Gs1000 Bonneville Bike

[stevef.]

Hey everyone, a friend and I have decided that we want to go land speed racing and shoot for some AMA records. We have been looking at the production modified/production modified partial streamliner chassis classes with classic (1981 and older) gas and classic fuel engine. The records in these classes seem reasonably attainable for 1000 and 1350cc sizes. I know there is a lot of aftermarket support for the GS as many of you do go drag racing. At the moment we have not yet purchased a bike so I would like to ask for input on things to search for and steer clear of. I know to stay away from the "g" designation as it is shaft drive and we would not be able to gear up. But otherwise, is there a "good year" or year range of the GS1000 or 1100 from 1981 or earlier?

we are thinking that our first outing next year will probably just be with top end work and re-ringed pistons but nothing too crazy. The chassis modifications will also be pretty mild for these classes as well. We would like to be able to progress and continue to have options going forward.

Let me know now if I need to clarify anything else and I look forward to your input!
Thanks!
-Len

 

[Jonathan]

What an interesting proposition. As with any racing the first question is budget.... read the rules very carefully especially re engine sizes. I don't know details of hopping up GS1000/1100 or GSX1100 but the bottom ends are very strong. I will follow your progress with interest

 

[Steve]

The only 1000 engines in 1981 were G models, so you will be looking at 1980 and older.

The 1979 and older heads had smaller intake ports for the VM26 carbs, the 1980 heads were larger for the BS34 carbs, so should flow a bit more air.

Starting in 1980, the 1100 was a four-valve engine, which could breathe a lot easier, if the rules allow 1100cc.

.

 

[850 Combat]

The 1980/81 11100 has tons of potential. They were the center of pro drag racing for years, and rules had to be changed to make other bikes competitive at all. Long after the GSXR line existed, the GS1100/GS1150 16 valve motors were what was drag raced, as I recall anyway. Rapid Ray on this site would know how to make one go well.

Not that long ago I rode my 1000G out to El Mirage to see SCTA speed trials out there. It is pretty cool. You can get up close to everything at the start and in the pits. Just not on the speed runs.

Lots of interesting and innovative hardware. Most racing has every contestant racing stuff that resembles all the rest of the entrants very precisely. Land Speed racing is nothing like that. It is much more individualistic. Everybody has their own ideas and goes with them.

 

[GregT]

Read the rules VERY carefully....The GS1100 is age eligible but the 1000cc Katana version is 1982/83. If you're allowed to decrease engine capacity to fit a class, then I'd use the 16V engine for the 1000cc class, with the 1000 barrels and pistons - the crank's the same.
If you're not allowed to reduce capacity, then you're stuck with the 8V 1000 engine - which is pretty bulletproof anyway.
Have fun.

 

[stevef.]

Thanks for the replies!! I'm thinking I'll stick to finding either 80 or 81 GS1100. I don't think decreasing displacement is allowed in the class I want to run, but the classic engine 1350cc records should be attainable with the 1100. It seems as though the pre-82 class is not all that competitive at the moment. Which works well for us because we're thinking these will be the cheapest era of bike for this purpose and to go after a record.

-Len

 

[850 Combat]

I know a guy with two records more than 30 years old, with an alcohol turbo Honda 350 four. I think that if it was easy, someone else would have taken them by now.

What sanctioning body are you planning on racing with?

 

[stevef.]

Well good for your buddy, that sounds like a cool bike and also nowhere near what I'm trying to do. The sanctioning body is the AMA. It looks like we will basically need to go 140mph to make these records. A couple of these specific classes that we want to go for don't have existing records at the moment and ones that do have records at the 120-130mph ball park. Not that it will be EASY. But we're thinking that this looks worth pursuing. The rule book with posted records in it are on the website.

 

[salty_monk]

A Stock GS1000E will pull in the region of 120mph n the flat. With pods & pipe & dialed in Cams you may get 5-10mph more I would think...

There is a guy on here that has a 1000 with head work, cams etc but haven't seen him around for a while (it's a monoshock).

He may know where he tops out at...

 

[stevef.]

Cool, yea my 1982 750 will hit ~120. It has pods and exhaust and jets. I don't think anything else is done to it. I did strip it way down. Had it on a scale at 467 with half a tank of gas.

But anyway I figure we should be able to get a GS1100 with some engine work and lots of stripping down to go 140 on salt.

We shall see!

-Len

 

[bonanzadave]

I smell a documentary movie...

"Worlds fastest Skunk "

 

[limeex2]

140 seems slow for a record. I am assuming it is non streamlined. As mentioned read the rule book very carefully. I believe stock gearing will get you up to 135? Getting a GS1000 to go 140 is obtainable but it will take more than HP. Its many factors one needs to consider. HP, tuning for altitude, weight, wind management and your first time will be a huge learning curve. Go and talk to the people, it seems like this group is like the vintage roadracers I meet. Friendly,full of advice and helpful. Be careful, speed is addictive...

 

[Jonathan]

Frontal area is the biggest factor limiting max speeds. There's only so much you can do to reduce cD on a motorcycle and the cD numbers are pretty huge anyway, numbers around 1.0 are usual compared to 0.35-0.5 for cars but there is much to be gained my minimising frontal area. Search the Internet for the formulae, plug in your drag coefficient, frontal area and target speed and see how much hp you need to get there. Play with the numbers and see how much different parameters affect things.

finally. Do post stuff here, it will be a good read

 

[stevef.]

140 seems slow for a record. I am assuming it is non streamlined. As mentioned read the rule book very carefully.

I agree, it's weird but that's what it is. The trend seems to be that the "classic" engine designation looks like there are some relatively attainable records. Per the AMA rule book C designation is 1947-1981. I think that maybe just most people want to go newer or older. You are correct about the streamlining. We are looking at non-streamlined and partially streamlined classes.

Ive been poring over the rule book the past few days and digesting it. Next I need to find the right 80 or 81 GS1100!

 

[GregT]

I agree, it's weird but that's what it is. The trend seems to be that the "classic" engine designation looks like there are some relatively attainable records. Per the AMA rule book C designation is 1947-1981. I think that maybe just most people want to go newer or older. You are correct about the streamlining. We are looking at non-streamlined and partially streamlined classes.

Ive been poring over the rule book the past few days and digesting it. Next I need to find the right 80 or 81 GS1100!

Gearing will be one of the problems. I have made up an 18T front sprocket for our GS1000 so as to give us a wider range of options for roadracing. Once you have your bike, I'd see what is the biggest front sprocket you can fit and work back from there. With a bigger front, you'll be looking at rear sprockets in available sizes which will fit on a stock cush drive.

 

[limeex2]

What do the rules state for head work? Specifically 2 ir 4 valves? Big difference. Correct me if I'm wrong, but if there is no written rule against it, its legal. When we roadraced "production" bikes this made for very imaginative and creative ways to go faster

 

[Agemax]

Gearing will be one of the problems. I have made up an 18T front sprocket for our GS1000 so as to give us a wider range of options for roadracing. Once you have your bike, I'd see what is the biggest front sprocket you can fit and work back from there. With a bigger front, you'll be looking at rear sprockets in available sizes which will fit on a stock cush drive.

I run a 19T front sprocket,48 rear on my GS1000, (530 size) but i have a GSXR 17" rear wheel. I think 19T is the biggest that will fit, i certainly havent seen any bigger ones for sale.

 

[stevef.]

Gearing will be one of the problems. I have made up an 18T front sprocket for our GS1000 so as to give us a wider range of options for roadracing. Once you have your bike, I'd see what is the biggest front sprocket you can fit and work back from there. With a bigger front, you'll be looking at rear sprockets in available sizes which will fit on a stock cush drive.

Noted, I suppose we will have to see. We do have a good friend who's father is an excellent machinist by trade so he may be able to help with this if need be.

What do the rules state for head work? Specifically 2 ir 4 valves? Big difference. Correct me if I'm wrong, but if there is no written rule against it, its legal. When we roadraced "production" bikes this made for very imaginative and creative ways to go faster

The rules for that engine class say that the engine needs to use the original crank casings, cylinders, and head. Since the 4v design was initially manufactured prior to 81, it's legal. But I do need to start with a bike that originally came with it, which is why I am pretty latched onto the GS1100 at this point.

 

[RichDesmond]

Gearing will be one of the problems. I have made up an 18T front sprocket for our GS1000 so as to give us a wider range of options for roadracing. Once you have your bike, I'd see what is the biggest front sprocket you can fit and work back from there. With a bigger front, you'll be looking at rear sprockets in available sizes which will fit on a stock cush drive.

Sprocket Specialists will make anything you want as long as it's physically possible.
(Well, they did last time I checked.)

 

[RichDesmond]

What do the rules state for head work? Specifically 2 ir 4 valves? Big difference. Correct me if I'm wrong, but if there is no written rule against it, its legal. When we roadraced "production" bikes this made for very imaginative and creative ways to go faster

Depends on the sanctioning body. Back when I roadraced, CCS was like that, if it's not prohibited it's allowed. WERA was the opposite, if it wasn't specifically legal, it was illegal.

As always with racers and rulebooks, there will be "creative" interpretations.