1978 GS1000 bored out to 1173 by RC Engineering

[jskellington]

Keith, thanks as always for your insight. I'm inclined to believe you're right about tightening the steering head. The bearings themselves are probably in pretty decent shape; the bike has less than 9,000 miles on the clock. In comparing my single front disk 1000 against this bike, I'm interested in knowing why the double disk wheel feels so much lighter. I know the rotors are drilled, but you'd think the extra caliper and rotor would offset the weight savings. I'm guessing a lighter front end and loose steering head bearings is a bad combo. The day after Thanksgiving I'll belch a few times and try your technique. . . I'll let you know how it works.

Terry, the old Supertrapp race header was rusty and holed like a cheese grater and is probably being melted down to make corned-beef hash cans even as we speak. Amazed the old ignition got to you so fast. Stay tuned for future wheel developments.

[KEITH KRAUSE]

Well, it isn't really my technique, just basically tightening the stem more than you have it right now.
It's common to feel no play/slop in the front end but once you go down the road at speed...uh oh!
So 1/8 turn at first is what I'd try. If it improves but doesn't completely go away, them maybe another 1/8 or even less than that might do it.
Just as long as the bars don't start dragging too much. The bars/drag will tell you when you're tightening to much.
As for loosening the fork pinch bolts, it's always made sense to me. If you loosen only the center and side pinch bolt, then tighten the steering nut down some, re-tightening only the center bolt will cause the upper bracket/clamp to possibly bind/flex. The upper clamp should go straight down and evenly, not just down more near the front.
Some people get anal about it and loosen the lower fork pinch bolts too. I will too, if I see that the forks tops no longer align flush with the top of the upper bracket/clamp after the additional tightening.

[terry]

Terry, the old Supertrapp race header was rusty and holed like a cheese grater and is probably being melted down to make corned-beef hash cans even as we speak. Amazed the old ignition got to you so fast. Stay tuned for future wheel developments.

No worries Jack, thanks for that, and if you see a spare set of those alloy rimmed wheels lying around, let me know mate? Cheers, Terry.

[KEITH KRAUSE]

Also, I've never weighed the "E" front wheel assembly against the spoked/single disc assembly, but I'd have to believe the dual disc/cast wheel E model weighs more.
Seems like the only way the E model could feel lighter is if it's more solid or something's wrong with the spoked front end, such as something loose. I know low tire pressure can give you that heavy feeling, along with loose parts.

[jskellington]

Did my first valve adjustment a month ago. I could see right away that underside of the cam cover had been ground in places to accommodate the high-lift cams.

Engraved at the end of the intake camshaft were the numerals .515 and, of course, R.C. Engineering.

What does that figure represent?

Thanks in advance,

Jack

[salty_monk]

It's wrong to be a duration figure so perhaps it is maximum lift in inches??

Dan

[Big T]

Also, did all the 1978 bikes run alloy rims like yours? I'd love a pair of them too, I'm not keen on the current 17 inch rim fashion, I understand the technical advantages re: fitting modern tires etc, but don't much like the look? Have a good one Jack, Cheers, Terry.

The US had 2 models in 1978, the standard (sometimes called the C) with wire wheels and one front disc. It came in red (like Jack's) and blue (like mine)

The E model (aka Skunk) was black with a white stripe, cast wheels, 2 front discs and some other minor differences, like a 17" rear wheel

The GS1000 had standard aluminum rims, which is nice. They had standard plated spokes, which is bad. I've had both of mine converted to Buchanons SS spokes. I see spoked wheels regularly on Ebay for reasonable costs.

Jacks has an E model fork, calipers and discs mated to the wire wheel.

Beautiful bike, Jack!

[BadBillyB]

Did my first valve adjustment a month ago. I could see right away that underside of the cam cover had been ground in places to accommodate the high-lift cams.

Engraved at the end of the intake camshaft were the numerals .515 and, of course, R.C. Engineering.

What does that figure represent?

Thanks in advance,

Jack

When you adjusted the valves, were the shims on top of the cam follower like stock ????.....In order to run higher than .400" lift cams, the 650 Kaw style cam followers with the small shim underneath MUST be used......Billy

[jskellington]

The shims were sitting under the cam lobes, just like stock.