All 650's (Engine?) rattle

[ADIOS600]

That's good news THOMAS. Sometimes these little niggles get in your mind and we think the worst, talking about it can help, and when its sorted move on to the next worry lol. I don't think these old girls suffer too many problems.

 

[Duncan]

good to hear that many of the issues appear normal.
It's always good to understand the base level of normal for the bike. if it changes then you know for sure that something is going on and can better advise the mechanic of what has changed.

 

[Thomas]

Another update: It still does it. I just accepted it. It´s nothing serious, most likely some fairing noise.
Now derestricted and with a fresh big 24k service. Behaves and feels perfectly fine.

 

[John Eddy]

Noises I get from the bike.

1200rpm, in moist conditions and I get a misfire of sorts, the PAIR system rattles stupidly.
3000rpm: buzz in instrument cover plastics.
5000rpm: hard clunking through the bars. sort of like a hammering. but I also asked the salesman about the harshness of the bike on a flat throttle on the bike when I test rode it, 105,000km ago. It felt like a cylinder was running lean or in need of a carb balance.
6000rpm+: high rev vibrations typical of an inline 4 with no balance shaft for secondary reciprocation forces. can come through bars, pegs and other but I also look to not crash into stuff when in that part of the rev range so, it's mostly out of mind.

Hard to pin down stuff.
Clutch noise. it makes a bit of extra noise most of the time which is mostly noticeable when you take the slack out of the actuator cable* and such or pull it in all together.
* I do lots of work in traffic so cover the clutch a great deal. thus I get to notice these noises.

The Chain
An older chain can start catching the edge of teeth on the rear sprocket and as such increase incidental noises as it catches. this is most often noticeable during acceleration and is a good sign to review the end of life replacement of the chain.

Re the 3000rpm buzz.... try small flat washers under rear vision mirror mounting bolts. It fixed mine!

 

[Kingsleh]

Re the 3000rpm buzz.... try small flat washers under rear vision mirror mounting bolts. It fixed mine!

I'm curious to try it out. Do you mean between the fairing and the mount, or between the mount and the mirror?

 

[John Eddy]

I'm curious to try it out. Do you mean between the fairing and the mount, or between the mount and the mirror?

Remove the mirrors from the fairing... turn mirrors upside down and place 4 small flat washers on bolts and refit mirrors. Washers go on bolts between mirror base and fairing.

 

[Kayman29]

I started running 94 octane gasoline and my knock got far less loud and often so I am definitely thinking the pair valve is my issue which is funny cause in Thailand my 650F doesn't have them and it's super quiet and smooth. Hopefully more km makes it work in a bit more.

 

[ADIOS600]

I started running 94 octane gasoline and my knock got far less loud and often so I am definitely thinking the pair valve is my issue which is funny cause in Thailand my 650F doesn't have them and it's super quiet and smooth. Hopefully more km makes it work in a bit more.

No pair valves, well that's one less job 😎

 

[FogDucker]

Today I managed to capture it a bit while running on idle after start. It´s not really loud but sice I pointed my phone towards the direction of the "source" you can hear it a bit better. That ticking, rattling in the background. I hope you can hear it. Excuse the quality of the video.



At around 17s I moved the phone and you can hear it a bit more. I guess that is that noise getting a bit louder when slightly accelerating from lower speeds and rpm.

Is it an Akra pipe?! if yes, its a normal noise! it not air leak or anything else. Akra tends to echo this engine (PAIR?) noise more than any other brands. I have heard it on 3 other CB650s. All the same

 

[Daniel]

Was trying to find where to put this piece of info, but here seems best.

I've just finished reassembling the bike after a valve check, and on the way up, as I was clipping in the bank angle sensor, I noticed it was completely loose.



I've never tampered with it. But I could freely move it and it wasn't seated solidly at all. Wrt. the image below, the nut[1] was tight, but there is a rubber grommet on the frame between parts [4] & [5] . It's wider than the frame it's fitted to though, which is why the nuts were tight but the sensor was still able to freely rock. So, by doing the nut[1] up even tighter and deforming the rubber grommet, it's now solid instead with no movement. This could be another reason for a buzz if anyone encounters it whilst riding. I put mine down to PAIR valves, but I have a feeling it might have been this instead.

 

[miweber929]

Most BAS units I’ve seen have been rubber mounted and have some movement. I’d think a tight fit would/could wreck the fluid cavity that would activate the tilt sensor. My thoughts at least.

 

[JDude]

Did the nuts have the paint pen marks that means it was checked/torqued when the bike was assembled?

 

[Daniel]

Most BAS units I’ve seen have been rubber mounted and have some movement. I’d think a tight fit would/could wreck the fluid cavity that would activate the tilt sensor. My thoughts at least.

True, except the points of contact for the fixtures were not applying any pressure to the central part of the sensor. The holes also had a mettalic inner ring to prevent the sensors plastic housing from being crushed.

Did the nuts have the paint pen marks that means it was checked/torqued when the bike was assembled?

Nope, none. It's only 8.5Nm anyway.