Author Topic: Bits of metal found near inlet valve  (Read 1019 times)

Offline nairb

  • SOHC Member
  • Posts: 113
    • View Profile
Bits of metal found near inlet valve
« on: December 31, 2023, 12:25:58 PM »
Hello, I have owned the bike for over 11 years.  Its done at least 5k miles and has had several oil changes.  I decided to do a general service and check all the usual things.  Its been running ok, but it's winter time so never a better time.

I thought to check the valve clearance on all valves, so off with both the covers.  On the LH inlet side, there were some metal bits around the valve stem.
Pic of the lh inlet valve
[ Guests cannot view attachments ]
and a pic of the bits of metal.  A solid ring of sorts
[ Guests cannot view attachments ]

I am wondering if the cam chain tensioner has started to break up.  The cam chain is not as tight as I expected.
Is it possible to remove the lower cam tensioner (below the carbs) without taking the head off.

Has anybody else found bits like these.
Ta
Nairb


cb550k3, cl450k5, re5m, xs650xs2, mt500, kettle, gt550 x2,  gt380 Kz750 twin cb360K0

Offline Skoti

  • SOHC Expert
  • Posts: 322
    • View Profile
Re: Bits of metal found near inlet valve
« Reply #1 on: December 31, 2023, 06:10:32 PM »
It can seen from your photos that the tappet cover gasket has been scraped off with something very sharp which may have dislodged particles of alloy into the head.

If the particles are alloy and not metal as you state, then remove them and you're probably good to go, if not then it looks like a winter strip down and inspection is required...


Either way, good luck and Happy New Year.

Skoti

 
« Last Edit: December 31, 2023, 06:13:31 PM by Skoti »
Motorcycling is Life, anything B4 or after is just waiting...


1976 Honda CB750F1

Offline nairb

  • SOHC Member
  • Posts: 113
    • View Profile
Re: Bits of metal found near inlet valve
« Reply #2 on: January 02, 2024, 02:28:54 PM »
Well, I have pulled the cam chain tensioner out and expected to see some problem with it.....
For good or bad, it seems to be ok.
[ Guests cannot view attachments ]

It would be better to find out what's wrong without pulling the engine apart.  It's not been apart before, and I would prefer it to stay that way.
cb550k3, cl450k5, re5m, xs650xs2, mt500, kettle, gt550 x2,  gt380 Kz750 twin cb360K0

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal