nut & bolt, then use the bolt to push in on the plunger: if you push pretty hard, you can feel it moving the chain in. It will spring back a little after that, because the forward slipper shoe is curved a little, like a spring, and the chain reflects that tension against the plunger. This will verify that the plunger is not stuck, and is indeed applying the proper tension against the inverted portion of the tensioner loop. Then reinstall and tighten the bolt, and nut.

If it is still real noisy after that, it may be time to consider new rubber pieces in there...

[jcarthel]

Thanks Hondaman!  Can you still hear the "swishing" noise at say 70mph in fifth gear?  My cam chain swishes, but does not rattle.  I am hoping everything is okay.  The previous owner tore everything apart 4500 miles ago and installed new rings, a three angle valve job, and syncronized and rebuilt the carbs with full kits.  I have hope that he made sure all was well with the cam chain tensioner.  For starters, I will email him and ask him about the condition of the tensioner.  Previous owner did all the work himself.

Justin in Texas

[HondaMan]

Thanks Hondaman!  Can you still hear the "swishing" noise at say 70mph in fifth gear?  My cam chain swishes, but does not rattle.  I am hoping everything is okay.  The previous owner tore everything apart 4500 miles ago and installed new rings, a three angle valve job, and syncronized and rebuilt the carbs with full kits.  I have hope that he made sure all was well with the cam chain tensioner.  For starters, I will email him and ask him about the condition of the tensioner.  Previous owner did all the work himself.

Justin in Texas

I should think that at 70 MPH it would sound more like singing (my friend here calls it "zinging") across the top sprocket.

Here's a thought for you: ask him if he remembers the condition of the D-shaped rubber stops that hold down the axle of the main idle roller. If these were shrunk from heat and were not replaced, it can wiggle back and forth a little at speed and make the chain a little noisy. New ones require some force to press into place, and then they tend to pop up while you're trying to install the cylinders onto the pistons, very annoying. Nothing serious, just one of the finer points of rebuilding a 750 engine.