Characteristics of a parallel twin?

**Chisanga** · 24th January 2007, 19:57

Thanks for the huge response to my questions on the Characteristics of a Triple thread I started a few weeks back.

I saw an interesting Kawasaki today that is a Parallel Twin, could you engine-techo- bods out there explain its characteristics and how it differs from a V-Twin. I know about the positioning of the cylinders and that is about all

Thanks in advance

**crazybigal** · 24th January 2007, 20:02

boring and flat!

**nudemetalz** · 24th January 2007, 20:03

Would that be a ER-6N ?

The parallel twins generally (I say "generally") vibrate a lot more than v-twins unless counterbalancers are used.
Kawasaki make good parallel twins. (ie GPz500's).

V-twins are the way to go for any given capacity though.

**James Deuce** · 24th January 2007, 20:28

Parallel twins make good vibrations, unlike some fours which can have killer high frequency vibrations that numb hands and 'nads.

The best Parallel twin I've ridden (I also owned it so I'm biased) was a TRX850, which isn't boring and flat at all, and frequently ended up pinging off the rev limiter, all the while making a lovely Ducati-like noise thanks to a 270 degree firing order - that is, a cylinder fires once every 270 degrees rotation of the crank.

Some have a 180 degree firing order (early TDM 850) and some are every 360 degrees. Some have pistons that rise and fall together, some alternate. Horrible rocking couple on the alternating one.

**crazybigal** · 24th January 2007, 20:32

i take that back, you are right trx850 is a cracker of a bike.
but i think smaller para twins are not that great. zzr250 gsx250

Originally Posted by Jim2

Parallel twins make good vibrations, unlike some fours which can have killer high frequency vibrations that numb hands and 'nads.

The best Parallel twin I've ridden (I also owned it so I'm biased) was a TRX850, which isn't boring and flat at all, and frequently ended up pinging off the rev limiter, all the while making a lovely Ducati-like noise thanks to a 270 degree firing order - that is, a cylinder fires once every 270 degrees rotation of the crank.

Some have a 180 degree firing order (early TDM 850) and some are every 360 degrees. Some have pistons that rise and fall together, so alternate. Horrible rocking couple on the alternating one.

**James Deuce** · 24th January 2007, 20:34

No worries dude - I was just pointing out some are good

There'll be some Brit-bike guys here soon - they're rabid, so watch out!

**crazybigal** · 24th January 2007, 20:37

yeah i think i have foot n mouth!!

Originally Posted by Jim2

No worries dude - I was just pointing out some are good

There'll be some Brit-bike guys here soon - they're rabid, so watch out!

**Crisis management** · 24th January 2007, 20:42

My first bike was a suzuki T500 (parallel twin) its characteristics were, smoky, noisy, reluctant to start, very reluctant to stop and fell over at corners.

None of these I found particularly endearing.

My next parallel twin was a Norton commando 750 which similarly was noisy, occasionally reluctant to start but didn't fall over at corners. Instead it tank slapped at times and vibrated like a bastard.

I bought a v twin after that.....

Hope that clarifies the matter for you.

**Chisanga** · 24th January 2007, 20:46

Originally Posted by nudemetalz

Would that be a ER-6N ?

I believe that it was. Sat on one at East City Motorcycles today. Just thought it was interesting ... and definately an interesting coulour - bright orange

**Chisanga** · 24th January 2007, 20:47

Originally Posted by Crisis management

My first bike was a suzuki T500 (parallel twin) its characteristics were, smoky, noisy, reluctant to start, very reluctant to stop and fell over at corners.

None of these I found particularly endearing.

My next parallel twin was a Norton commando 750 which similarly was noisy, occasionally reluctant to start but didn't fall over at corners. Instead it tank slapped at times and vibrated like a bastard.

I bought a v twin after that.....

Hope that clarifies the matter for you.

So why would a manufacturer choose to produce a Parallel instead of a V if the V-Twins are so obviously superior?

**Motu** · 24th January 2007, 20:49

The parallel twin was the standard package for decades,in 2 and 4 strokes,nearly every manufacturer past and present has produced a parallel twin of some sort.More have been made following the British style,made popular by Triumph and then every rival make had their own version.So they were a 500,650 or 750 4 stroke twin,generally making max power at around 7,000rpm and a flat power curve,although Triumphs were noticeably camy coming on strong at 4500rpm.Always a 360 crank with even firing impulses.

Honda tried upset tradition in the '60's and '70's with small capacity parallel twins with a 180 crank,there was no advantage in balance - they solved the primary balance of the 360 crank,but doubled the secondaries and gave a rocking couple.Every kid has turned their pushbike upside down on the seat and pedaled like mad with their hands....stand back and watch a rocking couple.

Parallel twins can be made to rev very high,but their claim to fame is medium capacity grunt.A V twin is not better than a parallel twin,and as Jim2 mentions,they can be made to give a V twin firing impulse easily enough.It's the packaging - early twins were fitted into single cyl frames,no changes being made at all.Just a little wider,an exhaust down the other side and that's about it.Manufacturers like BSA used the same frame,gearbox and forks for 350 and 500 singles,and 500 and 650 twins....no separate production lines and maximum shared componentry.

**Crisis management** · 24th January 2007, 20:54

Originally Posted by Chisanga

So why would a manufacturer choose to produce a Parallel instead of a V if the V-Twins are so obviously superior?

But the manufacturers' of superior bikes only make vee twins?

Have I misunderstood your question?

**nudemetalz** · 24th January 2007, 20:58

Kawasaki have never really made sports v-twins before, I guess going with the ER-6 series basically show that they can make an engine configuration that is unfashionable work well.

I think the latest MZ1000 is a parallel twin too. That's also a rarity of a twin that large.