crazy thought: smaller into bigger

[Phil B]

I asked a curiosity question on a completely non-related thread, but probably no-one will read it, so thought I'd ask here:

I've seem mention of various projects to squeeze a bigger engine in a gs500 frame. But what about putting a gs500 engine, in a "bigger" frame instead?
Anyone know of such an attempt? ie: gs500 ->gsx 600. or something completely crazy, like cross-manufacturer?

On the one hand, it would be a pain in the rear to do this.
But on the other hand, it would probably be crazy good for canyon riding, plus actually lighter than a stock gs500... hmm?

[Dr.McNinja]

Bigger frames are heavier. A 500 engine in a 250 frame might be interesting. A 500 engine in a 600 frame is a waste of a frame.

[burning1]

The GS500E engine is actually pretty heavy for the horsepower output. A modern GSX-R 600 engine is probably similar in weight, but 3x the power.

FWIW... I'm planning to build a gs450/gs500 hybrid, since it will make my bike legal to race in 250 superbike.

[burning1]

FWIW, you do sometimes see people shoehorning single cylinder bikes into bigger frames, due to various race regulations. Gerry Piazza, a local guy who does amazing frame work has a completely custom bike, featuring a 600+cc single in an R1 frame, with fuel in the frame among a number of other things. But you usually only see that sort of things when it makes sense per race regulations.

[Phil B]

Bigger frames are heavier. A 500 engine in a 250 frame might be interesting. A 500 engine in a 600 frame is a waste of a frame.

How is it that a gsx600 is 50 lbs lighter then? gs500=400 dry. gsxR600=350 dry.
Are you suggesting that, for example,  the frame is 50lbs heavier, but the engine is 100lbs ligher than a gs 500's?  somehow I find that difficult to believe.

Going by what burning1 said: lets presume the engines are actually the same weight.
So then putting a gs500 engine in a R600, would still give give you a 50lb lighter bike.. PLUS the fat ol tires that its actually *designed* for rather than a hackjob. Better suspension, etc, etc, etc.

You dont get that in a 250 frame.

[gtscott]

why not leave the bigger engine in the bigger bike, that was designed to be in there, that makes more power, than some hack job gs500 engine thrown in?

[burning1]

How is it that a gsx600 is 50 lbs lighter then? gs500=400 dry. gsxR600=350 dry.
Are you suggesting that, for example,  the frame is 50lbs heavier, but the engine is 100lbs ligher than a gs 500's?  somehow I find that difficult to believe.

Going by what burning1 said: lets presume the engines are actually the same weight.
So then putting a gs500 engine in a R600, would still give give you a 50lb lighter bike.. PLUS the fat ol tires that its actually *designed* for rather than a hackjob. Better suspension, etc, etc, etc.

You dont get that in a 250 frame.

The GS500 frame is made of steel. A modern GSX-R has an aluminum frame, which should be lighter than the GS500.

Fat tire really isn't a benefit at all - the GS500 doesn't have the power to make use of it. With that said, a modern GSX-R wheel is so much lighter than the GS500 wheel, that it would be a slight improvement. An ideal tire would probably be a lightweight 4.5 inch rim - perfect for a 150/60/17 or 160/60 tire (lots of options in that size,) but not horribly over-speced for the GS500. I'm doing a RGV swap for that reason - the swingarm/rim are much lighter than GS parts, and there is better rubber. If not for the weight advantage and tire options, I'd stick with the smaller rim on a stock engine.

Keep in mind that all quoted weights are for the GS500 in stock form. Strip off the center stand, headlight, handle-bars, etc then replace them with lightweight parts and the GS is a little lighter than a 600.

Putting the GS500 in a Ninja 250 is a stupid idea. GS engine is significantly heavier than the Ninja engine, and the Ninja frame is barely stiff enough for the Ninja engine, nevermind the weight and power of the GS500 engine. Even then, be aware that the Ninja isn't significantly down on power compared to the GS. The swap would be like trying to stuff a GSX-R 1000 engine in a GSX-R 750.

Keep in mind the best benefit of the GS500 is availability and cost of parts. When we get too crazy with mods, we loose that benefit and it starts to make sense to start with a better bike to begin with.

Modern sport bikes do an amazing job of matching the frame to the engine. In most cases, the ideal engine is the stock part.

[Phil B]

Keep in mind that all quoted weights are for the GS500 in stock form. Strip off the center stand, headlight, handle-bars, etc then replace them with lightweight parts and the GS is a little lighter than a 600.

Verra INteresting!
Would be nice to have some official list (ie: on the wiki, ideally) of these "etc" parts, along with approximate prices, and weight benefit per piece

[Phil B]

Keep in mind that all quoted weights are for the GS500 in stock form. Strip off the center stand, headlight, handle-bars, etc then replace them with lightweight parts and the GS is a little lighter than a 600.

Verra INteresting!
Would be nice to have some official list (ie: on the wiki, ideally) of these "etc" parts, along with approximate prices, and weight benefit per piece

why not leave the bigger engine in the bigger bike, that was designed to be in there, that makes more power, than some hack job gs500 engine thrown in?

some people dont particularly WANT more power. strange as that may be for you to understand :-}
people who like canyon riding, dont have particular use for 100+hp monsters. It's only track racers, (and people who will soon either lose their license or be dead), that really have a desire for that.

and I like the linear pull of the gs500 too

[burning1]

I'm in kind of the opposite camp. I find that low horsepower bikes are a lot of fun on the track, where I can really focus on corner speed. There is a huge learning curve to riding the GS competitively on the track, but that steep learning curve forces me to constantly work to improve.

On the street, huge horsepower is nice. Enter the corners a little slower, accelerate hard out. Safer approach than trying to carry a lot of momentum.

[BaltimoreGS]

Bigger frames are heavier. A 500 engine in a 250 frame might be interesting. A 500 engine in a 600 frame is a waste of a frame.

How is it that a gsx600 is 50 lbs lighter then? gs500=400 dry. gsxR600=350 dry.
Are you suggesting that, for example,  the frame is 50lbs heavier, but the engine is 100lbs ligher than a gs 500's?  somehow I find that difficult to believe.

Going by what burning1 said: lets presume the engines are actually the same weight.
So then putting a gs500 engine in a R600, would still give give you a 50lb lighter bike.. PLUS the fat ol tires that its actually *designed* for rather than a hackjob. Better suspension, etc, etc, etc.

You dont get that in a 250 frame.

I don't know the numbers but I would have to assume that the bigger aluminum frame of a GSXR would be equal to if not lighter than a GS500 steel frame.

-Jessie

[gtscott]

if you dont want the power, wouldnt it be easyer to restricted the 600cc motor than a transplant

[Phil B]

if you dont want the power, wouldnt it be easyer to restricted the 600cc motor than a transplant

Interesting thought. but would you still get 58mpg from it?

Plus... i dont see any web references so far, of anyone even trying this before.
Which isnt too surprising, since most people, if they want a lower powered bike, buy something cheaper than a fully functional 600R.

[kidsixteen]

The most fun bike I've ever ridden was a Honda Hawk GT with a CR500 2-stroke stuffed in it.

That motors weighs like 4lbs and makes about 10 million horsepower... the combo weighed about as much as a big dirtbike and rode like a bmx with a rocket engine attached to it and a brick wall of engine braking. SO awesome.

[werase643]

I had a spare GSXR750 chassis with a DR 650 mocked up in it.   then I found a hella rare RG-V250 chassis....then I had to start selling off toys..... thanks X

[makenzie71]

I put a 1993 Katana 750 motor in my 1981 GS750...it is technically a smaller motor.