Top End Noob

[Nessism]

The piston in that photo doesn't look bad at all. Those nicks are nothing and the skirt scuffing is minimal.

[MisterCinders]

I removed the valves with a 6" c-clamp and a notched out deep socket.

Those valve stem seals are a real bear to pull out. Will replace.

The valves themselves have a healthy layer of carbon crud on them, but don't appear bent/burned.

The mileage on the bike is about 18,000 IIRC.

[MisterCinders]

Some ongoing questions:

Valve Crud The valve faces are pretty crudded up but look clean on the stem side. Any good chemicals to get the crap off?

New Valves? A couple of guides suggest swapping in new valves. Is that overkill? If that's worthwhile, better to get that done now while it's all torn down.

Lapping Seats Either way on the valves, I need to lap the seats. This frightens me. Clymers and the Service Manual are pretty thin on guidance here. Do I need to go to a machinist for this? Are there any good how-to guides for this? The valve replacement guide on BCliff's site requires some funky video player that I lack and won't/can't download at the office.

New Rings At 18,000 miles, do I need new piston rings? The current rings look OK, I think.

Flex Hone When I do the brush hone, what size do I use? The Flex-Hone comes in 64mm and 67mm. Stock width is 65mm, but my measurements so far come in about 0.3 - 0.5 below that (i.e., 64.70 - 64.50 mm). The mfc claims that the brushes are slightly oversized, so if you are honing out a 3" bore, the 3" brush will work because it is a little larger. It also suggests that if your size is not listed, go the next largest size. Will a 67mm brush be too large though for just a de-glazing?

Sorry for all the questions, but I want to place an order for the parts I need, and don't want to leave something out.

Thanks for continuing with this drama.

[7981GS]

Here are some pics of the No 3 Piston. Those small dings on the edge are pretty damn sharp, though it's hard to tell from the picture.

Take a very small file and gently smooth out the sharp spots.
Finish by hand sanding.

Daniel

[mike_of_bbg]

Some ongoing questions:

Valve Crud The valve faces are pretty crudded up but look clean on the stem side. Any good chemicals to get the crap off?

I dropped mine into my can of Berryman's. A bit of scrubbing with a toothbrush got them clean.

New Valves? A couple of guides suggest swapping in new valves. Is that overkill? If that's worthwhile, better to get that done now while it's all torn down.

If they're not chipped or cracked, there's really no need. Check the condition of the seats.

Lapping Seats Either way on the valves, I need to lap the seats. This frightens me. Clymers and the Service Manual are pretty thin on guidance here. Do I need to go to a machinist for this? Are there any good how-to guides for this? The valve replacement guide on BCliff's site requires some funky video player that I lack and won't/can't download at the office.

Google will find lots of guidance, but this is one of the easy parts. Betcha there are even a few YouTube videos. All you need is lapping compound and a lapping tool - basically a stick with a couple of suction cups on either end.

http://www.amazon.com/Alltrade-648448-Double-Lapping-2-Piece/dp/B004BWEPF4/ref=sr_1_2?ie=UTF8&qid=1308590112&sr=8-2

New Rings At 18,000 miles, do I need new piston rings? The current rings look OK, I think.

There should be specific measurements in the manual for end gap, ring free end play, etc.

[Nessism]

Lapping is easy. No reason for concern. Like suggested, check out some videos. You won't be afraid after you educate yourself.

I'd use that 64mm flex hone. 320 grit would be good.

I'd replace the rings. You can reuse them if necessary but considering the time and gasket cost to pull the head, I'd just error on the safe side.

[MisterCinders]

Shopping for new piston rings now. How do I figure out what size I need (i.e., std, +0.5mm or +1.0mm)?

Should I err on bigger, so I can file down to fit?

[Nessism]

Shopping for new piston rings now. How do I figure out what size I need (i.e., std, +0.5mm or +1.0mm)?

Should I err on bigger, so I can file down to fit?

Those sizes relate to the bore size. You use standard rings on standard pistons, etc.

[MisterCinders]

First of all, Ed is a saint for putting up with all these questions.

Ordered full set of new rings, new valve oil seals, new OEM base gasket and rubber parts, piston snap rings, new valve keepers, lapping tool and compound.

Received my FLEX-HONE today.

Will continue to clean up the valves, mating surfaces, etc. while waiting for parts.

Finally checked out that valve replacement video. After downloading the player, and the video, the damn thing cuts off in the middle after he explains the shop-built valve compressor (which I already dealt with) but before going into the actual valve work. In particular, the step-by-step on re-installing the valves is what I am looking for.

For instance, I am not going to hammer out the valve guides, they look fine. OTOH how do you pull the bottom spring seat? Clymer's/Service Manual suggest that it plucks right out, but I cannot get in there to pull it and don't want to manhandle anything in that space.

Of course, Clymer's/Service Manual also said merely to "use needle-nose pliers to remove the valve oil seals" -- and that was a much tougher task.

[MisterCinders]

Ugh - got my parts order in.

One of the valve keeper sets contained only one half. More delays. Also figured out that my order for snap rings did not make it into the form. Guess I'll wait another week for parts.

FML

[Nessism]

You can reuse the old valve keepers. Why are you changing them?

By snap rings do you mean for the piston pin? If so, you DO need to change the ones you extract out of the piston, but not if it is left in the piston.

[MisterCinders]

Clymer's said to discard the valve keepers and replace. Even if I could reuse them, I pitched them already. v0v

Yes, snap rings are the piston pin circle clip.

Also, I have new rubber o-rings for the base of each jug. The old ones look like they are embedded into the cylinder and do not budge. Do these actually come out? Figured I would double check before picking them out of there and replacing them.

[Nessism]

Clymer's said to discard the valve keepers and replace. Even if I could reuse them, I pitched them already. v0v

Yes, snap rings are the piston pin circle clip.

Also, I have new rubber o-rings for the base of each jug. The old ones look like they are embedded into the cylinder and do not budge. Do these actually come out? Figured I would double check before picking them out of there and replacing them.

Valve keepers are reusable on the GS bikes. Another example of Clymer's having their heads up their backsides.

You can download the factory service manual from basscliff's website for free. Please go get yourself a copy and use that as the default authority. If Clymer's supplements the FSM information, fine. But don't believe Clymer's if they contradict Suzuki.

You can dig those O-rings out with a pick or pin. They don't do much of anything anyway so you could have reused the old ones.

Sounds like you are getting close. Keep going...

[MisterCinders]

I do refer to both manuals. Of course the Service Manual says to drive out and replace the valve guides, and I am not doing that. heh

The snap rings are what **** me off the most because I had them on my list, but amidst my confusion between Z1 (who have some circle clips, but not the right ones) and Part Shark (where I had not set up a profile before) I managed to leave them out of my order. Now I have the whole thing ready to go back together . . . in a week when the damn clip-rings (snap rings? circle clips?) arrive.

I am close though. So close I can taste it.

[MisterCinders]

Holy crap! I have a new and deep hatred of those valve keepers. Took me an hour to get only 2 valve assemblies installed. Fiddling with those keepers sucks.

Tried small flathead with grease, small needle-nose pliers, etc., but fishing the keepers into that gap is maddening. Is there some better technique for this? I see a number of $50 tools that appear to pop the keepers into place, but I am not trying to buy one of those.

Other ideas?