Cam timing experts needed

[Harald]

My 2007 FJR1300 has been in spec for all previous valve clearance checks until the latest one at 110,000 miles. The outboard #4 exhaust was too tight and 3 other valves were at the lower limit, so all 4 were adjusted.

The crank gear was positioned correctly, the #1 cam lobes were pointing outward and a cursory check of the cam holes showed them up. Shims were replaced and cams reinstalled. After rotating everything a few times, I lined up the crank gear at TDC and verified with the #1 cam lobes. Using a light and sighting down the head flange, I see that the cam gears are both off a little. Can’t figure out how that could happen because I had zip ties on both cams and both cam chain guides, so theoretically it must be still be in time but it’s off a little.

Here’s a picture of the cam hole position when the crank gear is set to TDC:

I should note that it's more obvious looking at the marks on the gears, but you can barely see those let alone take a picture of them.

Here’s a picture of the crank gear position when the cam timing marks are both lined up per the FSM:

So I shifted the chain one tooth on the crank gear and this made it much worse. Crank gear chain positioned back to starting position. I then moved the chain one tooth on the cam gears and this also resulted in worse timing.

My problem started with me not more carefully checking the cam timing before ripping things apart, so I don’t know how it looked before I started. At this point it looks like I’ve got it as close as can be or am I missing something? Is what I’m seeing normal for the FJR? I know there’s lots of you that have done this task and I’m a FJR cam timing newbie. At this point I’m thinking stretched chain, but I haven’t heard of anyone needing to change a chain for this problem. Any ideas?

 

[Constant Mesh]

That's likely just fine. There are 19 teeth on the crankshaft sprocket and 38 on the camshaft sprockets.

360 degrees / 19 teeth = 19 degrees between teeth on the crankshaft.

The crankshaft error you're showing is nowhere near 19 degrees.

The circumference of the camshaft lobe (assuming it is round) is 78 mm.

78 mm / 38 teeth = 2 mm

So, you'd see a 2 mm alignment error using your ruler if you were mis-timed by one tooth on the camshaft sprocket.

That would be quite obvious.

No doubt the sprockets wear a bit as well as the chain.

I'm also curious if the long chain guide/damper on the front (exhaust side) doesn't wear a bit over time allowing the chain to appear to be longer between crankshaft and exhaust cam. Looking at a side view drawing it appears that guide ever so slightly deflects the chain from a perfect straight line path. Maybe the guide wears just a bit over time and the chain is deflected less and less. If there is an effect you'd guess it would be very, very small.

 

[RaYzerman19]

The primary datums are the marks on the right (outboard) side of the cam sprockets, see FSM. Before removing cams it is advisable to set the TDC, etc. and verify those marks. When you get it back together you can recheck those marks. The holes in the cam to me are verification that you're in the ballpark. In this case, it looks like to me you are fine. You can always verify by looking at those sprockets. Admittedly, it's a gunsight job with a good flashlight and some would use a small mirror.

 

[Donal]

"Here’s a picture of the crank gear position when the cam timing marks are both lined up per the FSM:"

Your crank gear timing marks look slightly off in the picture above. You might want to re-set that and then try your alignments again.............

 

[Biquer]

The dealer gave me back my bike with the cam timing out. Best way to check is to use the timing marks on the chain wheels/cam sprockets. There are pictures on this forum of that. You need a ruler, a light and a small inspection mirror to check the timing marks, the dots on the cams are open to interpretation. When mine were out the marks on the cam sprockets were nowhere near horizontal. It was obvious they were out.

 

[Harald]

"Here’s a picture of the crank gear position when the cam timing marks are both lined up per the FSM:"

Your crank gear timing marks look slightly off in the picture above. You might want to re-set that and then try your alignments again.............

This photo was posted only to show where the crank needs to be positioned when both cam gear marks are perfectly lined up. The problem is that if I try to move the chain on either the cams or the crank sprockets, it gets even further out. So it looks like I'm timed as good as can be with possible cam chain stretching or rub block wear?

 

[Harald]

The primary datums are the marks on the right (outboard) side of the cam sprockets, see FSM. Before removing cams it is advisable to set the TDC, etc. and verify those marks. When you get it back together you can recheck those marks. The holes in the cam to me are verification that you're in the ballpark. In this case, it looks like to me you are fine. You can always verify by looking at those sprockets. Admittedly, it's a gunsight job with a good flashlight and some would use a small mirror.

Thanks. I'm using the marks on the cam gears, but just couldn't post a picture of those with the camera equipment I have and the engine in the frame.

Hindsight is 20/20 and I really wish I had checked the cam gear marks more closely before pulling things apart, but too late for that now. At this point I'm just milking the collective minds of the FJR experts to determine whether this is an acceptable tolerance or if there's something I can do to get it better (I can only think of new cam chain or replacement chain guides).

 

[Harald]

That's likely just fine. There are only 19 teeth on the crankshaft sprocket and 38 on the camshaft sprockets.
360 degrees / 19 teeth = 19 degrees between teeth on the crankshaft.

The crankshaft error you're showing is nowhere near 19 degrees.

The circumference of the camshaft lobe (assuming it is round) is 78 mm.

78 mm / 38 teeth = 2 mm

So, you'd see a 2 mm alignment error using your ruler if you were mis-timed by one tooth on the camshaft sprocket.

That would be quite obvious using your ruler.

No doubt the sprockets wear a bit as well as the chain.

I'm also curious if the long chain guide/damper on the front (exhaust side) doesn't wear a bit over time allowing the chain to appear to be longer between crankshaft and exhaust cam. Looking at a side view drawing it appears that that guide ever so slightly deflects the chain from a perfect straight line path. Maybe the guide wears just a bit over time and the chain is deflected less and less. If there is an effect you'd guess it would be very, very small.

Thanks for the math. Hard for me to quantify how many degrees off it it visually, so I'll print out a degree wheel to get a value: https://www.blocklayer.com/degree-wheel.aspx

 

[Fred W]

The first photo of the cam alignment does not look to be perfectly in time. It looks like the dot is slightly ******** to the arrow mark on the cam cap. Plus, your photo is not from directly above the cam. I can tell by looking at the two cap bolts. They should have equal parallax and they do not. So, if you advanced the cam to where it would actually be correctly timed, what does the crank mark look like? It should make the error even larger than in your second photo.

Alternatively, set the crank mark to perfectly correct and then take a shot of the cam from immediately straight above it (watch those bolts).

Or is this what the photos are supposed to be showing? The amount the cam is off when the crank is perfect and the amount the crank is off when the cams are perfect. If that is what you were showing then this may be as good as you can get

 

[hppants]

Disclaimer - I'm no cam timing expert, as abundantly evident throughout this forum.

Sir, I feel your pain. I just went through this with MikeP1300's bike. You can read about it here:

https://www.fjrforum.com/forum//index.php/topic/167122-bent-valves-or-no/

If it is any consolation, we read and listened to the fine people on this forum (many of which have already jumped in on your thread), and in the end, we persevered. BELIEVE me when I state that if I can do it, you can succeed too.

Also, FWIW - when we took the motor apart and re-timed it following the EXACT instructions on my thread (hint: lead the cams into their place), all of the timing marks and checks ended up PRECISELY on mark - not even a knat's arse off.

Good luck.

 

[Constant Mesh]

For your ruler (right angle tool) I'd recommend letting the excess extend out toward the front (exhaust side) of the engine.

With this orientation you don't have to look over the top of the ruler to see the cam pip. This should be particularly helpful when viewing the exhaust cam pip since it's difficult/impossible to get a good top down view at that location. But, with the edge of the ruler down against the cam lobe you can get a good view of the pip's position without having a direct overhead line of sight.

As I mentioned a 2 mm rotational error should be fairly obvious when comparing the pip location to the end of the ruler. From your photo it appears that the pip has a diameter less than 2 mm. So a one tooth error would be larger than the pip.

 

[audiowize]

I was just helping Fontaman adjust his valves on Monday, and his timing marks show the exact same behavior as yours do. As you noted, if you're a tooth off, it's pretty obvious!

 

[Harald]

Fred W wrote

-snip-Or is this what the photos are supposed to be showing? The amount the cam is off when the crank is perfect and the amount the crank is off when the cams are perfect. If that is what you were showing then this may be as good as you can get

Yup, exactly what the photos are showing. I think you might be right that it's as close as I can get it and I'll need to live with it. I just can't believe I'm the only one to experience such slop in the timing (of course I'm one of the rare S7 spider failure victims too). There's just that perfectionist in me that doesn't like such an error. I suppose that's why I got into aircraft maintenance - because "good enough" doesn't fly there.

 

[Harald]

Audiowise wrote:

I was just helping Fontaman adjust his valves on Monday, and his timing marks show the exact same behavior as yours do. As you noted, if you're a tooth off, it's pretty obvious!

That's great to hear I'm not the only one. Maybe it's our Pacific North West climate that causes this anomaly?

 

[eflyguy]

I'm no expert either, but I agree with those that say if anything was a tooth off, it would be more obvious.

My question is - would it hurt anything to simply try and start it? Just to ensure it fires up, then shut it down. Of course, turning it over by hand first to ensure there's no interference.

 

[ionbeam]

...My question is - would it hurt anything to simply try and start it?...

The cam gears can be off a tooth and it won't cause mechanical interference. If there really is a timing issue it isn't worse than one tooth.

if there's something I can do to get it better (I can only think of new cam chain or replacement chain guides).

That's what the CCT is there for, to adjust for any wear and keep appropriate tension on the chain. Your '07 should have the new and improved CCT so that shouldn't be an issue. The chain slippers that I've seen appear to be nearly indestructible and the cam chain wear very minor.

 

[eflyguy]

So fire her up for a couple of seconds to put your mind at ease, then button everything up!

 

[RossKean]

Your '07 should have the new and improved CCT so that shouldn't be an issue. The chain slippers that I've seen appear to be nearly indestructible and the cam chain wear very minor.

The '07's were not all the new design of CCT. Mine was without a dot - blue, green or otherwise.

 

[Harald]

...My question is - would it hurt anything to simply try and start it?...

The cam gears can be off a tooth and it won't cause mechanical interference. If there really is a timing issue it isn't worse than one tooth.

I've confirmed that by shifting the chain off 1 tooth at the crank gear and also at the cam gears. With either intentional skip of the chain, the marks were much further off.

if there's something I can do to get it better (I can only think of new cam chain or replacement chain guides).

That's what the CCT is there for, to adjust for any wear and keep appropriate tension on the chain. Your '07 should have the new and improved CCT so that shouldn't be an issue. The chain slippers that I've seen appear to be nearly indestructible and the cam chain wear very minor.

My 07 actually had the old CCT in it and I replaced that probably 60,000 miles ago. I haven't heard of any cam chain wear on the FJR, but the more I think about it this is the most probable cause of a slight timing error. The timing is really determined by the chain position on the intake cam, exhaust cam and crank gear in that order due to direction of rotation. If you visualize the chain stretching along it's run from the exhaust cam to the crank gear, then you would have to rotate the crank gear a little more clockwise to take up the slack - You would end up with the crank gear positioned exactly like mine in the picture. What I find odd is that so far I only know of me and Fontanaman having this timing issue. Are we the only ones experiencing cam chain wear?