I found this interesting about v 4 engines

[cruiserlover]

https://en.m.wikipedia.org/wiki/V4_engine#Advantages_and_disadvantages_of_the_V4_engine

 

 

 

I dont understand why the indirect driving of the cam would be a viable design, or its efficiency or longevity against other designs.Some of this complexity of engine design would probably prohibit use of a chain drive versus driveshaft?

[RSTDdog]

Not sure what you mean by indirect driving of the cam on the V4? Cams on V4's are driven much the same as on inline and other motors although there are no pushrod V4 engines I can think off. Early Honda V4 (VFR750 Interceptor) had gear driven camshafts-direct drive from the crank. You haven't heard whine till you have heard a gear driven cam Honda v4 spool up. The Yamaha uses a chain to drive the overhead camshafts. The Honda ST1100/1300 uses a timing belt like a car to drive the over head cams.

 

VFR 750 is a v4 chaindrive motorcycle. The output shaft on the Yamaha V4 has to make a 90 to accommodate shaft drive. Shaft drive is more complex than a chain inline or v4 doesn't matter. The guys who build high horsepower drag Vmax bikes, eliminate the 90 and the shaft and convert them to chain. Too much torque twist on the driveshaft for the HP they produce modded. The longitudinally mounted Honda ST1100/1300 V4 have the output shaft straight in line with the driveshaft so no right angle needed as with the Yamaha. That said the ST1100/1300 V4 would not convert easily to chain drive, where as the Yamaha and other transverse V4 models either will convert or already do have chain drive to the rear wheels. By and large most V4's were in cruising/tour bikes thus the shaft drive.

[Great White]

Actually, shaft is converted to chain on drag bikes to eliminate the power loss of the double 90 degree turn. Same reason on sport bikes (well, eliminate shaft jacking too). Chain is the most efficient way to transmit drive power on a bike, but it is also the messiest. Anything cruiser or tourer gets shaft for that reason. The VMax got a shaft because Yamaha didn't see the worth (ie: cost) in changing the xvz design to chain when Mr max already had 145 hp on tap.....a absolutely huge number for a bike back in 85.

 

Honda made all kinds of chain and shaft v4's.

 

First out of the gate was the sabre and magna v45's, (1982), which were shaft drive and chain driven cams. They got shaft drive for ease of maintenance: sabre was marketed as a tourer, manga as a cruiser. Neither market was seen as wanting the maintenance, mess and fuss of a chain.

 

The v45 interceptor was out the next year (83) with chain driven cams and chain final drive. The interceptor got chain drive because it was a no holds barred superbike and for ama homologization. Vf1000f followed suit in 84.

 

The vf1000f was a poked and stroked vf750f, the sabre and magna v65 were a separate (but similar) design.

 

The 500 v4's (84) were all chain final drive since they couldn't sacrifice the power needed for the 90 degree turn for the shaft. All chain cam drives. The vf500's were actually poked and stroked vf400's from Hondas Japanese model lines.

 

First gear driven cams were in the vf1000r (86). The next year (86) the VF/F interceptor was changed to the vfr750 with gear driven cams since chain drive was seen as the root of the Honda v4 cam problems. Honda blamed a lot of things on the v4 cam problem but the cause was the cam bores not being line bored in previous models. They never admitted it, but once they started line boring the cam journals, the cam problems went away. The switch to gears was as much a marketing ploy as anything to make the public think Honda had fixed the chocolate cam problem of previous v45's. Alas, it was not to be as the Honda v4's had cemented that poor reputation. The v45 wouldn't be redeemed until years of soldiering on as Hondas only v4 model in the sport touring pigeon holed vfr750/800.

 

The vf line was dropped after the 86 (vf1000r was the last vf) and only the vfr750 soldiered on until the ST line came out and Honda began a new dabbling with transverse v4's.

 

Yamaha had its own love affair with the v4. Obviously the xvz line and the vmx12 line (which is actually a pair of siamesed xz550 engines), but they had a whole host of v4 2stroke race bikes and eventually one street model, the rd/rz500. Ah the rd500; such sweet, sweet memories....

 

Up until Honda jumped in with the sabre and magna, Yamaha actually was the company with the most v4 experience....albiet on the track rather than the street.

 

All Honda really did was give the v4 design a black eye in the early years. I have and 85 interceptor, great bike. But you have to watch the top end like a hawk.....

Edited October 13, 2015 by Great White