Fed up with the head (a little long)

[Afzzr12]

I have been rebuilding a 95 gs for a about 2 months now.  I have slowly been working on it between school and work.  I almost have the motor done except for the freakin head. 

I cleaned the valves and measured everything.  It all adds up according to the Haynes manual.  I lapped the valves back into their original locations and thought everything was good.  I flipped the head over (valve head side up) and poored gas into the dome to see if it would hold it.  NO, NEGATIVE, F@#$ leaks.  I measured again and lapped again and cleaned even more around the valve seats and still have the leak. 

Anyone have any good ideas.  I might just buy the 89 head that is for sale on here.  I think I am fighting a loosing battle.  The only thing I can think of is the valves springs were not 100% straight.  They only had a slight bend to them but I didn't think it was bad at all.  (I am a machinist too so I understand tight clearances and such).

Thanks
Alex

[coll0412]

The valve springs being crooked really shouldn't matter.

Since your a machinist, put some machinist ink(I cant remember the technical name...something blue) on the valve and give it a spin. Take alook at where the ink got rubbed off. Those valves have a 2 angle valve job, so it could be that it needs to be recut.

[GeeP]

What's the radial play on the valve tip?  Are you sure you don't have a valve guide problem?

Barring bad guides, blue them out and see what they look like.  If the valve or seat prints a crescent shape or shows obvious signs of wear, grind the valves and seats.  You can turn a pilot to fit a standard seat grinding stone and save some money.  You can grind the valves on a tool and cutter grinder as long as you have a collet to hold the GS valve stem.  The grind angles are in the service manual.

After grinding the valves and seats you may need to grind the valve tip to gain back nominal shim clearance.

Edit:  You can also grind the valves on a lathe with a toolpost grinder.  If your shop has a Hardinge HLV-H or a Monarch 10EE with a tight spindle you're good to go!  Make sure you check the spindle runout first!  Use a collet, or bore an emergency collet!  Go slow, all you need to do is dress them, not remove metal!

[sledge]

Further to Geeps comments regarding a possible valve guide problem. Worn valve guides and valve stems can and do cause problems lapping in. If they are substantialy worn it causes the valve head to run out while its being spun making it difficult to obtain a truly circular and clean ground seat. You make no mention of any inspection of these parts so I suggest you check them and compare with the figures I have lifted from the Suzuki service manual before going any further.
All dims` are in mm and being a machinist, I am sure you are aware of the importance of using accurate and calibrated measuring equipment.

Guide to stem clearance. Inlet 0.025 to 0.055   
                                        Exh   0.040 to 0.070
 
Guide I/D. Inlet and Exh  7.000 to 7.015

Valve stem O/D. Inlet  6.960 to 6.975
                           Exh   6.945 to 6.960

Valve stem run-out. Inlet and Exh 0.05 max

Valve head radial runout. Inlet and Exh 0.03 max