Whats the deal with the 16 valve engines?

[nejeff]

A quick refresher please, been a while since I needed any GS guidance. A friend is asking about any known issues with the 16 valve engines. I have no experience with them but I seem to remember they may have had some top end issues? Lubrication maybe? Please refresh me.

[Rob S.]

Never heard of (or experienced) that.

[fbody_mike]

The only issue I know about on a stock setup is the valve cover bolts easily strip out the threads in the cam bearing cap and require a thread insert for repair. I have seen people alter the upper end oil supply, but these were always modded motors. I think there is plenty more to worry about on 30+ year old motorcycle than the top end. But the worse thing is a motor with 20,000 miles where no previous owners adjusted the valves past the initial break in. That will kill any motorcycle motor, be it the 2 valver or 4 valver.

[Steve]

I think it was the 750s that had the oiling problems.

.

[Nessism]

Yup, the 750 had oiling problems. Shimming the oil relief spring was a (at least partial) fix. The 1100E's weren't easy on their cams, followers, and valve guides either. For the most part they were durable though. It's just that the 8V GS bikes were legendary in their durability. Most of them would run to 100k miles whereas many of their contemporaries wouldn't

[GregT]

Yup, the 750 had oiling problems. Shimming the oil relief spring was a (at least partial) fix. The 1100E's weren't easy on their cams, followers, and valve guides either. For the most part they were durable though. It's just that the 8V GS bikes were legendary in their durability. Most of them would run to 100k miles whereas many of their contemporaries wouldn't

Correct. Not surprising when you realise that it's the same oil pump from the first GS750 8V through the plain bearing 16V 750 right up to the last 1100. As time went by they asked the same pump to do more and more.
When you compare the pressure side of the first GSXR750 pump to the old GS one you see immediately how much change was needed. And on the GSXR they asked it to do less than on the last 16V aircooled engine.
But IMO some good engineering and metallurgy made those engines last pretty well.

[bwringer]

Yep, the 16V 750 had it the worst.

Shimming the relief spring was a partial fix, but I believe there is or used to be a top end oiling kit for the 16V 750 that would pipe extra oil up there.

The 1100/1150 kit seems to be available, since these are still used in drag racing. Not sure whether any new kits are still available for the 750, or whether this one fits, but this is the idea.

https://store.schnitzracing.com/ward-top-end-oiling-kit-suzuki-gs1100-gs1150/

In close to stock form, the 1100 and 1150 didn't really have any widespread top end oiling issues, but the 750 could. In the one I saw personally, the bike was completely stock and ridden very gently, but the cam journals on the right starved for oil; it looked like the "uphill" side didn't get enough oil when idling on the kickstand. Once they start to gall, it's all over. So avoiding idling while on the kickstand is probably safest.

[gustovh]

Ride a well tuned 1100 16 valve and you won’t have to ask that question.

V

[Rob S.]

Ride a well tuned 1100 16 valve and you won’t have to ask that question.

Amen to that! Why not put your year and model in your signature?

[gustovh]

Amen to that! Why not put your year and model in your signature?

I’ts there, right at the top. 1980 GS1100LT.

V

[mrbill5491]

70,000+ miles on my 750, no oil problems.

[storm 64]

70,000+ miles on my 750, no oil problems.

Just curious Bill. Do you run Synthetic Oils or Regular? Not that it makes much of a difference...