Topic: CB 650 motor in a 550 frame?

[KeithTurk]

Okay guys... I've never heard of a CB 650 until recently here...

Is this thing identical to the 550 in appearance and fit?

What years were they produced and how hard are they to fine?

If they are "good" motors I might want to find and stick one in my truckster... ( the 4th 550 that lost it's motor on the Mexico trip )

Keith

[Geeto67]

650 motors are not identical looking but the mounts are the same and you can swing them into any cb550 frame with minimal drama and no fab. The hardest part I would think is getting the ignition sorted as some of the 650s use pulse controllers and the 550s use points.

650 motors are slightly harder to find as the bikes are still regaurded as throw aways so when you find them they are cheap but less were made than 550s and people are not really saving them.

They are good reliable motors, about the same as a 550. As with any honda motor as long as you keep on the maintenance they will last till the end of the world.

cb650 motors are from 1979-1982.

[Soos]

from what I have read, yeah...
Haven't tried myself though.

A search nets lots of results using "cb550 cb650 swap"
http://forums.sohc4.net/index.php?action=search2



l8r

[ghost]

my understanding is that all of the 650's had the pulse ignition, no points here.

[cb650]

Yes all 650's had "CDI" iggy.   83 went to the dual cam completly diff motor.

[ghost]

Yes all 650's had "CDI" iggy.   83 went to the dual cam completly diff motor.

that's what i thought. they introduced the nighthawk name on the 82 cb650sc then added the second cam in 83 ending the run of the sohc 4.

[Ryan 550k]

I was recently looking into doing this conversion with my 550.  Turned out the 650 engine I looked at was seized.  No thanks.  BUT, I heard from a buddy that someone on here had done the conversion.  Soos is right, tons of threads.  Do a search, no doubt you'll find something usefull.  My buddy thought it was you SOOS that did the conversion but apparently it wasn't.

[paulages]

650 motors are not identical looking but the mounts are the same and you can swing them into any cb550 frame with minimal drama and no fab. The hardest part I would think is getting the ignition sorted as some of the 650s use pulse controllers and the 550s use points.

650 motors are slightly harder to find as the bikes are still regaurded as throw aways so when you find them they are cheap but less were made than 550s and people are not really saving them.

They are good reliable motors, about the same as a 550. As with any honda motor as long as you keep on the maintenance they will last till the end of the world.

cb650 motors are from 1979-1982.

there is minor fabrication involved if you want to keep the 550 airbox. i haven't put a slide carb engine in a 550, but the CV carb ('81-'82) engine required that the intake plenum (between the airbox and carbs) opening be glassed shut and recut to the correct position for the 550 airbox, which is on centered to the left rather than the right.

[cb650]

Yes a 79/80 would be a better fit cause of the carbs.

[fdbrat]

I did this engine swap. But now im trying to figure out what to dop about the Electrical stuff. any body??

Go points or should I keep the pulse??? and how

[BVCB650]

Why would you want points? Why use 50 year old tech when other methods are available? To the OP, I have seen many engines available. Throwaway....LMAO. If you want some more power, stick a 650 cam in a 550, but before you do, read up on other items as to why the 650 isn't just a big brother to the 550.

[cb650]

The 650 didnt have a kickstart either.   My biggest bit*h about it.    I have never had any probs with any of the electrics on any of my 650's but many people have.

[Ecosse]

Why would you want points? Why use 50 year old tech when other methods are available?

it might be old tech but it doesn't equate to 'bad'. if something fries in the cdi (rare or not) you're stuck. in all the (auto) electronic ignitions i've owned i've had black boxes and such crap out, but with the older cars, even with dual point systems, i've never had one just go t!ts up.

regardless, with the 650 ya don't have much choice.

read up on other items as to why the 650 isn't just a big brother to the 550.

ain't that the truth. nothing wrong with a 550 but the 650 was the sohc/4 swan song.

[BVCB650]

Why would you want points? Why use 50 year old tech when other methods are available?

it might be old tech but it doesn't equate to 'bad'. if something fries in the cdi (rare or not) you're stuck. in all the (auto) electronic ignitions i've owned i've had black boxes and such crap out, but with the older cars, even with dual point systems, i've never had one just go t!ts up.

regardless, with the 650 ya don't have much choice.

read up on other items as to why the 650 isn't just a big brother to the 550.

ain't that the truth. nothing wrong with a 550 but the 650 was the sohc/4 swan song.

\\






I'VE HAD POINTS FRY WHERE IT WOULDN'T START TILL i FILED THEM A BIT ALONG SIDE A CORN FIELD. Sorry. Freaking cap lock. Too lazy to re-type. For the same reasons. the 650 isn't the lillte bro' of the 750 either.

[Soos]

The 650 is more the pre-cursor to the DOHC family.

LOTS of new tech's on the 650 were standard on later bikes.
Although the early cb650 carbs are based off the '77/'78 cb750 carbs.





l8r

[fdbrat]

I like points. There is nothing wrong with them. Well i Supose im stuck with stock. Is there any links to creating electronics box from scratch. That is where I stand. the only wires I have are the old cb550 electrics box. The Newer 650 wont adapt.

Any links, Ive searched High and low.

[paulages]

I like points. There is nothing wrong with them. Well i Supose im stuck with stock. Is there any links to creating electronics box from scratch. That is where I stand. the only wires I have are the old cb550 electrics box. The Newer 650 wont adapt.

Any links, Ive searched High and low.

you're not stuck if want points or a dyna s, you just need to know that the locating pin for the cam plate is 180 degrees off and that the center mounting stud's O.D. is larger. i covered that in the 550/650 big bore thread if you want to see pictures.