32 replies to this topic

[robelst]

Good morning campers, hi-di-hi!

Now then, finally started working on replacing that cam-chain.

I got Haynes next to me while doing all this. After some initial stages in the demolition process I am about to take off the camchain sprockets.

According to Haynes, one should turn cylinder 1 into TDC (cam-lobes facing away).
After doing this, you should get a situation where the "I" mark on the inlet side should align the "E" mark on the exhaust side.

Well, this is what I am looking at:


It's no less than 2 teeth out of line
Does this mean I have been riding around with the wrong timing (is that possible without things blowing up?), or does Haynes description apply to the older TDM/XTZ engines and not the 270 degrees engine and this is correct on mine (2001 model TDM)? I am possibly talking bollocks here but rather that than bollocksing the engine by changing it.

Thanks for suggestions, I am a bit at a loss at the moment

Edited by robelst, 13 January 2007 - 02:24 pm.

[Stink-Foot]

It's no less than 2 teeth out of line
Does this mean I have been riding around with the wrong timing (is that possible without things blowing up?), or does Haynes description apply to the older TDM/XTZ engines and not the 270 degrees engine and this is correct on mine (2001 model TDM)? I am possibly talking bollocks here but rather that than bollocksing the engine by changing it.

The timing is definitely wrong! The "I"-line should be aligned with the cylinder head, now it's about two teeth too late as you mentioned. You had loud rattle coming from the camchain area, didn't you? If so, we're looking at the reason.
Since the inlet valves have been opening later than they should they propably haven't touched the pistons. They could have suffered from burning though since they propably haven't been fully closed when the air/fuel mixture ignites. It's suprising it hasn't been backfiring in to the airbox.

You should check the chain tensioner carefully becouse it looks like the chain has jumped at some point. Either that or some (home)mechanic assembled it wrong after shim change.. wouldn't be the first time..
I would do a compression test before taking the head off. With a little luck the valves might be just fine.

[dapleb]

IFFFFFFFF you have set the engine up to TDC on #1 cyl (left) using the static markers and the cams on the left are facing outwards, then it looks loike yer toiming is oooot.

Some pics of how it looks on mkI tdm: http://www.carpe-tdm...o...0&hl=timing

Boop
dapleb

[Stink-Foot]

IFFFFFFFF you have set the engine up to TDC on #1 cyl (left) using the static markers and the cams on the left are facing outwards, then it looks loike yer toiming is oooot.

Actually I think the timing is out whether the #1 cyl is at TDC or not.. It looks like the E on exhaust is lined up with the head but I on inlet isn't. Of course if crank isn't at the right position it could be the exhaust side that's off.

On Mk1 there are sort of a punch marks on cams near the chain cogs which should point up when cyl #1 is at TDC. No idea if Mk2 cams have them too.

[dandywarhol]

Definately out - are you sure they didn't jump when you initially took the tensioner out???

I'm still pondering over your statement some time back about the tensioner on it's last click robelst..............surely the tensioner extends under the spring tension when you remove it from the engine block?? It's been bugging me a bit for a few weeks but I just haven't got round to looking at an 850 tensioner I have somewhere in my garage...............

PS..........is that really you in the avater?.......cos every time I see it I think of a half cooked bit of chicken I got out of a fast food joint in London 30 odd years ago - I've never entered one of their joints since............

Edited by dandywarhol, 13 January 2007 - 03:47 pm.

[Stink-Foot]

...surely the tensioner extends under the spring tension when you remove it from the engine block?? It's been bugging me a bit for a few weeks but I just haven't got round to looking at an 850 tensioner I have somewhere in my garage...............

If it doesn't extend it's stuck or the spring is broken. It's really simple design, there's just the spring and a latch that keeps the tensioner from moving backwards.

[dandywarhol]

Thats what I mean Pongo...........so you can't you tell the condition of the chain by that method cos the tensioner goes fully out........ The 900 is a different and inferior method IMHO - it seems to be a nut and screw arrangement which relies on the fact that a nut cannot unscrew a bolt if that makes sense........

[Stink-Foot]

Thats what I mean Pongo...........so you can't you tell the condition of the chain by that method cos the tensioner goes fully out........

You can tell how far the tensioner has extended if you unscrew the bolt at the outer end and remove the spring before removing the tensioner itself.

I think it's extremely easy to make the chain slip a tooth or two by following Haynes instructions. I'm pretty sure they say that the engine should be at #1 TDC when removing the tensioner but at least on a Mk1 there's slight valve pressure on one of the cams (can't remember which one) at that time. Removing the tensioner makes the cog slip and timings off... I would never remove the tensioner unless cam cover is off so I can see what's happening.

[robelst]

I'm pretty sure they say that the engine should be at #1 TDC when removing the tensioner but at least on a Mk1 there's slight valve pressure on one of the cams (can't remember which one)

That'll be the inlet cam (on the MK2 anyway, even on mine, despite the retarded inlet. ).

I left the tensioner on while turning cil.1 to TDC, to avoid jumping, so I am reasonably certain I have actually driven the bike like this

What puzzles me the most is how well the TDM ran on this setup. I've only had it for a few months and can't really compare with a properly timed TDM, but it's been a good starter (cold and warm), revving like there's no tomorrow, did 48 mpg (20 mls fast(ish) motorway-trips only, so pretty good) and no back-firing or other misbehaviour apart from flaky throttle response but had that resolved already. All valve clearances are spot-on too (all of them), and all guides seem in perfect nick.
The only reason I am doing all this was because of the loud cam chain. I noticed the new chain is only a tiny bit shorter than the old one, but that's not measured under load.


Thanks for all your responses.
Will check compression just to be sure, and will also take the tensioner to the friendly Yamaha dealer to ask their opinion (seems perfectly fine but then the bike ran perfectly fine too ).

Edited by robelst, 13 January 2007 - 05:25 pm.

[Stink-Foot]

The only reason I am doing all this was because of the loud cam chain. I noticed the new chain is only a tiny bit shorter than the old one, but that's not measured under load.

Your old cam chain is propably just fine. I bet the wrong timing caused that loud noise. I once had put the timing off by one tooth on my first bike and it made a loud ticking noise.

[robelst]

Your old cam chain is propably just fine. I bet the wrong timing caused that loud noise. I once had put the timing off by one tooth on my first bike and it made a loud ticking noise.

Hmm, I was already surprised the chain being this noisy after "only" 35k.
Interestingly I am also changing the drive chain, which is almost 2 links longer than the new one I about to put on; I had only half a mark-line left on the tensioner. Now that is a worn chain
Anyone interested in a used cam-chain?

PS..........is that really you in the avater?.......

It's a webcam. If you join the platinum membership of Carpe-TDM you can see me taking my clothes off
(actually, it's Johnny Painter from the Fast Show: It's the chap that goes bonkers while painting a rustic scene and discovering something in the landscape that is kind of.. black! ..... BLACK! ..... B L A C K!! Black is the colour of evil!! Lock me in the cellar and feed me pins!!! Blaack!!!!
Well, I thought it was funny )

Edited by robelst, 13 January 2007 - 06:48 pm.

[dapleb]

Well, I thought it was funny )

Pished me'sen when I saw it and you bike colour description.

[wicklamulla]

fookin hell PK i hope yer gonna be round (he he he) when i refit me cams and chain !

[wicklamulla]

Thet's by far the easiest bit of yer rebuild wick, are you gonna check the shims when it's in bits.

gonna check them and more while it's apart.

[robelst]

Checking the shims is dead-easy while you got the whole thing apart to fit a new chain: Just wiggle the cams around and get those feeler gauges out. I bet it gets a bit trickier though if you find you actually need to change any of the shims

[dapleb]

fookin hell PK i hope yer gonna be round (he he he) when i refit me cams and chain !

Not aboot much now.....once van is mot'd im off again and then to US in March!

[dandywarhol]

Ah......of course - I'd forgotten about Johnny Painter.........

[SPIN]

you could be looking in the wrong place for the noise
if poss check radial springs in back of clutch basket
you have to take it of mine were shagged at 40k makes
a noise like cam chain rattle