Topic: CB750 k5 oil light at idle

[70CB750]

Using 10/40 oil will not wear out the valve guides any quicker than 20/50.In fact just the opposite as when cold 20/50 will take longer to get to the top of the engine. The reason that you find wear on the valve guides is probably due to not changing the oil and filter at regular intervals and oilways get blocked.

So you got it wrong, but you can justify your error. 

[commando1954]

Who got what wrong?

[heymak]

I changed the oil today for 20/50 and the light is still on,
I need to order some O-rings and drop out the pump, do the O-ring kits on eBay work 15mmx2.5mm not listed in kit
or do I order OEM parts ?

[HondaMan]

I changed the oil today for 20/50 and the light is still on,
I need to order some O-rings and drop out the pump, do the O-ring kits on eBay work 15mmx2.5mm not listed in kit
or do I order OEM parts ?

15 x 2.5 are correct. They are a standard size: most seal stores have them for about 50 cents each in small quantities. Buna 70, the most common type, are fine.

[heymak]

The only O-rings I can get local are 14mm x 2.5 mm or 16mm x 2.5mm .
the 16mm x 2.5mm look like they are good fit ,so shall I fit them or not,
any know anything about being 1mm oversized ?

[bryanj]

http://www.polymax.co.uk/o-rings/rubber-nbr-oring/2-5mm-cross-section-nitrile

[heymak]

Hi, have been away working for a couple of weeks , so here is an update
changed the oil to 20/50 mineral oil , oil light still on below 2000 rpm ,still running really sweet as ever ,
so I dropped out the oil pump replaced the 3 x O-rings with 16mm x 2.5mm they are not the correct size but went ahead anyway , the O-rings that came out were intact but I replaced them and refilled the oil , still oil light below 2000 rpm, I ordered the correct  Honda 15mm x 2.5mm O-rings from David Silvers and will fit them tomorrow iff I got time ,
I really hope it that as I am starting to run out of faith