Gs1000 Bonneville Bike

[pservino]

I have an 1981 for sale $1500

[pservino]

I have an 81 for sale in MD

[salty_monk]

If you file the "stop" off the front plate you can turn the petcock to an "off" position. Tkent had a "howto" somewhere. Might take some interesting levers to turn it far enough...

[stevef.]

Hey everybody, we have finally been able to pick this project back up and we are making good progress. We are getting ready to mount all of the electrical components this Sunday but we are unsure of how to go about installing the dyna ignition box. Does anyone have experience with this and could you give us some ideas?

as always any constructive feedback is much appreciated!!

-Len

[Kordyte]

I'm Stevef's buddy working on this bike with him - thanks for the input so far everybody!

We're scaling back our engine building plans for this year, focusing on the chassis, ergonomics, and a fairing this year to get our feet wet at Bonneville. Next year will be the big motor build.

For now we are focusing on reliability and tunability for the engine. At this point our plans are the Dynatek ignition and coils, a healthy selection of jets for the stock carbs, the GS750 oil gear, an oil cooler, and a top end oiler kit. The bike already has a V&H exhaust and pod filters - as far as we know though, it's pretty stock otherwise.
The spec fuel for the event is at least 100 octane, with several options of higher octanes.
Seeing as we'll have reasonably high octane fuel plus the ability to control ignition timing and jetting, I'm wondering if we might as well bump the compression a little bit with a thinner headgasket. I've searched the forum to see what people are using for headgaskets, but it seems to be mostly for street bikes. What do you guys recommend we use on this "stock plus" engine we're using this year? Would a $70 set of adjustable cam gears with the stock cams be helpful with this? We don't want to go too carried away with buying engine parts this year, as it'll all be thrown away next year anyway.

[80GS850GBob]

-Do you have to stay stock cam grind?
...not too sure if any added adjustability is needed, but, you could have a machinist mill the cam gear holes into minor slots...via a rotary index jig....to yield added adjustability for dialing in to a different cam timing.
-Do you have to stick with stock compression?(I dont know the class rules...)...if you can tweek it you could shave .010 or so off the head and run a thinner gasket....you could add a thicker gasket if it doesnt work out.
-Frame stengthening....needed in a straight line? I would think it would add unwanted weight...add fairing attachment braces and/or a steering stabilizer...but that's all I'd do if I were to suggest anything.....KISS..
You should pull the motor apart to make sure it'll take the added tweekes and WOT it'll be up against.
-Fuel...airplane gas runs high as 145 I thought....

[Kordyte]

-Do you have to stay stock cam grind?
...not too sure if any added adjustability is needed, but, you could have a machinist mill the cam gear holes into minor slots...via a rotary index jig....to yield added adjustability for dialing in to a different cam timing.
-Do you have to stick with stock compression?(I dont know the class rules...)...if you can tweek it you could shave .010 or so off the head and run a thinner gasket....you could add a thicker gasket if it doesnt work out.
-Frame stengthening....needed in a straight line? I would think it would add unwanted weight...add fairing attachment braces and/or a steering stabilizer...but that's all I'd do if I were to suggest anything.....KISS..
You should pull the motor apart to make sure it'll take the added tweekes and WOT it'll be up against.
-Fuel...airplane gas runs high as 145 I thought....

We don’t have to stay stock cam grind, but we want to - simply because whatever cams that would be good for this stock motor will not be appropriate for our serious build next year (big bore, welded crank, flowed head, 38mm flatslides, etc, the works) We are trying to save money for this.
The rules are really wide open as long as the cases, heads, etc are based on the stock parts (can’t swap a GSXR head or anything like that). For now though, we are trying to see if we can pick up some easy and safe horsepower through a bump in compression for the price of a gasket.
You think stock cam timing will be sufficient?

Weight isn’t a huge concern for top speed, nor is a super strong frame, but we will do a little bracing to be safe. Steering damper is mandated in the rules and we are installing one.

The fuel is spec - we have 4 fuels to choose from, that vary from 100 octane to 118 or so. We probably want to use the 100 octane, I doubt we can get any benefit from extremely high octane with this stock motor this year.

[RichDesmond]

My 2 cents...
Don't bother with adjustable cam sprockets unless you have known good numbers to use. Not worth the time otherwise.
Don't cheap out on the steering damper, get a good one, it does make a difference.
Sounds like you're doing this the right way, get the overall package sorted, then add power.

[stevef.]

Hey guys I've got a couple of progress pics from this afternoon. We have gotten a lot done. Without further ado:

https://imgur.com/gallery/GaTqBZL

enjoy! Ask any questions you may have about the thing!

-Len

[GregT]

See what you can do to fill in the underside of the seat. It will help eliminate turbulence.
How are you operating the rear brake ? And following that, is there clearance for the muffler with the pegs there ?

[stevef.]

See what you can do to fill in the underside of the seat. It will help eliminate turbulence.
How are you operating the rear brake ? And following that, is there clearance for the muffler with the pegs there ?

You mean like making a plate to go under the tail section?

rear brake will be operated using the right side lever. We will not be having a front brake.

Funny you you bring up the muffler as we spent a decent amount of time looking at it and discussing what to do with it. We will be chopping the pipe down to make it fit there. Our pipe doesn't actually contain any insulation and sound deadening, it's just a megaphone.

-Len

[GregT]

If you can 'glass in the whole underside of the seat - maybe using a section of mudguard to give some tyre clearance - that helps remove pockets of turbulence.

The tailpipe is important for power...Try and lose as little length as possible - even if you have to convert it to a sidewinder configuration.

[stevef.]

If you can 'glass in the whole underside of the seat - maybe using a section of mudguard to give some tyre clearance - that helps remove pockets of turbulence.

I think what you're describing is more of a full streamliner type of tail section. We cannot cover the rear wheel with fairings for our classes.

[GregT]

Understood - but what I'm suggesting is turn the seat into a closed box by adding a bottom to it. This does have an effect on aerodynamics.

[Kordyte]

Understood - but what I'm suggesting is turn the seat into a closed box by adding a bottom to it. This does have an effect on aerodynamics.

It's hard to see in the pic, but we do have a stock fender under the tail there. It covers most of that area. It can be improved on a bit I'm sure, but it's going to work well enough for our purposes for now I think