1978 GS550ET top end inspect/rebuild

[steveb922]

You shouldn't have a problem getting new studs via Suzuki - they are still available. I expect you are aware that there are two different sizes. The outer four differ from the inner eight.

Just to make sure you don't encounter any difficulty ordering spares, I should point out that you have either a 1978 GS550EC, or a GS550ET from 1980. There are a few differences - but not where the studs are concerned.

[Nicholk]

Spares

Thanks Steve...as luck would have it, 1 of each stud was needed. As you said though....no probs getting them....helpful chap at Crooks Suzuki had stock of 1 stud and nut, the rest are ordered.

Keith

[eil]

Always a relief when a stubborn bolt, stud, or nut finally is finally worked free!

I'm not familiar with a Stilson, is that what we across the pond call vise grips?

[Nicholk]

Stilson

Hi, not vice grips......it's also called a pipe wrench:



Not recommended as a stud remover normally as it can and does damage the
metal but as these 2 were already damaged it was OK.

Cheers.

ps vice grips commonly referred to here as "mole" grips.....I believe from the original manufacturer that were the first
available this side...!!

[Nicholk]

Studs

OK, received the new studs etc yesterday so work can continue....in a week or so......going back for some Yorkshire ale and visit family. Meantime I'vr cleaned some more stuff and been checking valves/spring measurements.
All are good apart from a couple of outer springs down to 1.673" Still well above service limit though so should be OK.
Worried about some more studs now though.....should have cleaned/inspected before initial order. See photo below.....not sure if this is poor initial finish or pitting corrosion....pretty sure it's the latter. These are the studs that came out when the head was removed and the ends are the block (lower) ends.
My inclination is to replace them as well but would welcome opinions.

[Nicholk]

Vapour blasting

OK, back to the grindstone again after a longer than expected break.
Have now received the bits back from vapour blasting and they're looking so much better now. See pics:



And these are the before and after shots of the head and barrels:








My worry now is that the head may still need skimming:

This is a closeup of the worst part of the head



Has anyone fitted a head like this before..?? Will the gasket seal sufficiently if I use jointing compound as well..??
All advice appreciated

[Nicholk]

Head skim

Mmmmm.......more research seems to suggest use of jointing compound is a really big mistake. Looking closer it's a skim reqd and possibly block refaced as well. Off to the shop it is next week. I'll also get the bores mic'd up and either honed or rebored depending on results. Time to get the wallet emptied again...!!

[Nessism]

The critical sealing areas are a band around each cylinder and around the cam chain opening. Pitting in the areas away from combustion pressure are no worry unless they are really deep. I suspect your head will be fine as long as you use OEM Suzuki gaskets. No NOT use Athena or other cheap aftermarket gaskets.

[Nicholk]

Skim

Thanks for that........sadly there is some pitting around the cam chain opening and at the side of 2 of the combustion chambers....the photos don't show it up too well. I took it to the local shop this morning and they were in agreement so a light skim is being done...same for the barrels. Here's hoping the skim does not produce new problems..!!

[Nessism]

Skimming should pose no issues. The GS engines have really thick deck surfaces. Only problem is the cost and finding a reputable shop you trust to do the work.

[Nicholk]

Gaskets

OK, still waiting for the bits to come back from the shop. Meanwhile I've been looking at obtaining the gaskets. As several posts have advised the use of OEM for the base and head gaskets, I've found that these are still available here in the UK as well.......cost £65 for the 2. That's just over $100 so comparable with most of the posts I think. My question now though is should I also go OEM for the other gaskets and O rings..? I can get a pattern full set for £60 and just not use the head/base gaskets from this....are these OK in peoples opinion..? Otherwise it's order individually as the OEM set is no longer available

[Nicholk]

Skim done

Head and barrels back and looking good. Next week will see the valves lapped before final clean and air blast before reassembly. Cylinder i.d checked and still well in spec so no new pistons or rebore reqd. Will be taking barrels for glaze bust then final clean and air blast as well before fitting new rings.

[Nessism]

You might want to check the US ebay site for gaskets. These guys can save you some money...http://www.ebay.com/itm/SUZUKI-GS550...p=mtr#shpCntId

Using a pattern set for the non critical gaskets shouldn't be a major concern. In my experience, the OEM gaskets that are critical are the base, head and valve cover. The valve cover isn't critical per say, but the OEM gasket will typically last longer since it's more tear resistant as you go forward doing valve adjustments with the bike in service.

[Paul]

A great thread, lots of stuff covered that the book doesn't... cheers good luck with it!

[Nicholk]

O rings

Thanks for that, looked at the gasket from USA and it is not quite the p/no I was looking at....I would think it's a backward sub? My main worry would be transit damage with a gasket. Suspect I'll stick with the new one I've priced already....I'll be doing a bulk order so can (should be able to) guarantee good
packing in a box.

My question now though to all who have done a rebuild before....
The 4 O rings that go at the bottom of the barrels..... 09280-61001....for the life of me I have been unable to find any sign of these having been fitted..!!
They weren't in the recesses and were not stuck to the base.....has anyone seen this before or is there any chance they would drop down into the crankcase..? I can't see any sign of them and am somewhat concerned.

Thanks

Keith