Cosworth CB550

[Trigger]

Has anyone owned or seen one of these before ? >>> http://www.ebay.co.uk/itm/honda-cb550-four-/262743180362?hash=item3d2cb6c44a:g:-aYAAOSw5cNYP-lV

[JamesH]

Was going to ask you Graham. Interesting bike - possibly a Cosworth prototype head / proof of concept??

[Johnwebley]

Why would Cosworth take the time to produce pistons that small. They are a car engine specialist and their pistons are far larger. Casting on head has been soldered/welded on, you can see the crack where it doesn't meet the fin properly. The ONLY way you'd know if the engine has been modified is to open it up after buying it and by then it's too late, why no mention of a cam to allow these pistons to work properly???

 I tend to agree with Oddjob,the basic head casting has all the same casting marks of  a standard Honda,the name plate  looks "not quite right"

 try contacting Cosworth to see if they have any record,


http://www.cosworth.com/

[Trigger]

Cosworth did do piston, cams, rods and other mods for the Yamaha YZ250, but never heard anything about a CB550. 

[K2-K6]

I've never seen or heard of anything like that, doesn't mean it's not true though. I've seen a lot of stuff from that era in things from endurance racing where there was all sorts of weird and wonderful things going on but never seen any connection to cosworth.

They've done alot of consultancy work for different companies over the years some of which will never be seen. They worked on things like MAE engine in mid sixties which was ford anglia based block but at 81mm bore it's way past having any piston commonality with the honda engine. It revved to 10,000 though and made up to 140bhp from 997cc though so pretty advanced in power terms.

Their obvious specialist area though is twin cam sixteen valve heads which if it was like that then it would be very interesting. It doesn't appear from the outside to be anything different though, so as already said you'd have to strip it to see what's in there.

I didn't understand Trigger the yz250 reference as I though yz was used on motocross range by yam. I had a yz250h, last of the aircooled engines.

It'd be intriguing to get to the bottom of it though.

[Trigger]

I've never seen or heard of anything like that, doesn't mean it's not true though. I've seen a lot of stuff from that era in things from endurance racing where there was all sorts of weird and wonderful things going on but never seen any connection to cosworth.

They've done alot of consultancy work for different companies over the years some of which will never be seen. They worked on things like MAE engine in mid sixties which was ford anglia based block but at 81mm bore it's way past having any piston commonality with the honda engine. It revved to 10,000 though and made up to 140bhp from 997cc though so pretty advanced in power terms.

Their obvious specialist area though is twin cam sixteen valve heads which if it was like that then it would be very interesting. It doesn't appear from the outside to be anything different though, so as already said you'd have to strip it to see what's in there.

I didn't understand Trigger the yz250 reference as I though yz was used on motocross range by yam. I had a yz250h, last of the aircooled engines.

It'd be intriguing to get to the bottom of it though.

I was born and worked in motorsport valley, started of at Wealdstone engineering, moved to Cosworth, then on to Arrows. Yes, you see a lot of R&D in that area. Years ago, just nip in for a pint in any Newport pagnell pub and you would find a Aston martin engineer, and learn a lot of secrets over a pint.
The YZ250 was for Cosworth Yamaha Dixon racing

[K2-K6]

Ah, I've got it, I was going back to the two stroke era (which is what i raced) as mine was the last before they went water cooled.

A friend had YZ400 four stroke which I rode, bigger brother of the one you're talking about. Dixon racing confused me as well with the original Yoshimura dealer that used to be in Dorking.

My background is engineering too from toolmaking at RAE Farnborough,  quite a few from there went into places like mclaren, Williams etc.

[MeilakJ]

Today I saw this post on Face book regarding aftermarket aluminium wheels made for the Honda CB500 550 and 750 !

It is something I never seen and there is also a brocher of them

I guess there might have been companies which at that time might have tought as an investment in aftermarket parts.

[K2-K6]

I always thought those wheels looked really good, don't know if I saw them over here but often in American bike mags.

The Cosworth casting,  I'd guess Honda wouldn't have a need to use their services being completely capable themselves of carrying out the same work internally.

But if you look for someone who may have commissioned some preliminary research in relation to that engine, then perhaps De-tomaso who owned and built the Benelli 500/4 (which I understand is a straight rip off of the Honda) if they were getting research done in the prototype stage of that bike.

Someone else who worked with that engine and also commissioned bespoke manufactured things possibly in that area could be Bimota.

You'd have thought if it was a Cosworth owned project, then it would have been a twin cam to fully demonstrate their skills, certainly in that era of their mainstream products.

As we've said,  you'd need a much more detailed look at it to decide if that legend is cast properly into the head at the foundry. If true Trigger may me able to add some provenance to it given his own background.

[neilg]

Looks like a poor job at tacking on those labels. I hope any engine work was to a better standard. The only UK supplied pistons that I can recall for the 550 were from Hepolite and I think these were manufactured abroad and only marketed and distributed by Hepolite. 

[royhall]

Why would anybody try to get the best price for a bike with pictures like that. At least drag it out into the sunlight and give it a wash. He said have a look at the Cosworth website which I did, unless I missed it I cant find reference to a 550 Honda. Dodgy geazer.

[mike the bike]

That's what I thought.   Most people that sell bikes at least chuck a bucket of water over it, wheel it out of the shed to take the photos and rotate the photos if they're upside down.   If he doesn't take care of his ebay listing,  what does that say about how he's looked after the bike?

[Chris400F]

I also tried the Cosworth web site, with the same result.
Also searched via Google, no results there either.
Looking at the seller feedback he has one negative, from some time in the last 12 months, when he 'sold' a Honda 550 (I'm suspecting the same bike, he says it was advertised before) but cancelled the sale when the final bid was 'only' £1020. The winning bidder was not impressed .... Roy's summation of the seller sounds about right.

[K2-K6]

I don't know Trigger's original reasons for putting it up but it has the potential to be interesting.

I can see the conventional judgment regarding the seller and also that it may be completely false in identity, but, if it did turn out to be genuine, wouldn't anyone find it quite interesting?

There's plenty of stories of someone spotting what they recognise to be a prototype part that turns out to be historically significant if you are interested in that type of machine. I couldn't find anything about it in searches either so don't know what the seller is referencing in his statement. As far as I can see that element of Cosworth would seem to be owned now by Mahle, so connection to the era of that part if it existed at all would be unlikely to be available.

Just because the casting looks a bit rough doesn't really confirm anything, plenty of prototype work is never made presentable as it is just proof of design that may or may not survive any testing.

Is it worth anything? Search me.

[royhall]

Point well put k2-k6, it would be a top find if it was genuine. My problem is why the seller referred to a website that doesn't appear to exist. If it did exist surely he would refer to it fully as it would enhance the bikes value no end. I am going to email him when I get home tonight and ask for a web address. Will report back when and if I get an answer, but I won't hold my breath.