Author Topic: camchain tensioner  (Read 4793 times)

Offline bigmockuk

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camchain tensioner
« on: July 27, 2025, 12:55:38 PM »
ive had to take the head of my 550 k3 3 times to find out what the loud tapping sound was,it sounded like a very loose tappet even tho i knew they were all set,bike was misfiring on no 2 so while i had the head off i removed the valve springs thinking one had broken but all was good,so after i took out the camchain tensioner i saw what the issue was,about an inch n a half up from the bottom (facing towards back of engine) something has been hitting against it,so i thought maybe it had came out of place since i had did about 100 miles since barrel was last off,so i put it all back together and noise was still there  >:( so pulled it apart again and put a slight bend where the shiny groove was from whatever could be hitting it,built it up and hoped it would be ok but its not,its not as loud but still there,any one any ideas as to what could be hitting against the bottom of the tensioner?

Offline SteveW

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Re: camchain tensioner
« Reply #1 on: July 27, 2025, 02:16:36 PM »
Is the bottom end of the tensioner sitting properly in its groove in the case?

Very easy to fit it without it sitting in the correct place.
1974 CB550 K0 (with a 650 cam)
1980 CB650
2000 CBR929RR Fireblade
1966 Lambretta LI150 Series 3
1981 RD350LC
1972 Raleigh Chopper
1974 Raleigh Tomahawk
2011 Henry Hoover

Offline DomP

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Re: camchain tensioner
« Reply #2 on: July 27, 2025, 02:46:17 PM »
Do you have any photos of the tensioner?
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline Seabeowner

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Re: camchain tensioner
« Reply #3 on: July 27, 2025, 07:30:27 PM »
The bottom of the tensioner sits in a pocket in the crankcase. Best to remove the sump and check that it is correctly inserted.
Phil
1971  CB500K0  Candy Jade Green or Candy Gold
1973  CB500K1  Candy Ruby Red
1975  CB550F1   Shiny Orange

Offline bigmockuk

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Re: camchain tensioner
« Reply #4 on: July 27, 2025, 08:46:06 PM »
i dont have pics which is totally unlike me i take pics of everything i work on,my next question has just been answered,can the tensioner be seen from below when sump pan is removed? so thats my next job,if its half dry tomorrow i`ll get the pan off,take some pics n hopefully find a solution,so i`ll upload pics of what i find,cheers guys

Offline bigmockuk

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Re: camchain tensioner
« Reply #5 on: July 27, 2025, 08:52:41 PM »
steve W,the book says it just drops in,aye right! i had to fiddle with it before i could get it to sit properly and when the barrel was right down it wobbled like it was`nt sitting flush so took a few attempts to get it right,but i should see fom below if it is actually correct,cheers

Offline Johnny4428

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Re: camchain tensioner
« Reply #6 on: July 27, 2025, 09:50:21 PM »
This is what happens if the bottom of the tensioner is not seated in its location.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1974 Honda CB550K1
1978 Honda CB550K3
1999 ST1100 Pan European 50th Anniversary.
1975,1984,1986 Honda C90’s
1973 Honda CB750K3
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Offline SteveW

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Re: camchain tensioner
« Reply #7 on: July 27, 2025, 09:56:41 PM »
From memory, I think the Haynes manual says drop it in with the barrels. When the barrels are 10mm or so from being fully down, guide the end of the blade into its slot.
1974 CB550 K0 (with a 650 cam)
1980 CB650
2000 CBR929RR Fireblade
1966 Lambretta LI150 Series 3
1981 RD350LC
1972 Raleigh Chopper
1974 Raleigh Tomahawk
2011 Henry Hoover

Offline Johnny4428

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Re: camchain tensioner
« Reply #8 on: July 27, 2025, 09:57:33 PM »
This is the tensioner in the correct position. You can see a mark on the outside of the tensioner pocket where the bottom of the tensioner was before I stripped the engine.
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1974 Honda CB550K1
1978 Honda CB550K3
1999 ST1100 Pan European 50th Anniversary.
1975,1984,1986 Honda C90’s
1973 Honda CB750K3
1977 Honda CB550 (almost)

Offline bigmockuk

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Re: camchain tensioner
« Reply #9 on: July 27, 2025, 10:18:33 PM »
jonny4428 that pic you have of the marks on the tensioner is identical to the marks on mine!! which means its still not in place  :-[ cheers for the other pic it lets me see what to look for when i drop the pan,ive seen two vids on youtube now that shows the tensioner being fitted to the barrels prior to lowering the barrel? might be a good idea to do this,could take away the guess work

Offline Murf

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Re: camchain tensioner
« Reply #10 on: July 28, 2025, 10:46:49 PM »
This is the end of the tensioner I took out of my engine which had not been fitted into the pocket by the PO. 
The wear is from it being worn down by rubbing against the side of the primary chain, could that be the noise you are hearing.  It’s on a K1 so could be a bit different to yours.

Offline Murf

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Re: camchain tensioner
« Reply #11 on: July 29, 2025, 01:23:26 AM »
Also I don’t feel that it’s possible for the tensioner to properly tension the cam chain when the bottom end is not supported in the boot. There must be a degree of flexing which would  allow chain slap.  This is often most noticeable on tickover and on the overrun, this could be mistaken for  tapit  noise. 

Offline bigmockuk

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Re: camchain tensioner
« Reply #12 on: July 29, 2025, 09:37:35 AM »
ye definately murf,that pic posted by johnny is exactly the same as mine so its hitting that chain,i hope to take it apart again either today or tomorrow so i`ll post my findings cheers

Offline bigmockuk

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Re: camchain tensioner
« Reply #13 on: July 29, 2025, 10:23:24 PM »
got engine top half stripped down today and can verify that tensioner is i the wrong place,i also noticed a bolt had worked loose by quite a bit so eith vibration or PO not nipping it up

Offline bigmockuk

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Re: camchain tensioner
« Reply #14 on: July 29, 2025, 10:26:12 PM »
having to upload 1 pic at a time as it wont allow 2 or more ?
« Last Edit: July 29, 2025, 10:27:51 PM by bigmockuk »

 

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