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Valve Clearances


bajjer9

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Well my brother just finished putting the engine back in my bird and checking the valves. Thought I would post up the measured gaps. Not bad for a 10 year old bike with 94k on it?

Valve Cylinder 1

INT .002 .003

EXH .007 .006

Cylinder 2

.002 .002

.006 .007

Cylinder 3

.002 .002

.008 .006

Cylinder 4

.006 .007

.007 .007

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Interesting. Normally the clearance tightens up on the exhaust side.

Does anybody know how the clearance changes as the engine reaches operating temperature??? Increase or decrease??

It looks like it, as least doesn't change much or it increases, as in this instance some intake would have been held open.

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Wait a second,those intakes are tight like MoFo, 0.002 inch, it is about 0.05 mm ,right ?, or am I wrong ?.I did pull my cylinder head at 94 k miles,clearance was in spec,but valves and valve seats is a different story.

If it is really 0.05 mm clearance on intakes, with those miles there is a good chance valve`s sealing area and seats are damaged.

Those exhausts are almost too tight,but I don`t have manual here,,,,,,,

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I think your right.

It should be

.19mm - .22mm - .25mm for exhaust valves

.13mm - .16mm - .19mm for intake valves

I recently did mine.

Starting Measurements

EX #1 - .20mm

EX #1 - .20mm

EX #2 - .23mm

EX #2 - .23mm

EX #3 - .23mm

EX #3 - .23mm

EX #4 - .20mm

EX #4 - .18mm

IN #1 - .13mm

IN #1 - .15mm

IN #2 - .13mm

IN #2 - .13mm

IN #3 - .13mm

IN #3 - .15mm

IN #4 - 13mm

IN #4 - .13mm

Final Measurements

EX #1 - .23mm

EX #1 - .25mm

EX #2 - .25mm

EX #2 - .23mm

EX #3 - .25mm

EX #3 - .25mm

EX #4 - .23mm

EX #4 - .23mm

IN #1 - .18mm

IN #1 - .18mm

IN #2 - .18mm

IN #2 - .16mm

IN #3 - .20mm

IN #3 - .18mm

IN #4 - .16mm

IN #4 - .16mm

IN #3 is .01mm wider than the suggested service limit of .19mm, but I would rather have it loose than tight. Besides I ain't taking it apart again for .01mm.

The Hot Cams shim kit I used only had shims in .05 increments, makes it a little trickier.

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IN #3 is .01mm wider than the suggested service limit of .19mm, but I would rather have it tight than loose. Besides I ain't taking it apart again for .01mm.

The Hot Cams shim kit I used only had shims in .05 increments, makes it a little trickier.

I thought if you had to choose between slightly tight or slightly loose that loose was better because you want that valve to close completely not be held partially open? I have read you can burn a valve seat from tight valves, is that true?

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my brother did the work and he use to work for honda till this past month and now works at suzuki. He said all were within specs according to the manual with a couple close but not outside..runs good and compression is good...wouldnt failing valve seats show up on a compression test?

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IN #3 is .01mm wider than the suggested service limit of .19mm, but I would rather have it tight than loose. Besides I ain't taking it apart again for .01mm.

The Hot Cams shim kit I used only had shims in .05 increments, makes it a little trickier.

I thought if you had to choose between slightly tight or slightly loose that loose was better because you want that valve to close completely not be held partially open? I have read you can burn a valve seat from tight valves, is that true?

but I would rather have it loose than tight.

That's what I meant to say, cause your absolutely right.

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my brother did the work and he use to work for honda till this past month and now works at suzuki. He said all were within specs according to the manual with a couple close but not outside..runs good and compression is good...wouldnt failing valve seats show up on a compression test?

According to my '99 Manual, the clearance specs are .006" +/-.001" for the intake and .009" +/-.001" for the exhaust. Things look a little tight all around.

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but I would rather have it loose than tight.

That's what I meant to say, cause your absolutely right.

Whew, for a while there I thought my memory and loose hold on mechanical factoids was failing...

On a side note, I have to adjust the intakes on my 450 dirt bike about every 15 to 20 hours because they get tight. The exhausts don't move much after they set. I start with them at the loose end of spec and then adjust them again when it starts running crappy. I understand those valves in that single are just pounding there way into the seats. Glad my Blackbird isn't like that.

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