Author Topic: CB500K2 four 1975 timing chain tensioner fitment  (Read 1525 times)

Offline martin_uk

  • SOHC Expert
  • Posts: 473
    • View Profile
CB500K2 four 1975 timing chain tensioner fitment
« on: February 19, 2025, 05:27:38 PM »
Continuing the engine reassembly find pressure needs to be applied to top of tensioner to fit top bolt through head.

Is this normal ?

I didnt notice a locator in crank case for bottom of tensioner and concerned that may have missed.

Now difficult to see with barrels and head fitted.

Can you remove and refit tensioner without removing head? (camshaft not fitted)

Thanks

Martin
1977 CB750F1
1977 CB750f1 836
1978 CB750F1
1975 CB500K1

Triumph Street Triple 675R
Ducati 800 Icon Scrambler
Triumph 3TA
AJS 350 mod16
BSA BantamD1
Honda C90zz
Honda CB500X
BSA WD B40 350

Offline McCabe-Thiele (Ted)

  • Grogu
  • *
  • Posts: 8234
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #1 on: February 19, 2025, 05:35:32 PM »
Can you look up from the sump end?
« Last Edit: February 19, 2025, 06:01:41 PM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Oddjob

  • SOHC Jedi
  • Posts: 4588
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #2 on: February 19, 2025, 05:58:46 PM »
Remove sump and you can see if it's in the slot. Sounds like it's not. A lot of tensioners get bent due to misfitting, most get damaged by the primary chain which runs right by the side of it when this happens.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline martin_uk

  • SOHC Expert
  • Posts: 473
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #3 on: February 19, 2025, 06:03:04 PM »
Thanks guys will check
1977 CB750F1
1977 CB750f1 836
1978 CB750F1
1975 CB500K1

Triumph Street Triple 675R
Ducati 800 Icon Scrambler
Triumph 3TA
AJS 350 mod16
BSA BantamD1
Honda C90zz
Honda CB500X
BSA WD B40 350

Offline martin_uk

  • SOHC Expert
  • Posts: 473
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #4 on: February 19, 2025, 06:55:26 PM »
Good shout, sump off and bottom of tensioner out of recess.

Even with tensioner compressed not able to angle in enough as up against inside of head.

Will try again tomorrow, but suspect head may need to come off to get correct angle unless anyone has a special technique?
1977 CB750F1
1977 CB750f1 836
1978 CB750F1
1975 CB500K1

Triumph Street Triple 675R
Ducati 800 Icon Scrambler
Triumph 3TA
AJS 350 mod16
BSA BantamD1
Honda C90zz
Honda CB500X
BSA WD B40 350

Offline Oddjob

  • SOHC Jedi
  • Posts: 4588
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #5 on: February 19, 2025, 08:02:59 PM »
Most require the head off again. Lift the barrels an inch or so, compress the tensioner by hand and lock it off with the locknut, Then lower the barrels whilst making sure the end of the tensioner goes into the slot. Check the tensioner body isn't bent, a lot are. It should look straight to the eye. If it's bent straighten it.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Johnny4428

  • SOHC Jedi
  • Posts: 2738
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #6 on: February 19, 2025, 08:54:11 PM »
Might be of help? This is a picture of mine, you can clearly see where the tensioner end was! Now sitting in the correct position.



Sent from my iPad using Tapatalk
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1974 Honda CB550K1
1978 Honda CB550K3
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3
1977 Honda CB550 (almost)

Offline martin_uk

  • SOHC Expert
  • Posts: 473
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #7 on: February 20, 2025, 08:39:58 AM »
Might be of help? This is a picture of mine, you can clearly see where the tensioner end was! Now sitting in the correct position.



Sent from my iPad using Tapatalk

Thats great really helps
1977 CB750F1
1977 CB750f1 836
1978 CB750F1
1975 CB500K1

Triumph Street Triple 675R
Ducati 800 Icon Scrambler
Triumph 3TA
AJS 350 mod16
BSA BantamD1
Honda C90zz
Honda CB500X
BSA WD B40 350

Offline martin_uk

  • SOHC Expert
  • Posts: 473
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #8 on: February 20, 2025, 08:42:20 AM »
Might be of help? This is a picture of mine, you can clearly see where the tensioner end was! Now sitting in the correct position.



Sent from my iPad using Tapatalk

Thanks, it really helps
1977 CB750F1
1977 CB750f1 836
1978 CB750F1
1975 CB500K1

Triumph Street Triple 675R
Ducati 800 Icon Scrambler
Triumph 3TA
AJS 350 mod16
BSA BantamD1
Honda C90zz
Honda CB500X
BSA WD B40 350

Offline martin_uk

  • SOHC Expert
  • Posts: 473
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #9 on: February 22, 2025, 12:40:31 PM »
Unfortunately, as others have commented, can't fit the tensioner into locator with the head on.

The problem is the adjuster stud holds tensioner too far over before it can be inserted to bottom fixing.

Will try with head off but suspect barrels will need to be lifted as suggested to insert adjuster stud before lowering.
1977 CB750F1
1977 CB750f1 836
1978 CB750F1
1975 CB500K1

Triumph Street Triple 675R
Ducati 800 Icon Scrambler
Triumph 3TA
AJS 350 mod16
BSA BantamD1
Honda C90zz
Honda CB500X
BSA WD B40 350

Offline martin_uk

  • SOHC Expert
  • Posts: 473
    • View Profile
Re: CB500K2 four 1975 timing chain tensioner fitment
« Reply #10 on: February 23, 2025, 12:01:12 PM »
Most require the head off again. Lift the barrels an inch or so, compress the tensioner by hand and lock it off with the locknut, Then lower the barrels whilst making sure the end of the tensioner goes into the slot. Check the tensioner body isn't bent, a lot are. It should look straight to the eye. If it's bent straighten it.

Thanks Oddjob.

This was the only way to do it.
1977 CB750F1
1977 CB750f1 836
1978 CB750F1
1975 CB500K1

Triumph Street Triple 675R
Ducati 800 Icon Scrambler
Triumph 3TA
AJS 350 mod16
BSA BantamD1
Honda C90zz
Honda CB500X
BSA WD B40 350

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal