Cant get my valves to measure right

[FlordiaMan]

Hi everybody, im tryna do some of that routine mainence on my bike right now but im having a hard time. Im measuring my valve clearance and i keep getting different measurments and measurments that seem wrong. Like for instance, i measured my 4th cylinder intake doing, and it was .08mm, but when i measured again using the method in the book, it was .12mm. and then when i measure other cylinders, im getting measurments of below .03mm. I cant even fit my .03mm feeler guage into the valve. I have a hard time believing that my valve clearance is below .03mm. And im doing it the way my Clymer manual says i should, with the lobe perpendicure to the head. Anyone have any advice or is it rly just my clearance is not?

[Rich82GS750TZ]

First tell us what bike. Better yet, put it in your signature. 8v or 16v?

[Nessism]

There are many many threads on this topic in the archive. Bottom line: follow the Suzuki method because that places two adjacent valves on the base circle at the same time. The Clymer method will result in the adjacent valve to the one your measuring being depressed, which skews the cam in the journal clearance causing the valve you are measuring to have too much clearance (oddly, the opposite of your measurements.) You better go back and double check.

Regarding your valves measuring less than .03mm, that indicates someone abused your bike and didn't do maintenance like they should. The valves pound into the seats with miles and the valve clearance will decrease. Eventually all the clearance goes away and then the valves won't close. At that time carbon builds up as the valves, hang open, and sometimes they even burn and crack. You will likely have to move the shim sizes two steps compared to what shims are installed now.

Lastly, I'd target clearances of .05 to .10mm. Kawasaki's big 900/1000 engines, which were the basis for the GS family of engines, use clearances like these with good results so no worry with going with a little more clearance. It extends the checking interval too.

[Rich82GS750TZ]

If it's an 8V engine, member Steve has developed a spreadsheet to help with this job. find him and send him an email, ask him for his valve clearance spreadsheet.

[1948man]

Any chance you are sometimes getting oily gauges stuck together on the times your measurements are going from 8mm to 12mm. I've had 2 feelers stick together a few times.

[Steve]

If it's an 8V engine, member Steve has developed a spreadsheet to help with this job. find him and send him an email, ask him for his valve clearance spreadsheet.

I'll make it easy. Look in my signature.

.

[FlordiaMan]

There are many many threads on this topic in the archive. Bottom line: follow the Suzuki method because that places two adjacent valves on the base circle at the same time. The Clymer method will result in the adjacent valve to the one your measuring being depressed, which skews the cam in the journal clearance causing the valve you are measuring to have too much clearance (oddly, the opposite of your measurements.) You better go back and double check.

Regarding your valves measuring less than .03mm, that indicates someone abused your bike and didn't do maintenance like they should. The valves pound into the seats with miles and the valve clearance will decrease. Eventually all the clearance goes away and then the valves won't close. At that time carbon builds up as the valves, hang open, and sometimes they even burn and crack. You will likely have to move the shim sizes two steps compared to what shims are installed now.

Lastly, I'd target clearances of .05 to .10mm. Kawasaki's big 900/1000 engines, which were the basis for the GS family of engines, use clearances like these with good results so no worry with going with a little more clearance. It extends the checking interval too.

so sorry. It’s a 82 GS1100G, and I went online and found a Suzuki manual that said you could measure with either the valve perp to the head or parallel, and I tried parallel and I was actually able to get feeler guages into it. And for the most part they all seemed in clearance but is there anyway it could be wrong. The guages slipped through, but they wouldn’t when I turned the lobes to perpendicular. So I’m confused on the proper way.

[Steve]

... I went online and found a Suzuki manual that said you could measure with either the valve perp to the head or parallel, and I tried parallel and I was actually able to get feeler guages into it. And for the most part they all seemed in clearance but is there anyway it could be wrong. The guages slipped through, but they wouldn’t when I turned the lobes to perpendicular. So I’m confused on the proper way.

The proper way is according to the Suzuki manual, but you have to READ IT CAREFULLY.

Start on the left side of the bike.
- Rotate the crank so that the lobe on EX1 is pointing FORWARD and EX2 is pointing UP. WITHOUT MOVING ANYTHING, measure BOTH, EX1 and EX2.
- Rotate the crank 180°.
- You will find that the lobe for IN1 is pointing UP, IN2 is pointing REARWARD. WITHOUT MOVING ANYTHING, measure BOTH, IN1 and IN2.
- Rotate the crank another 180°.
- You will find that EX4 is pointing FORWARD, EX3 is pointing UP. WITHOUT MOVING ANYTHING, measure BOTH, EX3 and EX4.
- Rotate the crank a final 180°.
- You will find IN4 pointing UP, IN3 is pointing REARWARD. WITHOUT MOVING ANYTHING, measure BOTH, IN3 and IN4.

If you look closely, with those specific positions, both valves on that side of the cam are on their base circle. Neither one will be pushing down on a valve, which will push the cam to the far side of the bearing, giving a false clearance on the other valve.

.

[portdave]

Great advice here. Where in Florida are you located?

[greg78gs750]

not unusual at all for clearances to measure below the .03, esp. if they haven't been done in...ever.

[Nessism]

The proper way is according to the Suzuki manual, but you have to READ IT CAREFULLY.

Start on the left side of the bike.
- Rotate the crank so that the lobe on EX1 is pointing FORWARD and EX2 is pointing UP. WITHOUT MOVING ANYTHING, measure BOTH, EX1 and EX2.
- Rotate the crank 180°.
- You will find that the lobe for IN1 is pointing UP, IN2 is pointing REARWARD. WITHOUT MOVING ANYTHING, measure BOTH, IN1 and IN2.
- Rotate the crank another 180°.
- You will find that EX4 is pointing FORWARD, EX3 is pointing UP. WITHOUT MOVING ANYTHING, measure BOTH, EX3 and EX4.
- Rotate the crank a final 180°.
- You will find IN4 pointing UP, IN3 is pointing REARWARD. WITHOUT MOVING ANYTHING, measure BOTH, IN3 and IN4.

If you look closely, with those specific positions, both valves on that side of the cam are on their base circle. Neither one will be pushing down on a valve, which will push the cam to the far side of the bearing, giving a false clearance on the other valve.

.

An (arguably) even easier way to think about cam position...

1) Rotate engine until 4E (exhaust) is pointing forward at gasket surface. Measure clearance on 4E and 3E.
2) Rotate engine until 1E is pointing forward.... Measure clearance on 1E and 2E.
3) Rotate engine until 1I is pointing 90 degrees to gasket surface. Measure clearance on 1I and 2I.
4) Rotate engine until 4I is pointing 90 degrees.... Measure clearance on 4I and 3I.

[Redman]

....................., but when i measured again using the method in the book,........?

I expereinced similar, until Steve set me straight.
Follow the Steve proceedure, like in Suzuki manaul (not Clymer), so that both cams on that side are clear of the valve spring.

Also, if cant get smallest feeler guage in there, see if can spin around the bucket then you know there is at least some clearance. Concider the clearance to be just the smallewst amount over zero point zero, and figure the new shim based on that.
If cant spin around the bucket, then need to put in a smaller shim and measure/figure from there,to determine what is needed. But also be aware that could be some build up on the valve from not properly closing, and will want to check clearances again after running some (dont wait another 3 or 5 thousand miles).