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CB650F Top End Rattle

Arthur45

2017
CB650F ABS
May 2, 2018
Hi All,

My bike hasn't been run for a few weeks so I started it today and let it warm up. So when the revs dropped down to the normal idle position after a couple of minutes I revd the throttle a few times and could hear a noticeable rattle from the right side of the engine, top end.

It happens just when you come off the throttle. It sounds like cam/valve noise. It did decrease once the engine warmed up more and I stood it up right off the side stand.

I've recorded it and added the file but this site says the file has the wrong extension. So I cant upload it. It's a mp4 file. Anyone know how to get over this. Or im happy to email it to someone to listen too.

Needed to use the bike tomorrow and dont know if this noise is normal and I just haven't noticed it before.

Cheers

Arthur
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
That sounds like either the PAIR valves (normal), or possibly cam chain tensioner (I would hope not on a 2017 bike).

Third option is low oil level - have you checked it as per manual and topped up to max if required?

J
 

Arthur45

2017
CB650F ABS
May 2, 2018
The oil should be fine. It was changed only a few hundred miles ago. I take it the engine is designed to run on an angle with the bike on a side stand.

It doesn't sound like a cam chain but it is the same side.

Would the pair valve noise quieten as the engines warms?

Shame the video file wont upload so you can hear it.
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
Pair valve does get used less when the engine is warm. But mostly goes quiet under load.

The bike can lean just fine... However you can go from max to min on oil on 300 miles.

I'd check the levels every 200 miles until you learn what your bike uses.

Mine will go for a few hundred miles before I need to check it. Every engine is different though.
 

Arthur45

2017
CB650F ABS
May 2, 2018
Ok thanks. If it was the pair valve when you come off the throttle would it make more noise but then quieten down as the revs idle.

I've new had a bike with a pair valve and cant say I am loving it.
 

Arthur45

2017
CB650F ABS
May 2, 2018
The oil looks fine.

Does the cam/valve noise change on these as the engine heats up?

I had a 2010 XJ6 and on tick over the valves had a noticeable louder tapping at a certain temp range, but then quieten down as the engine passed through the temp range.

We obviously dont have a temp guage to see what the engines at.

But this is a noticeable rattle, not knocking, as you come off the throttle if you just rev the engine. Sounds top end, more right side. But again not on the increase in revs, just as you release the throttle and the engine revs die off then disappears as you reach idle.

Think I may have to ask the dealer to listen.
 

Arthur45

2017
CB650F ABS
May 2, 2018
I'll take her for a ride and try it at different temperatures.

It definately top end, under the tank area. Where exactly is the valve?
 

Arthur45

2017
CB650F ABS
May 2, 2018
Completed 100 mile ride. The noise seems to have gone when bike is up to full working temp. All I can think of is its pair valve related, or cam noise which changes as the engine heats up.
 

Drewster123

2017
CBR650F ABS
Feb 16, 2018
Hold your revs up slowly from idle up to around 2/3k does it give u some vibration? I'm sure this is the pair valve. Mine makes a right racket it's like someome has left a vibrater under the petrol tank.
 

Arthur45

2017
CB650F ABS
May 2, 2018
Ah thanks.....as said I left mine to warm up the other day as it had been started for a while. After a few minutes I blipped the throttle a few times taking the revs upto 5k ish and as the revs began to decrease you could hear a noticeable noise. I tried to record it and post it but this site wouldn't accept the file type....

Anyway I rode it yesterday and when the bike is at full working temp the noise has gone.

The pair valve is very noisy and I suspect what I heard was either this, although it did seem to be on top of the existing pair valve noises, or cam noise.

The bike generally is not as smooth vibe free and at idle the motor is not the quietest. But I am comparing it to my last which was a 2006 CBR which was quiet, smooth as anything.......and no pair valve😊
 

Enrico

2018
CB650F ABS
Mar 28, 2019
The bike can lean just fine... However you can go from max to min on oil on 300 miles.

I'd check the levels every 200 miles until you learn what your bike uses.

Mine will go for a few hundred miles before I need to check it. Every engine is different though.
Checked my oil level recently and was surprised to see it on low mark. I have been used to bikes going from annual service to annual service without oil needing topping up. Have had oil and filter changed now but should it really need checking every few hundred miles, how much oil do these bikes use ?
Is this a new phenomenon on modern bikes ?
 

Devilsfan

2018
CB650F
Jun 5, 2019
Tampa, Florida
How did you check it, on the kick stand or straight up? Will give you different readings depending on how the bike is leaning or not.

Also, did you check when cold or after a ride?
 
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