Project New acquisition - Honda Spada

Yep aware of the colour coding on bearings. Will also check the pump.

 

Hi Gizzi, having pulled these things out of the motor and having inspected them carefully, I can assure they are not hydraulically operated. Oil under pressure does not in anyway control the absolute force applied to the chain. Oil drips into the back of the unit from an oil squirter above. The oil just fills the piston assembly and provides damping for the spring. Much like a shock absorber on your suspension. If this damper is worn then the chain can likely oscillate during operation resulting in poor control of chain tension. If the damping piston sticks in the bore it could result in the full spring pressure not being applied to the tensioner arm. When full of oil, the damper provides considerable resistance to movement of the arm as you have stated.

 

Once I get the flywheel off, I can split the crankcase and inspect the bearings.

 

Yep. Lets just agree that the tensioner is not activated by line pressure from the engine oil pump.

 

Got a bit further with my engine disassembly today.
It looks like the main source of the engine noise was a big end failure.
Strangely only the big end for the front cylinder had failed.
Everything else looks ok, so far. Even the crank looks ok.
Not sure what the cause was, but certainly would explain why it took a little while to build oil pressure on start up.
It doesn't look like the engine has ever been opened. All std size bearings.

 

So the current plan is:
Lightly linish the crank journals.
fit new bearing shells
Very light bore hone
Fit new rings
Fit new cam chains
Check oil pump, if serviceable reuse
Fit new gaskets
Put it all back together.

I am going to source as much as possible off low cost internet sites.
I want this to be a bit of an exercise in seeing how cost effectively you can rebuild one of these little machines and still keep it reliable.

I figure I can get out of it with engine parts costing only $100 or so.

Peter.

 

Yep.
Ordered on Aliexpress.
Big ends, mains and rings for just over $57.
Complete gasket set for under $20
cam chains sourced locally for $25 for the pair.
New carb manifold boots and clamps $21.

Will probably take a month or so before all the parts come in.

I have used Aliexpress quite a bit for other things. Mostly the experience is good.

So much OEM stuff comes out of China now anyway.

It used to be Jap crap that we were wary of. Times are a changing.
It pays to keep an open mind. Hence my experiment.

 

Yes. The cam chains might be interesting. I will inspect carefully before using. Looks like I was lucky with the crank. I can not work out why one set of big end shells were so bad. Clearly they have gotten really hot. Where shells normally stay in the cap/conrod when you separate them. These stuck to the crank. The literally fall out of the rod if you try to sit them back in there. I am amazed the crank looks ok. A lot of metal has been chewed off the shells.

 

Thanks for the thought.
Being a V motor. Both conrods run on the same crankpin. Oil galleries in the crank are free. Only sign of silicone sealant is from original manufacture. As mentioned previously, it does not look like this motor has ever been pulled down. I am going to put it down to oil starvation at some point during its life or some sort of random bearing fatigue problem.

 

A bit more work on the Spada today.
Checked the condition of the oil pump. All looks good.
Still waiting on some parts out of China for the engine. This COVID stuff is seriously delaying deliveries out of China.
Checked my cheapy gasket kit that arrive some time ago. I thought it was correct, but appears that the head gaskets are for a slightly different model VT250 engine. The gaskets on my engine have an internal oil feed hole for the camshafts. The delivered gasket kit does not have this oil hole.
Does anyone know where to get compatible head gaskets for the Spada? OEM ones look to be expensive. Are there other options?