Topic: Cam identification , help needed. Cb 500/550

[Folsoe]

Hello guys.  I just Got another cb 500 into the garage
It seems it has been tuned a bit, when i compare to another engine i have in the garage :

The bore is 59.5 mm, which Should be more than 550cc? ( its a 500 i bought)
The intake port in cylinderhead is 26.5 mm, and have signs of grinding in the ports  ( the other i have is  25 mm)

So now i am wondering about the cam shaft.. 
On the photo you Will see it is marked A and then R 9.  With a lobe height on 33.5 mm there is a Y on the opposite side of the cam.

The other cam in the bottom of photo is marked C and then R 10. With a lobe height on 34.5 mm.  There is a K on the opposite side of the cam. 

Furthermore.  The other ends of the Cams do not look quite the same ..

Which is Right ? What is what ?  ??

[classic bike tuner]

these R numbers mean nothing at al   casting number or watever   

gerrit

[flatlander]

to get an idea you could measure lift and duration, and compare with stock and other, known cams.
numbers for some cams used in 550s are in this thread: http://forums.sohc4.net/index.php/topic,134461.msg1511798.html#msg1511798

[Bill/BentON Racing]

The Y cam marked A is a Yoshimura A grind, the milder of the two they offered, B was the Isle of Man TT cam.

[Folsoe]

Thanks guys

I feel lucky with this buy 
Ported head/ Big bore and yoshimura cam   and in great shape as Well

But it seems the lobe height is higher on the other cam than on the yoshimura cam ..
So Maybe also a kind of tuning cam..

How Can i measure the cams ? Only know how to find the lobe height..
And how many cc are a bore of 59.5 mm ?
Do i need to make ignition timing different on this Engine ? Or valve clearance ?

[CBGhia]

Sounds like Yosh 562 kit for the CB500   

Here is a link to piston rings on ebay
http://www.ebay.com/itm/Yoshimura-59-5mm-Piston-Rings-to-suit-Honda-NEW-/110641467774

[turboguzzi]

lobe height will give you an initial measure if you are stock or not

should have a stock cam somewehre in the garage, will measure and let you know.

Bill, the one yoshi cam that passed through my hands had the Y stamped rather than forged into the core like in that pic....

that said, we will all happily help you, but if you can figure out engine cc based on the bore, maybe you should get some basic reading on mechanics....

the 550 was 58.5mm stock bore, so could easily be a +1mm overhaul piston set & block bolted on 500 cases, it's that easy to do .
if the piston is pretty flat then very likely that's the case. if it has some crown, then maybe it's some sort of hipo kit.

[turboguzzi]

just checked: inlet lobes 35mm exhaust lobes 34.6mm

[Folsoe]

Thanks.   Total camfusion:)

[bambuhiphop]

The Y cam marked A is a Yoshimura A grind, the milder of the two they offered, B was the Isle of Man TT cam.

The A grind is milder than the B?

[bwaller]

Definitely is, yes.

[bambuhiphop]

Definitely is, yes.

Huh, cool. I thought it was the other way around. Learned something new! Curious though, how "wild" is the B considered?

[turboguzzi]

Thanks.   Total camfusion:)

first of all, IN and EX lobes are different, so you need to measure both. but according to the numbers you already have, doesnt sound like a performance cam.
34.5 could be like the EX lobe i measured , but 33.5 sounds like you simply didnt measure at full height.

[scottly]

It may be a re-ground cam. Measure the total lobe height, then subtract the base circle, measured perpendicular to the lobe height, to determine lobe lift. 

[bwaller]

Huh, cool. I thought it was the other way around. Learned something new! Curious though, how "wild" is the B considered?

The race cam TT Special. It's fairly close to the Megacycle 126-20 which I use in my race engine.

Intake opens 27d BTDC, closes 57d ABDC. Intake lift 9.0mm

Exhaust opens 56d BBDC, closes 27d ATDC. Exhaust lift 8.55mm

The Street Special

intake opens 20d BTDC, closes 50d ABDC. Lift 8.25mm

exhaust opens 50d BBDC, closes 20d ATDC. lift 7.80mm

[bambuhiphop]

Huh, cool. I thought it was the other way around. Learned something new! Curious though, how "wild" is the B considered?

The race cam TT Special. It's fairly close to the Megacycle 126-20 which I use in my race engine.

Intake opens 27d BTDC, closes 57d ABDC. Intake lift 9.0mm

Exhaust opens 56d BBDC, closes 27d ATDC. Exhaust lift 8.55mm

The Street Special

intake opens 20d BTDC, closes 50d ABDC. Lift 8.25mm

exhaust opens 50d BBDC, closes 20d ATDC. lift 7.80mm

Coolio, thanks much! I have a TT (B grind) sitting in the garage waiting to go in an engine. I look forward to seeing what it is like! Apologies for hijacking the thread.