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Project Brutus - 1966 CB600 K0 Black Bomber

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#43 ·
Hi Ronny this is looking good and I can't understand why I have not seen this recently. Although I have not had as much time online recently. I am really looking forward to the rest of this build thread :)
 
Discussion starter · #44 ·
Finally, after over a weeks chase of another UPS parcel I got my toys from David Silver today. Among them this (CB125/CB160) head light bucket I will use to get the Bomber look. Thought the K1/K2 chrome rim and reflector I have laying around would fit but no, it's too big for the CB125 bucket so now I have to start hunting for those parts. :roll: :grin:
 
#46 ·
Ronnie, looking good. Any thoughts on the piston selection? Will you use a CB500 crank?
 
Discussion starter · #48 ·
Thanks! Jim, I'm actually going to use a CB500T engine but I have not yet decided which route to go regarding the pistons. Either I'll go with hi comp forged racing pistons or a low comp alternative.
 
#49 ·
I haven't verified this yet, so it only a theory... Honda moved the wrist pin hole higher on the 500T pistons from the 450 DOHC pistons. The distance would be 1/2 the difference in the stroke. Cb450 stroke = 57.8; CB500 stroke = 64.8. 1/2 the difference is 3.5mm. This is assuming the same deck height. This way they could use the same rods. Back in the day, General Motors would do this. I know Pontiac V8 engines from 326 to 455 ci all had interchangeable rods. The bore and stroke varied. The pistons would not interchange even with the same bore.

You got me going on this. There might be a big engine in my future. Have you though about cooling? There were some big Triumph Twins back in the day. I have heard they would run hot.
 
#50 ·
JamesPal said:
I haven't verified this yet, so it only a theory... Honda moved the wrist pin hole higher on the 500T pistons from the 450 DOHC pistons. The distance would be 1/2 the difference in the stroke. Cb450 stroke = 57.8; CB500 stroke = 64.8. 1/2 the difference is 3.5mm. This is assuming the same deck height. This way they could use the same rods. Back in the day, General Motors would do this. I know Pontiac V8 engines from 326 to 455 ci all had interchangeable rods. The bore and stroke varied. The pistons would not interchange even with the same bore.

You got me going on this. There might be a big engine in my future. Have you though about cooling? There were some big Triumph Twins back in the day. I have heard they would run hot.
Click to expand...
What sort of cooling are you looking for JamesPal?

If you are talking oil - have a look at what Cappellini make for just this problem.
 
#51 · (Edited)
JamesPal said:
I haven't verified this yet, so it only a theory... Honda moved the wrist pin hole higher on the 500T pistons from the 450 DOHC pistons. The distance would be 1/2 the difference in the stroke. Cb450 stroke = 57.8; CB500 stroke = 64.8. 1/2 the difference is 3.5mm. This is assuming the same deck height. This way they could use the same rods. Back in the day, General Motors would do this. I know Pontiac V8 engines from 326 to 455 ci all had interchangeable rods. The bore and stroke varied. The pistons would not interchange even with the same bore.

You got me going on this. There might be a big engine in my future. Have you though about cooling? There were some big Triumph Twins back in the day. I have heard they would run hot.
Click to expand...
How would wrist pin position affect the displacement? The stroke's determined by the offset between the center of the crank and the crank pin. wrist pin position on the pistons and con rod length will affect power due to leverage but if you're after more displacement the con rod length or wrist pin position won't affect this. It will affect the compression ratio and leverage of the piston on the crank
 
#52 ·
On a 500T piston the wrist pin or Gudgeon pin as we know it is 17mm OD the height to the deck from the top of the pin is 18mm so the centre of the pin to the deck is 26.5mm. I hope that this is helpful information.
 
#53 ·
Simo said:
How would wrist pin position affect the displacement? The stroke's determined by the offset between the center of the crank and the crank pin. wrist pin position on the pistons and con rod length will affect power due to leverage but if you're after more displacement the con rod length or wrist pin position won't affect this. It will affect the compression ratio and leverage of the piston on the crank
Click to expand...
This is about the deck height, not the displacement. Deck height from the top of the piston (in the case of a CB450 the top of the squish band) and the top of the cylinder block. I've never measured it, but on the 450 the piston looks about 1-1.5 mm lower than the top of the cylinder block.

Starting from the center line of the of the crank shaft (at the main bearings) 1/2 the stroke plus the length of the rods plus the distance between the center line of the wrist pin to the top of the piston gets you to how high the cylinder block needs to be. Of course this is a mute point since Ronny is using a CB500T engine. But it is something to consider if he would want to use a 450 head and pistons
 
#54 ·
nigelrharris03 said:
On a 500T piston the wrist pin or Gudgeon pin as we know it is 17mm OD the height to the deck from the top of the pin is 18mm so the centre of the pin to the deck is 26.5mm. I hope that this is helpful information.
Click to expand...
Nige, what is he dimension on a CB500T? BTW- thanks for the translation to the Q's E!
 
#56 ·
JamesPal said:
This is about the deck height, not the displacement. Deck height from the top of the piston (in the case of a CB450 the top of the squish band) and the top of the cylinder block. I've never measured it, but on the 450 the piston looks about 1-1.5 mm lower than the top of the cylinder block.

Starting from the center line of the of the crank shaft (at the main bearings) 1/2 the stroke plus the length of the rods plus the distance between the center line of the wrist pin to the top of the piston gets you to how high the cylinder block needs to be. Of course this is a mute point since Ronny is using a CB500T engine. But it is something to consider if he would want to use a 450 head and pistons
Click to expand...
Sorry I misconstrue the context of your statement since you made no mention of compression,ratio,squish or swirl ( or the British equivalent) :D
 
Discussion starter · #59 · (Edited)
JamesPal said:
I haven't verified this yet, so it only a theory... Honda moved the wrist pin hole higher on the 500T pistons from the 450 DOHC pistons. The distance would be 1/2 the difference in the stroke. Cb450 stroke = 57.8; CB500 stroke = 64.8. 1/2 the difference is 3.5mm. This is assuming the same deck height. This way they could use the same rods. Back in the day, General Motors would do this. I know Pontiac V8 engines from 326 to 455 ci all had interchangeable rods. The bore and stroke varied. The pistons would not interchange even with the same bore.

You got me going on this. There might be a big engine in my future. Have you though about cooling? There were some big Triumph Twins back in the day. I have heard they would run hot.
Click to expand...
If it should run a bit hot I have an oil exit on my Cappellini paper oil filter conversion kit so I could install an oil cooler.



EDIT:
The difference in deck height (from top of wrist pin to the piston crown) on a 450 and 500T piston is about 2 mm.
 
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