Performance build question

[azr]

So I'm going to be building my 79' GS1000 Wes Cooley replica track bike this winter. I have a new old stock set of Weisco 73.5 pistons. Vince was very generous and donated the 8V 1100 cylinder needed for those big pistons. I have a set of VM29mm smoothbores that could be used as well. I've done a head job on the 1000G but other than that I don't have much of any experience with engine building. I'm hoping some people with experience can chime into this thread and help me figure out what I should be doing with the engine. Do I need to have the crank welded? should I be porting? and what the heck is porting?? I'm pretty sure I should be doing something in the line of a beefed up clutch basket. I'm guessing the 1100 baskets are the thing to do and have someone cut it down to size. The 'S' frame has already been cut to accomodate the Yoshi pipe it came with but I'm not sure if I should leave it that way or weld the pieces back on and get a different pipe. And with the frame should I be doing some bracing before I have it all powder coated? As always any input is appreciated.

[GregT]

First decide what you want and what level you want to compete at....Initially, you probably won't need a welded crank. The 29mm carbs are not a good match for a big port 1100 head - but my preference is the small port head anyway as gas velocity is higher and it'll give you a wider power spread.
The one real essential is a better clutch basket. Get a pro shop to do it as it's not really a home job.Heavier shock absorbing springs and a better backplate.
Whatever you do to the frame, don't powder coat it if it's a race bike. There will be things you want to change or repair and powder is a major pain to weld around. Plenty of pics floating around of bracing the 1000 frame.
Look at it as a work in progress - your riding will develop with experience on it and you'll work out what you need to change. Going straight to a full house race engine will most likely put you off riding it as they can be brutal. Our one took around five seasons to get to where it is now. I developed it as the rider got better on it.

[azr]

This is going to be purely a street bike. I'm not looking for anything 'too' crazy, I just happen to have the Weisco 73.5 piston set on hand so I thought I would throw it in but then I started thinking "if you're going to do that you might as well go all the way" but I'm not exactly sure what that entails.

[Big T]

Rob, if you're going to leave it at a street bike build level, a typical beefed up clutch basket will suffice.

Porting is reshaping the intake and exhaust ports for better flow. Not something for a beginner. Are you going with a hotter cam? As Greg T says, velocity thru the port is more important than big ports and carbs (like on a drag bike)

I'd recommend the big pistons, better clutch basket, a bit more cam and some mild head work. On the head, you should chamfer the edges of combustion chamber to prevent hot spots and cc them so they all have the same volume.

Frame bracing? Not a bad idea, but I can't find the photo right now

[azr]

I guess I'll have to find a local builder that has a good rep.

[80GS850GBob]

You, sir, are so in luck. Two days ago I found this frame bracing article and saved it...I now pass it along to you, Enjoy!

http://oldskoolsuzuki.info/archives/category/modifications/frame-modification

[80GS850GBob]

Oh, and I'll add this as well.....if your going for a "Pops" restomod, I would keep the Yosh pipe...just makes sense in my jaded opinion.

[Nessism]

For a street bike there is no benefit in adding metal "bracing" the frame and increasing weight further.

The big bore kit should add some nice torque.

If you already have a head that's in decent condition I'd use what you got. Again, this is a street bike so eaking out every single hp won't matter.

Porting by removing the sharp edge on the short side radius and excess metal around the seat pocket is easily doable by yourself. Beyond that, you are going to have to pay someone because it's a learned skill relative to knowing what should be changed. In order to take advantage of a higher flow head you also need high flow carbs and exhaust, including cams.

A clutch hub rebuild with HD backplate and springs is a big improvement to just about any GS1000. I bought a GS1000 with a HD hub and it was a big improvement over stock; less noise and smoother clutch action. I would keep to the standard chain drive 1000 hub size. The clutch plate diameter is larger than the 1100E and shaft drive hubs, which make up for this with more plates. Only issue is finding a kit to rebuild the hub. They seem to be nonexistant in the USA. There is a place in the UK that seems to have them but they reference a US manufacturer so I'm not sure.

Those VM29's will be a huge improvement over the stock carbs. I'd either run them or get some more modern RS carbs. VM29's are worth a good bit of money these days and you could probably sell them and have enough money to get the RS's if that's what you would like to do.

Good luck. Sounds like a fun project.

[80GS850GBob]

What Ed said, but to a minor point. The added frame stiffeners will add a little more weight to an already heavy bike...I'd guess that any added frame stiffeners would run the gambit of an additional 5 pounds...maybe ten tops. Not a lot when she's 600ish pounds already...but that's still heavy either way you look at it. Since you have the S fairing that will add a touch of weight for the fairing and the mounting bracket. Your going for the period correct track racer "look" and I get that. The bracing, though probably un-needed on the street, would add to your build theme, so do it if that's what you really want. Keep the braces light enough to not add a lot of weight but still help - that was the theme then as it would be now.
I'd side with Ed again about the improved clutch basket {I'll watch the progress on that for my own interest}, as that sounds like a really usable mod and I'd try your carbs too since you already have them. That's my American two cents worth.....usefulness may vary from location to location....

[sharpy]

If you have weisco pistons, deburr the valve pockets. that nice sharp edge isnt good inside a hot engine. Powder coating a frame is a no no in my opinion. Cant mod the frame further easily if needed and hides minor cracks if they develop. Beefed up clutch/backing plate, welded crank and welded 2nd gear. Running 29 smoothies atm but have 2 sets of 33 round slide smoothies waiting for my S and E. So with 1075 Weisco kit, good pipe, 29's, mild ported head and stage one yoshi cams i have 105HP RWHP. Good for 1st gear roll on wheelies and 2nd gear ones if use the clutch, find a crest or use the rebound method from a 1st gear wheelie. Using a 40th rear sprocket as bike has good grunt and cruises better at 60-70mph. Ask around for cam degrees, some nice info from good people. Think of a oil cooler aswell (750 gears maybe) and mine gets hot and needed one. Plus they look super cool

[azr]

All good info everyone, sure appreciate it. You're the 2nd person to say no powder coating, it's just that powdercoating is so durable, when ever I seem to paint a frame it always winds up getting some rust here and there. Looking around online it seems Web cams is the way to go, likely 118 grind. Maybe a nice set of Ohlins or YSS shocks.

[80GS850GBob]

All good info everyone, sure appreciate it. You're the 2nd person to say no powder coating, it's just that powdercoating is so durable, when ever I seem to paint a frame it always winds up getting some rust here and there. Looking around online it seems Web cams is the way to go, likely 118 grind. Maybe a nice set of Ohlins or YSS shocks.

I gotta ask.....whatcha doin for front forks?

[azr]

So far the plan is 83' 1100E forks blocked off, with emulators and sonic springs. Twin pot calipers with Dan's conversion and some sort modern reservoir.

[80GS850GBob]

So far the plan is 83' 1100E forks blocked off, with emulators and sonic springs. Twin pot calipers with Dan's conversion and some sort modern reservoir.

Cool...you might not want to read my thread then on the front end conversion I'm doing now for the 1000g.
The 1.0 sonics with Dan's upgrade works fine {10w fork oil, s/s lines, concours calipers, EX650a MC and no emulators}...I just want to go to the next level on this next bike.

[azr]

Cool...you might not want to read my thread then on the front end conversion I'm doing now for the 1000g.
The 1.0 sonics with Dan's upgrade works fine {10w fork oil, s/s lines, concours calipers, EX650a MC and no emulators}...I just want to go to the next level on this next bike.

Yes I was reading that, should be a night and day improvement for sure but I'm trying to stay era specific. It's not going to be an 'exact' replica but it'll somewhat 1979 ish. The gauge cluster will probably be the most glaring part that won't be era specific.