Noisey CB250N

Pretendra · Derestricted Danger Joined: 10 Aug 2008 Karma :

Hello, there is a loud progressive knock from the bottom end of the engine. could some one please help.

I just finished the restoration job last week and fired the engine. The engine was pretty smooth except for the balance chain, which was rubbing against the lower crank case due to excessive slack. i rode the bike for around 8 kilometers and noticed that the oil pressure indicator was illuminated, turned around and headed home. i opened the engine and noticed that the oil strainer was completely choked. After cleaning the strainer the oil pressure was back to normal. But noticed that the engine has become extremely noisy and becomes louder as the rpm rises.
Due to my stupidity and ignorance i feel i will have to completely redo the engine.
I guess i need to work on the crank.
Could some one please advice on the procedure. never worked with shell bearings on a bike.

Finglonga · World Chat Champion Joined: 27 Jul 2004 Karma :

Pretendra · Derestricted Danger Joined: 10 Aug 2008 Karma :

Finglonga what you said is true. i should have done that.

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Yes. Unfortunately, Honda oil lights are a device which tells you that your oil pressure dropped well below adequate about five minutes ago and your engine is now screwed.

You'll almost certainly get a reconditioned/second hand crank or a second hand engine for less than it would cost to rebuild your current one.

If the bottom end has starved of oil, you'll probably want to check the condition of the camshaft and the oilpump too.

I just checked, there are two CB250N cranks on ebay right now for under £50 delivered.
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Pretendra · Derestricted Danger Joined: 10 Aug 2008 Karma :

When i bought the bike it was unused for a while, i really didnt know the oil strainer could get clogged this bad, but after i cleaned the strainer and checked the oil pump for wear the oil pressure was back to normal. I am thinking of getting the crank ground if it really works. what are the bearing size that are available, i am a bit confused about the colour codes for the bearing.
need advice.