[Twinrider]

Hi all,
I seem to remember reading somewhere that Suzuki basically took a Busa 1300cc motor and halved it to make the Burgman's 650 powerplant. Anyone got a source on this info?

Thanks

 

[billmeek]

I'm sure that's just a play on words where Burgman 650 owners are calling their bikes "half-a-busa".

 

[frugality]

I'd read that here, too, but in doing some research, it looks like that's probably false.

The Hayabusa is 1299cc, with 81 X 63mm pistons/stroke.
http://www.suzuki-bikes.com/hayabusa1300.php

The Burgman 650 is really 638cc, with 75.5 X 71.3mm pistons/stroke.
http://www.suzuki-bikes.com/burgman650.php

So not only is the 650's displacement not exactly half of the 'Busa's, the size of the pistons and stroke of the crank is different as well.

Still, I think the term "Halfabusa' is cool. 8)

 

[pauljo]

At least one magazine used that "half a Busa" term in an early write up on the Burgman 650. I do not think there are many common parts between the engines. The Burgman pistons fire together, the Busa fires alternately (one engine is designed for high torque - the other for max horsepower), which dictates a different crank design as previously noted.

 

[frugality]

They fire together? That doesn't make much sense to me. Why wouldn't they fire alternately -- one firing while the other is on the intake stroke? I would think that both firing at the same thing would make the thing more of a 2-cylinder 'thumper' and lead to more vibrations.

I do see that the crank throws are on the same side of the crank:
http://tfic.com/v-web/gallery/Burgman650/an650k4fe005
but since a 4-stroke fires every other revolution, I'd think they'd be firing alternately.

 

[pauljo]

The 650 engine is silky smooth. This is achieved through use of counterbalancers. Harley twins also fire both pistons at the same time (but are not silky smooth of course). The older British bikes were set up this way also (but were not smooth by any stretch of the imagination).

The 650 engine is designed for torque, which complements the the use of the ecvt transmission. This design is better at producing torque than horsepower.

 

[lycheed]

The TMax 500, SilverWing 600 and Burgman 650 all have 360 degree cranks, which means that both pistons are in the same position all the time. The massive vibrations that you quite rightly highlight necessitate the dual balancer shafts that are fitted to all parallel twins.

Interestingly, Yamaha altered this firing order to 270 degrees on it's parallel twin engined TDM 850 in the late '90s to make it sound and feel like a V-twin.

 

[rich b]

Pauljo: i believe Frugality is correct about the pistons going up & down togeather but firing alternately.this is what the old brittish parallel twins did in fact do.this works because the engine is a 4 stroke which means the pistons fire once every 2 revolutions of the crankshaft.were the engine a two stroke this would not work because 2 strokes fire every revolution.as for the harley v twins, they cannot possibly fire both cylinders on a 45 degree twin,with a single common crankpin,at the same time.that would mean one piston would fire at about 36 deg.before top dead center(normal running spark advance) and the second cylinder,if it fired at the same time, would be firing at either,81,before or 9 degrees after top dead center.neighther of these would work.i am certain that harley uses the same spark advance,on both cylinders.this would be impossible,if both cylinders on a single crankpin v twin fired at the same time. rich b

 

[dero]

Removed

 

[lycheed]

Hi Dero,

You are indeed correct. The application used in MotoGP, 2 stroke GP500 before that, and WSB with the V4 RC45 before that was to increase grip as you indicate. However, with a parallel twin it is a necessity - otherwise the vibrations would make the thing unrideable.

Incidentally, whilst 360 degree cranks did go towards taming the monster 500cc GP bikes if the '90s, they also made the V4 2-strokes sound like the V2 250s (by pairing up the cylinders) which was very unpopular with the fans. The return to the 'screamers' was welcomed by all, and saw a thaw of the stagnant lap times that had preceeded. The sound of an NSR500 screamer is second to none. The RC45 sounds very good though, that V4 drone will never leave an Endurance Racing fan's ear.

Ferrari and TVR use 'flat plane' cranks with 180 degree firing orders that pair up the cylinders of their V8s to make them fire like 'big bang' 4 cylinders - just as Ford did with their legendary Kart/F1 DFRV8. With 4-wheelers there is no grip problem, however making the V8 fire like two four cylinder engines enables the engine to rev higher, which in turn allows it to make more power. This helps the Ferrari F360 to make 400bhp at 8,500rpm from 3.6 litres, whereas the cross-plane cranked Corvette makes it's identical 400bhp at 6,000rpm from 6 litres.

 

[lilleyen]

Now we're cooking.
Keep it coming.
This is getting good.
I'm soaking up data like a sponge :wink:

 

[pauljo]

Pauljo: i believe Frugality is correct about the pistons going up & down togeather but firing alternately.this is what the old brittish parallel twins did in fact do.
rich b

I believe you right about the alternate firing of the pistons. I looked in my service manual and it does appear that the cam lobes are reversed for the left and right pistons.

 

[Pete]

I wouldn't even begin to offer up any technical insights here but....

I usually let Moonpie warm up before I twist and go. While I sit there on her, garnering my safety "karma" :wink: while waiting, I have noticed that, even though she is smooth as silk, there is, (to me anyhow) a very slight, but discernable left/right vibration as the engine sits there underneath me warming to op temp. Sort of like the arms on the robots on the rock 'em sock 'em robot game that I had when I was a kid (if you alternately "triggered" each arm separately). Which leads me to believe that there has to be some sort of offset combustion chamber firing sequence. You're right Paul, a close inspection of the cam lobes would tell the story (I'd presume.)

 

[Sails]

Maybe we should talk to these Guys!

http://gizmag.com/go/3838/

118 BHP from a 600cc Suzuki or the winner!

 

[Pete]

Holy crap Ken - that's astounding! I wonder if those numbers are brake HP or Net HP. With those numbers I'd think brake but....who knows. I darn sure wouldn't mind more juice! :twisted:

 

[Sails]

Whatever they are, they are at the rear wheel!

 

[Pete]

That's Net. Brake is at the crankshaft, Net is at the wheel, parasitic drag included.

Again - Wow!

:shock:

 

[NormanB]

I believe you right about the alternate firing of the pistons. I looked in my service manual and it does appear that the cam lobes are reversed for the left and right pistons.

Can you tell from this pic?

My instinct (with limited practical experience) is that is just too **** smooth for it to be firing both simulataneously it would make no sense!

 

[pauljo]

Norman,

You can't really tell from that picture. But the picture in the service manual shows the cams installed, and you can see that the lobes are 180° offset for the two cylinders (both intake and exhaust).

 

[rich b]

Pauljo: nice detective work on that cam lobe analysis.you are an astute objective & stand up person.i guess a prerequisite for being a burgman owner,is that your an unconventional individual,in a very good way.i have always been a maverick,but this is a special fraternity we have.
proud owner & member rich b