Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: sgd37 on December 30, 2016, 05:31:59 PM

Title: Pitted journal and bearing
Post by: sgd37 on December 30, 2016, 05:31:59 PM: Merry holidays to all :)

I've been slowly getting ready to reassemble my engine, but the more you look the more you see. So I noticed this pit (possibly due to corrosion) on the #4 rod journal which snags on my nail.
http://imgur.com/VzE6OWN
Is the crank still usable since I know you can't grind them on a cb500? Should I polish it?

Second there is a pit on the big end bearing of #3 rod which doesn't snag but can be felt with a finger.
http://imgur.com/f7LaYoo
Does it need replacing? and if so do both half shells need to be replaced?

Thanks for your help
Title: Re: Pitted journal and bearing
Post by: Bryanj on December 30, 2016, 05:35:50 PM: For peace of mind I would fit a replacement crank with shells, for a low use bike not used hard they may well both work for quite a while
Title: Re: Pitted journal and bearing
Post by: Trigger on December 30, 2016, 05:39:52 PM: I would get the journal metal sprayed, then ground to STD and fit new shells.
Title: Re: Pitted journal and bearing
Post by: MCTID on December 30, 2016, 07:38:57 PM: Trigger.....any recommendations for a Company who can Metal Spray and Regrind Cranks (I have some Triumph Twin cranks I want to reclaim).
Cheers.
Title: Re: Pitted journal and bearing
Post by: sgd37 on December 30, 2016, 08:01:13 PM: Thanks for the reply.

From my own research people have run knicked cranks after polishing. Would this not be a similar situation. Could this lead to engine failure?

Cheers
Title: Re: Pitted journal and bearing
Post by: Trigger on December 30, 2016, 11:16:12 PM: Quote from: MCTID on December 30, 2016, 07:38:57 PM
Trigger.....any recommendations for a Company who can Metal Spray and Regrind Cranks (I have some Triumph Twin cranks I want to reclaim).
Cheers.

I would use T&L at Bedford. If you phone, wait for Derick's extension number to come up. He is the Brit engineer at T&L ;)
Title: Re: Pitted journal and bearing
Post by: kevski on December 31, 2016, 11:39:16 AM: They look like corrosion marks, if the snag on the rod journal is not a raised one just give it a light polish to take off any sharp edges, and the bearings i would replace, though you could run with that for years oil will fill these while running, it won't lead to engine failure as the damage is very slight and i assume you will not be running flat out for prolonged periods anyway.
Title: Re: Pitted journal and bearing
Post by: sgd37 on January 04, 2017, 05:10:19 PM: Cheers for the reply and happy new year.

When it comes to polishing could I use the strip of 600 grit and shoelace technique?
Title: Re: Pitted journal and bearing
Post by: matthewmosse on January 04, 2017, 06:56:20 PM: If it does prove rough, I think I have a few spare cranks that could be dug out and checked. Are 500 and 550 cranks the same?
Title: Re: Pitted journal and bearing
Post by: Bryanj on January 05, 2017, 07:39:44 AM: Yes matt all the cranks are the same (except 650 before somebody shouts) As to the polishing crocus paper with oil
Title: Re: Pitted journal and bearing
Post by: kevski on January 05, 2017, 09:31:51 AM: At least 1200 grade, i have a 1200 grade mesh that i use for things like that, i got it when i was a plating tech.
Title: Re: Pitted journal and bearing
Post by: Bryanj on January 06, 2017, 12:17:17 PM: 1200 is too rough, i got some 3000 somewhere, otherwise known as bog paper with pimples!