Timing problem?

Saint UK · Post by **Saint UK** » Tue Mar 04, 2014 1:28 pm

Hey guys, I'm new here, and llyodie from Coventry bikers pointed me in your direction...

Basically, I've just done the valve clearances on my VTR Firetorm (00). I'm a bit new to all of this and I'm learning as I go, but I just wondered if anyone could give me some advice. All the clearances are now correct, but my problem is with the timing. when I align the crank marker for TDC on the compression stroke for the front cylinder, the marks on the cam sprockets don't align properly to the point they're supposed to. if I rotate the cams to the next teeth to try and adjust the alignment, it goes too far in the opposite direction. When I align the rear cylinder to TDC the cam sprocket markers align perfectly with the plane of the cam deck on both sprockets.

The miss-match on the front cylinder is probably only out by a couple of degrees or so, but I suppose my question is how critical is this? If I rotate the crank a few degrees further on then both cams are then correctly aligned to the cam deck. Is it normal to have slight discrepancies in the alignment of the markers, or does this point to another issue (or more likely something i'm doing wrong?) Unfortunately I didn't look closely enough before I removed the camshafts to know if this was how they had always been... Is this something that is often observed on VTRs or do I have a problem. I've been advised that this could be a stretched cam chain, but is this likely to cause me problems? I haven't tried running the engine up again yet until I'm confident I'm not inadvertently going to cause damage etc.

The bike already has manual CCTs fitted and correctly adjusted (I've read between 5-7mm of play between the cam sprockets...)

I hope I've explained that ok, but if I've not or you'd need more information, just let me know. Anyway, if anyone can give me some pointers on this it would be much appreciated. Looking forward to getting her back on the road to enjoy some more of the sun that I'm confident is just around the corner! Cheers.

Jamoi · Post by **Jamoi** » Tue Mar 04, 2014 1:34 pm

Hey welcome

I wouldn't worry about the timing marks being slightly out, as long as it's not more than a tooth.

So if you have tried them 1 tooth the other way and it makes them further out, put them back to the closest original position and you'll be fine

Make sure you crank it over by hand before firing it up, just to check theres no contact or nastiness going on.

No doubt there is someone here who can explain it with more accuracy than I

lloydie · Post by **lloydie** » Tue Mar 04, 2014 2:05 pm

Welcome :-)
As I said on cov bikers as long as it's not one tooth out it will be fine and as Jamio says get it as close as you can and all will be good .
The cam chain do stretch over time more so if the cam chain tentioners have been over tightened .

Veturinkuljettaja · Post by **Veturinkuljettaja** » Tue Mar 04, 2014 2:10 pm

I noticed the exact same problem couple years ago when I installed my manual CCT:s and adjusted the valve clearances. When the flywheel marking was spot on, cams were about half a tooth off.

Here is a discussion on the same matter: http://www.vtr1000.org/phpBB3/viewtopic.php?f=9&t=31293

So basically no need to worry... The reason why this happens, I can't quite tell.

It could be misaligned markings from factory, wear on camchain and related components, slack in the whole system, etc.

VTRDark · Post by **VTRDark** » Tue Mar 04, 2014 4:04 pm

Welcome

As has been said with wear and tear things stretch a little causing the marks to be off slightly. The problem is most likely that you can move one tooth in either direction but you need a half tooth to be spot on. Obviously it's not possible to stop at a half tooth as it falls in the middle of the link, so you end up choosing the best out of the two options. The Honda timing marks are not that precise so there is room for some error. Hope that makes sense! You will be fine

(:-})

E.Marquez · Post by **E.Marquez** » Tue Mar 04, 2014 5:50 pm

Veturinkuljettaja wrote:I noticed the exact same problem couple years ago when I installed my manual CCT:s and adjusted the valve clearances. When the flywheel marking was spot on, cams were about half a tooth off.

Here is a discussion on the same matter: http://www.vtr1000.org/phpBB3/viewtopic.php?f=9&t=31293

So basically no need to worry... The reason why this happens, I can't quite tell. It could be misaligned markings from factory, wear on camchain and related components, slack in the whole system, etc.

IF this is the issue,, ie the cams are timed correctly and the crank in proper position, with the cam markings still off a bit.. the issue is chain wear... Very common for ALL chain driven cams motors.

A fresh chain and manual tensioner set correctly will allow for better, more accurate timing over a longer period... then use of the ACCT (AKA ACCS..Automatic Cam Chain Stretcher)

Likely performance between a motor with fresh cam chain, degreed cams, and perfect cam timing and one that is 1/2 tooth off due to a worn chain.. is all but un realized using a Seat O Pants Dyno

darkember · Post by **darkember** » Tue Mar 04, 2014 6:36 pm

Ok one question I have & that is when I take up the tension on the exhaust side on the front pot how firm does it need holding while pulling it over the cam sprocket??

Veturinkuljettaja · Post by **Veturinkuljettaja** » Tue Mar 04, 2014 7:46 pm

E.Marquez wrote:
Veturinkuljettaja wrote:I noticed the exact same problem couple years ago when I installed my manual CCT:s and adjusted the valve clearances. When the flywheel marking was spot on, cams were about half a tooth off.

Here is a discussion on the same matter: http://www.vtr1000.org/phpBB3/viewtopic.php?f=9&t=31293

So basically no need to worry... The reason why this happens, I can't quite tell. It could be misaligned markings from factory, wear on camchain and related components, slack in the whole system, etc.
IF this is the issue,, ie the cams are timed correctly and the crank in proper position, with the cam markings still off a bit.. the issue is chain wear... Very common for ALL chain driven cams motors.

A fresh chain and manual tensioner set correctly will allow for better, more accurate timing over a longer period... then use of the ACCT (AKA ACCS..Automatic Cam Chain Stretcher)

Likely performance between a motor with fresh cam chain, degreed cams, and perfect cam timing and one that is 1/2 tooth off due to a worn chain.. is all but un realized using a Seat O Pants Dyno

Hmm.. Shouldn't the front and rear cam chain wear at the same rate? At least for me, the rear cylinder timing was pretty much perfect. IF there was a front CCT failure, could this stretch the chain and cause the timing to "stretch" a bit?

Jamoi · Post by **Jamoi** » Tue Mar 04, 2014 7:50 pm

Veturinkuljettaja wrote:
Hmm.. Shouldn't the front and rear cam chain wear at the same rate? At least for me, the rear cylinder timing was pretty much perfect. IF there was a front CCT failure, could this stretch the chain and cause the timing to "stretch" a bit?

My front cam chain is more stretched than the rear, never had a previous cct failure though.

So I wouldn't be too worried

parkergb6 · Post by **parkergb6** » Tue Mar 04, 2014 7:56 pm

I had exactly this same problem a few months ago when I rebuilt the front cylinder head.
Have a look and see if this is what you mean....
http://vtr1000.org/phpBB3/viewtopic.php?f=9&t=31293

I have put mine together and runs great if I can just stop transit drivers reversing over me.

parkergb6 · Post by **parkergb6** » Tue Mar 04, 2014 7:57 pm

Stupid me I see the same link was mentioned earlier.

Veturinkuljettaja · Post by **Veturinkuljettaja** » Tue Mar 04, 2014 7:57 pm

Jamoi wrote:
Veturinkuljettaja wrote:
Hmm.. Shouldn't the front and rear cam chain wear at the same rate? At least for me, the rear cylinder timing was pretty much perfect. IF there was a front CCT failure, could this stretch the chain and cause the timing to "stretch" a bit?
My front cam chain is more stretched than the rear, never had a previous cct failure though.

So I wouldn't be too worried

Nah, I'm not really worried.. Just curious about why the front chain would stretch more, after all, the load on the chain should be equal on both chains?

Jamoi · Post by **Jamoi** » Tue Mar 04, 2014 8:05 pm

Veturinkuljettaja wrote:Nah, I'm not really worried.. Just curious about why the front chain would stretch more, after all, the load on the chain should be equal on both chains?

Ahh right, sorry just trying to put your mind at ease

I'd be interested to hear anyone's theory on the front chain wearing quicker too

Veturinkuljettaja · Post by **Veturinkuljettaja** » Tue Mar 04, 2014 8:35 pm

Jamoi wrote:
Veturinkuljettaja wrote:Nah, I'm not really worried.. Just curious about why the front chain would stretch more, after all, the load on the chain should be equal on both chains?
Ahh right, sorry just trying to put your mind at ease

I'd be interested to hear anyone's theory on the front chain wearing quicker too

My mind has been at ease since I installed manual CCT:s...

Maybe it's the uneven firing interval that causes more stress on the front chain?

tony.mon · Post by **tony.mon** » Tue Mar 04, 2014 9:27 pm

Or the oil draining away from the front pot during wheelies and accelaration.

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