Author Topic: Why do we adjust camchain tension  (Read 2026 times)

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: Why do we adjust camchain tension
« Reply #15 on: February 15, 2020, 06:29:25 PM »
Capricious is a great word for our old bikes.

As long as they are female of course.

If your bike is male (mine is) then it’s either a “good old boy” or a “bastard”




Sent from my iPhone using Tapatalk
Thought everyone of our generation called them "she"
After all, they consume all your time, all your money, and still give you sh#i/ let you down when you really don't need it!

Sent from my POT-LX1 using Tapatalk
😂 😂 😂 😂 😂 😂
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline mattsz

  • SOHC Pro
  • Posts: 606
    • View Profile
Re: Why do we adjust camchain tension
« Reply #16 on: February 16, 2020, 10:55:19 AM »
I'll be naming my next CD "Smoky and Capricious"...


 ::)
Does it sound strange in english?

Not strange... just unusual and, to my mind anyway, amusing to see those two words together.  "Capricious" is a great word!

Carry on, marroinia, your English is 1000% better than my French will ever be!

Offline marroinia

  • Newbie
  • Posts: 35
    • View Profile
Re: Why do we adjust camchain tension
« Reply #17 on: February 20, 2020, 01:12:59 PM »
Well, I replaced the missing damper! The bottom one was in place so did't need to do surgery. I tried again to play with the horse shoe and it's still moving ok. The two blades are in good condition.

Unfortunetely, the chain is still noisy whatever the methode I try to tight it (set up at 1200rpm, set up while pushing on the kick, set up at few degrees after N*1 TDC...) I noticed a soft link on the camchain... best thing to do now is to replace that chain, I guess.
I hope I'm not to confident with the tensioner...

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: Why do we adjust camchain tension
« Reply #18 on: February 20, 2020, 03:03:09 PM »
If the tensioner is mobile and the blades OK but you still have a rattle then the chain must be beyond spec and needs changing. If its already got a soft link chain fitted, that means it's been changed from the standard endless chain in the past, so the one you fit will be its 3rd in 16,000 miles.... That is very strange and shows the engine has had a hard life.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline marroinia

  • Newbie
  • Posts: 35
    • View Profile
Re: Why do we adjust camchain tension
« Reply #19 on: February 20, 2020, 06:37:46 PM »
Like you said that engine eats too many chains, or the mileage is lying...even if pushing hard the revs, how come to screw 2 kits in only 25000km?

Just to be sure that it's a soft link, there is no darker link on the original chain, is it?

Anyway I ordered a new chain with soft link, if still noisy then I'll have to put the engine on the table. :-\

Offline marroinia

  • Newbie
  • Posts: 35
    • View Profile
Re: Why do we adjust camchain tension
« Reply #20 on: April 18, 2020, 08:39:16 PM »
Hi every one!

I finally replaced that camchain today.
The new chain is 63.7mm long when splitted, so was the one I removed...I feel like I spent time and money for nothing. It has been changed not long ago and that probably matches to head gasket change claimed by PO. Better be safe than sorry: the bike has a new camchain again... can't be bad -_-

Anyway, while playing around again with camchain tensionner, something poped up to my mind: I did a ride not long ago, after last time I opened the engine and post here, and deciced to "true" the tension to reduce camchain noise while engine hot, following normal procedure: noise became worst. Today, I noticed that the tension provided by the tensioner blade is stronger that the springs behind the pushrod.

When I screw the tensioner blade upper part [5] all the way down and untight the push rod bolt in front of engine [12]: the chain become loose.
I have to loosen the two screws [19] back around 6mm on the upper part [5] then lock the push rod bolt [12], then tighten the upper part to get proper tension on the chain.

I'm quiet lost here, the horse shoe isn't seized...did my tensioner blade become harder with age? Like it fossilized? Springs are too old with only 25000kms?

Anyone can help me? 


[ Guests cannot view attachments ]


« Last Edit: April 18, 2020, 08:41:04 PM by marroinia »

Offline Bryanj

  • Grogu
  • *
  • Posts: 10692
    • View Profile
Re: Why do we adjust camchain tension
« Reply #21 on: April 18, 2020, 09:09:12 PM »
It was never a good system from new.
There are several things that happen
1 the springs pushing the horseshoe go weak
2 where the clamping bolt tightens on the flat on the rod it makes a little indent and when you loosen the bolt the retighten the end goes back into the indent already there
3 the tensioner plunger gets a little tight in its bore.

My method for tensioning is loosen the clamp bolt,  put som weight onto to kickstart so that the engine is just about to turn then whilst holding this tension tighten the clamp bolt.

You can also remove the blanking cap and push on the rod end then tighten bolt but as you need to do that with engine running hands get hot on exhaust

Offline billywingnut

  • SOHC Associate
  • Posts: 56
    • View Profile
Re: Why do we adjust camchain tension
« Reply #22 on: April 18, 2020, 09:29:20 PM »
I tend to agree with your last post Marronia, I fitted  a new cam chain and guides when I had the engine down a couple of years back. I noticed the chain was noisier after adjusting when the engine was hot. I have the rocker cover off at the moment and checked the chain for play and was surprised by the amount of play. When undoing parts 19 the tensioner did lift part 5 slightly say 2 mm. I thought perhaps the rubber part 4 might be missing or damaged, but no, it is fine. So like you I intend loosen bolts 19 and increase the tension a little. To be honest it was n't very noisy but I like things to be as good as I can get it.

Online Orcade-Ian

  • SOHC Master
  • Posts: 1080
    • View Profile
    • Older Vehicle Web
Re: Why do we adjust camchain tension
« Reply #23 on: April 19, 2020, 09:13:46 AM »
Now that’s a strange coincidence,
I’m nearing completion of the ‘Scottish’ 400/4 and needed to get pictures for the agreed value at policy renewal so I didn’t fit everything finally around the cam cover.  Now I’ve finished zinc plating all of the cover bolts and other bits I decided to remove the cover for the new gasket, having read this post and thought I would investigate.  I had already sorted the horseshoe when I had the thing completely apart and it was as free as a new one.  I had NOS springs from years ago, new damper rubbers, new gen tensioner blade and new gen guide, together with a new genuine DS endless chain - everything Honda.
With the cam cover off, I loosened the adjuster and heard the whole thing move under spring tension.  HOWEVER, just as Billy and Marroinia report there is still slack in the chain.  I must admit, I’ve never checked the system this way before and not had problems. So what’s going on here?

Ian

Offline Bryanj

  • Grogu
  • *
  • Posts: 10692
    • View Profile
Re: Why do we adjust camchain tension
« Reply #24 on: April 19, 2020, 09:33:25 AM »
Ian, if you still have the cover off try adjusting again with the tension on the crank as i posted and see if the chain is tighter

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: Why do we adjust camchain tension
« Reply #25 on: April 19, 2020, 09:46:39 AM »
We have never noticed any slack on any of the 350/400 cam chains on engines built (after fitting everything new). A minute bit of sideway movement of the chain on the sprocket but no movement horizontally of the chain on the sprocket, ie, no play at all once adjusted.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline taysidedragon

  • SOHC Master
  • Posts: 1318
    • View Profile
Re: Why do we adjust camchain tension
« Reply #26 on: April 19, 2020, 10:07:25 AM »
If the cam cover is off then the cam and camchain gearwheel are not held securely in position. That shouldn't affect camchain tension because the cam is held down by by the chain itself, but the engine was designed to have the tension set when fully assembled and running.
If all the components are serviceable a bit of camchain noise shouldn't be a problem. If it's too noisy I would suggest there is a problem with worn tensioner blades perhaps, or weak springs on the tensioner rod?
Gareth

1977 CB400F
1965 T100SS

Offline marroinia

  • Newbie
  • Posts: 35
    • View Profile
Re: Why do we adjust camchain tension
« Reply #27 on: April 19, 2020, 10:16:57 AM »
I did your method as well Bryanj, without better result in my case. But I agree when you push the kick you give tension on the front side, the rear slacken and tensioner push further in, that make sense, but not on my bike.

When I removed the 2 bolts [19] it lift [5] up around 2 mm like said Billywingnut, I understand we need a bit of play especially when cold but I have no tension at all in my chain. The  cam sprocket have angle play,  giving to my opinion the erratic idle, knocking noise and random stall until engine shuts down.

The way i did tension by hand gives just a little slack in the chain and doesn't allow the cam sprocket to move around, I will give start today and see if everything sounds better.

Offline taysidedragon

  • SOHC Master
  • Posts: 1318
    • View Profile
Re: Why do we adjust camchain tension
« Reply #28 on: April 19, 2020, 10:24:00 AM »
The cam sprocket is fixed to the camshaft and shouldn't have any play or sideways movement. You need to check why it is moving.
Gareth

1977 CB400F
1965 T100SS

Offline marroinia

  • Newbie
  • Posts: 35
    • View Profile
Re: Why do we adjust camchain tension
« Reply #29 on: April 19, 2020, 10:29:08 AM »
taysidedragon, yep the cam is moving angle as well, its fixed to the sprocket but like you said the headcover is supposed to be in place and engine warm...

I think I'm going to buy that special bolt that pushes on the tensioner rod and adjust  by ear. I had  the chain noise on all the rpm range after I tried to adjust in normal condition.

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal