125 HP, 1000..possible?

[Anonymous]

Hey guys......as you may know I'm doing up my newly acquired 79 1000E & I wanna pump her up to 125HP or so, is it possible with a cam,carb, pipe combo without going to a 'bigblock' (still at 1000ccs)
I'm getting the impression cams are now collectors items and are far and few between, who should I go thru for a good cam?Grinds?
I'm more than willing to deal with a cantankerous idle. Another biggie is to weld or not to weld. She will be a pure street machine with the occasional blast up the tach.....I want to keep up with my wife on the 1150 just in case she wants to show me up.....Anyone out there with a similar build-up?
-----------------------------------------------Rick......

 

[Nerobro]

Yes... 125hp/l is nothing to special. As is it puts out 109? or is it 98? I am willing to bet that a proper 4-1 pipe, slightly larger carbs, port matching, and a three angle valve job would get you there. At least that's the opinoin of a guy who hasn't modified to much.

By staying with the stock carbs, or ones from say an 1100, you won't be over carburated, so you will retain drivability. Port matching, doesn't increse port size signifigantly, so you don't loose port velocity, but does improve flow. Same for the exaust manifold.

The 4-1 will reduce torque. But it's a 1000, you should be just fine in that respect.

The biggest thing you can do for valve flow is a good valve job. Of course, that would probally be the most expensive thing I've suggested.

 

[rosco15]

I think 125 would be a pretty serious street bike with a 2 valve motor $$$. It would be real easy with the 4 valve 1100. Can you just put an 1100 top end on your bike. 1260 low compression kit, good carbs, stock head and cams should about do it. Even an 1166 with stock head cams, good carbs, and a drag pipe should make about 125. Would probably be cheaper than all that headwork to your bike.

I used to have a kz1000. Would be about the same as the gs1000. High compression 1260 pistons, 420 lift cams, mikuni carbs, and the head was ported with oversized valves. A very serious motor. ran 136 in the 1/4. I would guess it was making around 140hp. It didn't last very long. Thats when I switched to the 4 valve suzuki. You don't have to get all crazy to make power.

 

[Hoomgar]

I believe without the bore and without any boosting or spray you?re going to be hard pressed to hit that number buddy. But I don't want to discourage you.

Here is what we are doing to my 78 1000 and what is the expected outcome yet to be seen.

Wiseco Big bore kit 1085
Port polished head
Heavy valve springs
Raise compression 1 point
Pops Yosh Stage II Cams
33mm Smooth bore carbs
Exhaust port work (the velocity dam)
Balanced and welded crank
Heavy duty clutch & welded clutch basket
All new bearings
Dyna coils and ignition
V&H 4 into 1 Megaphone
K&N Pods

Several other little things non-engine like balancing the rims etc...

I am hoping for triple digits with that setup. Joe wont make promises on that but tells me that we should hit between 101 and 109 range with it.

It could do better (I sure hope it does) but Joe said not to expect it.

I hope that gives you a little window to look through. Maybe more is possible, I don't know. I was told that boosting or spray would be needed with a street able setup if you want numbers like your looking for.

It would be nice if I was wrong

 

[KEITH KRAUSE]

You can get the 125HP, but I question the long term reliability.
You said you want to keep up with the 1150 and do the occasional blast. That sounds like me. I haven't raced an 1150, but I'm sure it would turn out about the same as my run against a '02 Triumph Speed Triple. I'm right there until 120, then it's all over for me.
I made some mod's to my '79 GS1000E, but I plan to always keep the bike and didn't want to sacrifice reliability. My bike is quick enough to have a lot of fun, but I'm sure more power would be even better.
The '79 came out with 85 HP. I'm guessing my 1085 kit, V&H pipe, K&N filters, DJ kit for the stock carbs, pick up 10 or 12 HP. Quite a power increase. I also welded the crank and clutch basket for reliability. A set of 29mm smoothbores would be all I could ask for. That would get you to 100 or so I'm sure. Plenty of power and great driveability.

 

[Nerobro]

Wow There are days I should check my facts. 125 horsepower is what... 140% of the stock horsepower... That's ouch territory on any engine.

 

[Hap Call]

It is possible but expensive unless you go with NO2...either way, reliability (for the top end) will be reduced.

Hap

 

[RacingJake]

I'd just drop the counter sprocket a tooth, cheap and easy to change then go run it and see if you like it.

If you make that kind of power then you'll just blow away your oem rear tire anyways.

But if it was me I go get that BUSA then you can pass her in 2nd gear when she is in 5th.

 

[rosco15]

Yeah BUSA. Someday I will replace the honda with one.

 

[saaz]

I have the 78 GS1000. If keeping the same head (smaller ports than later ones) 125hp can be achieved, but only with race cams, fully race ported head, big bore kit and higher compression, with 29mm smoothbores....and not running street petrol. The bloke who did mine used to do superbikes. Not a very practical bike, and you could swap the motor to a GSX-R one for far less!

 

[Guest]

Note of interest: I've got a 1978 GS1000. About 85 hp stock. At a wet weight of about 550 pounds, it still has a better power-to-weight ratio than the 2005 versions of the Dodge Viper, Ferrari 355 F1, Shelby Series 1, Lotus Esprit V-8, Porsche Carrera or Chevrolet Corvette.

Not to mention it's a hell of a lot more exciting at 100mph . . .

 

[massakins]

I rode mine on the street with a very liveable turbo combination that produced 188 rwhp on pump gas and electric starter. Reliability is proportional to length of time on boost, but the GS1000 is one of the stoutest motors going.

Welding the crank is recommended for even a stock motor if it is going to be ridden hard. One way to look at this though is to wait until it twists before welding it; if you're paying someone to do the work its probably not much more expensive to true and weld than to weld it first. And be sure to weld it under the primary gear while its accessible. Otherwise, if you weld it first, you'll never know whether you needed it or not.

If you do your own work, I'd weld it first. Always welded mine as soon as I got them. Flip of a coin perhaps.

 

[lecroy]

This would get you there, for a while.....

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4515996588&category=46093

 

[Anonymous]

1000 build

1000 build

OK:
After reading all you guys input 125 seems to be a bit of a stretch but here goes..I'll try using the G4 cams from cammotion, perhaps I'll shave the head .005" , get into the ports with the dremel & clean it out( just a pocket clean-up) match the ports, I'll find some 36s' from E-bay from the 1150, I have pods and the megaphone style 4-1 from Kerker.
As for the crank ,I have a relative who teaches welding at one of the community colleges here in town....assuming the crank is not allready out of spec, not twisted yet, why couldn't he just weld it right up? Common sense will tell us where to weld & clean up the welds with a grinder(Dremel)
Do they indeed need to be calibrated..indexed, retwisted into the spec, ideal locations?
I read some writings on the high lift cams as they try to spit out the shims....is this really a problem on the street driven motors?
------------------------------Rick......

 

[rosco15]

You need to balance it after it's welded.

 

[Hoomgar]

What Ryan said. The balancing is done after it is welded by shaving the weight off here and there as needed to achive a balance.

If your going to do what you have said then yes raising the compression a little bit is a good idea too. Just don't take it up so high you can't run it on pump gas anymore. As it is your going to have a high octane only bike when done. You don't want to push it beyond that if your trying to keep it for the street.


No mater where it lands on the Dyno Richard, it's gonna rock

 

[massakins]

Two thoughts based on personal experience:

1) When I had my cranks welded I simply had the crank pins and flywheels fused for approximately 3/4" where the pieces met using a TIG process with no filler rod added. This required no cleanup and they were never balanced. NOTE: Verify the crank is not twisted prior to welding anything; if all 4 rods line up such that the small ends are all aligned at the same time it is probably OK. Also be very careful where you mount your grounding clamp to ensure there is no arc damage from current traveling through the bearings; attach it to each flywheel and move it for every weld.

2) If the cam you have chosen has less than .424" lift then you can use the stock shim arrangement. If the lift is greater than .424" it is recommended that the shim underneath the bucket arrangement be used. NOTE: On a street motor I found that the HD valve springs, high lift cams and increased compression were beginning to tax the stock starter
clutches.

Have been doing this for over 20 years now in both race and street applications.