Two destroyed exhaust valves [with pics] - replace valves or entire head?

[TheDuke]

On second glance I found this:

http://www.ebay.com/itm/1979-SUZUKI-GS750-GS-750-LN-CYLINDER-HEAD/350438488992?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D18060%26meid%3D2314507141523349127%26pid%3D100005%26prg%3D8304%26rk%3D2%26rkt%3D5%26sd%3D350520362634%26

New head, with valves for $75 shipped. I could just rip the valves out of it and sell the rest. Might be a good option.

[Steve]

Ebay is a little light on exhaust valves for the '79 750 at the moment. Anyone have any for sale???

Did you happen to notice post #4?

If you find the seats in decent shape, I think I have a couple of valves that should work.

If you are interested, I will go out to the garage and verify.


By the way, you can expand your search a bit, here is a list of other bikes that use the same valve.

• 1978 SUZUKI GS400C - CAM SHAFT - VALVE
• 1978 SUZUKI GS400XC - CAM SHAFT - VALVE
• 1978 SUZUKI GS750C - CAM SHAFT - VALVE
• 1978 SUZUKI GS750EC - CAM SHAFT - VALVE
• 1979 SUZUKI GS425EN - CAM SHAFT - VALVE
• 1979 SUZUKI GS425LN - CAM SHAFT - VALVE
• 1979 SUZUKI GS425N - CAM SHAFT - VALVE
• 1979 SUZUKI GS750EN - CAM SHAFT - VALVE
• 1979 SUZUKI GS750LN - CAM SHAFT - VALVE
• 1979 SUZUKI GS750N - CAM SHAFT - VALVE
• 1979 SUZUKI GS850GN - CAM SHAFT-VALVE
• 1980 GS850GL - CAM SHAFT - VALVE
• 1980 SUZUKI GS450ET - CAM SHAFT - VALVE
• 1980 SUZUKI GS450LT - CAM SHAFT - VALVE
• 1980 SUZUKI GS450ST - CAM SHAFT - VALVE
• 1980 SUZUKI GS850GT - CAM SHAFT-VALVE
• 1981 SUZUKI GS450EX - CAM SHAFT - VALVE
• 1981 SUZUKI GS450LX - CAM SHAFT - VALVE
• 1981 SUZUKI GS450SX - CAM SHAFT - VALVE
• 1981 SUZUKI GS450TX - CAM SHAFT - VALVE
• 1981 SUZUKI GS850GLX - CAM SHAFT - VALVE
• 1981 SUZUKI GS850GX - CAM SHAFT-VALVE
• 1982 SUZUKI GS450EZ - CAM SHAFT - VALVE
• 1982 SUZUKI GS450GAZ (Automatic) - CAM SHAFT - VALVE
• 1982 SUZUKI GS450LZ - CAM SHAFT - VALVE
• 1982 SUZUKI GS450TXZ - CAM SHAFT - VALVE
• 1982 SUZUKI GS450TZ - CAM SHAFT - VALVE
• 1982 SUZUKI GS850GLZ - CAM SHAFT - VALVE
• 1982 SUZUKI GS850GZ - CAM SHAFT-VALVE
• 1983 SUZUKI GS450ED - CAM SHAFT - VALVE
• 1983 SUZUKI GS450GAD (Automatic) - CAM SHAFT - VALVE
• 1983 SUZUKI GS450LD - CAM SHAFT - VALVE
• 1983 SUZUKI GS450TXD - CAM SHAFT - VALVE
• 1983 SUZUKI GS850GD - CAM SHAFT-VALVE
• 1983 SUZUKI GS850GLD - CAM SHAFT - VALVE

.

[TheDuke]

Did you happen to notice post #4?

Must have skipped past it. I will get her all cleaned up this weekend and post some more photos for collective forum analysis. If valves are all I need we can chat about price. Thanks for the offer.

[Guest]

On second glance I found this:

http://www.ebay.com/itm/1979-SUZUKI-GS750-GS-750-LN-CYLINDER-HEAD/350438488992?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D18060%26meid%3D2314507141523349127%26pid%3D100005%26prg%3D8304%26rk%3D2%26rkt%3D5%26sd%3D350520362634%26

New head, with valves for $75 shipped. I could just rip the valves out of it and sell the rest. Might be a good option.

I would not pay more than $50 for that head. Doesn't have cam caps and it needs fixed.

[sparki]

tbh without the cam caps the heads is more hassle than what it's worth... clean up yours and see if it's damaged. buy nothing til then imo

[bbjumper]

Even if you buy a new head your gonna need to inspect and probably repair to an extent on the new one. As already stated the seats are very durable, the valves burn partially because they don't make contact with the head when out of adjustment and as a result don't cool properly. As long as the seats can be cleaned up I'd replace the bad valves and go with it.

Cheers

[SqDancerLynn1]

If it was mine I would replace all 4 ex valves.

[TheDuke]

If it was mine I would replace all 4 ex valves.

Because if two are fried, the other two are probably in rough shape too?

[tkent02]

Maybe, maybe not. If they were .010mm looser maybe none of them would not have burnt, maybe the other valves are fine. Or maybe they are burnt to shchitt too. Did you check the compression?

[TheDuke]

Yes, and 1 and 4 were fine. But I suppose it is best to replace them all while I have it all apart.

[Nessism]

How about some shots showing the valve seats after a good decarboning? As far as replacing all the valves, I'd measure the stems first and then decide. A quick spin on a valve facing machine and old valves get a new life so no need to replace them unless they are worn.

[TheDuke]

I plan to apply some elbow grease on Sunday or Monday and will post some pics of the seats then. Would lapping in the old-but-usable valves be sufficient? Or do I have to get those two survivors machined?

[Nessism]

I plan to apply some elbow grease on Sunday or Monday and will post some pics of the seats then. Would lapping in the old-but-usable valves be sufficient? Or do I have to get those two survivors machined?

I'd get them all faced. Should only cost a few bucks each. If the head has thin shims installed already, I'd have them shave a few thousands off the stem too, since that will shift the shim thickness range up the scale.

[TheDuke]

Good advice. I should have pics up this evening of the cleaned seats.

[TheDuke]

C1 intake


C2 intake


C3 intake


C4 intake


C1 exhaust


C2 exhaust


C3 exhaust


C4 exhast


Also, all of the seats appear normal, no gouges or scratches jump out at me. However, I did notice some odd pitting/texture with some carbon build up that I couldn't scrub out. I circled what I'm talking about below. Is this normal or should I get the seats machined too?