Possible cam chain tensioner noise, pictures included

[t-j-b 14]

Hey guys, I'm new here having just bought an NC700 2012.

 

Been doing the usual maintenance when getting a new bike (fluids etc) and noticed a rather aggressive rattle when the revs are dropping from > 4k. This signalled a cam chain tensioner issue to me (had a similar issue with a CBR600F many years ago).

 

Decided to take the tensioner out and have a look, I've attached pictures of the tensioner. It looked fine to me at first then I noticed some play around the pins. The appearance of the metal carrier is bent, I'm not sure if this by design but it does look wrong to me.

 

Also, is installing the tensioner a simple job, I can't find a good explanation of how its done, I assume the tension has to be removed as its put back in?

Thanks

[t-j-b 14]

Just to add to this the noise sounds like a loud "BRRR" rattling noise, hard to describe but if I had to like a heavy object knocking around in a can. Couldn't find anything loose fairing wise.

I have read a loose exhaust could cause this so I'll check all header bolts are tightened.

The noise seems to be louder when cold

Edited July 15, 2020 by t-j-b

[Graham NZ 1,186]

Let's hope it's something loose in or about the exhaust system.  Maybe, with the bike in neutral and on it's stand (preferably a centre stand) try revving the engine up and down through the revs while someone else investigates the exhaust system.  Bits coming loose inside mufflers etc. are not unknown.  How many miles/km has the bike done?

[Slowboy 20,408]

I think there have been one or two camchain tensioner issues reported with the NC, but they are very rare. It's worth a search on here to see.

 

edit: there you go

 

Edited July 16, 2020 by slowboy

[Griff 1,556]

There definitely was a tensioner issue mentioned over on the US forum at some point. Have a search on there also. However I would check the header for looseness first. 

 

https://www.bad link/

Edited July 16, 2020 by Griff

[t-j-b 14]

The bike is on 41k miles. I've poured over every post related to cam chain tensioners and saw a few comments regarding the noise they make and characteristics (knocking sound on overrun).

This is exactly how mine sounds, I've ordered a new part as a prevention.

Checked the manifold bolts, all torqued up properly. If it's not the tensioner I can only imagine it's the chain, there doesn't look to be anything else around (bar possibly a bearing on the topend?) that could cause this noise.

 

Also would like to say when removing the tensioner it's possible to remove the water pump cap for better access to the tensioner securing bolts. The cap is tight to remove but possible.

Edited July 16, 2020 by t-j-b

[Graham NZ 1,186]

t j b, please let us know if the noise disappears with the new tensioner fitted.

[t-j-b 14]

New CCT installed today. The bike does seem quieter, there's still a slight rattle on overrun.

 

The old CCT was noticeable warped compared to the new one, really wasn't expecting them to appear so different.

[Dunnster 1,650]

6 minutes ago, t-j-b said:

New CCT installed today. The bike does seem quieter, there's still a slight rattle on overrun.

 

The old CCT was noticeable warped compared to the new one, really wasn't expecting them to appear so different.

Any difficulties installing the new CCT? Hopefully you've many more miles without problems.

The NC engine is noisier and rattley when running, even being described as "like two skeletons shagging furiously in a large metal box" by Tex I recall 

[t-j-b 14]

10 hours ago, Dunnster said:

Any difficulties installing the new CCT? Hopefully you've many more miles without problems.

The NC engine is noisier and rattley when running, even being described as "like two skeletons shagging furiously in a large metal box" by Tex I recall 

 

Hahaha it's certainly not the quietest bike I've owned, that's mostly due to the decrepit clutch basket rattling away!

 

Very easy to fit, they come pre tensioned with a long pin that's easy to remove. The honda tech I spoke with told me to turn the engine over backwards a few times to set the tensioner (??) I did this and didn't notice much difference if the adjuster position.

[Dunnster 1,650]

1 hour ago, t-j-b said:

Very easy to fit, they come pre tensioned with a long pin that's easy to remove. The honda tech I spoke with told me to turn the engine over backwards a few times to set the tensioner (??) I did this and didn't notice much difference if the adjuster position.

 

Thanks for the info, if I ever have to do this job. I don't think I'll turn the engine backwards though seems counter intuitive.

[t-j-b 14]

3 hours ago, Dunnster said:

 

Thanks for the info, if I ever have to do this job. I don't think I'll turn the engine backwards though seems counter intuitive.

 

Feel free to drop me a DM if you have any questions, it's an easy job once you've done it once.

[Martin Robertson 3]

I,m having a nightmare fitting a cam chain tensioner. Cant see anywhere to instal the 2mm pin, and cant see any way of actuall getting tension at all. The springs etc dont seem to do anything at all, and def dont put any kind of tension on the plastic runner! Pulling my hair out trying to figure this out!