Firing order for 360 cranks

The '82-'83 Magna had a 360 degree, reverse-rotating crank and the firing order 1234. When Honda adapted that engine for the '83-'85 VF Interceptor they kept the 360 crank but changed the rotation to forward, which automatically resulted in the new order 1432. Somewhere along the way they did the same to the Magna. I guess it was in '94 when they replaced the shaft with a chain. I think the reverse rotation somehow works better with shaft drive. According to this, The VFR750R (RC30) also had a 360, reverse-rotating crank. I think the RC45 did, too. And all the V4 GP racers up to 2016. But why did they change to a 180 crank with 1324 in the VFR in 1986?

 

This is for the ST1100:

This one is for the ST1300: The cylinder numbers are swapped so 1/3 are on the left, 3/4 on the right. The two ST engines may rotate in oppsoite directions.

 

Thanks, Terry. I had no idea the ST had a 360, and now I'm wondering why. According to this, a 180 is supposed to have better balance and more power. A 360 is supposed to have better traction, and that's what Honda thought would win races But now Honda is claiming the RC213V-S "utilizes a 360-degree crank phase angle, which leads to more favorable exhaust pulses and increased charge efficiency for better power."

I've just made spreadsheets for 360 and 180 firing orders (open images below in new tab). The 360 looks better balanced to me. It has two power strokes with a 90 degree overlap. Reminds me of the "twin pulse" Panigale. Maybe I'll make a spreadsheet or two for the RC213V. According to Wikipedia, the firing order was changed from 360 and 90-270-90-270 in 2016 to 180 and 90-90-90-450 in 2017,

 

The STs have a different mission to the VFRs, being intended for more touring but also a lot of police work. The engines are tuned for low end torque and consequently are perfectly happy pulling top gear from 2000rpm smoothly. If you tried that on a VFR800 you just end up with a shuddering sluggish mess. My experience is the 180 crank engines are not happy at low revs, bizarrely the VTR1000F that I owned was much happier at low rpm even being a big twin.

If you want a naked V4-sounding 1000cc bike without breaking the bank, just buy a Yamaha MT-10! I love mine. Has most of the Honda traits being smooth, grunty but also seriously fast (dynoed at 150 rwhp, it pays to be pointed in the right direction when you twist the throttle).

"The new firing order results in a new sequence of combustion: 1-3-2-4, with the following intervals: 270° 180° 90° 180°".

 

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I wasn't aware there was a naked R1. Thanks for the info. I'll think about it. I did know the R1 sounds exactly like a VFR. I don't understand the attraction, but I suspect that even back in 1986 Honda put a 180 crank in the VFR because somebody in marketing liked the sound. To me it just sounds out of tune. They said it was for the more even intervals, but I'm thinking maybe it was to go easier on the cams. I think I'd prefer the 90-270-90-270 of the 360, but the sound is very low on my wish list. I do need a long test ride before buying anything because my hands go numb really easy. I think it depends on the frequency or something, but I made a big mistake buying an F4. You've got me interested in the ST being as it's a 360, but I might wait to see whether Honda offers an affordable new v4 in the coming year.

 

I think we will all be waiting a long time for Honda to make another V4 engine! Too expensive with 2x heads and cam drives, then a whole lot of emmissions testing to pass. Get used to more based on the Africa Twin 1100 twin.

I was suffering from a numb throttle hand and tried looser gloves, heated grips and taller bars. My problem was actually carpal tunnel syndrome, I had surgery and it went away completely.

My ST1300 is remarkably smooth, in addition to being a 90 degree V4 it also has two balance shafts. Bars are also rubber mounted.

The MT is very smooth when cruising but has some characteristic low frequency vibes when getting on the throttle, but it is a much more energetic bike to ride, the ride position is very humane with little weight on wrists and plenty of leg room.

This is how Honda explained the change in 1986:

 

I think this was the real reason (copied from a comment in another forum):
"It's a shame the VFR got slapped with the 180º back in 86... because prior to that year all
Honda's V4 were 360º Big Bang... it was marketing who discovered that
the buying public didn't like the drone of the Big Bang and Honda
could sell more V4s if they phased the crank 180º... but I hope that
the sounds of MotoGp Big Bangs may shift the buying publics preference
back in favor of the 360º over the 180º..." I think maybe marketing also concluded that consumers prefer a bike that can be easily wheelied over one that has good front-wheel traction.

 

Actually, I am one (?) who prefers the sound of my '86 VFR750.