Gs1000 Bonneville Bike

[80GS850GBob]

"140mph"
-sounded to me like the guidelines said the engine had to be stock heads, crank and cylinders...{but are internal mods ok?...over bore, added stroke via other oem rods and shorter height aftermarket pistons}
-does the gearing have to be stock offered ratios?...or can you gear stiffer for top end speed?
-if you can't change gearing {much} can you go to taller rims/tires?...or both?
Bonneville is a long run game and average of three passes...as I recall.

 

[stevef.]

"140mph"
-sounded to me like the guidelines said the engine had to be stock heads, crank and cylinders...{but are internal mods ok?...over bore, added stroke via other oem rods and shorter height aftermarket pistons}
-does the gearing have to be stock offered ratios?...or can you gear stiffer for top end speed?
-if you can't change gearing {much} can you go to taller rims/tires?...or both?
Bonneville is a long run game and average of three passes...as I recall.

"Classic Gasoline- The engines production date shall be prior to 1981. All engines shall retain the O.E.M. heads, cylindeers, and crankcases originally installed at the time of factory production. Above components produced after 1980 and exact reproductions may be legal in Classic class if they offer no competitive advantage. Documentation may be required to prove authenticity of classic OEM standard bore to remain in displacement class. Further increased displacement beyond the class limit shall place the motorcycle in the correct class. GASOLINE ONLY."

This is EXACTLY what the rulebook says. I don't see any mention of the rotating assembly or the valvetrain. Only that the design of the engine MUST have been in manufacture prior to 1981 and externally has to look more or less stock (obviously stated in more specific terms). I would like to avoid having to fight with them to allow an '82 (if they are in fact the same as earlier models) so I am sticking with looking for '80 and '81 models.

Gearing can be changed in any class per the rulebook.

Wheels can be changed in the chassis class which I am looking to compete.

Also, the speed is averaged over the center mile of the course and has to be averaged over two runs. This is done so that you can run both ways which negates any effect that wind could have on the run. So if the wind makes me go 150mph headed east, it could slow me down to 130mph when I head west and we will get the average.

There are different length courses depending on how fast you are able to go. I should theoretically be on the five mile course: two miles to build speed, one timed mile, and two miles to shut down. I could hit the center mile at 138, accelerate to 145 in that time, and my average will be somewhere in between. It's not about top speed, more about showing what type of speed you can maintain.

-Len

 

[Buffalo Bill]

Looks like you'll only be moved to a higher displacement class if you overbore, however this may put you in the 1000cc class.

 

[stevef.]

Looks like you'll only be moved to a higher displacement class if you overbore, however this may put you in the 1000cc class.

We're shooting for the 1350cc class. The current record with the AMA is around 130mph. The AMA events are not as competitive as the SCTA events and it appears as though the classic engine designations are also less competitive than the other engine designations. We specifically want to target the low-hanging fruit, so to speak.

 

[Sam 78 GS750]

This could be interesting. I'll definitely be following along.

 

[RichDesmond]

"Classic Gasoline- The engines production date shall be prior to 1981...

I read that as 1980 and earlier. 1981 wouldn't qualify unless you can show that they were identical.

 

[stevef.]

I read that as 1980 and earlier. 1981 wouldn't qualify unless you can show that they were identical.

Good catch!! I am thinking that most, if not all, bikes sold as 1981 model years were produced prior to 1981. But this is something I will be looking at closely on any bike I purchase.

-Len

 

[850 Combat]

Do you have any place that you can test?

This place is a lot closer than El Mirage or Bonneville

http://www.loringtiming.com/ They can't do real FIA records there, because they only race in one direction, and they doother reasons. A guy went over 300 on a sit down motorcycle there. It is paved. Obviously El Mirage and Bonneville are not. El Mirage is at 2800' elevation. Bonneville is at 4200' elevation. The elevation and the surface both slow down the speeds somewhat compared to what you might find on pavement.

 

[Guest]

says the head must be oem, but can it be worked?

 

[GregT]

says the head must be oem, but can it be worked?

I'd read that as the casting must be OEM - but all else is free.

 

[limeex2]

I believe they made 1980 GS1100"s? Coulda swore they had 2 and 4 valve 1100's in 1980

 

[RichDesmond]

I believe they made 1980 GS1100"s? Coulda swore they had 2 and 4 valve 1100's in 1980

If memory serves, they made a 4-valve 1100 (the square headlight ones) and the 2-valve 1000. At some point the 2-valve went to 1100 for the shaft drive models, but I don't remember exactly what year. Might have been '80, might have been a year or two later.

 

[limeex2]

If a 1980 4 valve was made, to get the HP numbers your looking for would be achievable. So would the speeds.

 

[stevef.]

Update: we are still in search of a bike for this. we will be going to look at one tomorrow, but finding '80 or '81 GS1100's has not been easy. Hopefully we will have fortune on our side and take a bike home this week!

 

[bobgroger]

In 1980 the GS1100L was 16 valve and chain drive. Just the L.

 

[maicojoe]

Hi Steve, try calling this guy, he may have what you need. About 4-5 months back I talked with the seller at length, seems like a pretty decent bike. Should do an easy 140mph as is, just gear it up, proper salt tires pumped way up, and a steering stabilizer. I don't think you would need any fairing at all. Just find a 105 pound 4' 11" pilot, and away you go.

https://blacksburg.craigslist.org/mcy/d/1981-suzuki-gs1100/6331775887.html

1981 Suzuki GS1100EX. 38,750 original miles. Complete engine rebuild done at 37,775 miles, details are below. It has a brand new Michelin front tire. Rear tire is also a Michelin with less than 1000 miles on it. This vintage bike is in superb condition. I have owned this motorcycle for 27 years. Always garage kept and covered. Meticulously maintained and cleaned. This bike has always been a local bike since new. It has never been raced. It has genuine Suzuki European spec gauges that read up to 140 mph. Below are all the details and upgrades.

If my ad is still up it means that the bike is still for sale, no need to ask that. I will promptly remove my ad when the bike is sold.

Price is firm at $3200.

The reason that I am selling is that I just have other interests now. I rarely have the chance to ride.

Complete engine rebuild at 37,775 miles
-Bored to 1168CC with Wiseco piston set
-Welded crankshaft
-GS1150 cams and valves
-Ported and polished head
-new valve seals and springs
-undercut transmission
-new plugs and regulator rectifier
-all machining done by Cooper Performance www.cooperperformance.com

Other details
-Mikuni 33mm smoothbore carbs with individual pod filters
-Michelin Pilot front and rear tires
-Progressive springs in front fork tubes
-83 GS1100 rear shocks with adjustable damping
-New style sealed battery bought less than 1 year old
-MSD box with Dyna ignition
-Accel coils and spark plug wires
-Heavy duty clutch basket with red springs
-Polished swingarm foot pegs and engine cases
-Frame was professionally painted while engine was out for rebuild
-indoor cover is also included in sale
-Murray X-style header (very rare)

For an extra $100, I will throw in the items below
-Yuasa trickle charger, Suzuki factory tool kit, Clymer service manual, Suzuki valve adjustment tool, Center stand, Brand new valve cover gasket, Brand new carb bowl gaskets, many spare hardware parts.

 

[dorkburger]

I thought that looked familiar.....

http://www.thegsresources.com/_foru...GS1100EX-The-one-that-you-ve-been-looking-for

Good luck with the Bonneville build. Looking forward to it.

 

[stevef.]

Oh that's a sweet bike in Virginia! I'll have to talk to my buddy on this one and see if we think it's worthwhile for us to cruise out there and get it. We'd probably put the money in for hotter cams and maybe also bigger carbs. Unfortunately, we do want to actually do the riding, so we'll need some extra power. Me being 6ft and 210lbs and my buddy being 5'9" and 155lbs.

Thanks for pointing that out!

 

[stevef.]

Has anyone here been on the salt with their bike? What do you know about tire choice? I'm reading that having something very resistant to heat and abrasion is a must, but I am unable to find one place where a specific tire is referenced.

-Len

 

[stevef.]

Alright, we got a bike!! Now to make a list of everything we need and get started with inspection and tear-down.