750K0 Lower Crankcase casting

[AshimotoK0]

Anyone know what the purpose  of the 750K0 Lower Crankcase casting circled in red  is?

it appears to be  broken off at the top on my 69 K0 crankcase.


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[MrDavo]

I can only guess that it’s an oil guide vane to make the oil go to where the engineers wanted it as the crank rotates. The main bearing shell has a tang to locate it, so it can’t be that.

Is it not there in later engines?

[Trigger]

They snap off a small bit at the top when the chain hits it, about 40 out of a 100 engines I do have it broken 

[AshimotoK0]

They snap off a small bit at the top when the chain hits it, about 40 out of a 100 engines I do have it broken 

Thanks Graham ... should I try to repair it or is it OK to leave it? There was no alloy bit in the engine when I drained it and the tensioner looked like it had recently been replaced... but I got a new one and chains just in case.

This is mine & the damage:-


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[K2-K6]

Generally things like that are part of "windage " mitigation that engine designers use.  It's to try and peel off excess oil from rotating crankshaft to prevent a rotating oil mass building up round the crank. 

Where oil comes back down from the head it drops onto the crank more than other extremes of crankcase, so it tries to seperate it to push it down toward the sump usually.  A bit like a potatoe peeler.

[UK Pete]

Wow some very knoledgeable answers
Btw I received my chains ash, thankyou very much

Sent from my SM-G930F using Tapatalk

[Laverda Dave]

I agree with you Pete and it's the reason why I need my daily fix of the forum 😊. Always a great read, intresting threads, fantastic rebuilds and a good bit of friendly banter. It's like meeting your mates in a Weatherspoons but without the punch-ups😉!

[Trigger]

Generally things like that are part of "windage " mitigation that engine designers use.  It's to try and peel off excess oil from rotating crankshaft to prevent a rotating oil mass building up round the crank. 

Where oil comes back down from the head it drops onto the crank more than other extremes of crankcase, so it tries to seperate it to push it down toward the sump usually.  A bit like a potatoe peeler.

I have found that they do nothing at all. I never repair them and have never had a problem. And it is always the same size and shape 

My theory is that Honda put it in the casting so, if your chains go loose then it chips the bit off and you find it in the sump. Just a reminder that your chains and tensioner need replacing     

[paul G]

Or it could be that Mr Honda put it there so when it did break it clattered round the engine, wrecked a bucket load of stuff and you spent thousands in the dealership getting all the damage repaired.

Alas for Mr Honda he didn't get his sums right and it just dropped to the bottom of the engine instead, which just goes to show, Mr Honda didn't always get things right. 

Ah but what about the bikes down under it would make a mess of them !

[K2-K6]

Or it could be that Mr Honda put it there so when it did break it clattered round the engine, wrecked a bucket load of stuff and you spent thousands in the dealership getting all the damage repaired.

Alas for Mr Honda he didn't get his sums right and it just dropped to the bottom of the engine instead, which just goes to show, Mr Honda didn't always get things right. 

Ah but what about the bikes down under it would make a mess of them !

Ah but it wouldn't have snapped it off in the first place with the chain hanging upside down 

[paul G]

Or it could be that Mr Honda put it there so when it did break it clattered round the engine, wrecked a bucket load of stuff and you spent thousands in the dealership getting all the damage repaired.

Alas for Mr Honda he didn't get his sums right and it just dropped to the bottom of the engine instead, which just goes to show, Mr Honda didn't always get things right. 

Ah but what about the bikes down under it would make a mess of them !

Ah but it wouldn't have snapped it off in the first place with the chain hanging upside down