I ported the heads to match the diameter of factory manifold. Replaced the filter airbox with a K&N air filter. Put in a high lift cam ,new valve springs, retimed the cam, bored it out to 650, rejetted the carbs. Had a Kerker header. Ran low 12s. Faster than my CBX. My favorite bike. Did 100,000 miles

My dad had one he never rode. I snuck it out & rode it to high-school a handfull of times. No license, no tags, no insurance. 14 miles each way. My dad woulda killed me

Honda CB550 - unsung hero award.

Had this CB 550 for a long time,then my son rode it for a few years same color.

Dude this was a revelation for me!!! Thank you for posting, I had no idea the vm 34 could be adapted to the Cb- amazing 🤙

It is interesting to see that you were able to evaluate the motor characteristics (so much more power, etc.) within your neighborhood in just over a mile of riding with tires that needed air… 😉

Learning a lot. Thanks for showing the whole process! I'm going to comment on all the videos I watch just to help your analytics. I hope that is cool.

It would be great to see a comparison between the mikuni and a rebuild stock carb. To really be able to judge. Thanks for showing these mikunis though!

Great Headline!! Even I had to see what you were going to do. Hope you are doing awesome!

While just a backyard mechanic I rejetted the 4 carbs (with K&N filters), installed a 4 into 2 Jardine pipes. Increased the motor sprocket by 1 tooth and decreased the rear sprocket by 2. Installed a Barnett clutch. Found out I could swap the stock 550 tank for a 750 tank, this required narrowing the rubber grommets (that mount to the frame) and moving the fuel lines to the other side. This gave me an extra gallon of gas. I also went up 1 size on both tires. Even with the Windjammer II fairing I could do 110mph, but that was top speed. I could ride 90 miles to work then put in 8-10 hrs. heavy construction work, and drive another 90 miles home.

damn sounds great with the new carb!!!

I have worked with a Canadian vintage road racer and have achieved very close to 75 RWHP with 592cc displacement. The bike has been a dominant vintage force over the past 10 years. A lot of effort in the cylinder head, parts and assembly (setting squish etc). The Megacycle 126-20 is the cam to use.

Friend of mine did this conversion on a CB750F2 1980 model and the difference was amazing..much easier to keep vacuum balanced and with better delivery..once set up right you'd wish you did it earlier ..

Old Hondas and fords I love it !!

Those had good bottom end torque, I could go round traffic islands in top

Since I've now watched several of your video's, I subscribed. I've had my 550F1 since new, June 1977. It's been 'retired' a while since it has over 106,000miles, 70,000+ with big bore kit. Always much preferred the smaller bike over CB750 which is too wide and too heavy to handle really well. Best conversion in my opinion is actually the 591cc mod (plus, the dual carb conversion didn't exist back then). The stock carbs are quite difficult to set up without stock air-box, (particularly if you have a later 550K which that appears to be - alternator cover has exposed screws with Honda cast in). I would figure out some sort of bracket for rear of carbs, they will droop over time and cause rich running if not supported Normal tuning doesn't seem to work so well, bigger main jets and raise needle just uses even more fuel but no improvement in running. Dropping needles one extra notch works better than raising them. I did mine 1979 or 80, modified CB750 K0 pistons (not to 1974 Cycle World 'Gentleman's Express' spec though) I still have way too many projects started but watch far too much You Tube to get much done (being hurt doesn't help, painkillers only do so much) Who would have thought teaching was more dangerous than riding motorcycles? (12 years at MMI) Oh, didn't know you had XS 650, I was really into them and did long rod conversions (Honda CR500 rods) with XV750 pistons to get 800cc motors. You need to fit oversize liners to cylinder though. Only saw Alfa at end, had a bunch of Alfa Sud, flat four is awesome motor. It was designed by a former Porsche engineer who told Porsche they were doing it wrong 😁

Really considering this for my 550 Four

I replaced the carbs on mine with cb750 carbs.

I'm interested in knowing how well the idle tunes on this setup? The four carb setup is notoriously tricky to get that perfect idle tune.. I want to hear a sweet, stutter free 1000rpm idle!!! Even a crap set of carbs sound good when you burp the throttle and hear that awesome CB-four tone!!

good job

Looks like an improvement over stock. Why not EFI? Or four into one? I bought a new 550K off the dealer showroom floor in 1975. It was a great commuter and cross country bike.

Do they have those kits for a 72CB 750? I’ve got a tip though take some 0000 steel wool and some mothers aluminum polish to the forks and the aluminum engine and you can get that bike looking shinier than chrome. then wipe off with a Terry cloth towel

have you got it dialled in yet? and have you noticed much diffrence in fuel useage? cheers

Going from 4 to 2 seems a bit counter-intuitive, was there something wrong with the stock carbs. Is it an issue that the new carbs weight is cantlivering off an extended intake manifold with no support from the air box.

I know this is a few months out by now. But I have a few questions. I just got the Murray's kit for my cb750. It started up but idling really high, routing of cable seems ok, but honestly sounding kind of similar to how your bike started up. I've been messing with it but haven't touched any of of the adjustments screws. It starts but idle is too high, but also a bit erratic and unpredictable 1. I notice when you give it a rev it does a like a 1-2 rev (22:02) was that a cable issue or an adjustment issue? I saw in your "its so good" video that it was revving/ riding great 2. Did you do much other than tweak air fuel screw? I've honestly only ever messed around with the cb750 round tops and I'm always worried about messing with carbs, I know it's a bit irrational but I'm always worried I'm going to do something irreparable

Is that an American truck, European roadster and Japanese bike? This guy is cool!

Hey I noticed the cb550 kit says coming soon. Is this the cb509 kit?

If both stock carbs and this swap are tuned properly, does this actually make more power? I can't imagine that the four-carb setup from the factory would produce less performance than these carbs, even if these are a little bigger. I have a 650 cafe racer that I just picked up. I'm not doing anything major yet, but down the road I plan to make it into a real screamer. Hopefully it'll be easier than I'm thinking it's gonna be, but probably not lol. There is almost nothing in the way of performance parts I can find for it besides Keihin CR29 carbs, so it looks like I'm gonna have to do a lot of work. 👍

Rub a little washing up liqiud on the rubber boots first it will fit easier and quicker.

Buddy just threw on some carbs out the box and the damn bike started up. where can i get this voodoo?

I noticed the 550 kit for the carbs says coming soon. Is this the 500 kit

I'm doing this with my 78 gs550

Im sick of chasing down issues on a very rough set of 78 carbs def getting a VM34 kit asap

let's see the "rocket" that sounded pretty rough. No timing check?

Running rich and check your advance unit for sticking

Doubt you much more horse power than the standard carbs with a re-jet and high flow air filters for the cost of new carbs . Devalues the bike as well .

The easiest way to turn a CB550 into a rocketship is, sell it & buy a Hayabusa

what a crock...the bike was clearly running so much worse than even a worn out stocker. Put the tools away....or the camera...or tell the truth