Valve adjustment

[HaulinAshe]

Hi Fred!

I disagree with your valve chain comment. At roughly 65k miles the typical FJR valve chain will have enough tolerance to induce a 1.5 to 2.0 degree shift in timing between the intake and exhaust cams. Remember that the chain PULLS from exhaust cam back to intake cam. The resulting retardation of intake timing (relative to exhaust timing) is noticeable to an experienced rider.

The chain will likely never break or wear excessively during the normal 200k-250k lifespan of an FJR. But performance does noticeably suffer from 0k to 65k, not so much 65k to 100k. However, I have seen 100k FJR chains induce a 3.0 degree timing shift.

My point, change the CCT, change the timing chain, enjoy the extra "pep in your step". Or don't worry about it. It WILL last almost forever.

 

[Fred W]

Hey Jeff, glad to see you posting, and to read that you got yourself another FJR.

Id be surprised to see much effect from a timing difference between intake and exhaust. The length of chain is pretty short between the two cam sprockets. There should be much more chain stretch in the several times longer length of the chain running from the crank sprocket up to the exhaust cam. That lengthening would result in retarded timing of both exhaust and intake, which would result in reduced performance like you suggest.

If my son ever rides my old 05 far enough to hit its next valve check, I may do a chain swap on that and see how much it has lengthened in all of those miles. Seat of the pants power measurements will be tough, though. The old 05 was peppier than my 2014 and Ive kind of gotten used to the 3rd Gen refinement.

 

[Harald]

Hi Fred!
I disagree with your valve chain comment. At roughly 65k miles the typical FJR valve chain will have enough tolerance to induce a 1.5 to 2.0 degree shift in timing between the intake and exhaust cams. Remember that the chain PULLS from exhaust cam back to intake cam. The resulting retardation of intake timing (relative to exhaust timing) is noticeable to an experienced rider.

The chain will likely never break or wear excessively during the normal 200k-250k lifespan of an FJR. But performance does noticeably suffer from 0k to 65k, not so much 65k to 100k. However, I have seen 100k FJR chains induce a 3.0 degree timing shift.

My point, change the CCT, change the timing chain, enjoy the extra "pep in your step". Or don't worry about it. It WILL last almost forever.

I posted about cam chain wear in this thread: https://www.fjrforum.com/forum//index.php/topic/168401-cam-timing-experts-needed/?p=1315066

At 110,000 miles on my 07 I had to adjust the valves for the first time. The marks didn't line up perfectly and I eventually figured out that it had to be from chain wear. I checked the difference with a degree wheel at the crank and it was approx 4 degrees off. Note that intentionally moving the chain 1 tooth off resulted in 19 degrees off. And yes, it does seem to have slightly lower power as read with my "Seat-O-Pants" dynometer.

 

[RossKean]

Hi Fred!

I disagree with your valve chain comment. At roughly 65k miles the typical FJR valve chain will have enough tolerance to induce a 1.5 to 2.0 degree shift in timing between the intake and exhaust cams. Remember that the chain PULLS from exhaust cam back to intake cam. The resulting retardation of intake timing (relative to exhaust timing) is noticeable to an experienced rider.

The chain will likely never break or wear excessively during the normal 200k-250k lifespan of an FJR. But performance does noticeably suffer from 0k to 65k, not so much 65k to 100k. However, I have seen 100k FJR chains induce a 3.0 degree timing shift.

My point, change the CCT, change the timing chain, enjoy the extra "pep in your step". Or don't worry about it. It WILL last almost forever.

I posted about cam chain wear in this thread: https://www.fjrforum.com/forum//index.php/topic/168401-cam-timing-experts-needed/?p=1315066At 110,000 miles on my 07 I had to adjust the valves for the first time. The marks didn't line up perfectly and I eventually figured out that it had to be from chain wear. I checked the difference with a degree wheel at the crank and it was approx 4 degrees off. Note that intentionally moving the chain 1 tooth off resulted in 19 degrees off. And yes, it does seem to have slightly lower power as read with my "Seat-O-Pants" dynometer.

Chain wear or sprocket wear? You can replace the chain but I don't think it is an option for the sprocket on the engine (part of the crankshaft). Part numbers are listed for the sprockets on the cams. At least these should probably be replaced along with the chain.

 

[Fred W]

Hi Fred!

I disagree with your valve chain comment. At roughly 65k miles the typical FJR valve chain will have enough tolerance to induce a 1.5 to 2.0 degree shift in timing between the intake and exhaust cams. Remember that the chain PULLS from exhaust cam back to intake cam. The resulting retardation of intake timing (relative to exhaust timing) is noticeable to an experienced rider.

The chain will likely never break or wear excessively during the normal 200k-250k lifespan of an FJR. But performance does noticeably suffer from 0k to 65k, not so much 65k to 100k. However, I have seen 100k FJR chains induce a 3.0 degree timing shift.

My point, change the CCT, change the timing chain, enjoy the extra "pep in your step". Or don't worry about it. It WILL last almost forever.

I posted about cam chain wear in this thread: https://www.fjrforum.com/forum//index.php/topic/168401-cam-timing-experts-needed/?p=1315066At 110,000 miles on my 07 I had to adjust the valves for the first time. The marks didn't line up perfectly and I eventually figured out that it had to be from chain wear. I checked the difference with a degree wheel at the crank and it was approx 4 degrees off. Note that intentionally moving the chain 1 tooth off resulted in 19 degrees off. And yes, it does seem to have slightly lower power as read with my "Seat-O-Pants" dynometer.

I assume that 4 degrees was that the cams were retarded by that amount (crank was past its mark when the cam was in time) right? Was that with the intake or exhaust cam at its timing mark, or were they too close to tell a difference? I would suspect that if the chain had lengthened enough to cause 4 degrees of error then there would be a smaller error between the two cams too, but may be too small to notice.
As for the sprockets causing error, any error due to sprocket wear would be very small as it is only the amount of wear on a single tooth (at a time). Chain wear is more significant since it is an accumulation of the wear at all of the links that causes chain length to increase. Even though conventional wisdom in drivetrains is to replace in sets, you could probably get away with replacing just the stretched chain in the timing system.

 

[Harald]

I assume that 4 degrees was that the cams were retarded by that amount (crank was past its mark when the cam was in time) right? Was that with the intake or exhaust cam at its timing mark, or were they too close to tell a difference? I would suspect that if the chain had lengthened enough to cause 4 degrees of error then there would be a smaller error between the two cams too, but may be too small to notice.
As for the sprockets causing error, any error due to sprocket wear would be very small as it is only the amount of wear on a single tooth (at a time). Chain wear is more significant since it is an accumulation of the wear at all of the links that causes chain length to increase. Even though conventional wisdom in drivetrains is to replace in sets, you could probably get away with replacing just the stretched chain in the timing system.

The cam marks were both lined up as far as I could tell when I measured at the crank. If there was a cam mark difference, I couldn't see with flashlight and inspection mirror and there's no way I'm pulling the engine to get a better look.

 

[Fred W]

Thanks for the reply, Harald. That totally makes sense. I'd estimate the length of chain between the crank and the exhaust cam as roughly 4 times longer than the one between cams, which means that with a 4 degree error from crank to exhaust, there should be about a 1 degree error between cams. That would be very hard to eyeball with the timing marks as they are with the engine inside of the frame.