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Trouble setting timing, exhaust cam lobe hits bucket and moves!

Started by utgunslinger13, May 25, 2010, 07:11:37 PM

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utgunslinger13

I am trying to set the camshafts and timing chain on the bike but I'm having some trouble lining everything up correctly.  The manual has me line up the signal generator on the right side of the bike to find top dead center.  When its aligned it will look like this:



The exhaust cam has a number 1 and number 2 notched on it for alignment, you are supposed to line number 1 up parallel with the gasket surface like this:



And the end of the exhaust cam has a notch that is supposed to face like this:



However, the left lobe on the exhaust camshaft hits the valve buckets when I try to align the number 1 parallel with the gasket surface and without depressing the valve there is no way to tighten the camshaft down in that position!  If I align the signal generator properly to find top dead center, this is the closest I can get the cams to aligning properly:



And the notch is off:



Once I rotate the engine around to line up the cams properly, the stator is off by a bunch of top dead center!





What the hell can I do????  Am I doing something wrong??? Should I figure out how much I should turn the crank before TDC and align the cams like I have been and try to get it so that when I turn to TDC the cams are aligned???  HELP!
Check out my current project build:

http://gstwins.com/gsboard/index.php?topic=41982.0

jeremy_nash

if you have a valve shim removal tool, use it to depress the bucket
gsxr shock
katana FE
99 katana front rim swap
vapor gauge cluster
14 tooth sprocket
95 on an 89 frame
lunchbox
V&H ssr2 muffler
jetted carbs
150-70-17 pilot road rear
120-70-17 sportmax front
sv650 rear wheel
sv650 tail swap
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utgunslinger13

I dont have that tool.  Should the left exhaust cam lobe be pointing towards the shim/bucket/valve with the number 1 parellel to the gasket surface?  I don't see how you can tighten the cam down as it is forced to turn because it hits the valves?
Check out my current project build:

http://gstwins.com/gsboard/index.php?topic=41982.0

jeremy_nash

dont have a clue, never had to tear my motor down that far
gsxr shock
katana FE
99 katana front rim swap
vapor gauge cluster
14 tooth sprocket
95 on an 89 frame
lunchbox
V&H ssr2 muffler
jetted carbs
150-70-17 pilot road rear
120-70-17 sportmax front
sv650 rear wheel
sv650 tail swap
gsxr pegs
GP shift

lopee

im pretty sure you set the exhaust cam and then count like 18 links in the timing chain laying it in place as the manuel says. then release the spring on the cam chain tensoiner, ill check tomorrow. shouldnt be that confusing. its layed out pretty good in the clymers.
Grumble : Grumble . . . . . . .

burning1

So... You're saying that the timing marks on the cam don't line up with the valve when your crankshaft is at top dead center for the #1 piston?

It sounds like your valve timing is off - most likely because the previous valve adjustment was performed incorrectly. Always rotate your engine through a few full revolutions and re-check all your timing marks.

First... For the initial measurment, the only thing that matters is that the cam lobes are pointing away from the shims. Simply rotate until the lobes are in the correct place, and measure. It sounds like you're going to pull the cams when you replace the shims. Fix your timing then.

My advise... Get the crankshaft to TDC, and adjust your cams to match the crank. Once the chain is loose and the cams are out, the only way you can really rotate the crank is by removing both cams... Which sucks to do.

the mole

It sounds like you're worried that when you have everything aligned one of the cam lobes is going to push down on a valve bucket as you tighten the cam bearing caps. Do I have that right?
If so, that is normal, just tighten the bearing caps down evenly and the valve will gradually depress. There's no position you can set it up where no cam lobes are facing down!
Don't worry, be happy :thumb:

Allen

I have an idea, how about you remove the left ex shim.  Then that lobe could face directly downwards and you could set the timing and get everything buttoned down, then rotate the engine some, loosen the cam cap and slip the shim in, retighten the cap, and test rotate a few revolutions.  Maybe?

Allen

I would be worried about breaking the cam cap if I had to screw them in so it depresses the bucket, I followed another thread about someone breaking the cam cap. Is it possible to release the tension on that chain so you can make it skip a tooth or two until it is lined up?

the mole

I've taken my cams on and off with no problem the way the manual says, also done it to cars with bucket and shim systems. I wouldn't do it without the shim in there, because the cam will press on the edges of the bucket and likely scratch the cam. Your cap will only break if its already faulty, in which case better it does it now than when you're riding.

utgunslinger13

Thanks for all the replies, but I'm not sure if I'm explaining this correctly or not but I'll try again while adressing each response.

Lopee:

I understand the counting 18 links part, but setting the exhaust cam is the part thats not lining up correctly.  Before counting the links you have to line up the marking number "1" on the exhaust cam so that it is parallel with the gasket surface.  When you line up that marking the left lobe is pointing at the valve therefore the cam doesn't sit like it is supposed to.  When I tighten the left exhaust cap down, the lobe hits the valve and turns the entire cam backwards about 15-20 degrees.  I can't figure out how to tighten that cap down with the lobe pointing at the valve and NOT HAVE IT TURN 15-20 degrees counterclockwise.

Burning1:

I had to replace the gasket between the cylinders and the engine case, so I had to disassemble the engine and am now in the process of putting everything back together and can't get the timing set correctly.  I did the shim measurement as a by product of having the valve cover off before disassembly.

The Mole:
I think you understand my issue, but HOW DO I TIGHTEN IT WITHOUT THE CAM TURNING?  Because of the lobe pointing at the valve, when I tighten it there is nothing preventing it from rotating counterclockwise.  It rotates so the lobe is just touching the valve/bucket, but that causes it to be off by 15-20 degrees, which if I count 18 links backwards from there causes the intake cam to be off by the same amount with the engine still at TDC!

Thanks again for all your help!  I know I'll get this figured out with all your help!
Check out my current project build:

http://gstwins.com/gsboard/index.php?topic=41982.0


burning1

utgunslinger13,

When I performed my valve adjustment, I had the same problem. When you aligned the exhaust cam to the valve cover surface, and the crank to the timing mark, everything looked okay. As soon as I tightened down the exhaust cam, and ran the engine through a full revolution, the exhaust timing went to shaZam!.

What I ended up doing, was to simply count the number of pins that the exhaust cam needed to be rotated forward in order for the timing marks to line correctly. With the crank at TDC, I loosened up the CCT, and the exhaust cam, rotated the exhaust cam forward, and tightened it back down. Afterwords, I checked the number of pins between the exhaust and intake cams to make sure that the intake timing was correct.

I hope that helps.

burning1

With that said, next time I'm simply going to mark the alignment directly on the chain and cam sprockets using a white automotive marker, so that I don't need to deal with this again.

utgunslinger13

Burning 1,

The problem I run into is that as soon as I tighten the exhaust cam cap I can tell its off by 20 degrees!  I don't even have to rotate the engine through a revolution, I start with the exhaust cam lined up with the gasket surface, tighten the cap, and its off by 20 degrees.  With the lobe pointing at the valve (just starting to open the valve) as I tighten the cap, there is nothing to stop the cam from rotating backwards to relieve the pressure on the cam lobe.

I don't know if I followed your second paragraph correctly but.....can I start with the number "1" alignment mark below the gasket surface (say 15 degrees clockwise of parallel) and do the timing just like the book says?  In my head this would mean that as I tighten the exhaust cap, the lobe is pressed into the valve and it will start to rotate counterclockwise until what little slack there is in the chain between the crank and the exhaust cam is taken up and the cam should stop rotating counter clockwise.  My hope is that by figuring out how far clockwise to start will have the alignment marks correct after all is said and done.
Check out my current project build:

http://gstwins.com/gsboard/index.php?topic=41982.0

pandymai

do you have the cam chain tensioner off or at least wound back to leave slack on the chain? i would imagine that making everything easier. you could try bolting down the ex-cam first, turning the crank, then placing the chain onto it? then place the in-cam and count the links over. any loose chain should be below the in-cam and tightened when the tensioner is put back in right? that's my logic at least..



i havent gotten to where you are yet but i hope to within this coming month. I havent had time to get back to drilling out the head bolts, but when i do, i'm going to helicoil and put studs in, then just use nuts to hold my exhaust on. im lucky school is over for the semester so i dont NEED my motorcycle, i just walk/get rides everywhere. but the weather's been fantastic and i just want to ride so badly. i hope i dont hit too many hiccups once i finally get my exhaust bolted back on. im probly going to need to pull the head off completely since i lifted it anyways and replace the gasket.. woo.
rustbucket on wheels that go vroom vroom and stuff.

Quote from: Homer on July 08, 2010, 08:34:38 PM
If this freshershest-thread-ever gets spoiled by petty fighting, I'm gonna be so mad.  

burning1

No, let me clarify...

I ran into the same problem when I performed my last valve adjustment. If I aligned the timing marks as the manual indicated, tightened everything down, and just like in your case, the timing of the valves was off.

But, that gives us a starting point.

So... With everything tight, Align the crank to the timing mark. Now, take a look at your exhaust camshaft - it's going to be aligned incorrectly.

See how, in your picture, it looks like the camshaft is a full link retarded from where it should be? Good. Loosen the CCT, Unbolt the exhaust camshaft. Rotate it forward by a full link on the cam-chain. Ignore the timing marks completely. Bolt it back down. Tighten the CCT. Run the engine through a full revolution - the timing marks should now be correct.

Does that make sense? Essentially, here's what we are doing: 'Oh look! The camshaft is retarded by a full link. Let's advance it by a link.'

burning1

Quote from: pandymai on May 26, 2010, 12:31:47 PMcould try bolting down the ex-cam first, turning the crank, then placing the chain onto it?

That doesn't work. There isn't enough clearance between the cam sprocket, the chain, and the wall of the engine to rotate the crank without also turning the cam.

utgunslinger13

Burning 1,

The only problem I see with your way would again be the fact that the cam would rotate when tightened.  Maybe by moving it forward a link, when it rotates it would then in fact line back up.  But I see that as no different than starting with the alignment mark slightly below parallel.  That seems to me to be exactly what your doing.  I have no problem lining things up and counting 18 links.  But when I tighten the left exhaust cam cap thats when things move.

Also, by doing it the way you suggest you would then be putting 19 links between the intake and exhaust cams so the timing would still be off.  You would need to move the intake forward 1 tooth as well in order to keep 18 teeth between the alignment marks.
Check out my current project build:

http://gstwins.com/gsboard/index.php?topic=41982.0

burning1

You cannot align the intake camshaft until the exhaust camshaft is aligned. I'm ignoring the intake cam for now; we'll fix it later.

Yes, the exhaust camshaft will still rotate when you bolt it down, but the most important thing - the alignment between the exhaust camshaft and the crank should be correct. After you tighten down the cam and rotate the crank through a couple cycles, the exhaust and crank should be aligned correctly. Once the exhaust is aligned, you'll need to re-align the intake camshaft... but that should be trivial, since none of the intake valves will be open during the alignment procedure.

Keep in mind... Once the cam chain is on the exhaust camshaft, the camshaft cannot turn without also turning the crank. What happens with the exhaust is that your initial alignment was incorrect. This can happen for several reasons:

- You have slack between the crank and the camshaft when you set the timing.
- The crankshaft moved when you set the timing.
- The camshaft timing marks gave you a false alignment, because the cam lobe prevents the cam from sitting in place unless bolted down.

Again, so long as the crank and the cams are aligned correctly, it doesn't matter if the exhaust rotates a little when you bolt it down. Hell, because we know from your pictures that the exhaust is exactly 1 chain link retarded from the crank, if you advance the exhaust cam timing by 1 link, even the crank could turn, and everything would work out fine.

Remember - the timing marks are reference points. Those reference points have shown us that your exhaust camshaft is retarded by 1 link. All you have to do is rotate it forward and bolt it down - the marks have already served their purpose.

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