cam/crank timing

[raptorman13]

Has anyone out there done the chain tensioner and had questioned cam to crank alignment when done? I just replaced cct with updated yamaha part, did not have valvwe cover off so not sure if the holes in cams align exactly with arrows on cam brg cap before. Has anybody out there done the valve check/adjust and when the "T" mark is lined up with split in crankcase do the holes in the cams aline exactly with arrows on caps or are they just slightly behind?

 

[RadioHowie]

I've kinda, sorta done a cam chain replacement and alignment on my '04. Details are HERE.

And a perfectly aligned set of cams and crankshaft results in the perfect alignment of the holes in the cams with the pointers on the cam caps:

If the holes are NOT aligned, when the TDC mark on the timing sprocket on the crank is aligned with the case-split, then your cams are NOT timed correctly.

Be VERY, VERY careful....the motor can survive being run/turned-over with the cams off by ONE tooth....

....the loud banging noise you might hear during a restart attempt could very well mean you're off by more than one tooth.

 

[Peter Murray]

I would remove the valve cover and inspect too much on the line at this juncture.

 

[mattster31]

Has anyone out there done the chain tensioner and had questioned cam to crank alignment when done? I just replaced cct with updated yamaha part, did not have valvwe cover off so not sure if the holes in cams align exactly with arrows on cam brg cap before. Has anybody out there done the valve check/adjust and when the "T" mark is lined up with split in crankcase do the holes in the cams aline exactly with arrows on caps or are they just slightly behind?

If all you did was remove the old CCT and re-install the new CCT, then there is nothing to worry about. The chain will not jump teeth by itself during that procedure. BTW the timing is not adjustable on the FJR. Either the marks line up or they don't. Even if it is out by one tooth it would be clearly obvious. The tolerances are so tight I don't think you could turn the motor over (by hand) without a valve touching a piston (If the chain jumps 1 tooth). With the new CCT, just use a socket wrench and a 14mm to turn the engine over (CW) one complete revolution. If it does it it's fine........

EDIT.....Just read RH's post.......perhaps two teeth then

 

[lnewlf]

beg to differ..the chain will obviously not jump teeth on the cam sprockets-but the resultant slack from removing the CCT might allow the chain to hang off the crank sprocket and swap teeth down there..especially if there is valve spring tension on the cams which might rotate them slightly..definitly good idea to remove the cam and timing covers and zip tie the chain in place before removing the CCT..

 

[mattster31]

beg to differ..the chain will obviously not jump teeth on the cam sprockets-but the resultant slack from removing the CCT might allow the chain to hang off the crank sprocket and swap teeth down there..especially if there is valve spring tension on the cams which might rotate them slightly..definitly good idea to remove the cam and timing covers and zip tie the chain in place before removing the CCT..

Ok.....Then we can agree to disagree(no offence). I did a valve clearance check over the winter and found all of them to be tight so I had to remove the cams. I removed the CCT after I had the covers off to see what happens. You are correct that the chain will slack a bit between the cams as there is pressure on the cams that will move them slightly. However I noticed no issue with the chain becoming too slack that it would slip a tooth. If you held pressure on the CCT bolts (without backing off the spring) and "suddenly" removed the CCT, then perhaps what you describe could happen. Just speaking from experience having just done it over the winter. Here are a few photos of the alignment marks. These were taken before cam removal (just as a precaution)

Cams out (sorry for the blurry photo)

Alignment marks (there is NO adjustment to the timing on an FJR)

Line up the line below the T where the casting meets. This means you are a TDC on cylinder one.

you can see the Arrows align with the head (I moved the chain one tooth just to see what it looks like and there is a definite difference - to be honest, If you follow the manual, you can't screw it up IMO)

Line up the holes with the arrows

This is just a view from the other end, there are no alignment marks here

 

[Crash Cash]

And a perfectly aligned set of cams and crankshaft results in the perfect alignment of the holes in the cams with the pointers on the cam caps.

If the holes are NOT aligned, when the TDC mark on the timing sprocket on the crank is aligned with the case-split, then your cams are NOT timed correctly.

Damn, I did not know that... that's a LOT easier than trying to see the marks on the sides of the gears with the frame in the way. THANKS!

 

[raptorman13]

Hello guys, thanks for all the responses. I rechecked and found my error. Yes the cams were off, actually what happened was I did not apply tension to the

guide to keep chain tight when I removed the cct. The chain dropped on rearward side and when I installed new tensioner, it did not take up all the slack so

when I rotated crank by hand, I heard faint click type noise(not normal), thats when I removed valve cover again and checked and found the error. The cams

were still in time with each other but the noise I heard was the crank skipping one tooth. I thank you for the pictures, they helped clear up. I will get

back to it in next few days, just too busy with other things at the moment.

 

[FJRMGM]

I did a valve clearance check over the winter and found all of them to be tight so I had to remove the cams.

Wow - given how unusual it is to find even one that needs adjustment this seems extreme.

 

[mattster31]

I did a valve clearance check over the winter and found all of them to be tight so I had to remove the cams.

Wow - given how unusual it is to find even one that needs adjustment this seems extreme.

12 of them were over by 0.02mm and more (to the tight side) the other 4 were right on the line. I figured I might as well swap them and adjust the clearance to the loose side (I was lucky enough to re-use 7 shims and only needed to purchase 9). I shouldn't have to worry about clearances for quite a while.....I hope :huh:

 

[Constant Mesh]

On my '04 all of the exhaust clearances were mid range or looser. The intakes were typically on the tighter end of the range and I changed two shims for a bit more clearance.

It's my speculation that they intentionally set up the exhausts at the upper end of the range. The intakes were set at mid range or lower to maximize fuel/air input and power.

 

[charismaticmegafauna]

It's been my experience (not FJR-specific -- M/Cs, in general) that the exhaust valves are (often) 'hell-for-tough' (designed to operate in a brutal environment and are a bit smaller); while the inlet valves, which are bigger, are often made lighter for high revs -- and seem to suffer more over time.

None will last forever -- but, they're alot better than they used to be...

 

[RaYzerman19]

And a perfectly aligned set of cams and crankshaft results in the perfect alignment of the holes in the cams with the pointers on the cam caps.

If the holes are NOT aligned, when the TDC mark on the timing sprocket on the crank is aligned with the case-split, then your cams are NOT timed correctly.

Damn, I did not know that... that's a LOT easier than trying to see the marks on the sides of the gears with the frame in the way. THANKS!

Just went through this at the Owosso Tech Day. If you are very precise, you can use the holes as an indicator, but I prefer to double check with the marks on the cam sprockets. It's easy to gunsight them when they are lined up, with a nice bright flashlight.