CL / CB / CA Crankshafts - differences

Wilf · Post by **Wilf** » Sat May 29, 2010 8:26 am

Sorry about the mis-information, G-man. And thanks for setting me straight, LM

Wilf

LOUD MOUSE · Post by **LOUD MOUSE** » Sat May 29, 2010 8:43 am

Ya thought ya was right. .......................lm

Wilf wrote:Sorry about the mis-information, G-man. And thanks for setting me straight, LM

Wilf

teazer · Post by **teazer** » Sat May 29, 2010 9:04 am

LOUD MOUSE wrote:Do ya know how to tell the 250 cranks from the 305 cranks?. ............lm

Not sure that I do. Most of the bikes I modified in Australia were 250s and all of the motors/bikes I have in the US are 305s - too far apart to compare :-(

Wilf · Post by **Wilf** » Sat May 29, 2010 9:06 am

It's not the first time, and for sure it won't be the last!

Wilf

LOUD MOUSE · Post by **LOUD MOUSE** » Sat May 29, 2010 9:32 am

I use my middle finger.
I put it in the outside balance hole.
If it fits the hole with a little loose it's a 305.
If it's tight it's a 250.
Of course ya would need at least one of each to compare but if ya only have the 305 then the hole will be loose. ................lm

teazer wrote:
LOUD MOUSE wrote:Do ya know how to tell the 250 cranks from the 305 cranks?. ............lm

Not sure that I do. Most of the bikes I modified in Australia were 250s and all of the motors/bikes I have in the US are 305s - too far apart to compare :-(

G-Man · Post by **G-Man** » Sat May 29, 2010 9:52 am

LM

Thanks for nudging us along here. I realise now that it's not just the small hole in the tapered shaft but a drilling through from the inner end (crank web) that lets the oil through. The con rod on my CB77 crank is rusted solid and covering that hole. I understand how the oil gets in now - apologies for not seeing that earlier. I was struggling to understand how the oil got inside the shaft to come out.

I have attached a pic or two of the three cranks I have to hand. Not only are the hole sizes different (and smaller mains on the 360 crank - early(?) )but the flats on the crank webs are different too, and not particularly consistent with the hole size.

With a quick measurement I have

CB77 Hole 20.67 mm Flat 63.5 mm
C(A)72 Hole 19.17 Flat 68.0mm
CL77 Hole 23.3 Flat 62.4

Looks like I have to do quite a bit of work to convert CL77 to CB77......

G

onchiman · Post by **onchiman** » Sat May 29, 2010 7:47 pm

LOUD MOUSE wrote:I use my middle finger.
I put it in the outside balance hole.
If it fits the hole with a little loose it's a 305.
If it's tight it's a 250.
Of course ya would need at least one of each to compare but if ya only have the 305 then the hole will be loose. ................lm

Well,..this is one post that you don't want to just pop into the middle of without reading the prior stuff first....if you know what I mean.