Is this bad?

Hi all, I posted yesterday re cam chain noise. Today I took the rocker cover and flywheel of my 426. The chain is new, and the tensioner and guides are fine.

The only thing I'm not sure of is the crank sprocket - see photo from this link.

Is this bad enough to cause chain noise? And more importantly is this worn enough to allow the chain to jump at the bottom?

There's nothing wrong with the tension when it's static.


Well, from what I can see in the picture, the teeth faces are worn quite a bit. Undoubtedly, this is creating some sort of noise (whether it come from the abnormalities that are there or the continued progression of the abnormal wear). I doubt it would cause the chain to "jump" teeth, but I would bet any good engine builder would advise you to replace it....I know, this isn't cheap/easy, but an ounce of prevention is worth a pound of cure.

Just my $0.02

Looks usable to me.

Thanks for that. Funny how we listen to what we want to hear the most.

Got a season of hare scrambles starting soon so fingers crossed.

I will price up a new crankshaft anyway.

BTW I don't suppose anyone ever had the sprocket built up again?

Any other thoughts welcome. Cheers.

Looks usable to me.

Gray's usually right on the money with things, so you'll be okay. The hard part is going to be ignoring the sounds of the motor that are exaggerated by your fears of it breaking.

Just be sure there is nothing else causing a noise that indicates harm being done. Just because you're sure it's the cam chain doesn't mean it is.

I'm with Gray racer on the noise thing, it could be something total different. Noise can travel through the whole bike, it could be something so simple. Just my .02cents:thumbsup:

Cheers for that. As any of you who have heard cam chain noise it is very distinctive. in my case you can even pin point it to making the noise on the front guide area.

I can't usally put these things out of my mind, but having found no mechanical issues, I think I'm just going to have to get on and ride.

We buy these things to enjoy - so it starts today :-)

If I'm unlucky so be it. Thanks for the advice fellas.

Once I heard a weird noise coming from my engine . This strange noise started shortly after I had shimmed the valves . I just knew something was about to let go . :censored:

Turns out , it was the drive chain slapping on the swing arm . Tightened it up a little and wha-la , no more cam noise ! :ride:

I believe thumpertalk has that crank for 270.00....I believe I priced it once before..

The first 6 months I had my 426, the noises drove me crazy...I was always thinking , this things gonna blow up..I put new sprockets, chain , slider on and eliminated 80 percent of the racket coming from down under..I also replaced the cam I just ride..

Think about using a manual cam chain tensioner.

Think about using a manual cam chain tensioner.
Why? Don't have enough to do without constantly managing the cam chain tension?

It's odd how so many people have this thing about auto cam chain tensioners. Unless you ride an '80s Honda road bike they're usually reliable- if maintained.

Is that 270 US for a crank? Wow that's cheap- even in pounds. I expected double that.

My noise is present when stationary too. I can't hear it when riding cos of all the other mechanical drama going on down there- and my laughing at how much fun these bikes are.

It's odd how so many people have this thing about auto cam chain tensioners. Unless you ride an '80s Honda road bike they're usually reliable- if maintained.
The design employed by Yamaha is so simple and foolproof that it's truly ingenious. Having seen the designs used in many different OHC setups in cars and bikes alike, this one is simply brilliant. advertise a hot rods heavy duty complete crank kit for the 450 for 229pound may be worth tryin them for one to fit yours

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