Author Topic: CB550 - CB650 interchangability (Read 19056 times)

kayaker43 · « **on:** July 02, 2006, 07:42:20 PM »

I know these two engines were built on the same assembly line and share bore centers and cyl. stud patterns. I've heard that top end parts are interchangable to some extent, but the cam chains are different.

Can a cb650 head and/or cylinder be fitted to a 550 by using the 550 cam chain sprocket? If not, will the 650 crank fit so I can use the right cam chain? I assume I may have to bore the cases, or clearance something for the stroked crank. I'm sure some ex racers out there must know the tricks?

My fuzzy memory also recalls that the engine mounts are the same, the 650 carbs will fit a 550. Also remember hearing that the 650 crank and a 590 kit works out to 750cc? I was roadracing a 590 back when the 650 came out and heard but never confirmed these rumors. Anyone know for sure what can be swapped??

bill440cars · « **Reply #1 on:** July 02, 2006, 09:55:19 PM »

There was a tread about this earlier this year but, for the life of me I don't remember exactly when. Seems like almost everything from a 650 (motorwise) will fit in a 550 crankcase. Bearing in mind that, if you put a 650 head on the 550 motor, you'll have to use a 650 exhaust also. Also, according to what I'm told, the 650 motor will bolt into the 500/550 frame and vice versa. If you get a chance, you might check back into the files and see what comes up on it. Also, maybe one of those guys, who knows more about this subject, will kick in some more precise info on the subject. Later on, Bill

I just got through trying to do a search and I guess I'm just not wording it right because, I'm not having any luck. Sorry. Gone again,, Bill

kayaker43 · « **Reply #2 on:** July 03, 2006, 10:10:14 AM »

Yeah I did some searching too but didn't turn up a dedicated thread. Did find a few treasures buried in other threads but not much new. Apparently the 650 cam will fit a 550 but the tach reads too high. I read somewhere the primary drive ratios are different so the 650 clutch and gearbox is less stressed. Oh yeah,.. the carb spacing is the same till 81 when the 650 went to CV carbs.

If anyone can direct me to threads with more info I would appreciate it. If anyone wants to sell me a 650 motor cheap, I can do a complete autopsy and comparison. This needs to be documented and made into a "sticky" post.

bill440cars · « **Reply #3 on:** July 03, 2006, 10:18:23 AM »

I hear ya, it does get a little frustrating when you can't find what you need and
you know that it should be there, somewhere. After a couple of days go by, being the 4th
and all, you'll probably get more guys puttin' info out to you on this matter. Well, I'm outta
here. You have a good 4th of July and I'll let you know if I run across anything useful.

Later on, Bill

Pinhead · « **Reply #4 on:** July 03, 2006, 11:10:39 AM »

I know you're looking for information, but I've got a 650 and was wondering the same thing... That 590 kit question intrigues me, are the 650/550 pistons the same, only a longer stroke on the 650? If so, that'd be some really usefull info because I'd like to bore my 650 out but can't find any kits for it (it's a '79). I could take some measurements, though I don't have my engine tore down because I drive it every day. I did have an offer out for a completely rebuilt 650 motor, was going to give $250 for it shipped but the guy seems to have disappeared. If I get that motor, I'll be able to tear down my current one and get some measurements. Good luck!

bill440cars · « **Reply #5 on:** July 03, 2006, 12:51:44 PM »

kayaker43 & Pinhead,

Don't know where either of you are but, Tim's Cycles in Berryville (Northern Central) Arkansas
has an 82' CB650SC motor that ran but had a noisy timing chain for $249.99 Buy It Now price. Only
thing is, he doesn't ship. If I had a bit more of a budget, I'd consider getting it myself and I'm in
western central Arkansas. Just a thought. Later on, Bill

bill440cars · « **Reply #6 on:** July 05, 2006, 06:40:12 PM »

Isn't there someone who was either in on the previous subject of mixing CB500/550 &
650 motor parts or has some input on the subject? These guys are looking for info and could use
your help here. What do ya say? We (me included, cause I've been trying to help them) can't
seem to put the right words in to search out the info. Thank you to anyone who might step
forward and lend a helping hand. Later on, Bill

Tommy Neimeyer · « **Reply #7 on:** July 05, 2006, 08:20:42 PM »

Hello All,
I have a 550 frame, 2 550 motors and 2 650 motors. I want to build the 550 frame with a 650 motor or a 550/650 hybred. I did some searching in the archives for 550/650 hybred info. There were many references to Ted Hayes. I tried to send e-mail to him and a few others but all the mail bounced back.

Ted if you read this please contact me.

Anybody else that has some info about building a 550/650 hybred please contact me. Having read through the archives, I know there are differences that have to be worked through. Things like different piston styles, combustion chamber aand cam chains. I also read that when putting the 650 cylinders and head on the 550 it requires the case to be bored.

Some of the questions I have are;
What are the advantages of using the 550 case and the 650 crank and top end over a regular 650?
The 650 having the HiVo primary, why use the 550?
When using a DOHC 650 oil cooler, can you plug the through hole and force all the oil through the cooler?
Which clutch is better the 550 or 650 (realizing they attach to the shaft differently)?

Anybody that has done this swap I would appreciate any pics and info.
Please send or contact me at 3cbxs@ev1.net

Cheers, Tom N.

scunny · « **Reply #8 on:** July 05, 2006, 10:31:08 PM »

if it was me,i'd go for the 650 mtor in the 550 frame cause it will be easier.
there's your goer, then you can play around with the combo motor at your own leisure

Pinhead · « **Reply #9 on:** July 05, 2006, 11:29:24 PM »

If you do get this project going, post a lot of pictures! I'm trying to work on my '79 CB650 but can't find any parts. I'd like to know what parts can go from a 550 to a 650, motor-wise. Good luck!

cb650 · « **Reply #10 on:** July 06, 2006, 04:44:05 AM »

Some one did put a 650 in a 550 frame. Someone else put 650 carbs 79/80 on a 550.

Terry

cb650 · « **Reply #11 on:** July 06, 2006, 04:52:31 AM »

I have a 80 motor that is junk. Cam chain sawed throught the cyl. Been pulling parts off here and there but its still mostly there. In Denver CO

Terry

bill440cars · « **Reply #12 on:** July 06, 2006, 05:51:04 AM »

Hey kayaker, Have you seen the new thread on the 550/650 subject? Maybe you'll be
able to pickup some info there. Check it out, when you get the chance. Also, check with
Terry (cb650) on what he's got and maybe you'll get some insight for what you want to do.

Later on, Bill

dusterdude · « **Reply #13 on:** July 06, 2006, 06:24:31 AM »

Quote from: bill440cars on July 03, 2006, 12:51:44 PM

kayaker43 & Pinhead,

Don't know where either of you are but, Tim's Cycles in Berryville (Northern Central) Arkansas
has an 82' CB650SC motor that ran but had a noisy timing chain for $249.99 Buy It Now price. Only
thing is, he doesn't ship. If I had a bit more of a budget, I'd consider getting it myself and I'm in
western central Arkansas. Just a thought. Later on, Bill

arkansas,so thats what it is.

bryanj · « **Reply #14 on:** July 06, 2006, 07:10:40 AM »

Attached is a document i had from Ted Hates a while back. Steve might be worth putting in the FAQ's as it seems to pop up relatively regularly

bill440cars · « **Reply #15 on:** July 06, 2006, 07:26:22 AM »

Quote from: dusterdude on July 06, 2006, 06:24:31 AM

arkansas,so thats what it is.

Quote

Yeah duster, that's what it is and your point is...........?

I see that you're a
Virginia boy yourself. If I didn't live in Arkansas, I'd like to be in Virginia. That is, if you didn't
ban me from doing so.

Bout the only thing I don't like about living here is the fact that
all the good deals, on the old Hondas, are always somewhere else.

So, if you're trying
to mess with me about where I live, think about this. I have spent 28 years in the military
(6yrs Air Force w/4 active & 2 inactive and 22yrs Army Reserves) and I've been around all
kinds of people and endured all kinds of harassment & kidding about Arkansas and I'm still here
buddy.

And the thing about it is, if you're messing with me, you're leaving someone
else alone.

Ha!Ha!Ha! Gotta go for now. Keep the rubber on the road and I'm gone. Bill

bill440cars · « **Reply #16 on:** July 06, 2006, 08:03:29 AM »

Quote from: bryanj on July 06, 2006, 07:10:40 AM

Attached is a document i had from Ted Hates a while back. Steve might be worth putting in the FAQ's as it seems to pop up relatively regularly

bryanj,

I, for one, would like to thank you for that document. I've downloaded and saved it as a
possibility of something that I might want to do myself someday. I've already got 2- 550Ks, 1-
500K and 2- 500K motors. All I'd need are the 650 parts and the 750 liners along with pistons.
And the time, place and money to do the job. I can't believe I'm talking this, with all the
projects that I already have and the ones I want to do besides that. Now if I could just clone
myself and had a shop w/ a crew

(ZZZZZ (POP!) Boy What A Dream!!!!!

Back to reality.

Thanks again for the 550/650 info. Later on, Bill

Tommy Neimeyer · « **Reply #17 on:** July 07, 2006, 11:11:33 AM »

I appreciate all the replys, some good info.

Another quick question, in several threads I have read that a 550 cam cover will fit on a 650. While I do think it will bolt on, to me, it does not look like it will seal. Is there anybody who has actually run a 550 cover on a 650 head?

Thanks again and Cheers, Tom

bill440cars · « **Reply #18 on:** July 07, 2006, 11:16:32 AM »

I'd like to know the answer to that one myself (seems like I've seen something on that
somewhere) as it would be cool to hide 650cc (or more) inside a 550 shell.

Later on, Bill

kayaker43 · « **Reply #19 on:** July 07, 2006, 08:15:24 PM »

I did check out the 550/650 thread and printed the word document too. All of this is good, but it sure would be nice to compile all these revelations into one place. I do know now that interchange is possible if you pay close attantion to the details. I was really surprised that the 550 cam cover would seal to the 650 head. The sealing surfaces are much different but must overlap enough?

I would like a motor that is externally like a 550 for my cafe racer, but with 650 guts, big bore and cam. The 650 complete bottem end sounds much better with different primary ratio, better clutch and shifting etc. Plus you don't have to bore out the cases. I presume the 550 starter cover and sprocket cover will fit the 650, as well as the dyno cover and old charging system? The only thing left to give away its identity is the clutch cover difference which isn't too bad. I suppose a 550 clutch and cover can be made to fit and would benefit from the new primary drive ratio??

I keep finding cheap 650 motors on ebay, but no one will ship them. I have both 500 and 550 motors plus lots of rare yoshimura hop up parts, rods, cams, close ratio transmissions etc. When I do find a 650 motor I can build up a hybrid and document everything for posterity. I roadraced a 590 for 5 years and in its final form it would outrun GPZ550's and 500 interceptors easily, and run even with GPZ and interceptor 750's. I got out of it when the CB650 came out and wondered how much more potential it could have had?

bill440cars · « **Reply #20 on:** July 07, 2006, 08:57:03 PM »

kayaker,

when you do document your build, I (and others, I'm sure) would like to have access to
it for our own use. I'd like to have the look of the 500/550 and an evil 650 innards ready to
pounce on the unsuspecting ones, and I believe you know what I mean. Later on, Bill

scunny · « **Reply #21 on:** July 07, 2006, 10:33:19 PM »

count me in on the "I want to know" my next target is a 500, I have a spare 650 motor and might think about the wolf in sheeps clothing

cb650 · « **Reply #22 on:** July 08, 2006, 07:55:17 PM »

One big ID item on the 650 case is no fn kickstarter.

Terry

kayaker43 · « **Reply #23 on:** July 08, 2006, 08:40:04 PM »

Yeah, bummer about the kickstart, I was hoping to lose the e-start to save weight. The big question is whether the cases themselves are different or just the clutch cover. I'm surprised these things aren't well known yet?

There's two 650 engines being parted out on ebay, but I want a complete one to start with. I did buy a head real cheap though. Dennis Kirk has 650 valves on clearance for $1.99 each!

cb650 · « **Reply #24 on:** July 10, 2006, 05:03:10 AM »

Remember the heads/carbs break down into 2 groups. 79/80 and 81/82.

Terry

News:

Author Topic: CB550 - CB650 interchangability (Read 19056 times)