New member 1979 GS1000: introduction, pics, and leaky cylinders!

[ecirmo]

New Development: got the thing torn apart and started cleaning the cylinder head domes, and noticed what appeared to be some significant wear:
12804276_986875174731741_498502089_n.jpg

Is this salvageable? I'm was going to take the head and valves in to be lapped, but if this head is shot than it's not worth it. Thoughts?

[Nessism]

Can't tell from that photo.

How about taking some more photos and uploading them on photobucket? Then if you link the [img] link the photo will show up in high resolution.

[Big T]

Ed, I believe this is classic "nobody ever adjusted these valves for 20,000 miles" result
Ethan, you might try lapping that one and see whether there's a good seat under there. More pics of the valves and head, please

[tkent02]

Ed, I believe this is classic "nobody ever adjusted these valves for 20,000 miles" result

If that was the case the valve would be burnt. What do the valves look like?

[ecirmo]

I'll work on the photobucket thing. In the meantime, here are a few more of the domes and the worst valves:

https://drive.google.com/open?id=0B-IMdmfv0aPjcFlZdW5sQ1hCelE

https://drive.google.com/open?id=0B-IMdmfv0aPjT25hOVlHQWI4dGc

https://drive.google.com/open?id=0B-IMdmfv0aPjZmFzN3c5Z0Y2U3M

https://drive.google.com/open?id=0B-IMdmfv0aPjeFRUWlQwQ3VFRGc

https://drive.google.com/open?id=0B-IMdmfv0aPjNU5vRjdSVlNndVk

https://drive.google.com/open?id=0B-IMdmfv0aPjeVRfcG5fZkpfSUU

These aren't cleaned up yet, but they definitely are pitted and gouged/scored in various places in thee seal area around the domes. In some cases the edge of the dome appears rounded off a bit.

Everything else has looked great so far. The pistons are quite good, only superficial carbon on the face, all rings free and very little carbon on the sides. The cylinder walls look like mirrors. Sigh, should I start trolling ebay for a new cylinder head?

[tkent02]

Can't see your pics, can you fix it so we don't need permission to see them?

[ecirmo]

Oops, fixing the problem...standby

Ok, here's an album link instead!

That oughta work.

[tkent02]

I didn't see anything that a little bit of lapping wouldn't fix. No obvious burnt spots, don't look too worn. Everything looks oily though.

[ecirmo]

Any advice for removing the thick carbon deposits from the valves and domes to clean things up before taking it to the machine shiop? I've been reading that apparently lacquer thinner does a good job, as well as chem-dip.

[Nessism]

The guides are bronze guides. The head looks to have been serviced before.

Lapping may get it, but some light cutting on the seats and valves would be better.

[ecirmo]

I think my plan at this point is to get it cleaned up as much as possible and have the shop lap the valves, valve seats, and the cylinder head surface as well. More than I was hoping needed done, but alas. The rest of the top end seems to be in quite good repair. Hopefully the shop won't tell me I need a new head.

[tkent02]

Well as long as it's apart, might as well do it all. The cylinders looking like a mirror might be why the compression is low.

[ecirmo]

Interesting! I figured that was a good thing. I was going to forgo honing; would you recommend I have the cylinders honed as well then?

[tkent02]

Interesting! I figured that was a good thing. I was going to forgo honing; would you recommend I have the cylinders honed as well then?

Yes! Absolutely hone the cylinders! See if the rings are still in spec, or just replace them. Pistons too, measure them and the bores but they are probably going to be fine with only 53,000 miles. Then break it in properly, which means opening and closing the throttle. NO GENTLE CRUISING!!!


Whatever you do, read this first:

http://www.mototuneusa.com/break_in_secrets.htm

[ecirmo]

Alrighty all,

Just heard from the machine shop. My heads overall are fairly good, some pitting in a few of the exhaust seats, but otherwise fine. The main problem is that apparently my valves are "cupping." My options at this point are to either throw everything back together or to get all new valves, guides, and machine new seats. I am inclined to take that route, since it would be a proper long-term fix. That said, it would push me into the $1200 area.

The guy doing the work was fairly straight ahead, and said that if we just lap everything and put it back together, it would run fine, and might even run a long time still, at which point I could just pull the head again when the time comes and do the new valves/seats etc. The question is, how long will that be?

I'm sure it's a crap shoot, but I am interested in your opinions on whether I should do the whole shebang up front and not have to worry again, or if the cheaper and shorter term route sounds reasonable.