Topic: Just picked up a cb550 confused on the model

[dave500]

its not a #$%*en hydraulic clutch lucky?its the normal corkscrew #$%* thing that honda used for years.

the e clip c clip isnt correct,it looks like this if its correct with the offset spline plate lucky,lucky it didnt fly off?thats the only lucky thing here?they wobble on the shaft aswell,they are supposed to.

[Deltarider]

Homegrown Frankenbike. Nothing European about it (you will not find any 022A carbs overhere) and sofar I've seen nothing typical K3like. Strange as it is, somebody combined a 550 barrel and head with a 500 clutch.

[dave500]

the whole bottom end delta!

[Tews19]

I was going to mention the bottom is 550 as well but Dave mentioned it... Possible Gentleman's express??

[bryanj]

Don't care what the numbers say that is a 500 motor, the 500 clutch cover WILL NOT FIT on 550 cases and you cannot put the 500 clutch operating pushrod in the 550 as there is an oil pump in the gearbox.

A better pic of the engine number, cleaned off well might help

[TwoTired]

Don't care what the numbers say that is a 500 motor, the 500 clutch cover WILL NOT FIT on 550 cases and you cannot put the 500 clutch operating pushrod in the 550 as there is an oil pump in the gearbox.

I'm not arguing, but what if one simply removed the trans oil pump?  ...And put the 500's pieces for the clutch rod in there?

[bryanj]

TT the clutch cover still wouldn't fit mate the crankcase is a completely different shape---compare the gaskets if you have them to hand

[lucky]

Thanks TT here is a few more pics I took the sprocket cover off.

The sprocket side of the one we are talking about has the shifter rod that the 500 had. Could this be a European model..

Doubtful it is a European Model.  The Honda shop manual would have SOMETHING about such a configuration, I reason.  Clean off some of the gunk where the clutch shaft enters the case on sprocket side.  550's had a seal there.  Is what you have there look like it was drilled under all that crud?
This bike also has the CB500 clutch and clutch cover, I'd bet.

I simply don't believe this is a factory built Honda configuration.  Perhaps a Honda shop alteration.  But, I don't see why, or any benefit to it.

The front sprocket looks to be an aftermarket part.  Count the teeth on it.  Stock ones are 17T.  Unless I counted wrong, yours is 16T, a common drag race type mod.  Count the teeth on the rear sprocket, too.

Honda Dealers do not do alterations or fabrication.

[Bankerdanny]

I'm with two-tired here. It's a frankenbike ... it's a bitsa.

Was there a clutch actuation pin sticking out through the left side of the case behind the left side cover you removed?  Maybe I missed it but I couldn't see exactly how your clutch actuates in the pix posted.

My question would be, given the relative crappiness of the cb500 clutch system (the reason why they dumped/replaced that in 74), why would anyone attach that to a cb550 bottom end?

Pix below.  The innards of a complete (and completely disgusting) cb500 left side cover showing the rube-goldberg-esque clutch system

You want to see Rube Goldberg check out the clutch and gearbox lever setup from a pre-unit Indian made Royal Enfield Bullet.

It uses a similar, but mirror image clutch setup with the cable and actuator arm on the right and a rod through the case to the basket on the left. Then there was an elaborate and fiddly arm and shaft setup to convert the natural right foot #$%* gearbox to left foot shift.

[dave500]

#$%*?that extra 550 oil pump is on the friggin output(counter) shaft,the clutch rod will go through the 550 main shaft!the 500 clutch cover does fit the 550 with a slight mismatch,those cases dont have the 500s shift drum locating bolt on the top!

get that clutch cover and basket off and give us a clear photo of whats behind it,heres a 500 one,with the shift drum locating bolt.

heres a 550 one,different drum detent star aswell as the linkages,the case opening gives a slight mismatch with the 500 cover.

[Bankerdanny]

Apparently I had a typo when I typed the word shift. Freudian slip I suspect. The Bullet gearbox is pretty aweful.

[Mcwilliams570]

Looks like a 550 motor to me...







Matt

[TwoTired]

I didn't know it was possible.  But, it looks like there may be a Cb500 lower case mated to a Cb550 upper.

Someone sure worked hard to get those parts together.

Is that gasket sealant oozing from the shifter rod seal?  Hard to imagine Honda would do that.

I wonder what else can be found inside the motor that is "special".  39 years with no historical record.

[Scott S]

 But didn't he say the engine # on the lower case was a 550 #?

 Maybe Honda was like VW and used up existing parts when there was a model year change over. You often find old VW's with a mix and match of parts right from the factory, using up inventory.

[bryanj]

Honda were very good about changes always being from a specific number and not "using up" parts.

That does look like a 550 top half and a 500 bottom half and with thet sort of bodgery going on i really hate to think what else has been done internaly---personaly i wouldn't trust it for 5 yards or 5 seconds whichever came first

[dave500]

itll be ok once sorted,not sure how precise the main bearing clearances would be with mismatched cases though?definately 500 lower and 550 top cases,to use the 500 basket the 500 primary gear has to be used,be interesting to check its bore size,might have some suped up custom #$%* going on in there?show us the head ports with the valves removed and the camshaft.

[RAFster122s]

Wow, what a Rube Goldberg PO you had. At least you might have some decent parts for a 550 engine build up once you find a set of cases. Tom Witt has been parting a bunch of 650s, maybe a 650 lump that needs rebuilt could serve as a 650 hybrid build a la Paulages style. Upping the bore to 750 overbore pistons with long throw crank of 650 and hemi head of 650 you could have a nice motor. He has sold the 650 cams so, that would need sourced.

Those cases/covers have some serious oxidation/corrosion going on.

Maybe this one rolls into a corner for later...

If the carbs are serviceable and a few other things are as well and you have a straight frame with title, then you didn't get burned on the bike as a parts bike. The Konis will be expensive to have rebuilt but, they will be primo shocks for less than a new set.

David

[Tews19]

If the bottom is a 500, how come the vin states 550E?

[TwoTired]

If the bottom is a 500, how come the vin states 550E?

The engine/trans case consists of two halves.  An upper half that sports an engine ID (VIN)  and a lower half that does not.  The lower case halves are normally treated as a mated pair.  The casting features of the "confused" engine say otherwise for this example. 

The "top end" of the engine consists of the piston cylinder assy., which sits atop the engine/trans case half components.

The VIN number for this engine is of limited use, particularly for parts replacement needs.

[dave500]

so far weve found its a 500 lower case half with the 500 clutch assembly and cover,with all 550 above it tews,the engine number will pertain to the top half of the engine.

[Mcwilliams570]

Ok got the bike stripped down and the engine out. Will post some pictures but the pistons and everything look stock. The camshaft is marked R12 CX not sure if that means anything. I havent taken the valves off yet ran out of time everything looks stock to me.

TwoTired and Dave500 I have a  question for you guys. I have only worked on 550 never a 500 I have a 72 500 parts bike but never have had to go in the engine.

-How can you tell that is a 500 bottom case? The only difference that I see is the two metal rods going through they both just pull right out not sure if thats right.

 I am not sure with the serial numbers but is this a later build or a earlier one. I was talking to Tews about it and it got me thinking about how I see the cb750 guys talking about how close their engine and frame numbers are but most of them are off by a bit. From what I read due to quality issues or customer blowing up a engine they would pull them off the line hence why they arent the same. I am probally wrong but with the serial numbers on this bike it was around the 9000 mark when it was made. I find it odd that the frame and engine numbers would only be off by 4 having them made that many.

I would like to think the guy who did this had some sort of a plan however misguided. I just cant for the life of me figure out why he wanted to top half of 550 on there. I can see something happened to the 550 engine he had a 500 engine decided to put the top half of the 550 on it but why that top case that is alot of extra work for what. Maybe the state he was in the title used the engine serial numbers why he wanted it back on. Just a thought its that top 550 case that keeps throwing me off..

Thanks for all the comments

Matt

[TwoTired]

Perhaps a clue.
I recall reading that CB550 barrels don't always fit into the Cb500 upper case without some machining done.  If one was just assembling parts without machining...

-How can you tell that is a 500 bottom case? The only difference that I see is the two metal rods going through they both just pull right out not sure if thats right.

Look at the gasket surface casting shape below the kick start mechanism in the posted pictures.  Different shape between the 500 and 550.  Yours has a 500 lower half.

[lucky]

I was wrong about the hydraulic clutch.
You are right Dave 500.

I went back and looked more closely at the photos.
You know these models much better than I do that is for sure.

You sure jumped on me hard for that one.
But at least this IS an interesting case!

[dave500]

no worries lucky,those two metal rods are one broken rod matt!,its common for the 500 to break this rod,as two tired pointed out we can tell its a 500 lower case if you look close at the two pictures i posted,looking at the case gasket surface just below and forward of the kickstart shaft,between two of the cover bolt holes is a little dip on the 550 where on the 500 its straight in the same area,this would cause a leak putting a 500 clutch cover on a 550 lowercasing,unless it was filled with jb weld or something?your doing a good job i want it!