NC30 Engine rattle/noise.

[Dave8106]

Hey folks,

I was out for a ride the other day on my wee vfr400 & when I was coming home I noticed a loss of power & a rattling sound from the engine?!

I took the bike home & checked her over to see if anything had came loose, but couldn't find anything. I checked the oil level also & It was just bellow the full line.

I left parked the bike up until the next day, I then started her up with no issues. She ran fine with no noises etc for around 5 or 10 minutes then the rattle noise returned .

Has anyone else on here experienced this issue & beable to point me in the right direction to diagnose this please? Thanks.

I have added a clip capturing the noise on my YouTube - Linked bellow -

https://youtube.com/shorts/0s73j-DFNhA? ... kjzDXU-hHM

[CMSMJ1]

Are you sure this is internal - not something loose?

Clackety clack - or just a rattle?

[magg]

Link doesn't appear to work. Maybe a valve sticking. Did engine reach operating temperature during the 5 or 10 minute run and the engine ran rough once the rattle started.

[Dave8106]

Sorry, I have now re-uploaded the video on my YouTube channel - https://youtube.com/shorts/0s73j-DFNhA? ... kjzDXU-hHM

It doesn't sound like something loose to be honest it's more of an internal engine sound.

[mechannibalism]

A sticky valve would be my first guess, I would also check the gear drive and the carrier for cracks/loose.

[MadMotoUK]

Sounds a bit tappety/valvey. You may also have a vacuum leak as it appears to hang revs.

[Swingarm]

Can you describe the loss of power?

[Dave8106]

Yes, There is some loss of power also feels like she's running on 3 cylinders & revs are hanging.

Before this tapping noise the bike reved normal & had full power no signs of a vacuum leak.

Thanks

[Swingarm]

Other folks on here are far more experienced and qualified than I am but of it were my bike I'd start with a compression test.

[Dave8106]

Hey guys,

Just a wee update, had the valve clearances checked & a compression test done also all where 100%.

But the tapping sound is still there think it's further down the engine, Possibly the gear drive or shell?!