Best Engine Swaps?

[chris900f]

So I took a job at a bike wrecker.

Last week my new boss makes a few calls and a '98 GS500 shows up an hour later.

That evening we pull the GS engine and just shove in a (1975?) Kawasaki 500 2-stroke triple to see how it looks.

Apparently in the Kawi triple world, the GS' perimeter frame is considered a great upgrade from the original Kawi

chassis and offers a lot of space for welding mounts.

When I told him I had a GS he started pointing out which engine I should swap in (he's kind of an enthusiast).

We have one of those KTM390's just sitting there, an R6 that looks very compact, and he's even offered a few old RD350/400 2-stroke engines....hmmmm.

Anyhow it got me thinking...what would be your dream engine swap (for your "other" hypothetical GS, of course)

I'm thinking a DR650. It would be super fun and torquey, air-cooled, still Suzuki, and they sound awesome thru a 'Busa can....

What do you think?

[SK Racing]

How about a Busa engine? 

Seriously, I think the best upgrade would be an electric motor. I'd love to go electric.

[Bluesmudge]

No idea if they would fit, but I've always like all the big torque inline 4 monster Suzuki engines. GS1000, GS1150, Bandit 1200/1250, Hayabusa. The DR650 would be fun too, but I doubt it would be any more fun than in a DR650 frame.

[chris900f]

No idea if they would fit, but I've always like all the big torque inline 4 monster Suzuki engines. GS1000, GS1150, Bandit 1200/1250, Hayabusa. The DR650 would be fun too, but I doubt it would be any more fun than in a DR650 frame.

The 4's are all pretty wide, even the R6 engine would be a stretch. The DR650 engine is probably lighter that the GS500's. The DR650 bike is just OK
but the engine is why they continue to sell. They don't really corner without a few thousand in upgrades. Pop the motor into a GS, and now you have
something that already handles well, but now has actual low-end torque...the compromise would be on the top-end, with only a 5-speed. Kind of a moot
point though since DR's seem to avoid the wreckers(not many GS500 parts either, but I found a nice '89 exhaust today)

I was pretty excited about the DRZ400sm when they first came out, booked a test ride but found it really
disappointing. Its weak with a terrible seat and the frame geometry is dodgy past about 80mph...I was never so happy to get back on my Honda.

Anyhow it's all just for fun, I told the boss...no..no.no My GS will be the "control group" in this experiment, we'll put them both on the dyno and see
if you actually made any gains by swapping in the Kawi 500. I think it will be very close.

Then I'll install the EFI and pods

[The Buddha]

A DR 650 would be the effing bomb. I know, I have an MZ660. British designed, east german built, Italian suspension and brakes mostly - paioli forks, brembo brakes, Jap everything else - Yamaha 660 5 valve single with keihein twin carbs (yes 2 carbs on a single - a CV one for low throttle opening, a smooth bore for higher and that point is adjustable) and mitsuba electrics (though some bosch is in there too - but this is early 90's Bosch, when it was 1/2 decent. Not the crap they have now with wiring made of soy. Yes I'm not kidding. Environmentally safe wiring made of soy in the new BMW's and most other german cars. An added bonus - tank is made of plastic. Will never rust. LOL.
Not only is it narrower than the GS the better running gear especially suspension makes it a far better bike especially to push the limits. Anyway a DR motor, 4.5 rear wheel, katana or GSXR FE will do nicely.
Cool.
Buddha.

[Jim Knopf]

Servus,

Put the 2stroke Engine from the RD in the Frame and you will have fun

[chris900f]

A few pics, but they don't really capture the scope of the chaos.


a fine example
same type of motor in the GS
KTM390, not really a beginner bike...
it's an open warehouse, find it yerself!!
R6: too many of these end up here (might fit)
motor hell
A familiar face 23,000kms

[chris900f]

A DR 650 would be the effing bomb. I know, I have an MZ660. British designed, east german built, Italian suspension and brakes mostly - paioli forks, brembo brakes, Jap everything else - Yamaha 660 5 valve single with keihein twin carbs (yes 2 carbs on a single - a CV one for low throttle opening, a smooth bore for higher and that point is adjustable) and mitsuba electrics (though some bosch is in there too - but this is early 90's Bosch, when it was 1/2 decent. Not the crap they have now with wiring made of soy. Yes I'm not kidding. Environmentally safe wiring made of soy in the new BMW's and most other german cars. An added bonus - tank is made of plastic. Will never rust. LOL.
Not only is it narrower than the GS the better running gear especially suspension makes it a far better bike especially to push the limits. Anyway a DR motor, 4.5 rear wheel, katana or GSXR FE will do nicely.
Cool.
Buddha.

That's what I'm talking about



One thing about the shop is that we work on all the old bikes in the area, there is a huge, ancient, semi-sorted parts inventory that goes back to at least the late 60's.
I bought my 81' Honda from this place in '96 (different owner, and it has moved since) and I found the original beat up exhaust pipes from my bike, that I had them replace
in the purchase deal with a better used set they had on hand....1996!!

One of my first jobs here was a Jap-market import Honda 250 Clubman single with 2 carbs and 2 headers. The carbs worked similarly with the second throttle
staring to open around 1/2 twist.

The MZ660 looks like a blast. I like the light weight of the GS, but big-single torque and the occasional throttle wheelie would put it into a whole new class.

[The Buddha]

The scorpion is lighter than the GS, by like 30-40lb. After you put the 4.5" rear wheel and the 43mm suspension on the GS its like an extra 10lb.
However I also dislike the MZ's rear wheel. Its horrendously heavy. The simple upgrade on that is a 4.5 Kat/SV wheel, and for good measure swap the front one too cos that's also some commie era apartment building type construction, just not as bad as the rear. Remember replacing spinning and unsprung gets you far greater gains in the real world than just what the scales say. So I cant imagine how much better it would get, cos its already pretty freaking fantastic.

I replaced a suzuki savage 18" steel front wheel with a 21" aluminum one from a dirt bike - so a lighter wheel that spun slower at the same speed, raked the bike 9 degrees but reduced the trail to near 0, and ended with a bike that handled as light as a feather vs the overloaded wheel barrow a stock savage handles like.

Cool.
Buddha.

[mr72]

Buddha, how did you get one of these? Were they ever sold in the USA?

The alloy frame likely is where most of the weight is shed. Seems one of these would be a great platform for an adventure bike conversion.

My quick google-fu sez they are like 381 lb, and a GS500E of the same era is like 386 lb supposedly DRY weight. Dunno if the MZ is dry weight. 4 gal tank gives mine another 24 lb, making it about 30 lb heavier than the MZ if you don't count the stuff I took off and if the MZ is wet weight. Similar power. That's about 25 lb heavier than a DR650. With some lighter wheels, or better yet, alloy spoke wheels, front 19" rear 17", some 80/20 tires, Bob's your uncle.

They seem to be cheap in Europe.

Of course, I don't see much wrong with the GS500 engine, or really why a 650cc single would be better, unless you just love thumpers and want something different. With low gearing, the GS has plenty of torque and the 180 twin gives good spacing for the tire to hook up in gravel or loose conditions. I have considered the other way round, cramming a GS500 engine into a DR350.

[The Buddha]

They were sold in the US from 1994 or so to 2003 or so. They were the only motorcycles you could have got with the 5 valve yamaha 660 engine because that motor was known as the raptor motor. Yamaha made a 660 engined dirtbike - I think called a tenere - whatever it was, was europe/asia/australia/africa etc etc only in that time frame, in fact even as far back as 1992 it was never put in a bike bound to the us dirt or street.
The funny thing is, my black 1995 bike came from Rhode Island, where the guy bought it off a dealer in Agawam MA in ~Aug 1995. The funny thing is, I was standing next to a black MZ at the same dealer in May-June 1995 looking for sparkplugs for my Katana. I might have been right by the bike I came to own 20 yrs later.
Anyway I see all the numbers, I wont say the MZ is any faster than the GS really, or even lighter, but weirdly, my fully upgraded GS is slower than the stock MZ. Worse yet, the MZ is easier to upgrade. 2 wheel swaps later it will leave the GS in the dust. Not that I really even care. Its super super fun, and for any one who is a 2 cyl guy, really a 1 cyl is the ultimate upgrade. We're not above admitting that we're slow, or small ... but we are surprising.

Its like those guys who spend 1000's upgrading a YSR50. Like WTF, you cant even ride it on the road and its smaller than a car tire with you on it. Its like owning the world's fastest mouse.

Cool.
Buddha.

[chris900f]

Last time I did any really good riding was when I visited my friend in the interior of BC. The area is all hills and mountains,
you might as well be in Italy or Greece (but with Canadian sized roads). Even the main highways are winding and the
side roads are wild.

The locals are fast in these super tight areas. I traded bikes with my friend who was on a KLR for a bit, and that motor worked
really well even though the KLR has less than 1/2 the RWHP of my CB. It was so much lighter and easier to change directions,
even on Trail Wing tires...it was an eye-opener for this flat-lander.

I could have bought a CB919 or CBF1000, but neither of those bikes need much improvement and I'll probably get one or
the other as a next bike anyway. But I see the GS500/F as more of a platform than a finished product; hence more fun, in more ways
than something that's already been perfected.

If a DR engine fell into my lap I would probably go for it, but that is fairly unlikely, somewhat expensive, and it would deprive me of the
fun of mucking about with the stock twin first.

I think the EFI and some exhaust work will net some nice gains. I may even have to trailer it out to BC to test it out on those windy roads.

[chris900f]

Interesting short doc on MZ, the invention of the expansion chamber, and how Suzuki stole the tech.

https://www.youtube.com/watch?v=1qccejmqbPg

[The Buddha]

Interesting short doc on MZ, the invention of the expansion chamber, and how Suzuki stole the tech.

https://www.youtube.com/watch?v=1qccejmqbPg

Didn't watch, but 2 stroke ? Thought Yamaha was in front in those days with kawi close behind, then suzuki then honda. In fact honda 2 strokes are literally non existent in the same vein as Yamaha RD's, Kawi H1's and Suzuki's Titan's. Seriously I cant think of what honda corresponds to that era.
Cool.
Buddha.

[chris900f]

Interesting short doc on MZ, the invention of the expansion chamber, and how Suzuki stole the tech.

https://www.youtube.com/watch?v=1qccejmqbPg

Didn't watch, but 2 stroke ? Thought Yamaha was in front in those days with kawi close behind, then suzuki then honda. In fact honda 2 strokes are literally non existent in the same vein as Yamaha RD's, Kawi H1's and Suzuki's Titan's. Seriously I cant think of what honda corresponds to that era.
Cool.
Buddha.

The doc was focused on GP 2-stroke tech in the 60's, but it mentioned Honda making exotic 20,000 rpm 4-strokes to match the power of the 10,000 rpm 2-strokes.