80' gs1000 build, the beginning

[FreuderLocks]

So, since the bike i bought (in perfect working condition mind you) came with a working second motor and tranny, I've decided to start work on the secondary motor prematurely.

The current motor runs strong but i think by the time something worth fixing goes wrong im going to want a bit more power and something that sets my bike apart from the others.

Ive been looking for cams, high compression pistons and carbs and such and seem to be having trouble finding them to begin with.

What i want to do: As far as cams go, i would like something a little more agressive than a stock cam, both intake and exhaust. Can someone reccommend a good set for me?

In conjunction with the cam upgrade, i would also like either a mild stroker kit (Absolutely nothing more than a 100cc increase) or high compression pistons. Can I acheive the same gains by going either direction? Im only looking for a few horsepower here. Any suggestions?

And finally: What kind of supporting modifications must go with these type of upgrades? Im fairly competent building cars but have come to realize that bikes are different in the way that they function. I would elaborate but I feel I would be preaching to the chior so to speak.

What i think i have: The second motor is stock, but would receive the
4-1 exhaust (Vance and Hines) that came with the bike. Im pretty sure there are very few if any other modifications that I currently have accessable. There may be a jet kit on the installed motor.

Thanks again everybody.
-FreuderLocks

 

[80GS1000]

Nice choice in bikes! Spare motor too? Got any pics?

Are you planning on racing or will this be a streetbike?

APE and Dynoman have good prices on cams and oversized pistons. APE will cut you a deal on boring your block if you buy pistons from them. As far as cams go, I'm very happy with the Web Cams .395 lift cams in my bike. Once the revs hit 4K it's off like a rocket to redline. If you want a broader powerband the .365 lift cams are a good choice.

If you've got the cash and like to accelerate hard off the line you may want to get your crank welded/indexed/trued and the clutch basket beefed up. Falicon can handle this for you.

If you've got a 4-1 V&H pipe then go with a Dynojet stage 3 jet kit along with some K&N pods for a bit of a power increase and a sweet howling intake sound.

 

[Big T]

A lot of the items you're looking for are rare. I doubt you'll find a stroker crank.

The most common conversion is to use Wiseco 1085 pistons, cams, larger carbs with K&Ns and a header.

While your bike is "newer" welding the crank is probably a good idea.

You can get the clutch basket upgraded, adjustable cam sprockets, all sorts of stuff.

There comes a point where you can spend a lot more money for very little gain. See First Timers post on what he contemplated and what he is doing, it'll give you some good ideas, as will Renobruce's Beast build.

Both of these guys are actually into their builds, so I'm sure you'll find some inspiration in what they are doing.

Geez, 3 GS 1000 supermotor builds this winter. I'm feeling horsepower deficient!!

BTW, your original premise is incorrect. GS 1000 motors just don't wear out. Build up the spare anyway.

 

[FreuderLocks]

Thanks guys, This is a ton of help! Ive come to realize there are expensive parts that sometimes only facilitate another part making a gain, my 92 eagle talon TSI is a great example, 500awhp and only worth $4500! Bleh!

A 1050 set of pistons from Wiseco seems like a great idea, right in the area of size that i was aiming for. Though I have a few questions about cams. As far as overlap and cam durations go, can or should i expect about the same as cars or is there some sort of extreme difference? I just thought i would ask because im honestly not sure. For .365 and .395 cams which is the more extreme, i know 80GS1000 described breifly the difference. which of these would be considered the more extreme of the two?

Would i change both the intake and exhaust cams?

Oh and BigT, I have extensive experience destroying that which is indesctructable. Powerful, well built machines fall in unison and utter dismay to my right hand/foot, one day my block will be conquered, but not intentionally of course.

If i went through with a 1050 and some extreme cams, pods and a jet kit what maximum output or increase could i expect to achieve, At this point i realize that 10hp is alot. And honestly nothing will dissapoint me but is altitude going to screw me?
FreuderLocks

 

[80GS1000]

The two sets of oversized pistons from Wiseco are a 1085 cc kit and a 1100 cc kit.

.365 vs. .395 are the valve lift in inches. So the .395 is the more "extreme" of the two. Here's more info: http://www.webcamshafts.com/pages/motorcycle/suzuki/suzuki_gs_1000_(78-82)_dohc_8v.html The .395 requires a new set of heavy duty valve springs. The kit comes with intake and exhaust cams so you'd swap out both.

Not sure about the HP increase because I've never dynoed the bike but it has much more torque than before. Great fun on the street when getting on the freeway etc. Faster to 100 MPH in fact than my 06 GSXR 750 racebike.

At my secret northern Utah test facility* at 4500 feet, top speed with these parts is around 135 to 140 MPH, and it pulls hard all the way up to 130ish.

 

[Big T]

Yes, both cams

I think you'll gain 20-30 HP from a stock 80 rwhp, depending on how extreme you go.

But like the man says, it's the torque that you'll notice

 

[FreuderLocks]

Cool, thanks for all the input, this is exactly the stuff that i wanted to know. My winter vacation starts in 2 weeks here so once that begins, so shall I on this motor. Pictures and descriptions of all work will follow, see you alll in 2 weeks.
FreuderLocks

 

[Guest]

Can't stroke the 1000. Here are the pistons. http://gszone.biz/pistons.html

Jay

 

[BadBillyB]

The GS1000 2valve motor came in 2 flavors.....One has the "big port" head and was fitted with CV carbs. The other has a much smaller intake port and came with VM carbs. They can be identified by the size of the intake boot. Are both of your motors identical ????.....If you are going to be using CV carbs you want to use the "big port" cylinder head.......Billy

 

[fast pom]

Can't stroke the 1000. Here are the pistons. http://gszone.biz/pistons.html

Jay

Yes i think you can stroke a GS1000 , Sorry i am not talking from personal experence . have a look at oldskool suzuki site go to aircooled look for GS1000 strip and rebuild by yoshi jonney

 

[trippivot]

Start :

A. weld the crank

B. back cut 2 and 3 gear

C. decide on displacement- buy pistons

D. NEW CAMCHAIN

E. HEAD
. 1. decide on valve sizes
. 2. port or not to port intake side
. 3. flow bench test
. 4. match cam lift to flow bench results
. 5 mill the flat surface for more combustion effy. ( raise compression)
. 6. slot the cam sprockets
F. Buy Bigger Carburetors
G. Dyna electronics



this is just a rough plan

 

[first timer]

No one mentioned squirreling away about 5K in cash so you can pay for all this go fast stuff.

You might beable to do it cheaper but if you want it right it's going to cost you.

First figure out how big your wallet is then figure out what you can do with the size of your wallet.

 

[trippivot]

yep the first -first thing to do is make a plan and assess your budget.

do not forget machine shop costs. gaskets? custom gaskets

being honest with expectations and intentions for use is tougher that one may think.

like to wrap $3000 in a $800 crapper?? go right ahead. and when the rods fly out the front of the engine and saw it in half , know it was a hell of a journey!!!!

,

 

[first timer]

So whats the problem? A little JB weld will fix that right up !

yep the first -first thing to do is make a plan and assess your budget.

do not forget machine shop costs. gaskets? custom gaskets

being honest with expectations and intentions for use is tougher that one may think.

like to wrap $3000 in a $800 crapper?? go right ahead. and when the rods fly out the front of the engine and saw it in half , know it was a hell of a journey!!!!

,

 

[trippivot]

if only life were that simple.
JB does a lot but????

I really wanted a picture window for my crank to enjoy the view of the drag strip.

those are 2 separate explosions I'm making these rare by the minute.

1 was #1 rod failure
the other can't tell if the seat dropped or the valve stem broke after kissing the piston