Valve adjustment on the fence.

[Nessism]

Lobe UP/away from the shim is the most accurate way.

BUT, lobe at 90 degrees to the shim is also acceptable.

The factory has you do it that way on some of them so that you don't have to turn the motor as many times.

Actually Robert, with the factory cam position both valves adjacent to each other will be on the base circle thus neither valve spring will be pushing on the cam. This position is ideal since the cam will be in the most neutral position as opposed to having one valve pushing on the cam and skewing it in the journal clearance.

Might be a situation of splitting hairs but considering the clearance is so tight, it's hard to justify going against the factory method.

[BassCliff]

Lobe positions

Its totally odd ball that the exhaust side were all in spec, but the intake was up to four sizes out.

Mr. TCK,

Forgive me for asking the obvious. After you replace a shim, do you spin the engine a few times to make sure it's properly seated in the bucket before you re-measure? To go down 4 sizes (i.e. 2.8mm to 2.6mm) with a shim seems excessive.

Here is a view of the #1 exhaust lobe when properly positioned (pointing forward) to measure the clearances for exhaust #1 and #2.


Position #4 exhaust lobe in the same manner to measure both #3 and #4 exhaust clearances.

Here is a view of the #4 intake lobe position used to measure clearances for intakes #3 and #4.


Position #1 intake lobe in the same way (pointing up) to measure #1 and #2 intake clearances.

This picture shows the relative positions of all lobes when checking clearances (looking from the right side of the motor).


Basically, when checking exhaust clearances, point the outside lobe forward and measure both on that side. And when checking intake clearances, point the outside lobe up and measure both on that side.

Now I'll shut up before I display any more of my ignorance. I'm just relaying what I've learned from the Suzuki Shop Manual and my experience.

Thank you for your indulgence,

BassCliff

[Colin Green]

Mr. TCK,

Forgive me for asking the obvious. After you replace a shim, do you spin the engine a few times to make sure it's properly seated in the bucket before you re-measure? To go down 4 sizes (i.e. 2.8mm to 2.6mm) with a shim seems excessive.

Here is a view of the #1 exhaust lobe when properly positioned (pointing forward) to measure the clearances for exhaust #1 and #2.


Position #4 exhaust lobe in the same manner to measure both #3 and #4 exhaust clearances.

Here is a view of the #4 intake lobe position used to measure clearances for intakes #3 and #4.


Position #1 intake lobe in the same way (pointing up) to measure #1 and #2 intake clearances.

This picture shows the relative positions of all lobes when checking clearances (looking from the right side of the motor).


Basically, when checking exhaust clearances, point the outside lobe forward and measure both on that side. And when checking intake clearances, point the outside lobe up and measure both on that side.

Now I'll shut up before I display any more of my ignorance. I'm just relaying what I've learned from the Suzuki Shop Manual and my experience.

Thank you for your indulgence,

BassCliff

Thank you BassCliff.

Just what I needed.

[Road_Clam]

I for one, never understood the reasoning behind the factory specified position of the cam lobe in relation to the tappet for the purpose of adjusting the valves. One would think that rotating the cam lobe exactly 180 degrees away from the tappet would yield the minimum lobe base circle, but there must be a specific reason Suzuki want's the lobe at to odd placement angle....

[renobruce]

I for one, never understood the reasoning behind the factory specified position of the cam lobe in relation to the tappet for the purpose of adjusting the valves. One would think that rotating the cam lobe exactly 180 degrees away from the tappet would yield the minimum lobe base circle, but there must be a specific reason Suzuki wants the lobe at to odd placement angle....

Their method puts the cams in a more "neutral" position. Putting each cam lobe 180 degrees from the tappet will sometimes leave other lobes pushing down on tappets, which can skew or "bend" the cam shaft and give you false readings.

[tkent02]

The spec for the cam clearance in the cam journal is .025mm - .053mm

If the cam lobe on the adjacent cylinder is down at the time, it will raise the cam by this distance, severely skewing your shim clearance measurement. Doing it the way Suzuki intended gives an accurate and repeatable result.