SOHC.co.uk Forums > CB350/400

I need to split the crankcase soon any advice on doing this?

<< < (4/4)

taysidedragon:

--- Quote from: Macabethiele (Ted) on March 06, 2021, 03:57:49 PM ---I have safely removed all of the pistons - when I came to mark them with a cylinder number on the inside of the skirt I found that they had been done before albeit in my view back to front.
To me number 1 cylider is on the nearside (left) of the bike with number 4 cylinder on the offside (right / clutch side). There is the possibility that they were put in back to front - that might explain the poor cold compressions.

--- End quote ---

I've dismantled 2 400f engines and they were both numbered back to front like yours. I wouldn't worry about it too much. As long as the same person took them out and put them back they should be in the right place.
When I cleaned up my pistons and measured them there was too much wear in the ring slots and they had to be replaced anyway. You may find the same.

McCabe-Thiele (Ted):

--- Quote from: taysidedragon on March 07, 2021, 11:29:55 AM ---
--- Quote from: Macabethiele (Ted) on March 06, 2021, 03:57:49 PM ---I have safely removed all of the pistons - when I came to mark them with a cylinder number on the inside of the skirt I found that they had been done before albeit in my view back to front.
To me number 1 cylider is on the nearside (left) of the bike with number 4 cylinder on the offside (right / clutch side). There is the possibility that they were put in back to front - that might explain the poor cold compressions.

--- End quote ---

I've dismantled 2 400f engines and they were both numbered back to front like yours. I wouldn't worry about it too much. As long as the same person took them out and put them back they should be in the right place.
When I cleaned up my pistons and measured them there was too much wear in the ring slots and they had to be replaced anyway. You may find the same.

--- End quote ---
I've now decided to have a rebore as it would be daft not to now that the engine is being fully dismantled -  the cold compressions were pretty poor plus there is a lip on the cylinder bores.
A case of do it once; do it right.

Bryanj:
Lip on the  bore? You may need 2nd o/s (0.5mm)  you dont often see lip on Hondas even over 100,000 mile ones

McCabe-Thiele (Ted):

--- Quote from: Bryanj on March 07, 2021, 08:01:10 PM ---Lip on the  bore? You may need 2nd o/s (0.5mm)  you dont often see lip on Hondas even over 100,000 mile ones

--- End quote ---

I'll leave that to Trigger when the block arrives tbh it was what I thought was normal at the top of the cylinder.
As I know the pistons have been out before there it might not be the original block who knows after 42 years?

McCabe-Thiele (Ted):

--- Quote from: Bryanj on March 07, 2021, 08:01:10 PM ---Lip on the  bore? You may need 2nd o/s (0.5mm)  you dont often see lip on Hondas even over 100,000 mile ones

--- End quote ---

Turns out the lip was carbon deposits - bores showed signs of previous partial seizure & freeing off probably from years of storage - having +0.25 rebore.

I have removed the  external gear shift mechanism so once I have prepped the various bolts ready for removal I will seperate the halves early next week - provided it stays warmish.

I'm going to make a small wooden support frame for holding the engine casing upside down to make seperation easier. (I am a hoarder of wooden offcuts.)

Navigation

[0] Message Index

[*] Previous page