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When Is A Camchain Worn?


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#1 drewpy

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Posted 24 October 2016 - 02:17 pm

Hi Folks,

 

 

Just doing the shims on the TDM at 34,500 miles and looks like it's never been done :unsure2:

 

the cam peened over the alloy bearing surface so I had to use a rat tail file to dress the edges just to get the buckets out.

 

Anyways, to the main part of the post. How do you know when the cam chain is fubarred?

 

the tensioner has 10mm left on the ratchet (say 3/4 used) is this the only indicator?

 

doesn't seem particularly noisy in operation either. I've only had the bike a month so not au fait with the bikes yet.

 

cheers Me dears


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#2 Studley Ramrod

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Posted 24 October 2016 - 05:35 pm

If the chain has stretched, you'll find it impossible to line up the valve timing so it's spot on.  That said, it'll still run fine if it's half a tooth out.  Sounds like you've got plenty of adjustment left yet though. :)


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#3 drewpy

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Posted 24 October 2016 - 05:46 pm

If the chain has stretched, you'll find it impossible to line up the valve timing so it's spot on.  That said, it'll still run fine if it's half a tooth out.  Sounds like you've got plenty of adjustment left yet though. :)

great news, saves a few pennies

thanks


"As I Lay Rubber down to street, I pray for traction I can keep. But if I skid and begin to slide, please dear god protect my ride"

Mods; Oil pressure switch, neoprene rear inner mudguard, scottoiler, highway pegs,  fenda extenda, 1999 carbs and airbox, Kais suspension setup, later clutch springs, LED lamps, Metmachex swingarm, Hagon Shock, Oxford heated grips, 4 way fused accessory Bus, 17" 3CV front wheel, Michellin R6 tyres, GPS speedo, 5' ignition advance.


#4 fixitsan

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Posted 24 October 2016 - 07:43 pm

Having had a new chain in my hands, i find that bending the extended chain sideways across the direction of the pins and comparing it to a new chain shows how much it has worn

 

Because the stretching of a chain is actually the link pins wearing, a very worn chain can be 'bent' considerably more than new one

 

The problem is that the gap between the two cam chain sprockets is not adjustable in any way, so once the chain has worn beyond a certain point the timing has to slip out in order to take up the slack. If some of the link pins have not worn equally then while that section of chain is on a sprocket you can have a little bit of slack, or excessively high tension, because the tensioner cannot release tension momentarily in order to allow the chain on the tensioned side to take up any inequality in chain run lengths

 

Another way to check is by pushing two adjacent links together and then pull them apart....sometimes you can find that one link seems to have much more free play than the rest....if you do then change the chain

 

 

 

If you have the chain off (any chain) you can find which is least worn by bending them and laying them side by side. These are camchains from a different bike, the top one is clearly least worn, and in fact could be new... 

https://www.flickr.c...N02/7583223482/

 

https://www.flickr.c...N02/7583223482/

 

 

 

another way is to use calipers to measure the length of 10 links under tension, divide by 10 and then compare that the specified chain pitch


Edited by fixitsan, 24 October 2016 - 07:59 pm.

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#5 fixitsan

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Posted 24 October 2016 - 09:59 pm

Hi Folks,

 

 

Just doing the shims on the TDM at 34,500 miles and looks like it's never been done :unsure2:

 

the cam peened over the alloy bearing surface so I had to use a rat tail file to dress the edges just to get the buckets out.

 

 

 

 

 

 

i'ld worry about that peening over. The reason I've just changed my mk2 head is for exactly the same problem. Other owners have had the same problem. The oil feed hole also gets peened over, reducing it's diameter and eventually there is too little oil in the journal

 

Attached File  cam.jpg   78.55KB   6 downloads

 

 

Mine was the Cyl1 inlet cam... what was yours ?


Edited by fixitsan, 24 October 2016 - 10:00 pm.

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#6 dandywarhol

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Posted 24 October 2016 - 10:49 pm

The first time I've heard someone use the correct term for chain wear - chains don't stretch - the pins wear.  :clapping:


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#7 fixitsan

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Posted 24 October 2016 - 11:07 pm

The first time I've heard someone use the correct term for chain wear - chains don't stretch - the pins wear.  :clapping:



I deserve a payrise ;)..... actually the holes in the link plates wear quite often too, not just the pins, being pedantic though

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#8 dandywarhol

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Posted 24 October 2016 - 11:08 pm

I deserve a payrise ;)..... actually the holes in the link plates wear quite often too, not just the pins, being pedantic though

 

I consider my wrist well and truly slapped


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#9 JBX

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Posted 24 October 2016 - 11:18 pm

Camshaft sprockets also wear, you need to check them too.

 

Timing chain &  camshaft sprockets should be changed as a whole.


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#10 fixitsan

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Posted 25 October 2016 - 06:41 am

I consider my wrist well and truly slapped


Damnit. No payrise for me ..... is it too late to request just cake ? :)

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#11 drewpy

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Posted 25 October 2016 - 08:44 am

 

 

i'ld worry about that peening over. The reason I've just changed my mk2 head is for exactly the same problem. Other owners have had the same problem. The oil feed hole also gets peened over, reducing it's diameter and eventually there is too little oil in the journal

 

attachicon.gifcam.jpg

 

 

Mine was the Cyl1 inlet cam... what was yours ?

most of them, a couple of the cam cap bolts were not very tight either. I'll check the holes.

 

The bike runs fine though, no horrible noises


"As I Lay Rubber down to street, I pray for traction I can keep. But if I skid and begin to slide, please dear god protect my ride"

Mods; Oil pressure switch, neoprene rear inner mudguard, scottoiler, highway pegs,  fenda extenda, 1999 carbs and airbox, Kais suspension setup, later clutch springs, LED lamps, Metmachex swingarm, Hagon Shock, Oxford heated grips, 4 way fused accessory Bus, 17" 3CV front wheel, Michellin R6 tyres, GPS speedo, 5' ignition advance.


#12 drewpy

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Posted 25 October 2016 - 09:55 pm

one hole was about 2mm, just opened it up with a 3mm handrill (was my grandads) with grease to collect the swarf.

 

cams are ok, just waiting for the new shims to arrive


"As I Lay Rubber down to street, I pray for traction I can keep. But if I skid and begin to slide, please dear god protect my ride"

Mods; Oil pressure switch, neoprene rear inner mudguard, scottoiler, highway pegs,  fenda extenda, 1999 carbs and airbox, Kais suspension setup, later clutch springs, LED lamps, Metmachex swingarm, Hagon Shock, Oxford heated grips, 4 way fused accessory Bus, 17" 3CV front wheel, Michellin R6 tyres, GPS speedo, 5' ignition advance.


#13 Apache

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Posted 06 November 2016 - 10:01 pm

Don't worry too much about your cam chain drewpy. My 4tx3 will hit 100000 miles soon and no sign of wear. Regardless of how much fresh oil I add between service intervals she still gets clean oil and filter every 4k miles. Seems to have kept at bay all the woes I read about on here, though I know it's tempting fate to say so.

#14 fixitsan

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Posted 06 November 2016 - 10:19 pm

I think if you set the engine to TDC and then wind it back clockwise by 30 crank degrees (cloxkwise when looking at left side). You can remive the tensioner spring and bolt, followed by the tensioner mechanism.....how far out the tensioner plunger sits will show how worn the chain is......then refit tensioner, then the spring.


The new chain which i just fitted was about 8-10mm shorter than the worn one. With so much wear the cam timing must have been out quite a bit (more wear = both cam actions retarded with respect to the crank position)

In my case both worn chains i tried had been oil starved at some ppoint.From experience, it is unusual for even a well worn chain of this type the break, but the valve timing change might be considerable, but probably no more than if a chain was half a tooth out

Edited by fixitsan, 06 November 2016 - 10:21 pm.

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#15 drewpy

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Posted 06 November 2016 - 10:37 pm

Thanks Guys, the PO had nice oil in there and I just changed mine along with the filter

 

I think I will also check the oil strainer too. Some PO has used silicone and just a bit worried that some will have found its way down there.

 

is this an easy job?


"As I Lay Rubber down to street, I pray for traction I can keep. But if I skid and begin to slide, please dear god protect my ride"

Mods; Oil pressure switch, neoprene rear inner mudguard, scottoiler, highway pegs,  fenda extenda, 1999 carbs and airbox, Kais suspension setup, later clutch springs, LED lamps, Metmachex swingarm, Hagon Shock, Oxford heated grips, 4 way fused accessory Bus, 17" 3CV front wheel, Michellin R6 tyres, GPS speedo, 5' ignition advance.


#16 fixitsan

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Posted 06 November 2016 - 11:39 pm

The sump needs to come off (exhaust off first) ...which gives access to the strainer underneath.

Might need to change the sump gasket afterwards

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#17 drewpy

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Posted 07 November 2016 - 02:36 pm

The sump needs to come off (exhaust off first) ...which gives access to the strainer underneath.

Might need to change the sump gasket afterwards

thanks, pretty straightforward then


"As I Lay Rubber down to street, I pray for traction I can keep. But if I skid and begin to slide, please dear god protect my ride"

Mods; Oil pressure switch, neoprene rear inner mudguard, scottoiler, highway pegs,  fenda extenda, 1999 carbs and airbox, Kais suspension setup, later clutch springs, LED lamps, Metmachex swingarm, Hagon Shock, Oxford heated grips, 4 way fused accessory Bus, 17" 3CV front wheel, Michellin R6 tyres, GPS speedo, 5' ignition advance.


#18 fixitsan

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Posted 07 November 2016 - 02:57 pm

thanks, pretty straightforward then

 

 

Yep....taking off the sump gives you access enough to peer into the underside of the strainer....actually removing the strainer is easy too, just 4 large philips head screws, but you would probably be able to pick out any dross without removing it completely


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#19 drewpy

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Posted 07 November 2016 - 08:44 pm

 

 

Yep....taking off the sump gives you access enough to peer into the underside of the strainer....actually removing the strainer is easy too, just 4 large philips head screws, but you would probably be able to pick out any dross without removing it completely

:badgerrock:


"As I Lay Rubber down to street, I pray for traction I can keep. But if I skid and begin to slide, please dear god protect my ride"

Mods; Oil pressure switch, neoprene rear inner mudguard, scottoiler, highway pegs,  fenda extenda, 1999 carbs and airbox, Kais suspension setup, later clutch springs, LED lamps, Metmachex swingarm, Hagon Shock, Oxford heated grips, 4 way fused accessory Bus, 17" 3CV front wheel, Michellin R6 tyres, GPS speedo, 5' ignition advance.


#20 PeterM91

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Posted 10 March 2019 - 11:21 am

Rather then starting a new thread....

In need of some advice. I'm checking my valve clearance and found the cam chain sprockets a bit off.

They appear to be off for just 1 mm on the markings.

What do you reckon: worn cam chain or normal wear?
The engine is running pretty smoothly. All the valves are with in tolerance.

Just 125.000 km on the clock.

Attached File  P1020135a.JPG   50.42KB   1 downloads

 

And with an allen key across the cylinder head just to make in more visible:

Attached File  P1020141a.JPG   53.79KB   1 downloads

Attached File  P1020146a.JPG   37.48KB   1 downloads

 




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