Cam timing question

[racer]

While checking my valves, I screwed up and tried rotate the motor after loosening the cam chain tensioner. I'm pretty sure I slipped a tooth or two on both cams. Most of my valves are on the tight side, so I will probably be removing the cams shafts anyway to change out shims.

I've read most of what I could find on the forum. Do I understand the cam alignment correctly? Put number one cylinder on TDC on compression stroke, (this will have the intake lobe at about 10 oclock and the exhaust lobe at about two oclock with the T mark on the timing plate aligned with the seam of the case). There are two little dots on right hand side of the cam shafts. When the cams are in the correct position, should those two dots line up with the arrows pointing towards the cam gear on the top of the cam shaft bearing? Are those dots and arrows the alignment marks?

I have the motor at TDC on number one cylinder and the two dots are sitting at about 10 or 11 o'clock instead of lining up with the arrows. I plan on removing the cams to so I can find out what shims to order, then line up the alignment marks when I reinstall the cam shafts. Am I correct the dots should line up with the arrows with the lobes on number one cylinder at about 10 and 2 o'clock?

Also, should I go to the expense of ordering a shop manual?

 

[RadioHowie]

Also, should I go to the expense of ordering a shop manual?

Sure...why not? You've already put the cart before the horse.

Screw up the cam timing and you're gonna be a riding season late and about $4500 short.

I'm all outta cliches now. Resume your work.

 

[madmike2]

Yes, buy a service manual. I'd order mine from Gary McCoy as found in this thread in the FAQ section.

Second, read every current thread on cam timing and cam chain tensioner on the Technical Discussion page. There are 3 or 4 just a few titles below this thread.

 

[Patriot]

check this thread: Ionbeam's successful tale of woe, but with bumps in the road

https://www.fjrforum.com/forum//index.php?s...6889&st=120

post #140 talks about two different marks on the balancer, but other info about rebuilding a head and cams, etc.

 

[Toecutter]

Racer,

Good fishin! That bait hasn't been used yet....

 

[RadioHowie]

Racer,Good fishin! That bait hasn't been used yet....

Saturday's top contender for "Spew-Worthy Reply of the Day!"

 

[madmike2]

Racer, you might also want to read this thread about a bike that wouldn't "hold idle" because one cam was 1 tooth out of time (from a dealer).

 

[racer]

Mad Mike, thanks for the new thread info. I've read all the other on this forum without any answers. Good to know one cog off won''t bend a valve. I rotated the engine by hand slowly a couple revolutions after the cog slip to get it to TDC. Hoping that didn't bend a valve.

BTW, I'm still needing to know how to set the cam timing if anyone out there has done this. I will be ordering a service manual. Thanks to all that have offered help. ToeCutter, what is the fishing thing about?

 

[Geezer]

I think your description of cam alignment is correct. The problem is that the cams each have two sets of marks. One set of marks is used if it's an intake cam, and the other set if it's an exhaust cam. You need a picture or something to know what it should look like when they are right.

 

[racer]

Thanks Geezer, I'll be ordering a shop manual before re-assembly. Hopefully, there will be picture like you suggested. However, I am almost certain I know what to do to align the cams. Mean while, today, I'm pulling the cams so I know which shims to order.

 

[Geezer]

I just looked at the parts diagram for cams on the '05, and only one camshaft is listed. It is the exact same part for both intake and exhaust. It surprises me that the exact same grind is optimal for both intake and exhaust, but there you have it. That explains why there are two sets of marks on each cam.

 

[olsonm3915]

IIRC the Concours (C10) also uses the same cam for intake and exhaust.

 

[racer]

I just got both cams out and all the shims mic'd (I can't read any numbers on the sims, they are worn away). Looks like I can swap four and will have to buy five. Everything is now lined up again(I think). Got lucky, both cams only jumped one tooth, so I don't think I bent any valves turning it engine over by hand a couple turns to get to TDC. In another post on this site, a dealer reinstalled a cam one tooth off after a valve adjustment, and it didn't bend any valves. Surprisingly, though the bike ran, not very well, but it would run.

All the intake valves were out of spec except one which was at minimum, .006. All the others were at .005 except one was .004. The exhaust valves were all mid range at .008 except two at minimum, .007.

I let this first valve check go a little long, 34,500 miles. I'll be putting all the clearances in the middle of spec since the valves have settled in the seat now.

You're right, Geezer, I was looking at the parts listing last night and noticed only on P/N for both cams.

 

[charismaticmegafauna]

While checking my valves, I screwed up and tried rotate the motor after loosening the cam chain tensioner. I'm pretty sure I slipped a tooth or two on both cams.

Uh-Oh -- "Danger, Will Robinson..."

Do I understand the cam alignment correctly? Put number one cylinder on TDC on compression stroke, (this will have the intake lobe at about 10 oclock and the exhaust lobe at about two oclock with the T mark on the timing plate aligned with the seam of the case).

Yes, for the cam lobes for #4 cylinder (Unusual, but Yamaha gives you directions using #4 -- since, your at that end of the engine).

There are two little dots on right hand side of the cam shafts. When the cams are in the correct position, should those two dots line up with the arrows pointing towards the cam gear on the top of the cam shaft bearing? Are those dots and arrows the alignment marks?

Sort of -- the actual timing of the cams (correctly) is by the cam-chain sprocket marks parallel with the edge of the cylinder head.

Am I correct the dots should line up with the arrows with the lobes on number one cylinder at about 10 and 2 o'clock?

See above...

I just got both cams out and all the shims mic'd (I can't read any numbers on the sims, they are worn away).

IME, that's unusual (but, not impossible) -- often, the etching can be very light and needs a good bright light to be seen.

In another post on this site, a dealer reinstalled a cam one tooth off after a valve adjustment, and it didn't bend any valves. Surprisingly, though the bike ran, not very well, but it would run.

Not impossible at all with mild cam timing -- but, critical on which direction the mistake is made...

Better to not make a mistake at all.... :blink: :blink:

Remember, too, if there are any bent valves present -- there will be very excess clearance (way out of normal adjustment range).

All the intake valves were out of spec except one which was at minimum, .006. All the others were at .005 except one was .004. The exhaust valves were all mid range at .008 except two at minimum, .007. I let this first valve check go a little long, 34,500 miles. I'll be putting all the clearances in the middle of spec since the valves have settled in the seat now.

Since, normally, 'wear' is not an issue (valves tend to, as you say, 'settle' in their seats) it's often best to err on the loose side -- when presented with the dilemma of choosing a thicker/thinner shim (pad).

You're right, Geezer, I was looking at the parts listing last night and noticed only on P/N for both cams.

Not that un-common -- but, note that they're timed differently (the reason for two sets of alignment marks on the cam-chain sprockets).

Altho not absolutely necessary (when following the shop manual instructions explicitly) -- it can be a very good idea to try to acquire an understanding of the overall cam-timing events. It helps to see it all on a single-cylinder engine (or, just focus on one of the FJR's four).

 

[racer]

Do I understand the cam alignment correctly? Put number one cylinder on TDC on compression stroke, (this will have the intake lobe at about 10 oclock and the exhaust lobe at about two oclock with the T mark on the timing plate aligned with the seam of the case).

Yes, for the cam lobes for #4 cylinder (Unusual, but Yamaha gives you directions using #4 -- since, your at that end of the engine).

This is not correct. If you put the lobes at 10 and two on number four cyclinger, you WILL bend valves. The service manual says the HOLES in #4 cylinder cam should line up with the arrows on the cam caps. When these holes are lined up this way, the cam lobes on number one cyclinder are at 10 and 2. See Cam Timing for Dummies thread.

 

[charismaticmegafauna]

Do I understand the cam alignment correctly? Put number one cylinder on TDC on compression stroke, (this will have the intake lobe at about 10 oclock and the exhaust lobe at about two oclock with the T mark on the timing plate aligned with the seam of the case).

Yes, for the cam lobes for #4 cylinder (Unusual, but Yamaha gives you directions using #4 -- since, your at that end of the engine).

This is not correct.

You are quite correct -- and I stand corrected. Those holes are merely an aid.

To further expound: In a previous thread (somewhere...?) I mentioned the cam lobes hanging-down (like ripe fruit...) -- that is incorrect, too -- in reference to the FJR and other DOHC direct-acting camshaft engines (it applies to engines with rocker arms -- which I see most often).

Suffice to say, it's really a good idea to have an 'understanding' of what's going-on with the camshafts/valves/pistons before attempting work in that area (if you can get your brain around all that...?).

Still, following the FSM instructions, exactly, will serve you (anyone) well.

When these holes are lined up this way, the cam lobes on number one cyclinder are at 10 and 2.

You are correct -- and are illustrating how an 'understanding' of the mechanics involved can be beneficial.

Also helpful is the valve timing chart/diagram posted on this Forum and the knowledge that the cams turn at half engine speed.

See Cam Timing for Dummies thread.

Very nicely done.

 

[racer]

Do I understand the cam alignment correctly? Put number one cylinder on TDC on compression stroke, (this will have the intake lobe at about 10 oclock and the exhaust lobe at about two oclock with the T mark on the timing plate aligned with the seam of the case).

Yes, for the cam lobes for #4 cylinder (Unusual, but Yamaha gives you directions using #4 -- since, your at that end of the engine).

This is not correct.

You are quite correct -- and I stand corrected. Those holes are merely an aid.

To further expound: In a previous thread (somewhere...?) I mentioned the cam lobes hanging-down (like ripe fruit...) -- that is incorrect, too -- in reference to the FJR and other DOHC direct-acting camshaft engines (it applies to engines with rocker arms -- which I see most often).

Suffice to say, it's really a good idea to have an 'understanding' of what's going-on with the camshafts/valves/pistons before attempting work in that area (if you can get your brain around all that...?).

Still, following the FSM instructions, exactly, will serve you (anyone) well.

When these holes are lined up this way, the cam lobes on number one cyclinder are at 10 and 2.

You are correct -- and are illustrating how an 'understanding' of the mechanics involved can be beneficial.

Also helpful is the valve timing chart/diagram posted on this Forum and the knowledge that the cams turn at half engine speed.

See Cam Timing for Dummies thread.

Very nicely done.

 

[racer]

Do I understand the cam alignment correctly? Put number one cylinder on TDC on compression stroke, (this will have the intake lobe at about 10 oclock and the exhaust lobe at about two oclock with the T mark on the timing plate aligned with the seam of the case).

Yes, for the cam lobes for #4 cylinder (Unusual, but Yamaha gives you directions using #4 -- since, your at that end of the engine).

This is not correct.

You are quite correct -- and I stand corrected. Those holes are merely an aid.

To further expound: In a previous thread (somewhere...?) I mentioned the cam lobes hanging-down (like ripe fruit...) -- that is incorrect, too -- in reference to the FJR and other DOHC direct-acting camshaft engines (it applies to engines with rocker arms -- which I see most often).

Suffice to say, it's really a good idea to have an 'understanding' of what's going-on with the camshafts/valves/pistons before attempting work in that area (if you can get your brain around all that...?).

Still, following the FSM instructions, exactly, will serve you (anyone) well.

When these holes are lined up this way, the cam lobes on number one cyclinder are at 10 and 2.

You are correct -- and are illustrating how an 'understanding' of the mechanics involved can be beneficial.

Also helpful is the valve timing chart/diagram posted on this Forum and the knowledge that the cams turn at half engine speed.

See Cam Timing for Dummies thread.

Very nicely done.

Thanks, Charismatic...........I'm just glad to have gotten it back together, fired up and back on the road.