Topic: Cb550 six cylinder conversion

[bert1]

Has anyone ever mated two  honda sohc4's into a inline 6? Interested in how it came out if yes. I have only seen millyard's z1 six so far online.

Wrapping up a yamaha rd triple right now, planning on doing 550 six cylinder later this year, interested in any finished examples from the past.

[Deltarider]

Benelli did exactly that. A Benelli Sei is a CB500 X 1,5. https://en.wikipedia.org/wiki/Benelli_Sei
The launch of the CB500 Four was followed by these reactions in Europe:
1. BMW said: "That's it, let's give up on motorcycles and return to making small cars again". (like the BMW 600). They've changed their minds later. Mind you: the BMW 600 boxer motorcycle was 10% cheaper than the Honda CB500. BMW's car had that same 600 cc boxer engine in the rear.
2. Porsche's boss declared: "This (the CB500) will be the motorcycle of the century". He was almost right: the CB750 won that title at the turn of the century.
3. De Tomaso, who was hired to rescue a sinking Benelli, gathered his workers in the assembly hall and gave a speech. "Forget about your Italian pride. First we must try to survive. I want you to build a Benelli CB500. It became the Benelli Quattro, which bike is so similar to a CB500, you can partly use the same parts.

[Laids]

Not an inline 6 but rather a elegant looking v8 Honda

[M 750K6]

Not an inline 6 but rather a elegant looking v8 Honda

That's pretty and clever. Be interested in how the carbs are mounted. It looks factory apart from the exhaust wrap.

I'd like one of those.

[HondaMan]

That's some fancy casting work!

[BenelliSEI]

Benelli 750 SEI.

[grcamna2]

John,your Benelli SEI had plenty of room under the tank for those tall Dellorto carbs.

[BenelliSEI]

John,your Benelli SEI had plenty of room under the tank for those tall Dellorto carbs.

It did. That frame and body were actually designed for the Benelli 550-4. It had four carbs. The SEI only had three on wishbone manifolds.

[MauiK3]

I wonder how that V8 had the carbs set up, not much room. I bet it sounds good.

[Deltarider]

And there is ofcourse the Benelli Dodici.

[grcamna2]

And there is ofcourse the Benelli Dodici.

Ouch 
12 cylinders.. it must be a very smooth 'beast'.

[HondaMan]

Benelli did exactly that. A Benelli Sei is a CB500 X 1,5. https://en.wikipedia.org/wiki/Benelli_Sei

I still remember the first time I saw one of those Benelli 750 Sixes. I started to walk past it and then stopped dead, turned around and went, "What?!" Then it showed up in the cycle magazines, so cool.

Someone here in the forums has (or had) one that he found in a big hole in a field somewhere, and he got it running after he got it out. It was years ago, I can't remember who it was?

[Tracksnblades1]

And there is ofcourse the Benelli Dodici.

Wonder what the max lean angle before touchdown??

Wonder what a hand full of throttle felt like on your wrist and on the seat of your pants…😳

[Tracksnblades1]

Benelli 750 SEI.

Always wanted one of them…

Buddy had a new 79cbx…Ran like a scalded, corn cobbed turpentined cat… chains chains chains everywhere even the oil pump if I remember correctly. when Kawadogs, Suzukes, and Yamahadogs were all making the gear transition. Them old maximums and seca’s had their alternator behind the cylinders to keep the engine really narrow.

[scunny]

I remember when the Seca came out, there were a few in the castrol six hour, they ended up in the weeds because the narrow engine outdid the tyre selection available. A friend bought one and suffered the same low side.

[Deltarider]

... and this 48 cylinder bike - the Whitelock Tinker Toy - will soon be auctioned in the UK.

[HondaMan]

John,your Benelli SEI had plenty of room under the tank for those tall Dellorto carbs.

It did. That frame and body were actually designed for the Benelli 550-4. It had four carbs. The SEI only had three on wishbone manifolds.

I missed that point on the one I first saw. I left there wondering how hard a 6-carb 'balance' job would be?

The CBX 'cheated' by using CV carbs...