Top end rebuild

[rapidray]

The stock valves are likely to be more durable than stainless valves so I'd go that way if possible. At any rate, you most likely won't need valves but measure everything and compare to the service limits. When rebuilding my old 450 head I tore apart the ebay head I purchased and the old head from the bike and took the best parts based on the measurements. Clean up everything, lap the valves, and reinstalled the best parts along with new valve stem seals.

Good luck.

Sorry but the Stainless valves dissipate heat faster & live LONGER than the stock valves. PLUS, they flow better! Ray.

[terry]

Thanks for the offer Ray, and I may well take you up on it, but I'm confused. How will I get the chain off and back on it I don't break it and rivet it back together. I'd have to split the cases to do that right? Wouldn't that mean removing the engine entirely?

Edit:
Ok, looked at the engine cutaway again. The cam chain is free all the way to the bottom end once the camshafts are off? So I can remove the head with the chain intact.... If so, whew, I was just confused. I though the chain HAD to be broken to remove the head.

To do the job properly, you need to split the crank cases to replace the OEM endless chain. If I was going to that length (which I will be shortly) I certainly won't be returning a 28 year old OEM chain when I can buy a new, heavy duty Tsubaki race chain for only 50 bucks from Z1 Enterprises. Here's a link: http://www.z1enterprises.com/detail.aspx?ID=2921

I know that there are plenty of low mileage bikes in the US due to the limited riding season in some states, but here in Oz there aren't too many sub - 50,000 mile bikes, and even my genuine "two careful owner" GS1000ST's cam chain was so stretched at just over 40,000 miles that the dinky OEM auto chain adjuster just couldn't take the slack out of it, and it rattled like a bastaard.

I built my own manual adjuster and this took the slack right out of it, but this isn't ideal either, so shortly I'll be stripping it down to the bare cases so I can do a top end rebuild, (welded crank, heavy duty APE studs, forged 12.5:1 1073cc RC pistons, Yoshimura "road and track" cams, heavy duty valve springs, shim under bucket conversion, etc etc) and once the cases are apart I'll be able to check all the gearbox bearings, selector dogs etc and clean and paint the cases.

I have used "soft links" before, and have no doubt that if done properly they're fine for a stock engine that's not going to be thrashed mercilessly by some diickhead who really wanted a GSXR1000 but couldn't afford it, but my natural conservatism forces me to err on the side of plenty of built in redundancy. Go the OEM chain/soft link option if you must, but ride your bike accordingly. Cheers, Terry.

[doctorgonzo]

Man... I really, REALLY don't want to have to pull the engine and split the cases unless I basically have no choice. I ride fairly hard. I mean it sees redline on occasion, but I don't totally abuse it by any means.

Step one is just get the new head here (which is coming by mule train for only $23 shipping) get it totally torn down, take it to the machine shop to be dipped and cleaned up and measure all it's components for spec. The bike is currently, barely rideable. It leaks pretty badly from around the one exhaust header bolt. I fire it up every couple days and put 15 or 20 miles on it, just to not have it sitting the whole time.

[hampshirehog]

Man... I really, REALLY don't want to have to pull the engine and split the cases unless I basically have no choice. I ride fairly hard. I mean it sees redline on occasion, but I don't totally abuse it by any means.

That ain't hard on a GS -I've always deemed the red line as 'for information only'

It's no great shakes to put on a new cam chain, just takes a bit of time as it's all straightforward enough. However, I've done a few and really I was wasting my time. Some of my past bikes have been thrashed mercilessly and for big miles but the cam chains have always been fine in reality.

I read an article from Reynolds that calculated theroretical cam chain life as 450,000 miles as it has an easy life. Highest mileage bike I've ever owned had done 125,000 miles and the cam chain had never been replaced.

[psyguy]

this kind of got lost amongst all the posts on how to remove the cam chain...
to replace the head you do not need to remove the cam chain at all
you can also measure it for stretch while its still on the crank
mine was totally in spec after 100000kms

[Nessism]

How many miles on the engine again? As stated before, I suggest you measure the cam chain instead of guessing about whether or not it is serviceable; replace it as necessary but it's not likely to need it unless the engine is pushing big miles.

Regarding the endless chain debate, quite a few pro's and con's involved. Personally I'd most likely go with a rivet link but make sure you purchase/borrow the proper tool. As long as the pin head is peened over properly it won't come apart.

Good luck.

[doctorgonzo]

How many miles on the engine again? As stated before, I suggest you measure the cam chain instead of guessing about whether or not it is serviceable; replace it as necessary but it's not likely to need it unless the engine is pushing big miles.

Regarding the endless chain debate, quite a few pro's and con's involved. Personally I'd most likely go with a rivet link but make sure you purchase/borrow the proper tool. As long as the pin head is peened over properly it won't come apart.

Good luck.

The chain on my current head which I'd be using is 30K miles. That's probably what I'll do, use a master link (as long as chain is in spec) unless I can do it without removing the chain at all which the manual seems to indicate you can (as well as psyguy) I want avoid splitting the cases as that will add a LOT of time to doing this and I want to get back on the road.

[doctorgonzo]

Bump for my salvage head finally arrived.

Well, on the day I was going to contact my bank about what fraud protection I had available on my Visa debit card (I feared none), my head finally arrived. It's a bit rougher than I had been led to believe. The valves are a bit rusty looking, and the whole thing is very, very dirty, but the bolt holes I have checked so far all look good. Tonight I am going to try and verify it's the correct head. All I can think of to do is measure the spacing on the intake ports, and compare to my current head. I couldn't find a part number stamped on it. Assuming it is the correct head I'm going to start tearing it down tonight. I'll keep you posted and progress and likely be back with more questions.

[Suzuki mad]

Well at least the 'new' head arrived.

Has it got buckets and shims also? When you say rust on the valves is that inside the head or on the valve stems?

I'd give the head a check for flatness also, just in case.

Sounds like you have some work on you hands, so as long as it fits OK you should be fine.

Suzuki mad

[doctorgonzo]

Wish I had digital camera access, BUT, I don't.

Pulled the cover off. Cams, cam ends, buckets and shims, all still there, and actually superficially look very clean, measurement to come. It's the other side, not the stem, but the what... head of the valve that has a tinge of rust to it, not rusted up, just you can tell moisture got in there. Step one, get it all taken apart, then off to the machine shop to be checked out.

[Suzuki mad]

Step 1 should be to check that its going to fit your bike. Why throw $$$$ at a head that won't fit. Stupid.

Suzuki mad

[psyguy]

I couldn't find a part number stamped on it.

nothing on the under-side of the bottom fin?

exhaust port spacing is the same on all 750 and up 8v heads
but taking the cam cover off should confirm that it's the correct head

[doctorgonzo]

The only markings on the underside of the head are S-2 Suzuki and B-8. I checked bolt center to bolt center between ports 1 and 2 on the intake side, and visually it also looks right. Before it goes to the shop I am going to pull the tank and compare it to my current head, to verify the carb spacing etc... That final "yes, it's the same head". I wouldn't even be that concerned if the salvage place I bought it from hadn't displayed shady behavior during the whole transaction.

I have decided I am going to go ahead and shoot the moon. New valves, guides, seals, etc... I know this involves some addition machine shop work on the valve seats, reaming the holes for the guides, etc... but I am going to go ahead (and assuming the shop tells me it's still "true") and make it a totally "new" head.

Now to my next question. How do I get the valve guides out? Service manual says to drive them out from the engine side using a special tool. Can I use a a wooden dowel... I have the valves removed and from the engine side it looks like the tube that protrudes up is part of the head and doesn't move. Does a dowel need to go IN the hole in that little tube where it will hit the seal/guide and them push it out the other side, or DOES that whole tube drive out?

The valve spring compressor used by Steve in his video and recommended by others worked like a charm. MUCH easier than I was expecting. I bought 1" PVC as that was what was used in the video, but on mine 1" was not a "snug fit" in fact it looked like 1.25" was probably the right size. (Is that and indication of the engine size by the way....). They were sold out of 6" clamps, so I had to get a much heavier duty 8" clamp which drove my total price to about $17.00.

EDIT: I think I found my answer. I'm going to have to get the machine shop to press the new guides in anyway, I might as well get them to press the old ones out. I'll just take ot to the shop with the guides still in place.

[doctorgonzo]

Valves, guides, etc....

Ok, some dififculty in finding a source for valves and guides other than OEM (I was gonna go stainless on the valves). APE only has 1100 and 1150, and Dynoman only has GS1000 pre 1980... any ideas? APE offers a 28.5mm for the 1100 and says that's max 1100 size. Anybody know max size for the 1000?

[Nessism]

Sorry...grumpy, middle-aged engineer here...but I still think you should measure everything before going off and dumping a bunch of money into parts you may not need.

Shim and bucket valve actuation is very durable from the standpoint that there is no side load on the valve stems and guides. This leads to excellent durability. If you have a micrometer, measure the valves from your old engine and the valves from the new/used head, and find the best ones. As long as the valves measure within the service spec, you will not gain anything by changing them. Use the best valves of the lot and then check the side clearance between the valve and guide - you will need a dial indicator. Chances are pretty good that the guides will be good as well but measure to make sure.

The Suzuki parts are very high quality and I seriously doubt you can get better parts from the aftermarket. Hot rod V8 guys like stainless valves but stainless steel is softer than the hardened carbon steel used in the stock valves. To improve durability, the better stainless valves have hard chrome plated stems - good luck finding something like this for your GS engine.

Also, I've seen lots of questionable work from machine shops over the years. Hope you know a reputable shop or are sending the head to someone like APE. There is a pretty fair chance your "rebuilt" head will be no better than the old one otherwise.

Measure the pistons and cylinder bores as well.

Replace stuff that's worn. To measure is to know (sorry, had to throw that in there again.)

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