1978 GS1000 bored out to 1173 by RC Engineering

[Guest]

Just bought this brute of a GS1000 from its only owner, after a heads-up from Tom MLC of this site. The original owner said he bought it new in 1978, carefully broke it in for 1,000 miles, then took it to Russ Collins Engineering for what he termed the Stage 2 treatment. This included porting and polishing the head, installation of race cams, bore to 1173 cc and box-forged pistons, Barnett clutch basket, springs and plates, Gerex ignition, automobile coils of some kind, Mikuni 29mm smoothbores with velocity stacks, and a Supertrapp competition header. It's got some other period paraphernalia as well: some sort of unidentifiable steering damper, a fork brace and a Lockhart oil cooler.

The guy I bought it from had clearly moved on to other projects, and the bike only had 8,600 miles on the clock. Almost all of the information he gave about the modifications was pulled from his memory, so I took it for a test ride. It started readily when cold, emitting a belligerent snarl, came off the choke quickly, and threatened to rip my arms off every time I twisted the throttle.

So I bought it. The asking price was $1495, which seemed reasonable, considering it came with new tires, a fresh tuneup, and some good bits that I can use on my other, more mannerly GS1000, namely the original clutch basket and plates (barely used), a new Supertrapp can, a strong rack and backrest, and a spare copper head gasket for when I blow the old one.

Okay, that's a long preamble to this question: anyone know much about the RC Engineering (the RC standing for Russ Collins, which I learned from Google) Stage 2 upgrade?

Second question: 29mm smoothbores were probably the best you could do in 1978. I'd like to replace the velocity stacks with K&N pods, to quiet the intake noise, and scrap the rusty old header for the same reason. Which carburetors would you speed demons recommend?

Thanks in advance for the help. I'll post some pictures shortly.

Jack

 

[rek]

yeah, i used to read all about them in motorcyclist and such (when i should have been studiing history or english). RC eng was founded by Russ Collins and when i was reading about them it was an article on his two golden boys that were shaking the world of drag racing with a GS1000. Those guys names
are Terry Vance (driver) and Byron Hines (wrench, guru etc.) that article was going on about how Byron would take home heads and play with them on his home flow bench to learn to extract the max form them.
that bike you have may have been massaged by the Hines himself.
they also used to make headers and bigbore kits.

 

[HiSPL]

Keep the carbs! You can put K&N's on it by removing the velocity stacks. You would have a hell of a time trying to get some other carb setup working right on that motor.

I'd say a Vance and Hines megaphone would be the ticket for an exhaust. It would look period correct and would go with the theme of the bike better than anything else.


Man, I'm jealous! That's one heck of a deal you got there!

 

[first timer]

don't even think of touching that bike, people would probly kill for the deal you got. plus it is no shade tree job, that bike was preped by one of the top guys of high performace bikes, it would be like owning a camero or sumtin preped by john force. every peice in that bike is complementing each other so to change anything on it is a very bad idea. except maybe going with some K&N air filters (model number rc-2450, i have a set of 29's as well). the 29 carb are the best you can probly get unless you feel like dropping $1500 on a set of fcr carbs or somthing and they probly won't fit. So leave it as is. and that means leave the jetting alone to, it is probly set up perfect and if you are having problem look to the boots and boot oring and the carb o rings before you go messing with anything elese.

for the header if it is not dented or have holes and is rusty, just find someone to sand blast it for you then get it re chromed or ceramic coated. you will be hard pressed to find another good exhaust.


oh yeah please post lots of pics, and keep in mind this is no city bike and probly will tend to run on the hot side so traffic jams would be a bad thing. this is a beast so take it out and cut up the road with it.
-ryan

 

[KGB]

WOW!!

That is like finding the holy grail of GS'.
Ranks right up there with finding a Pops Yosh GS1000S.

You've got a piece of history.
Try contacting RC Engineering and ask if they have any records.
It's only a phone call or email.
Who knows what could happen.


One thing, leave it alone. The bike is already setup and built to run very well. It's not broken, don't f'with it.

 

[Hoomgar]

Well it is impossible for me to say anything without repeating what others have already said but I still feel compelled to reply since this bike you got is IMHO the top representation of the GS in the world we know. This is the "original" Suzuki super bike that won the AMA world championships and put Suzuki out front as a top contender to be dealt with. They stayed there ever since and all the GSxxxxxxxxxxx revisions over the years have been spawned out of the success that this very bike generated.

As for your questions, you already have the best carbs for that bike on it. There are carbs that would maybe do a bit better like some flatslides or a few others but in reality they deserve to be put on newer bikes. This bike you have already has the period specific performance mods on it and as such can spank a whole heck of a lot of posers out there on much newer iron if this bike has an experienced rider. Just put the K&N Pods on like you want to because they will flow just about as well as the stacks but will protect the carbs and the engine from dirt much better. You will need to check plugs to see if rejetting is needed but you may not need to. As for the pipe, I'd get it blasted and ceramic coated. You could put a new pipe on but this is the pipe you want to go with that you already have if you ask me. If not, a V&H megaphone would be next in line.

Just under 1500 purchase price? I truly hope you realize how special the deal is that you just got. Very awesome, rare find my friend. Enjoy it.

 

[Guest]

RC Engineering at work

RC Engineering at work

Here's three photos of the new old bike.

http://s88.photobucket.com/albums/k175/jpmason_2006/GS1000/

The fork brace and steering damper, which look very Wes Cooley, have no steadying effect on the front end at speeds over seventy. First comes the eery lightness, as if the tire is preparing for lift-off, then the sharky headshake when rain grooves or microscopic imperfections in the road are contacted. Scary. The suspension, which features the original swingarm, shocks and forks, is going to require some attention. I've got an aluminum swingarm from a 1983 GS1100 that's getting bolted on for sure, followed by a 1989 GSXR750 rear wheel, then 1994 GSXR1100 front forks and a GSXR750 front wheel. I'll post photos as the mods are made.

Dig that crazy Gerex ignition box where the grab handle ought to be! The two loose wires near the steering head were formerly attached to a radar detector. Gee, I wonder why.

The stock regulator/rectifier is not regulating or rectifying too well. What a surprise. The surface corrosion on the frame beneath the battery box is testimony to boiling acid, and the recent service receipt confirms that the R/R is returning electricity to the battery at the upper end of the acceptable range.

So I've got an Electrex R/R coming. Can't wait to take the gas tank off and have a look at the coils. The brakes are squeaky; the rubber boots and dust seals and hoses date from the Carter administration. I'm willing to bet the bleeder bolts haven't been loosened since they left the factory. In other words, there's plenty to do, which is the whole point, right?

Thanks for all the valuable information and comments from the GS veterans on this site. The 29mm smoothbores stay put. I'm syringing Liquid Wrench onto the exhaust flange bolts and hoarding birthday candles in preparation for removing the headers and assessing their worthiness.

You know, the guy I bought it from said the RC Engineering modifications pumped the motor up to an estimated 130 horsepower. Seemed an exorbitant claim for an 8-valve motor, until I drove the thing. Wow.

Jack

 

[first timer]

can you post better pics of you steering stablizer where it mounts the to frame, the mounts look kinda under sized from the pic. sounds like some fun mods to bring the bike up to the motors specs.

-ryan

 

[KGB]

The steering damper has a knurled knob on the end.
Look at the end and see if there is an arrow :arrow: on the end.
You should be able to turn it, have the handlebars squared off, or straight across and then turn the nob.
I have a similar if not the same damper on my 1000, just mounted on the throttle side.
It does make a difference at speed. I also have a fork brace.

If you elect to change out the suspension DO NOT THROW ANYTHING AWAY!

As to the 130 hp claim, yea the ywill make close to that, not at the rear wheel, in street form, but yes they will make 100+ no problem.

Please keep us updated, yes we are bias, yes we love our bikes.

 

[BadBillyB]

Ahhhhh, something tasty to talk about. As far as info about RC's stage 2 package, the RC catalog from 1980-81 lists two possible cam choices for a 2v Kaw. Suzuki cams would be very close to the same.... Theres the RC370 Street racer cam. Then theres a RC388 Hot Street Cam. So expect to find a .388" lift cam set up in it. As far as the piston kit goes, expect to find aluminum wrist pin buttons, that are a light press fit into the end of the wrist pins. They are pretty trick. The ones I have seen are kind of like a slipper piston, designed for road racing, also very trick. The valve sizes are probably standard, as the GS's had generous valve sizes compared to the KZ1000. They may be aftermarket stainless though. The header is probably a RC piece as they were making them back then. Probably used a Supertrap silencer. The Gerex ignition is a few years ahead of my time, is totally period, and would end up in my spare parts bin as a Dyna S would get the nod. As far as the carbs go, I personally think they are too small for this particular engine. A set of 33 smoothies would not only look period, but they would gain you another 10HP to boot. 29's are great for a 1085 motor, but larger carbs are in order. The oil cooler lines need to be covered as they are too close to the header. As far as I know, and I was buildin' back then, Barnett never made clutch baskets. It's probably RC modified. Never had any luck with the Barnett stuff either. They're clutch plates are at the bottom of my list. The steering damper is very period and probably is not functional anymore. Try MRE or Star Racing for a replacement. Rotate the knob to max resistance and see if you can feel resistance while turning bars from side to side. Should be very noticeable. When you fix the charging system, see if the starter clutch has upgraded bolts in it. The alternator rotor may have also been lightened as this was an issue on my street killer (1175cc) back in the days.....BadBillyB

 

[Guest]

http://s88.photobucket.com/albums/k175/jpmason_2006/GS1000a/

A few changes since my last posting, as you can see from the above two photos.

I've put a wrench or screwdriver on every bolt on the bike, after a blast of SeaFoam or squirt of Liquid Wrench, and managed to loosen everything. The ancient header, which had a strange resonance that penetrated my earplugs while riding and left my ears ringing, came off easily, to my surprise. The resonance came courtesy of six or seven rusty holes that were the size of the holes you see on bamboo flutes. The header was swiftly dispatched to the metal recycler. I'm leaning toward the tried and true Vance & Hines megaphone, or perhaps fabricate some sort of 4 into two system with tunable Supertrapp cans.

The carburetors, obviously, have come off as well for a thorough cleaning and rebuilding. The dangling regulator and rectifier will be gone as soon as the Electrex replacement arrives. The Gerex coils, each the size of beer cans, have come off, as well as the ignition module that was fastened to a plate where the grab handle should be. The old ignition plate has come off as well. Dyna S ignition, green coils and new plug wires come next.

The steering damper may or may not be rebuildable. Dialing the adjusting knob to full damp created some resistance, but not enough to inspire confidence. I'll be looking for something far more effective as a replacement.

In studying the rear fender, I can see a natural place to chop off about six inches, fabricate an end bracket and raise the license plate and rear lamp a few inches. Not sure yet whether I'm going to go with a Wes Cooley look or some sort of cafe chop.

One thing I know for sure. This is fun stuff. Just cleaning up the old beast and replacing inferior fasteners gives satisfaction, and as I sort out the familiar charging system problems, it's a great comfort to be a part of this amazing forum, and to have recourse to the collective wisdom found here.

More pictures to follow.

 

[Hoomgar]

Looking good man, keep at it my friend

 

[West]

You got that bike for $1500? That was some deal.

I agree with the others here, you don't put a mustache on the Mona Lisa.

Leave the engine mechanics alone (add some filters, of course).

Congratulations.

 

[KGB]

J

Thanks for keeping us updated on this.


Any luck with that magazine? Just curious.

 

[Tom MLC]

Wow Jack, you don't waste any time! When I posted this bike in the for sale section (way back on July 12th), I was hoping someone would pick it up because it sure looked special. If I hadn't just bought my 1000, this one would be in MY garage.

But I'm glad you got it, and it looks like she's happy, too. Let me know when you're back on the road and we can hit the road together.

Tom

 

[Guest]

http://s88.photobucket.com/albums/k175/jpmason_2006/GS1000b/

As you can see, I've installed a new R/R. As you cannot see, I also installed a new stator. Also installed the familiar green Dyna coils and Dyna S ignition. The timing is dialed in. Got new intake manifold boots with nice stainless allen head fasteners, just waiting for the 29mm smoothbores, which are getting sorted out at Wired George's carburetor ranch in Texas.

Vance & Hines street megaphone is on the way. In the meantime, I'm gonna check the valve clearances and replace the paper gasket with the Real Gasket silicone version. When the carburetors arrive, I'll affix the K&N pods, synchronize and begin scaring myself, I hope, every time I whack the throttle.

Many thanks to the GS veterans who've provided so much useful instruction as I grope my way through this restoration.

More pictures when there's something to see.

Thanks,

Jack

 

[Tom MLC]

Nice work Jack. Your patience and attention to detail really comes through. Are you riding another bike while working on the hotrod? I got your PM. Gotta make it a point to ride up and see you.

 

[jimcor]

How's your battery? If I just did the R/R, Stator and ignition system I'd spring for a new battery too.

 

[Guest]

I'm guessing that with the pumped up motor I should select a number or two higher than the stock B8 on the NGK spark plug temperature scale. The bike came with B9's installed and a couple of packs of B10's in the spare parts bin the previous owner gave me. I'd be grateful for any advice from the drag racing drivers on this subject.

By the way, I installed the rebuilt carburetors this Sunday, screwed on the new K&N pods, installed the V&H four-into-one, put the gas tank back on, primed the carbs and thumbed the starter.

Ignition! Nice growl from the new pipes and steady idle at 1,000rpm! I didn't have a lot of time to test drive at multiple throttle settings, but the bike seemed eager to go. One fine-tuning question:

Should I keep the two carburetor vent holes with or without hoses? And what's the reasoning behind leaving them off when running pods?

I'll post pictures tomorrow. And thanks for the help.

Jack

 

[KEITH KRAUSE]

Remove the float bowl vent lines, leave the ports open. You'll likely experience fuel starvation if the lines stay on. Some bikes show fuel starvation more than others. Depends on mod's and how the engine flows. I really don't know how to explain it technically. Someone else may know how.
I've read a few opinions on what's happening and I have some of my own.
When going from a stock air box to pods, especially if you run a freer flowing exhaust, there's an obvious air flow increase. The float bowl venting ability differs in various carb types. Some designs are only adequate, while others have more venting ability and can vent adequately even if you go with pods.
With more air and fuel running through the carbs, the stock venting design can't keep up with the added demand and the result is poor venting and that makes it harder for the jets to draw fuel. Since you can't easily enlarge the venting passages/chamber, the best you can do to improve venting is to remove resistance by removing the line. To add, another opinion that was given to me from Dynojet was that a vortex actually forms in the line and that further inhibits adequate venting. Dynojet jet kits recommend to remove the lines, especially on bikes that are in California and/or used on freeways often.
Crosswinds also can effect pod/venting performance. While I'm no expert, I can see how crosswinds would effect the desired stream of air into the pods. No longer the desired stream, a turbulent/erratic flow of air is going to cause vacuum fluctuations and how easily/constant the fuel is drawn up from the bowl. If you add to this the compromised venting I mentioned above, you'll see fuel starvation, though it may be more severe from bike to bike. I've tested several bikes over the years and I don't hesitate to remove the lines anymore because I know what will happen. My '79 1000E with V&H pipe/K&N ovals was greatly effected. Very similar to when you first run out of fuel. I didn't believe it until I tested for myself. I see no problem with removing the lines as far as dirt/water/bugs entering. I've never read of a problem caused by dust/dirt or bugs entering. I can see where water could be a concern but have yet to hear of a problem related to rain. If you use a hose on your bike, just use common sense and don't point the hose right at an open vent.
I let people know about removing the vent lines several years ago and many have come back and said they were amazed that the reason for their "lean jetting problem" was really just poor bowl venting. The VM carbs appear to be effected more than the CV's but many CV carb owners said removing the lines gave a noticable improvement while some said they couldn't notice any difference. The vast majority of those that said there was no difference didn't have a noticable venting problem to begin with.
Your smoothbores are designed for an improved flow. How that factors into the venting/crosswinds opinions above I can't say exactly. It still varies from bike to bike. I can see where they may actually be effected even more than "regular" VM's. They may be effected less. I've assisted a couple owners in the past with their 29 smoothbores and the said they could feel surging that they thought was a lean condition and no richening of the pilot jets or jet needle position helped. After removing the lines, the surging went away. They did have a lean condition but it was from fuel starvation, not lean jetting.
Once in awhile someone shows up at this site and asks questions about smoothbores. I/we ask for them to tell the results of suggestions given here. Most of the time they get help and disappear. So for a lot of us here, our knowledge of smoothbores is limited compared with other carb designs.
I hope you'll share your results after doing some performance/plug read checks at various throttle positions.
You don't mention any vacuum synching of your carbs. They must be vacuum synched well to get accurate performance and plug reads. Before that, be sure your air screws are adjusted using the highest rpm method and your ignition timing is spot on, valve clearances correct too.