Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Athame57 on April 09, 2025, 05:08:15 PM
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Last night, or rather early hours of this morning I was riding around the empty (nearly) streets of east London looking for rats to squash et al ;D when a nice bit of straight road came along. I let rip with the throttle and then a surprise, at around 8,000 rpm the oil warning light flickered briefly. :o I never remember seeing that happen on a bike before. I checked the oil level, fine and new oil as well, is there much here to worry about? :-\
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Ooooh, err. Thats a bit odd.
My first thought would be oil filter as that's between pump delivery and where thecoil should go to.
By no means definitive, possibly worth a brief look at it though.
Could try the same revs again to see if you get a repeat.
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The sender units have been known to fail on 350/400/500/550 which i think are all the same unit, idealy fit a pressure gauge temporarily or replace the unit, i think Julie does a better priced one than Honda dealers
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Ooooh, err. Thats a bit odd.
My first thought would be oil filter as that's between pump delivery and where thecoil should go to.
By no means definitive, possibly worth a brief look at it though.
Could try the same revs again to see if you get a repeat.
I changed my oil filter a week ago together with the oil....... but what could be wrong with that item?
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The sender units have been known to fail on 350/400/500/550 which i think are all the same unit, idealy fit a pressure gauge temporarily or replace the unit, i think Julie does a better priced one than Honda dealers
Where do I find that on the bike?
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The sender units have been known to fail on 350/400/500/550 which i think are all the same unit, idealy fit a pressure gauge temporarily or replace the unit, i think Julie does a better priced one than Honda dealers
Where do I find that on the bike?
It looks like this George and is on top of the top crank case. But, if you only changed the oil and filter last week, I would be double checking the filter spring, spring seat washer and pressure relief valve. It could just be a coincidence but worth checking everything is where it should be.
[attachimg=1]
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Thanks for this Julie. I havn't managed to spot it on the CMSL diagram which is a brand new platform, looks like there it less on it. I see it is the oil pressure switch ( sender?) is it a crank splitting job to replace if indeed here is a problem with it?
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That's it were I've circled yes? Looks less of a worry, if this happens anymore I'm getting a new one.
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That's it were I've circled yes? Looks less of a worry, if this happens anymore I'm getting a new one.
Yes, that's it George.
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Another possibility is the wire from the oil light bulb down to the pressure switch getting grounded somewhere between the two, most likely inside the headlamp shell if the sleeve on a bullet connector is not in place or damaged and its touching the headlight unit or the chrome rim. More so if vibration or pot holes is introducing the fault. As well as what others have mentioned, what else has changed or been messed with since it last behaved itself. If I remember right it's just a bare wire termination to the switch which if stripped back too much could ground out if it's bent over.
If my bike hasn't run for a a while , I always kick it over with the run switch off until I see the oil light flicker off/on with each kick a few times just for piece of mind that the oil switch isn't sticky and the oil starting to move. Doesn't need much pressure to turn the oil light off.
[attachimg=1]
Regards
Dave.
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If the filter wasn't genuine Honda I'd check that it hasn't collapsed, had a pattern filter do that, the filter looked like it had spiraled, like it had been wrung out. The mesh on the strainer in the sump was almost completely covered in fine paper fibres, at high revs the oil pump couldn't get enough oil through to meet demand and that's why the oil light came on, at low speeds it just about managed.
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I'm just curious, did you get to the bottom of this problem?
I had a scary moment long time ago when I split the crankcases to replace the primary drive chain and cam chain. One of the blind seals on the gearbox shaft got put in back to front and blew out enough fit it to slowly dump all the oil, most of it on the back tire. Had to push it over a mile home that day when the oil light came on.
Regards
Dave.
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I'm just curious, did you get to the bottom of this problem?
It never happened again, I can't fid anything that may have caused it. Perhaps the acceleration it happened under caused enough weight transfer to effect pressure a moment and cause a flicker? :-\
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I'm just curious, did you get to the bottom of this problem?
It never happened again, I can't fid anything that may have caused it. Perhaps the acceleration it happened under caused enough weight transfer to effect pressure a moment and cause a flicker? :-\
And I thought it was only the yellow ones that had that kind of arm wrenching acceleration George 🙂.
Just thinking, when you check the oil level do you check it with the dipstick out and resting on top of the threads. If not you'll get a false reading thinking it's full when actually it isn't.
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Hi Dave
Yes, that's how I measure it. Next time we meet at the Ace Cafe we must have a drag race on the North Circular there. ( no high heels allowed! ;D )