Quick Valve Adjustment question

[Tim]

When I rotate the cam should the lobe be perpendicular to the shim or the cylinder casing to check the valve clearance ?

[tas850g]

go to Basscliff's website and there is a great tutorial on how to do this. I believe the number 1 exhaust lobe should be horizontal to the head/shim and the intake lobe is perpendicular to the head/shim. Again, the website explains this pretty well but i had the same question that you did. I went horizontal-exhaust and perpendicular-intake to the shim to be more specific. If this is not the case then i did it incorrectly.

[Steve]

Yep, look at BassCliff's site. The pictorial is great, but in a nutshell, the cam lobes for both cylinders on that side (whichever side you're on) will be at about 45 degrees to the valves. This prevents the cam from putting any pressure that might deflect the cam, causing erroneous readings.

It also makes it easier to check the clearances, as you can check both valves without moving anything.

Now, time for another shameless plug.
Toss an e-mail my way with a request for my valve adjust spreadsheet. I will send you a copy of what many have found to be a handy tool to calculate what shims are necessary and to keep track of your shims from one adjustment to the next.

Did you note the emphasis on the e-mail? I am somewhat surprised at the number of requests that I have gotten via PM. I can not attach anything but pictures to a PM, it has to be an e-mail. By the way, just click on my name to get my e-mail address.

144 'registered' users so far, and no complaints. Either it's good or nobody has used it.

.

[psyguy]

on the adjoining cylinders one lobe will be pointing forward and one lobe upward on the exhaust side
on the intake side, one lobe pointing back, one up (on the adjoining cylinders)
adjoining cylinders being 1&2 and 3&4

[AirCooledHeaven]

When I rotate the cam should the lobe be perpendicular to the shim or the cylinder casing to check the valve clearance ?

According to the official suzuki workshop manual the lobes should be perpendicular to the cylinder casing. In fact I looked it up this morning as I did mine today. And if anyone has 2 x 2.55 shims going to waste please let me know

[Nessism]

According to the official suzuki workshop manual the lobes should be perpendicular to the cylinder casing. In fact I looked it up this morning as I did mine today. And if anyone has 2 x 2.55 shims going to waste please let me know

The valves are adjusted in pairs so the positions vary depending on which valve you are adjusting.

If the valves are adjusted individually with the cam lobe perpendicular to the bucket, you are not following the Suzuki procedure. Not tragic or anything but the clearance will be different than if you follow the proper procedure as detailed in the manual or in BassCliff's tutorial.

[Steve]

... in a nutshell, the cam lobes for both cylinders on that side (whichever side you're on) will be at about 45 degrees to the valves.

on the adjoining cylinders one lobe will be pointing forward and one lobe upward on the exhaust side
on the intake side, one lobe pointing back, one up (on the adjoining cylinders)
adjoining cylinders being 1&2 and 3&4

According to the official suzuki workshop manual the lobes should be perpendicular to the cylinder casing.

Only one of the two lobes on that end of the cam will be perpendicular to the cylinder casing. The other lobe will be pointing forward on the exhaust cam, backward on the intake cam. You do not rotate the crank between checks on adjacent valves. When the cam is set properly to check exhaust #4, it is also set to check exhaust #3, etc.

If the valves are adjusted individually with the cam lobe perpendicular to the bucket, you are not following the Suzuki procedure.

I think the hardest part to understand for the first-timer is the fact that you don't move the crank (or the cam) until you have checked two adjacent valves clearances.
What I have found that works well is this: (I hope I have this right, I'm going off memory.)
Rotate the cams so you can check intakes 1&2.
Rotate the crank 180 degrees, check exhausts 1&2.
Rotate the crank 180 degrees, check intakes 3&4.
Rotate the crank 180 degrees, check exhausts 3&4.

If this is your first time checking the valves on your bike, you will want to take inventory of your shims to see what all you have in there. Record these numbers. (My spreadsheet is just perfect for doing this. ) Now you have an idea what you can move around and what you will need to buy to get all your clearances right. It will involve a lot more crank turning to do your shim inventory, but you only need to do this once, if you do it right. Whether you use my spreadsheet or a piece of paper, save it for next time and you will know what shims are in there, so you don't need to do another inventory.

.

[psyguy]

on the adjoining cylinders one lobe will be pointing forward and one lobe upward on the exhaust side
on the intake side, one lobe pointing back, one up (on the adjoining cylinders)
adjoining cylinders being 1&2 and 3&4

so, this is correct then

[Steve]

so, this is correct then

Yep..............

[GS750GUY]

Only one of the two lobes on that end of the cam will be perpendicular to the cylinder casing. The other lobe will be pointing forward on the exhaust cam, backward on the intake cam. You do not rotate the crank between checks on adjacent valves. When the cam is set properly to check exhaust #4, it is also set to check exhaust #3, etc.



I think the hardest part to understand for the first-timer is the fact that you don't move the crank (or the cam) until you have checked two adjacent valves clearances.
What I have found that works well is this: (I hope I have this right, I'm going off memory.)
Rotate the cams so you can check intakes 1&2.
Rotate the crank 180 degrees, check exhausts 1&2.
Rotate the crank 180 degrees, check intakes 3&4.
Rotate the crank 180 degrees, check exhausts 3&4.

If this is your first time checking the valves on your bike, you will want to take inventory of your shims to see what all you have in there. Record these numbers. (My spreadsheet is just perfect for doing this. ) Now you have an idea what you can move around and what you will need to buy to get all your clearances right. It will involve a lot more crank turning to do your shim inventory, but you only need to do this once, if you do it right. Whether you use my spreadsheet or a piece of paper, save it for next time and you will know what shims are in there, so you don't need to do another inventory.

.

I just stumbled on this conversation and after reading the dialog I'm now worried about the shim job I just did to my 78 GS750EC. I went by the instructions of my Hanes manual and some advice from the GS site and don't recall the issue of checking the gap at a specific lobe positon on the shim or checking them in pairs even being talked about. I followed the instructions primarilly from the Hanes manual and believe it just said to place each lobe perpindicular to each shim and even illustrates the position in this way.
The bike seems to run great and better than it did before I did the shim job.
GS750GUY

[BassCliff]

I just stumbled on this conversation and after reading the dialog I'm now worried about the shim job I just did to my 78 GS750EC. I went by the instructions of my Hanes manual and some advice from the GS site and don't recall the issue of checking the gap at a specific lobe positon on the shim or checking them in pairs even being talked about. I followed the instructions primarilly from the Hanes manual and believe it just said to place each lobe perpindicular to each shim and even illustrates the position in this way.
The bike seems to run great and better than it did before I did the shim job.
GS750GUY

Hi Mr. GS750GUY,

I think you're close enough. I don't know why the aftermarket manual procedures differ from the factory manual.

If I remember correctly, for example, when you turn exhaust #2 lobe "up", exhaust lobe #1 starts putting pressure on its valve shim, which could possibly throw off your measurement of #2, slightly. Using the factory procedure, you can measure both clearances on that side of the cam with neither lobe exerting pressure on its corresponding valve shim.

Thank you for your indulgence,

BassCliff

[Suzuki_Don]

144 'registered' users so far, and no complaints. Either it's good or nobody has used it.

.

it's good.

[Steve]

it's good.

Thanks.