What are the advantages of a water-cooled V-twin over a parallel-twin?

[Pwalo]

V twins (of varying geometry) and parallel twins both have their own advantages as far as engine configuration go, as has been stated by my fellow erstwhile posters.

Another factor is that the two configurations can affect chassis design. V twins tend to have a longer wheelbase (especially 90 degree twins).

As far as manufacturing costs, the parallel twin will probably always be cheaper to produce. One camchain, one cylinder barrel and head, one camshaft. It will also be cheaper to service, repair, etc.

All that aside I still prefer riding my current bike (V Twin), over my previous parallel twin.

[pete376403]

A 360 crank doesn't have a rocking couple,maybe some torque reaction on firing.These days a 360 is a good idea as balance shafts are so last century.A V twin with a staggered crank has a rocking couple - I could feel my XLV750 waddle as it went down the road,very noticable at idle too.

Really,the dividing line is capacity - a parallel twin is getting a bit porky over 800cc,where as a V twin can still be a respectable size with some huge capacities.I will be very interested to see this 1700cc Triumph twin.

Nortons Commando 850 was physically no bigger that the Dominator 500 that spawned it. And the 850 is still a long stroke (3.0 x 3.5) so it could still go bigger bore (assuming the cylinder block can take it, or maybe a custom block) and still be no larger externally. 3.35" bore would take it to 62ci (1012cc).
Also the Norton is a 360 with a central flywheel - and they vibrate like a dog shitting a chain. Dick Hurdemann (BMS) made a 270 crank for a Norton and apparently is was dead (relatively) smooth*. Of course he had to make his own cams and ignition but he's good at that sort of thing.
(*My brother in law worked at Russ Clarkes in Upper Hutt (engine balancer to the stars) and did the balancing work on the crank/rods/pistons)

[koba]

Nortons Commando 850 was physically no bigger that the Dominator 500 that spawned it. And the 850 is still a long stroke (3.0 x 3.5) so it could still go bigger bore (assuming the cylinder block can take it, or maybe a custom block) and still be no larger externally. 3.35" bore would take it to 62ci (1012cc).
Also the Norton is a 360 with a central flywheel - and they vibrate like a dog shitting a chain. Dick Hurdemann (BMS) made a 270 crank for a Norton and apparently is was dead (relatively) smooth*. Of course he had to make his own cams and ignition but he's good at that sort of thing.
(*My brother in law worked at Russ Clarkes in Upper Hutt (engine balancer to the stars) and did the balancing work on the crank/rods/pistons)

WOW! That is farken cool!

[Motu]

Nortons Commando 850 was physically no bigger that the Dominator 500 that spawned it.

The 850 took the design too far - they had to develop the superblend barrel shaped roller bearings to cope with the crankshaft whip.The old XS650 has been taken out to near 1000cc in the Wasp sidecar outfits.That's a strong crankshaft set up,but as I mentioned earlier,with the weight being further out from the centre line they are slower to turn because of the gyrocycloptics.Getting a vertical twin over 1000cc is not common,and yet is considered ''small'' for a V twin.So when is someone going to post a pic of the 1700cc Triumph?

[pete376403]

Post #9
http://www.kiwibiker.co.nz/forums/sh...t=1700+triumph

The round chrome caps on the cams make it look like an old GS Suzuki engine

[FROSTY:Me]

From my point of view a parallel twin is a heap better than V.
Only 2 Cams to replace, Only 1 Rocker cover,base and Head Gasket.
Carbs/injection system easier to access