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CB350/400 / 400/4 Engine noise, bodges and Primary chain
« on: June 15, 2021, 11:04:08 PM »
Just got my recently acquired 79 400/4 running.
My concern is the noise from the engine at tickover.
I shot a video on my phone and at 1200 revs there seems to be a rattling and lashing coming from the lower part of the engine. Please excuse the poor quality of the videos (shot lying on my back under the bike!)
https://www.youtube.com/watch?v=QWlwj_9bQik
It's definitely not ticking over smoothly and the PO said it needed the carbs stripping down and syncing.
But before attempting the carb strip down, I re-tensioned the primary chain, changed the plugs and did the tappets.
It seemed quieter less rattling sound but still the lashing.
So I decided to change the oil and filter and clean the sump to see what delights lay in store. Oil quite black but no metallic particles just some bits of gasket cement.
But what is this all about? Looks like someone has attacked the filter housing with a drill?
[ Guests cannot view attachments ]
Also one of the sump bolts had sheared and a fluted rod/drill was fixed into the broken stud on the sump. A double ended nut had been forced onto the end of the rod to hold the cover in place.
[ Guests cannot view attachments ]
Before re-fitting the filter housing and sump, thought I would have a look at the primary chain. There seems a lot of sideplay in the chain/sprocket/collar, is this correct? See video link.
https://www.youtube.com/watch?v=x5_cqHMzBuo
I've refitted the sump but dang it I managed to shear one of the Sump bolts. Haven't attempted to remove it yet. So now down to 9 bolts on the sump! I know it's bodged and hate leaving it as is. Just want to get the engine running ok and ride a few miles to see what else needs sorting.
Any advice gratefully received
Justin
My concern is the noise from the engine at tickover.
I shot a video on my phone and at 1200 revs there seems to be a rattling and lashing coming from the lower part of the engine. Please excuse the poor quality of the videos (shot lying on my back under the bike!)
https://www.youtube.com/watch?v=QWlwj_9bQik
It's definitely not ticking over smoothly and the PO said it needed the carbs stripping down and syncing.
But before attempting the carb strip down, I re-tensioned the primary chain, changed the plugs and did the tappets.
It seemed quieter less rattling sound but still the lashing.
So I decided to change the oil and filter and clean the sump to see what delights lay in store. Oil quite black but no metallic particles just some bits of gasket cement.
But what is this all about? Looks like someone has attacked the filter housing with a drill?
[ Guests cannot view attachments ]
Also one of the sump bolts had sheared and a fluted rod/drill was fixed into the broken stud on the sump. A double ended nut had been forced onto the end of the rod to hold the cover in place.
[ Guests cannot view attachments ]
Before re-fitting the filter housing and sump, thought I would have a look at the primary chain. There seems a lot of sideplay in the chain/sprocket/collar, is this correct? See video link.
https://www.youtube.com/watch?v=x5_cqHMzBuo
I've refitted the sump but dang it I managed to shear one of the Sump bolts. Haven't attempted to remove it yet. So now down to 9 bolts on the sump! I know it's bodged and hate leaving it as is. Just want to get the engine running ok and ride a few miles to see what else needs sorting.
Any advice gratefully received
Justin