Cam timing experts needed

[radiummadman]

I can't believe how smart you guys are, I need help adding coolant fluid.

 

[ionbeam]

Are we the only ones experiencing cam chain wear?

Only if the CCT has failed.

 

[PhilJet09]

I'm in the "you're probably ok" camp. I'd double check the chain guides are in their proper places and call it good. Out of curiosity, maybe take the tension off the CCT and see where the marks line up.

 

[rbentnail]

....intructions 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.

^^THIS^^.

All 4 times I've checked/reshimmed the valves on my '07 all 3 timing marks lined up dead nuts perfect. I'm in the "something's wrong" camp. Personally I'd take a day off from the bike, go back tomorrow and cut the tiewraps, position my cams at the timing marks per FSM and then reset the crank to match it's mark, even if I had to loosen the chain via CCT. IMO you're off a tooth somewhere, and no amount of duct tape, mechanic's wire, socket insertion or tiewraps will keep the chain from jumping one. Please DAMHIK this.

 

[hppants]

I had the cam chain zip tied to the crank and it absolutely moved at least one tooth.

 

[dcarver]

Me thinks I'm gonna have training classes for peeps on my spare, not running engine. Hell, it took Fairlaner 3 times to get it right!

 

[hppants]

If I was regional, I'd attend that training.

Hey - hold on a second....

I've got 12K on my bike now. I'm riding about 12K a year so this time next year, I should have 24-ish on the red beast. Now this time next year, I will be packing for the pilgrimage to Yosemite. About 2,000 miles away.

Carver - you up for a pre or post-Cali tour tech day at your house? Fair warning - if I see the Kawi six-shooter, I got to ride it, man. Even if it's just down the block...

 

[Harald]

....intructions 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.

^^THIS^^.
All 4 times I've checked/reshimmed the valves on my '07 all 3 timing marks lined up dead nuts perfect. I'm in the "something's wrong" camp. Personally I'd take a day off from the bike, go back tomorrow and cut the tiewraps, position my cams at the timing marks per FSM and then reset the crank to match it's mark, even if I had to loosen the chain via CCT. IMO you're off a tooth somewhere, and no amount of duct tape, mechanic's wire, socket insertion or tiewraps will keep the chain from jumping one. Please DAMHIK this.

I already tried lining up both cam marks per the FSM and then moving the chain on the crank. This resulted in a much worse picture than what I posted so I put it back to where it was. I then set the crank mark per the FSM and then moved the chain on the cam gears and this also resulted in much worse results than my timing picture.

Conclusion? A worn cam chain or chain guide are the only possible explanations for my slightly off timing (other than an OEM defect in marking the gears). It's interesting to note that Fontanaman had the exact same timing anomaly on his FJR with half the mileage of mine. I can't believe a cam chain would wear so soon, so maybe there is something to the manufacturing defect theory?

I double checked my clearances and timing and buttoned everything up. Bike runs fine and has plenty of power just like it did before I tore into it.

One little interesting observation about the clearances after adjusting a few shims. I was rechecking all clearances after putting the cams back in and noticed that some of the valves that were NOT adjusted had clearances now 0.01mm looser. I was scratching my head on this one and had to investigate. I remembered that the lock collar on my torque wrench had loosened when I was cranking it back to zero as I was putting it away. So I reset it to the correct torque setting and checked the cam caps to find that they were undertorqued. Not finger tight undertorqued, but undertorqued where the bolts move a little before the wrench clicked. With the proper torque applied, the unadjusted valves were now back to their original readings. Just something to be aware of when doing this job.

 

[Brodie]

Harald,

If it makes you feel any better, all 3 of my *FJRs looked like yours when I did them. I'm inclined to think that it is due to manufacturing tolerances. When I did my first one many years back, I also tried moving a cam gear 1 tooth in either direction. Your pictures look just fine to me.

* 2006 x 2, and a 2008; all 3 are Advanced Editions.

Brodie

 

[RossKean]

Are the photos with the cam chain tensioner engaged or with the cam chain slack on the forward side?

(Wondering if this makes enough difference to show)

 

[Harald]

Harald,If it makes you feel any better, all 3 of my *FJRs looked like yours when I did them. I'm inclined to think that it is due to manufacturing tolerances. When I did my first one many years back, I also tried moving a cam gear 1 tooth in either direction. Your pictures look just fine to me.

* 2006 x 2, and a 2008; all 3 are Advanced Editions.

Brodie

Thanks for that info! Definitely makes me feel better not being the only one with odd timing.

Are the photos with the cam chain tensioner engaged or with the cam chain slack on the forward side?
(Wondering if this makes enough difference to show)

The CCT was extended for the photos and the engine had been rotated by hand to settle the cam chain.

 

[audiowize]

I plan to replace my cam chain at roughly this time next year, I'll have to try to remember to take photos of the before and after timing marks.

One could also use some 1/4" dowel to manually check TDC on the crank vs. marks on the sprocket aligning properly.

 

[ionbeam]

I plan to replace my cam chain at roughly this time next year, I'll have to try to remember to take photos of the before and after timing marks...

Please check the new chain against the old chain and post up the difference (if any). A 40k mile cam chain was essentially within a degree or two of the new cam chain. Timing tape would be the best method to check the timing, you can find online resources for timing tape.

 

[audiowize]

Man, search terms are everything! I've wondered if such a tool existed, as I have been forced to use a plastic protractor or try to use my giant Bosch digital protractor (on car harmonic balancers), or attempt to estimate/calculate manually.

 

[Harald]

I forgot to follow up to my post here: https://www.fjrforum.com/forum//index.php/topic/168401-cam-timing-experts-needed/?p=1315099
I downloaded and printed the timing wheel I linked to and checked how far off the crank gear was and it looked like about 4 degrees. According to Constant Mesh's calculations, having the crank gear off 1 tooth would result in a 19 degree error. Not sure what I can do with that info because I'm not replacing the timing chain because the bike runs fine. I suppose if I take a lot of time to verify physical timing and verify the marks are correct (or remark them to be accurate) but I don't have that kind of free time.

 

[Fred W]

Cool. Gotta love having some data. 4 degrees is a number you can wrap your head around.

I think that it is fairly safe to assume that your timing marks are just fine. There's really no way for them to have moved. And I think it is also pretty safe to assume that the difference you are seeing in the timing is due to chain and guide wear. There is little doubt that everything lines up when it is new and unworn, and we know that wear is supposed to take place. Otherwise there would be no need for a chain tensioner to take up the added slack.

As the chain and guides wear it allows the cams to lag behind the crankshaft, which is the safer way for timing to change. It tends to make an engine run better at lower rpm, while losing a little bit of top end. If you know anything about variable valve timing used in many state of the art automobile engines, the manufacturer will intentionally retard the valve timing at lower RPM ranges with a mechanism, and then progressively advance it at higher rpm for increased maximum power. So on a dyno that 4 degrees of timing retardation may be perceivable, but I bet on the butt dyno it all feels fine.

Maybe in a few more years, if you decide to change out the chain and guides at some time in the future, the acute change in timing back to being "spot on" will be perceivable where the chronically slow wear was not.

 

[eflyguy]

What he said. Which is what I said, in less technical terms, a long while back.

If your error is significantly less than a tooth on either end, then it's fine.

 

[SkooterG]

I don't see how guide wear would have anything to do with it. Somebody please explain this to me.

 

[ionbeam]

I don't see how guide wear would have anything to do with it. Somebody please explain this to me.

Here.

 

[Fred W]

I don't see how guide wear would have anything to do with it. Somebody please explain this to me.

The front guide is somewhat curved (not straight) and runs in that curved line between the front exhaust cam and the sprocket on the crank pulling the chain down below. As the guide wears it allows the chain to take a straighter path between the two sprockets (shortest distance is a straight line), thereby making the chain appear to be longer.