Knock....Knock? - Wrist Twisters
 
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post #1 of 14 Old 07-27-2014, 07:46 PM Thread Starter
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Knock....Knock?

Hey Guys I need some advice.

The 919 has developed a strange knock. I sounds similar to the kickstand coming up and I can feel it slightly in the foot pegs. It seems to be from the lower end of the bike (crank case, tranny, swing arm area). As I let the clutch out and start off it begins at around 1500 to 2K RPM and gets faster with the engine RPM to about 3500 RPM and fades away, then repeats in 2 gear in the same RPM range knock......knock....knock..knock..knock and stops or is inaudible at higher RPM. Again, it's not related to the speed of the bike, but the follows the engine RPM. Only happens once the bike is warmed up, does not happen when it's cold and only happens under load and in gear.

Cam chain tensioner?

Any ideas?

As always, any help is greatly appreciated.

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post #2 of 14 Old 07-27-2014, 08:33 PM
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Vibrations - probably a broken exhaust mount, especially with where you described it.

Look under the center of the bike, about where the center stand would go - check that exhaust mount. It's known to break.

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post #3 of 14 Old 07-27-2014, 09:03 PM Thread Starter
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Hey Google,

Good to hear from you.

Checked and the exhaust mount and it looks fine. This is definitely mechanical and corresponds directly with the RPM - ie it get faster in unison with the RPM and does not seem vibe related.

Its too slow in revolution to be piston slap or journal slop. I'm stumped on this one.

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post #4 of 14 Old 07-27-2014, 09:32 PM
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Check your chain. Do you have a kinked link somewhere? Perhaps your chain stretched unevenly and now you have tight and loose sections.

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post #5 of 14 Old 07-27-2014, 09:36 PM
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If it's not the exhaust mount, then it's probably the chain as PV has suggested.

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2006 Honda 599 - Ex wrecked it :-D
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post #6 of 14 Old 07-27-2014, 10:19 PM Thread Starter
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Thanks PV and Google!

But, I cant stress enough that the rhythm of this knock corresponds directly with the RPM of the engine, NOT the revolutions drive line. So when I shift into 2nd gear the rhythm starts exactly where it was in 1st gear in relation to the RPM. If it was the chain (or cush drive, output shaft etc) - it would be faster in 2nd gear as the chain is moving faster.

So think of it like this - at 1500 rpm it's knocking 4 times and at 2000 rpm it's knocking 6 times, regardless of how fast I'm going.


Does this make sense?

I'll try to get a vid of the noise posted tomorrow.

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post #7 of 14 Old 07-27-2014, 11:14 PM
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Yeah, it makes sense Guy. As the chain speeds up it evens out. I've experienced this before when the chain would have several kinks or stretched unevenly.

Remember, its a 919. KISS principle applies. Inspect your chain closely.

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post #8 of 14 Old 07-27-2014, 11:39 PM
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Does it knock when the bike is stationary? How does the clutch feel? Any slipping or jumping out of gear?

Just kind of spitballing here. I'm by no means a professional mechanic :/.

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post #9 of 14 Old 07-28-2014, 01:32 AM
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Quote:
Originally Posted by Pvster View Post
Yeah, it makes sense Guy. As the chain speeds up it evens out. I've experienced this before when the chain would have several kinks or stretched unevenly.

Remember, its a 919. KISS principle applies. Inspect your chain closely.
This. Did you recently adjust the chain? I've experienced this when my chain needed to be lubed.

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post #10 of 14 Old 07-28-2014, 08:52 AM
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Also, how's the shift linkage - is it loose?

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post #11 of 14 Old 07-28-2014, 11:11 AM Thread Starter
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Thanks guys,

PV and Google - I'll give the chain a once over. How do you address a kinked link?

Niner - Nope, no noise when it's stationary, only in gear, under load at low RPM in 1st and 2ng gear (if I drag the rear break to increase the load its more noticeable). No clutch issues or jumping out of gear.

RMB - Thx! I'm checking it out.

Google - Shift Linkage is good (I replaced several parts earlier this year when the shifter fell off using thread lock on the important parts) but I will double check.

Thanks guys!!!!!

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post #12 of 14 Old 07-28-2014, 12:04 PM
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Starting to sound more like the chain, then, IMO.

If the chain were kinked really bad, I would actually take it off (remove front sprocket and rear wheel) and soak the heck out of it in some kerosene. Clean it really good, but leave it soaking for a day or two even. After that, soak it in a tub of lubricant for a good while, working the chain a bit as well to get the lube deep into the o-rings.

How old is the chain? Might also be worth just replacing it if it's that bad (if it does end up being the chain, that is).

What about rear wheel bearings? Does it get worse when leaned in corners?

2009 Aprilia Tuono - Ginger
2001 XR650R BRP (Big Red Pig)
2006 Honda 599 - Ex wrecked it :-D
2007 Honda CB900F (sold)
2006 Honda VTX 1300C (sold)
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post #13 of 14 Old 07-29-2014, 06:59 PM Thread Starter
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PV You are the man!

Flushed the shit out of the chain with some Tri Flow (on the bike) then nailed it with chain lube. Took it out tonight and rode the piss out of it and the knock is gone! Thanks man!!!

And thanks to every one else for pitching in to help a fellow 9er! You guys are the best!

I'm ordering a chain and sprocket set from LDH just for good measure. Got a couple of track days coming up and I don't want to take any chances.

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post #14 of 14 Old 07-29-2014, 08:55 PM
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Quote:
Originally Posted by That One Guy View Post
PV You are the man!

Flushed the shit out of the chain with some Tri Flow (on the bike) then nailed it with chain lube. Took it out tonight and rode the piss out of it and the knock is gone! Thanks man!!!

And thanks to every one else for pitching in to help a fellow 9er! You guys are the best!

I'm ordering a chain and sprocket set from LDH just for good measure. Got a couple of track days coming up and I don't want to take any chances.
Get the 17/44 set-up. You'll love it for freeway commuting as well as on the track. I have the 17/43 and while the numbers are very close, I can tell a big difference and I hate it. I'm intentionally running this chain into the ground so I can replace it when needed

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