Here’s the latest minor irritation...
Signs of a liquid leak on the exhaust.
It appears to be coming from this unprotected opening on the right-hand crankcase which is is a weep/vent hole for the water pump mechanical seal.
You guys probably know Honda uses a double-seal arrangement on the water pump shaft:
One seal keeps coolant inside the pump
One seal keeps gearbox oil inside the engine
Between them is a cavity
That cavity vents through that small hole
It is intentionally open to the atmosphere.
I think the theory is.
If coolant seal fails → coolant drips out of that hole
If oil seal fails → gearbox oil drips out of that hole
It prevents:
Coolant mixing with gearbox oil
Oil getting into the cooling system
So the hole is a warning system, not a missing bolt.
What I see is a blue colored oil, which make sense because the oil is Motul Transoil 10w-30 (which is 'oil coloured' rather than red or green) and the coolant (Engine Ice) is blue....in other words both sides of the seal are leaking!
Oil + Coolant = blue oil.
Only supply I could find was Pattern ones via WeMoto https://www.wemoto.com/bike/honda/nsr/250/1988/121
UPDATE: only helpful to the US based of you all but I forgot that Partzilla (over here) has a wealth of parts that are often compatible to the NSR...rule of thumb appears to be that if the middle 3 characters ARE NOT have KV3, such as for the mechanical seal 19217-657-023 https://www.partzilla.com/product/honda/19217-657-023 it's likely a more generic component that shares with bikes like the CBR600 and the rest and it's more readily available as an OEM Honda Part in the USofA.
