SOHC.co.uk Forums > CB500/550
Crank bearings good or bad
Acro1985:
Thanks Ted
I have sent you a reply
taysidedragon:
--- Quote from: McCabe-Thiele (Ted) on August 14, 2024, 09:43:28 AM ---I've sent you a PM I only have a pair of used Green Mains for a 500 for you to try for size using Plastigauge, sorry no used Browns or used big end shells with markings.
--- End quote ---
Used shells won't give accurate clearance information because of the wear on them. New shells should be used to get accurate information.
McCabe-Thiele (Ted):
--- Quote from: taysidedragon on August 14, 2024, 12:49:21 PM ---
--- Quote from: McCabe-Thiele (Ted) on August 14, 2024, 09:43:28 AM ---I've sent you a PM I only have a pair of used Green Mains for a 500 for you to try for size using Plastigauge, sorry no used Browns or used big end shells with markings.
--- End quote ---
Used shells won't give accurate clearance information because of the wear on them. New shells should be used to get accurate information.
--- End quote ---
Agreed but if a set of half decent used Green shells give you a clearance of say 55 microns you can be pretty confident that a set of Browns will be good. Likewise if your clearance with used Greens is 38 microns then Greens are good!
I've lent a sohc member here some used 400 shells previously - it worked for him as a starting point.
Paying out for a new set of Greens to find you need Browns is an expensive exercise if you have no legible shell colour markings. I would not have offered my shells if they were badly worn. One set out of three Greens I kept for such future use for myself or to help a member here.
If a member here has a spare set on new unused shells to sell at a reduced price or to lend out then clearly that would be better still.
Murf:
The numbers or letters are can be really indistinct, just scratched on, I think it was just a production line thing and not for the rebuilder 40 years later. In general one colour will dominate but you can’t rely on that. Look on the side of the shells for any trace of colour. Get a magnifying glass and a torch and check the parts at various angles to see if you can find the marks or numbers. On the CBX they used a mixture of letter, numbers and Roman numerals!!! If all that fails Getting a new pair of shells as a test set is a great idea.
But have checked the original bearings yet because if they are ok then you don’t need to worry about all this. I know it’s nice to change everything and have a virtual new engine, but I also think you have to take into consideration of how the bike will be used in the future. If you are going to thrash it or go long distance touring then change the bearings. If you are going to give it a nice quiet life with regular oil changes etc then maybe it’s ok on the old bearings.
Acro1985:
After cleaning the crank with petrol and WD40 and then trying various different lighting in the garage and the garden (My wife thinks I have finally lost the plot). I can defiantly make out four number 1s on the crank, and from my crude measurement of the journals 33mm this seems to correspond with workshop manual for the crank being a number 1. I haven't been able to find any paint on the shells yet, thought maybe I found some brown paint but think this is just burnt on oil as it mostly rubbed with a bit of petrol/degreaser and a paper towel.
just waiting for the plastigauge to be delivered so I can check the clearance between the crank and shells.
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