How to let GS to have higher rpm?

[oldschoolGS]

I think the easiest and cheapest solution to more rpm's it to put in a GSX750R motor, my '90 redlined at 12.500, limiter at 13.500. \\/

And that was the re-configured long stroke 750 motor. Big bore muscle bikes don't need to go above 10,500. A mild 1157cc Bandit motor makes over 100bhp at 6500rpm. Not thats grunt.

Rev On, Ed.
1983 GS750ED
2005 GSF1200SZ
1992 900SS

[Addy Leung]

Now, I see some key points here would help in getting higher rpm that they are need to have good balance on cranks, make moving parts lighter weight as possible, cams degree to 110/110, stronger valve springs and etc...

What are about the ignition timing? The stock on GS is mechanical advancer and it have 35 degree advance after 3500rpm and then all is same.
Do we need a programmable igintion unit to have more advance ignition timgin at higher rpm, let say after 8000rpm?

dose the modren bike have variable timing igintion control at different rmp?

[hungryman]

Now, I see some key points here would help in getting higher rpm that they are need to have good balance on cranks, make moving parts lighter weight as possible, cams degree to 110/110, stronger valve springs and etc...

What are about the ignition timing? The stock on GS is mechanical advancer and it have 35 degree advance after 3500rpm and then all is same.
Do we need a programmable igintion unit to have more advance ignition timgin at higher rpm, let say after 8000rpm?

dose the modren bike have variable timing igintion control at different rmp?

You can always power time an engine. What you do is set your timing at maximum advance (whatever RPM that would be), instead of at idle. This way your advance is correct at the top end. After all, if you are racing, who cares about idle?

This is an old drag racing trick. Of course, to make power all the way through the RPM range of interest you need to have an advance mechanism, either mechanical or electronic.

[QuaiChangKane]

Addy - trying to keep up with other riders is one of the things that causes a lot of deaths on the road - especially when it comes down to contests of top speed. Anybody can twist a throttle - it won't make you a better rider.


Appreciate your bike for what it is.



-Q!

[Nerobro]

Well.. the GS550 didn't buzz it's valves till 12k, and the motor has probally seen 13-14k. That's on a 60,000 mile set of valvesprings. And the motor survived.

There's a lot more to it than just "getting the motor to spin that fast". The bottom end components are pleanty strong. LIke it's been said it's the valvetrain you'd need to worry most about.

You won't see a broader powerband, but you may see more power. You will need new cams, you'll need to port it. You'll need bigger carbs. you'll need to re-enginer an exhaust to work with the higher rpms. You're looking at a massive project. All those things come togother to make a narrower powerband.

However, to address your questions. Those being wanting a wider powerband, higher top speed, and more horsepower? Those are all easily taken care off by changing the gearing of the bike, which will allow a higher theroetical top speed. You can use nitrous, a supercharger, or a turbocharger, to make the horsepower to use the new gearing. Turbochargers, and displacement superchargers all will widen the powerband as well. If you "do it" right. Centrifugal superchargers are a differnent story. As is nitrous.

[Big T]

The big question is

How much do you want to spend?

You can still get all the speed parts you'll ever need for that motor, but do you want to spend $3-5k to get it done?

Just saw a GS Superbike at Daytona. I think it was redlined at 11,000, not that much higher revs, but a lot more power

[Billy Ricks]

One other trick to a lighter valve train is center boring the cams. This was another trick used by old GS superbike racers.

[Addy Leung]

Does a MSD MC-4 programmable ignition system would be helpful to shift the ignition timing few degrees advance at high rpm range ( let say 5 degree advance between 8000 rpm to 11,000rpm)?
( Actually, I think it is by rotating the ignition pick up coils plat 5 degree advance and then using the MC-4 to set the ignition timing 5 degree retard between 0rpm to 7999rpm, so that it will have 5 degree advance between 8000 rpm to 11,000rpm)

[Jethro]

While you can certainly get your engine to make as much power as an R1, you will never get it to be as light. A race stock R1 weighs what... 340lbs? If you are one of the lucky ones, your GS might weigh 500 lbs bone dry. A big piston kit, race cams, some smoothbores and velocity stacks, a 4-1 pipe, Dyno tuned, easy to get 170 hp on a GS. But you'll never have the suspention to hold it up, the brakes to stop it, and a rigid, lightweight chassis to keep it tracking well. And let's not even talk about cooling the thing on the street.

Basically you can spend $8-12k building a 170hp GS with modern rubber and hardware, and still the R1 with a good rider will walk away from you on the twisties.

If you want an R1, buy an R1.

[Addy Leung]

Sorry for me giving a wrong impression to you that I am making a R1 by a GS foundation.
it may just want to explore some technology from modern sport bike and see anything learned to apply to the GS.
It is just like an everyday hobby. Sometime life is boring and having some extra leisure time.
Improving a GS step by step is a long time work and sure it is very interesting hobby to me. Every time adding something new to it and try it, it will give something extra and a silence answer to let me explore it, no matter it is a good result or getting worse but sure it is worth and interesting.
(I know I am look like a mechanic more than a bike rider)

[Billy Ricks]

Sorry for me giving a wrong impression to you that I am making a R1 by a GS foundation.
it may just want to explore some technology from modern sport bike and see anything learned to apply to the GS.
It is just like an everyday hobby. Sometime life is boring and having some extra leisure time.
Improving a GS step by step is a long time work and sure it is very interesting hobby to me. Every time adding something new to it and try it, it will give something extra and a silence answer to let me explore it, no matter it is a good result or getting worse but sure it is worth and interesting.
(I know I am look like a mechanic more than a bike rider)

Some people, including my wife, think I'm nuts for continually trying to make my bike work better. Anyone can go buy a cookie cutter bike. Making an old bike your own is much more satisfying.

[Big Jay]

The cylinder head is the limiting factor. It simply doesn't move enough air for a motor that size, so it has to make it's power at lower RPM.

Years ago we did some pro stock type heads that were 33/29 valves, huge ports, raised clear up into the camshaft area. These motors had to turn over 12,000 to make their max power.

Then Suzuki came out with the Hayabusa, and you could get the same head from your Suzuki dealer.

Jay

[RacingJake]

Just remove the tach and use a shift light with a 10K chip, then install a 14T upfront and a 46T rear and hang on \\/ With a 25-26 inch tall tire it should topout in 5th gear between 133-138mph, if it can get to 11K in 5th then that's 150mph. Remember half the fun is getting there and the other half is the taxi ride home from the police station 8O

[morthrane]

Not to beat the dead horse, but higher RPMs for more power actually means less powerband.

I have an 01 r1, with the 74x58mm bore x stroke. Stock crank horsepower peak is claimed at 150hp.

In 04 they made a much higher revving r1, with a 77x53.6mm bore x stroke. Claimed 180hp.

Can you guess which bike has more midrange stomp?


hint, its not the short stroke screamer


But back to the question at hand, you want a higher top speed, you're still in trouble. Its called aerodynamics... or in the case of the typical GSX, total lack thereof

[thr3shold]

Interesting read, I'm at least the 3rd owner on my bike and it doesn't hit the powerband till almost 8000rpms and then it's HOLDON for a whole 1k and I have to back down. I did notice that the heads are of a different design than what my Clymer book says they should look like. Instead of having boots that bolt up to the head it has tubes cast directly in the heads and then it is just some rubber tube that is clamped to that and my vm33s, any ideas?