OK fellas, we've been here before...but for me, it's still unresolved.

For background, I had the cam chain noise around 5000 to 6000 RPM. This one sounded like a faint metallic ticking, for lack of better words. In any case, installing the Kreiger manual cam chain tensioner elimated that one.

Around 8000 RPM, I still have the same rattle as before the manual tensioner, and it sounds distinctly different than the 5000 RPM rattle did. The 8000 RPM rattle sounds more like a set of keys or some loose change being shaken violently. (The 5000 RPM rattle was a little concerning - the 8000 RPM rattle sounds downright nasty). Additionally, it sounds more like it's coming from the front of the bike, near the triple clamps or front of the tank, rather than at the timing set; I will note though that it is very hard to pinpoint in motion. Finally, it seems to be somewhat intermittent, that is it won't necessarily do it every time the bike is in that rev range. I notice it most under heavy acceleration, and typically in higher gears.

I have not torn into the bike in search of the culprit (beyond the cam chain tensioner). I can't get my hand on it from a riding position.

So... has anyone else pinpointed and eliminated this rattle? If so what was it (or what do you think it was)?

 

Lutz, are you sure you don't have some detonation? Your comments about "under load" and in higher gear causing more noise can fit that issue of detonation. It's hard to diagnose something like this over the internet, but if it is detonation, that's something you'd better address quickly...usually with richer jetting or higher octane since the timing is relatively fixed. Oh, how was your cam chain spec length when you did the manual tensioner?...not that you have to check that spec to do a manual tensioner, but I was curious if you did.

 

Could be the valves hitting the piston?

 

Nope, I'm not sure that it's not detonation. Now that you mention it, it could be. I am fairly sure my jetting is a little lean on the main jet (not extremely lean, just slightly). I will say that I haven't yet done any purposeful troubleshooting specifically for this sound; i.e. I haven't nailed down the exact set of circumstances that cause it to occur, or exactly how repeatable it is.

I'll be working on that next - detailed troubleshooting - likely will (finally) try a larger main jet, possibly even premium fuel. I currently run 87 octane oxygenated pump fuel - 93 octane non-oxygenated is available in town.

Regarding the cam chain measurement, I haven't been into the engine at all yet...only 4500 miles on it. So I have not had opportunity to measure the cam chain.

Good god, I hope not.

If it comes down to it, I have access to a high-tech video borescope at work that I could use to inspect the cylinder through the spark plug hole.

 

I can't imagine spending the amount of dough on a bike then putting in a sweet big bore kit then not spending a little extra on premium gas...

The tank holds 2 gallons, so what are you saving .80 cents. I put premium in it every time. The 450s gets a splash of race gas to ensure the valves get some good ole lead.

 

This might sound dumb, but could it be something like the skid plate or something like that resonating at that particular frequency or vibration? Maybe take it off and see if it still happens.

 

For Less than $10.00 and a ride you can rule out detonation. Fill the tank with 93 (R+M/2 method) and go for a ride. If it still does it, then its something else.

NO the valves are not hitting the pistons. IS your valve adjustment correct?

Coolant and oil level proper?

David

 

Could it be as simple as your keys/keychain rattling? You said its coming from around the triples and front of the tank.

 

Thanks everyone for the thoughts and feedback. Good group we've got here.

I feel (felt) a bit foolish for posting before doing any actual troubleshooting myself - especially since the source of the problem was right in front of me the whole time, and should have been very obvious. I had mentioned that I hadn't put any significant effort into finding the source of the rattle; it was just something that I noticed while riding with other intentions in mind. If I had taken the step to sincerely look for the source of the noise, I would have found it right away.

Well, I finally had a chance to get serious about it this morning. First things first: fire it up and take it for a ride with the strict intention of troubleshooting the source of that rattle. Well, I found it by the end of the second block.

Before spilling the answer, I'll respond to some of the other posts.

I would run fuel with a higher octane rating if it were necessary for the application...but it's not. No reason to spend a penny more on fuel unless it is actually doing something beneficial. For the purposes of troubleshooting, it could have been beneficial...but as it turns out, I didn't even need to go that far.

No this doesn't sound dumb at all. What was thinking all along is a resonating part - that is until I started thinking about the possibility of detonation. If you're not careful, distraction is part and parcel to internet troubleshooting.

Yep, I always keep the oil and coolant in check.
And no it's not valves hitting the piston. As I said before, with 4500 miles on the bike I have not had reason to get into the motor at all, so don't know what my valve clearances are.
If I hadn't found the rattle immediately this morning, my next step would have been heading to the pump for a higher octane rating.

Yes, it is that simple, but no it's not the keychain. I checked that first time I heard the noise, and several times since. It really does sound like a keychain ratting, and it's in the same area.


OK, the source of the 8000 RPM rattle is...drum roll....the clutch lever.
I still have the stock clutch lever and perch, and clutch lever is ratting against the perch and pivot pin. It starts resonating around 7500 RPM or so and gets loud by 8000. It will quiet down or clear up closer to redline. It takes a fair amount of finger pressure on top of the lever to stop it. A little grease should quiet it right down. In hindsight, I've seen ratting clutch levers on other bikes, and I'm willing to bet some of you have too.

I guess to put a moral to this story...when you notice a problem (that is not catastrophic in nature), always do the simplest checks first.
It's a lesson I've learned lots of times already: Look for the problem before looking for the solution.

 

LOL!...a clutch lever. Well, like I said, trying to diagnose sounds over the internet is tough. Man, Lutz...that must have been one loud lever. At 8000 rpm, my hearing range "might" recognize the con rod coming out of the engine case...If I was lucky...and riding without a helmet...LOL!

Glad you found it. One sleeps better knowing the cause than wondering what's fixing to break.