Adjusting cam timing on GS550E

[2BRacing]

Just my 2 cents worth on the "to use or not to use a vice grip" issue:

When my son bought a Suzuki 400 16 valve last year, we went through all the maintenance items. On this motor, the valve cover retaining bolts turn into small "towers" on the cam caps. As the thread in one of these "towers" had stripped, we removed that cap and obtained a replacement cap from the local bike breaker.

While tightening the cap in criss-cross pattern, it cracked at one end just before being fully tight. This was caused by the cam being lifted a little by the force of the valve springs, despite the other caps on that cam being tight. I had not ensured that the lobes on that part of the cam were not pressing down on the valve. If I had used a vice grip to hold the cam down (or if I had used my head to first check that the lobes were not down on the valves), there would not have been a problem!

 

[rollingroland]

The exhaust cam is most likely one tooth off, and the intake cam is three off since there are 23 pins between the 2 and 3 marks, and there should be 20.

I am thinking, if you correct the exhaust cam position, would'nt that change the situation for the intake cam,the number of pins between 2 and 3 would not be 23 anymore.

 

[scott]

Thanks for all the tips. I took both cams out and was able to get the chain moving (it must have bundled up somewhere). I managed to keep it from falling into the engine - so far at least.

Here is my latest attempt at setting the exhaust cam. I clamped it down with vice grips because it looks different than when it's sitting "up" with the lobe resting on the valve shim. I thought it looked to be pointing a little low after clamping it down but in this pic, it doesn't look too bad. Am I ready to install the cam caps or is another attempt required?

Should I take another pic? Maybe this has an odd angle to it.

Regarding the clamping: I wasn't able to fit the vice grips to clamp the intake cam down. That seems less important for setting the timing but could still cause an issue with stripping bolts.

 

[Nessism]

That exhaust cam looks good. Just double check the crank 1-4 T mark and as long as it's aligned, slam on those cam caps.

 

[scott]

I have both cams installed and capped. The cam chain tensioner is not installed yet (haven't even received the shipping confirmation for the seals/o-rings so I plan to install it as is and address the seals later).

Here is what it looks like with the exhaust cam capped - still looks reasonable to me:

And here is with the intake cam added. It's 20 pins but the chain looks too loose. I didn't clamp the intake cam down (no room to fit vice grips) so it may have shifted when I was bolting down the caps. Should I take off the intake and try again?

 

[Nessism]

The 2 to 3 phasing looks good, as does the -1 mark on the exhaust cam. As long as the crank is still on 1-4 T you are good to bolt on the tensioner. Don't forget to check the valve clearances before you put the valve cover back on.

 

[hampshirehog]

I count 20 pins so it looks good. The chain will be loose as you haven't got the tensioner on there yet. That's what it does - tensions the chain!

 

[scott]

I installed the tensioner - it seemed to pull the Ex cam up a bit. Hopefully not enough to be an issue. After rotating the crankshaft several times to 1-4 T:

Don't forget to check the valve clearances before you put the valve cover back on.

Since I just did that a month ago, I never would have thought to do this. I did find some odd things though. Is the best way to do this to find the size where you can't fit the feeler at all and then say it's one size lower? My intake valve clearances are higher than before using this method. I'm not saying it changed - I think previously I was going up in feeler gauge size until I felt some drag but I think that may be a less precise way to do it. For example, on one of my intake valves I could put a .08 + .06 gauges in (with a decent amount of drag). A .08 + .07 would not go through at all.

 

[tom203]

I installed the tensioner - it seemed to pull the Ex cam up a bit. Hopefully not enough to be an issue. After rotating the crankshaft several times to 1-4 T:

Since I just did that a month ago, I never would have thought to do this. I did find some odd things though. Is the best way to do this to find the size where you can't fit the feeler at all and then say it's one size lower? My intake valve clearances are higher than before using this method. I'm not saying it changed - I think previously I was going up in feeler gauge size until I felt some drag but I think that may be a less precise way to do it. For example, on one of my intake valves I could put a .08 + .06 gauges in (with a decent amount of drag). A .08 + .07 would not go through at all.

Fantastic! I bet you even used a torque wrench on those cam cap bolts. Personally, I like a little extra valve clearance, but at 8k, this motor hasn't done much and , you'll be doing it again soon to satisfy your curiosity.Play with that tensioner, till you grasp how it works inside the motor when unlocked.

 

[Suzuki_Don]

I installed the tensioner - it seemed to pull the Ex cam up a bit. Hopefully not enough to be an issue. After rotating the crankshaft several times to 1-4 T:

Since I just did that a month ago, I never would have thought to do this. I did find some odd things though. Is the best way to do this to find the size where you can't fit the feeler at all and then say it's one size lower? My intake valve clearances are higher than before using this method. I'm not saying it changed - I think previously I was going up in feeler gauge size until I felt some drag but I think that may be a less precise way to do it. For example, on one of my intake valves I could put a .08 + .06 gauges in (with a decent amount of drag). A .08 + .07 would not go through at all.

Scott do I understand correctly that you are placing two feeler gauges, a .08 & .06mm together and sliding them between the lobe base circle and the shim to do your measurements?

The valve clearance for your motor should be .03 to .08, if you are inserting both feeler blades under the cam then that totals .14mm which is way too wide for valve clearance.

I repeat the clearance is .03 to .08mm or .001" to .003".

 

[Nessism]

Hate to say this but your exhaust cam may still be off a tooth. Looks like the 1- mark raised up when you installed the tensioner. How about another photo focusing on just that exhaust cam sprocket?

Sometimes it's hard to judge perfect alignment, and you have to check a couple of positions and then just pick the one that looks best because neither is perfect.

 

[scott]

Fantastic! I bet you even used a torque wrench on those cam cap bolts. Personally, I like a little extra valve clearance, but at 8k, this motor hasn't done much and , you'll be doing it again soon to satisfy your curiosity.Play with that tensioner, till you grasp how it works inside the motor when unlocked.

Actually, I did use a torque wrench. I finally broke down picked one up a few days ago (hard to find one locally that goes below 10 ft-lbs).

 

[scott]

Scott do I understand correctly that you are placing two feeler gauges, a .08 & .06mm together and sliding them between the lobe base circle and the shim to do your measurements?

The valve clearance for your motor should be .03 to .08, if you are inserting both feeler blades under the cam then that totals .14mm which is way too wide for valve clearance.

I repeat the clearance is .03 to .08mm or .001" to .003".

Yes - on the valve adjustment I did about a month ago, I could have sworn that IN2 valve had .10 mm clearance. Now, I can fit a .08 & .06 mm together (.14mm) and get it in there. It takes some effort / there's quite a bit of drag but it isn't until I do a .08 & .07mm together (.15mm) that I really can't fit it in. Oddly, there's drag on IN2 even at smaller sizes. I may need to get new feeler gauges (even though these are pretty much new). On a different valve, I had a .08mm go through smooth but the .07mm had drag. I did another check and this is what I have (Spot | Clearance Guess | Notes):

• EX1 | .09 | .08 is smooth, .09 has some slight drag, .10 does not fit
• EX2 | .08 | .07 has some drag, .08 has slight drag, .09 does not fit
• EX3 | .06 | .07 and .08 can be forced in but seems like too much effort
• EX4 | .08 | .08 fits smooth, .09 does not fit
• IN1 | .11 | .10 had some drag, .05+.06 was very smooth, .05+.07 did not fit
• IN2 | .13 | .08+.07 does not fit, .08+.06 some drag, .07+.06 some drag
• IN3 | .08 | .09 does not fit, .06 fits with ease, .08 has slight drag
• IN4 | .08 | .09 does not fit, .06 fits with ease, .08 has some drag, .07 has more drag

I guess it's safest to go to the feeler gauge that doesn't fit and assume it's 1 or 2 sizes below that.

IN2 definitely seems suspect so I'll look into increasing the shim size on that one.

 

[scott]

Hate to say this but your exhaust cam may still be off a tooth. Looks like the 1- mark raised up when you installed the tensioner. How about another photo focusing on just that exhaust cam sprocket?

Sometimes it's hard to judge perfect alignment, and you have to check a couple of positions and then just pick the one that looks best because neither is perfect.

It definitely raised up some with the tensioner. It's hard to say whether moving it would put the 1-mark below the surface or not. Here's another pic:

I assume it would move the distance between 2 pins. That SEEMS pretty low.

 

[Nessism]

Guess that's as good as it's going to get. Moving it down would put it way down. As the chain wears the mark moves up so maybe that's why the mark seems to be high.

 

[hampshirehog]

It's a job to tell from a photo but I would be wary of that being a tooth out. You have to get your eye bang on level with the top of the cylinder head and look along the gasket - the arrow should point at the gasket.

 

[tom203]

Actually, I did use a torque wrench. I finally broke down picked one up a few days ago (hard to find one locally that goes below 10 ft-lbs).

I misplaced my simple torque wrench for this stuff- My deluxe one doesn't go below 10 ft-lbs. Don't go crazy on valve clearances-err on loose side; I bet with some running, this motor will push the valves into their seats fairly quick as it's probably sat for a long while waiting for you.

 

[Suzuki_Don]

It's a job to tell from a photo but I would be wary of that being a tooth out. You have to get your eye bang on level with the top of the cylinder head and look along the gasket - the arrow should point at the gasket.

Scott, rotate the motor a couple of times by the end crank nut/hex and stop with the 1-4T lined up perfectly with the index mark then get a photo for us with the camera lined up exactly horizontal with the top face of the cylinder head where the valve cover sits so we can see exactly where the 1 arrow is pointing without any reflex error. If you know what I mean. Your photos are taken looking down slightly onto the motor and it's hard to see the exact position. We need to be able to se it square on.

Keep at it - not far away now.

 

[scott]

I did another check and this is what I have (Spot | Clearance Guess | Notes):

• EX1 | .09 | .08 is smooth, .09 has some slight drag, .10 does not fit
• EX2 | .08 | .07 has some drag, .08 has slight drag, .09 does not fit
• EX3 | .06 | .07 and .08 can be forced in but seems like too much effort
• EX4 | .08 | .08 fits smooth, .09 does not fit
• IN1 | .11 | .10 had some drag, .05+.06 was very smooth, .05+.07 did not fit
• IN2 | .13 | .08+.07 does not fit, .08+.06 some drag, .07+.06 some drag
• IN3 | .08 | .09 does not fit, .06 fits with ease, .08 has slight drag
• IN4 | .08 | .09 does not fit, .06 fits with ease, .08 has some drag, .07 has more drag

I guess it's safest to go to the feeler gauge that doesn't fit and assume it's 1 or 2 sizes below that.

IN2 definitely seems suspect so I'll look into increasing the shim size on that one.

I did adjust the IN1 and IN2 shims yesterday so my current clearances are roughly (Spot | Clearance | Shim)

• EX1 | .09 | 2.58
• EX2 | .08 | 2.63
• EX3 | .06 | 2.67
• EX4 | .08 | 2.62
• IN1 | .09 | 2.61
• IN2 | .08 | 2.67
• IN3 | .08 | 2.67
• IN4 | .08 | 2.56

Good enough.

Scott, rotate the motor a couple of times by the end crank nut/hex and stop with the 1-4T lined up perfectly with the index mark then get a photo for us with the camera lined up exactly horizontal with the top face of the cylinder head where the valve cover sits so we can see exactly where the 1 arrow is pointing without any reflex error. If you know what I mean. Your photos are taken looking down slightly onto the motor and it's hard to see the exact position. We need to be able to se it square on.

Ack! I already have the cam cover reassembled. I think at this point I'm just going to see if/how it runs.

Will my mixture screws be affected by the cam timing adjustment? This is what my plugs looked like when I removed them to do the cam adjustments. The plugs are only a month or two old so I assume Plug #4 is still usable.

I sprayed plug #4 with some De-Oxit so it looks a little better (different lighting but..):

I was planning to back out screw 1 a tad and turn in screw 4 a bit.

 

[tom203]

I did adjust the IN1 and IN2 shims yesterday so my current clearances are roughly (Spot | Clearance | Shim)

• EX1 | .09 | 2.58
• EX2 | .08 | 2.63
• EX3 | .06 | 2.67
• EX4 | .08 | 2.62
• IN1 | .09 | 2.61
• IN2 | .08 | 2.67
• IN3 | .08 | 2.67
• IN4 | .08 | 2.56

Good enough.


Ack! I already have the cam cover reassembled. I think at this point I'm just going to see if/how it runs.

Will my mixture screws be affected by the cam timing adjustment? This is what my plugs looked like when I removed them to do the cam adjustments. The plugs are only a month or two old so I assume Plug #4 is still usable.

I sprayed plug #4 with some De-Oxit so it looks a little better (different lighting but..):

I was planning to back out screw 1 a tad and turn in screw 4 a bit.

Well, you were doing lots of messing with those mixture screws, so I'd check them- 2 to 3 turns out is a start. Those plugs should clean out with some running. I think your cam timing is fine- the pics can be deceiving- and I think you grasped what was needed. Get this thing burning fuel!