Topic: Main bearing measuers sanity check

[RAZZ]

Hi

Im in the beginning of reassemblying my 900 ccm engine with a replaced ligthend APE crank

Cases are all B’s and I was told crank is all A’s

I have plastigauged all the mains with all new green bearings and came in with below plastigauge measuers - please see photos..

Im getting a little confused in the calculations between inches and mm..so Can someone with  experianceb and a fresh mind Help me recommend the correct bearing Colors to get the Oil clearance at 0,030 mm from here ? My Best guees at the moment is all Brown bearings Will do it -maybe the one at aprox 0,05 mm Will need a black ?



Thanks in advance


Razz

[PeWe]

My K6 has also an all B case.
Used green (measured crank journals)

I tightened the cases with crank in once before adding the strips to fully seat the shells, 25Nm if remember correctly.
Open up, add strips, close cases and tighten again.

I got around 0.050mm / 0.0020".
Max clearance according to the Honda manual is 0.046mm /0.0018".
The service limit is 0.08mm.

I got recommendation to use that slightly loose clearance, better oilflow, cooling in a modified engine.

http://forums.sohc4.net/index.php/topic,155014.msg1780022.html#msg1780022

Use 20W-50 oil as recommended for CB750
10W-40 cold days below 15C.
I use 20W-50 all the time. A few rides spring and fall below 15C.

A little bit longer time riding slow until fully warmed-up.

[Don R]

 I think I'd consider trying a brown one on the loose bearing and keep the rest.  My chevy race engine builder used to go up or down a thousandth on just one side. People didn't believe it but we never hurt a bearing even when the block cracked. I'm not saying it applies here but you never know.
 From yellow to black isn't very many thousandths I'd be curious to know what the spread is. 

[RAZZ]

Hi
thank you for your replies

I think I will try to put the cases together one more time whitout any plastigauge to sit in the bearings in the cases - and then make one more measurement with the all green bearings i already have, if I'm around 0,04 /0,05 ish mm I will keep them and probably change the one just over 0,05 mm to a smaller Brown or black to see the difference

Razz