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[Bullet Whisperer]

From a current project.
https://youtu.be/FyTY1hQoec4

[Haggis]

Exactly what I did to my previous C5 and will be doing to my present C5 over the winter.
Absolute agree that the ports not matching the manifold, throttle body and gaskets are shocking as standard.

[Rushour]

I'm saving up for the Hitchcock's twin port 4 valve conversion ....

[Cranky]

Exactly what I did to my previous C5 and will be doing to my present C5 over the winter.
Absolute agree that the ports not matching the manifold, throttle body and gaskets are shocking as standard.

Bore it out to 88mm I can guarantee it will impress. 88mm will leave you 2.1mm liner--ample.

[Cranky]

I have dumped all my EFI crap, its all in a box at the back, UCe, fuel pump, sensors and wires throttle body and everything.

My throttle body matches fine to the extension and the mounting. A pointless exercise on a single RE.

The stop start air flow of a single cylinder is not going to be improved by removing a shave off to match. If it were a multi cylinder its possible a few more pounds of torque can be clawed from such an exercise to increase volumetric efficiency by keeping a smooth air flow..

Maybe your engine is one of those strange ones that Re seem to pop out on a Monday morning and those that come out late on a Friday

[Bullet Whisperer]

The stop start air flow of a single cylinder is not going to be improved by removing a shave off to match. If it were a multi cylinder its possible a few more pounds of torque can be clawed from such an exercise to increase volumetric efficiency by keeping a smooth air flow..

Well, clearly all my work to build race winning, championship winning and lap record setting Royal Enfields has been a complete waste of time, as I clearly could have left the ports and everything else bog standard

[Wheaters]

It’s amazing what you can learn on t’internet.

I think I’m going to try putting a step in mine. Probably the easiest way is to fit a smaller carburettor.

[papasmurf]

Well, clearly all my work to build race winning, championship winning and lap record setting Royal Enfields has been a complete waste of time, as I clearly could have left the ports and everything else bog standard

Quite. Back when dinosaurs walked the earth my brother and I stripped a Morris 1000 engine down completely. We then rebuilt it, with great care, polishing ports, making sure the volume above the pistons in the cylinder head were the same.
Making sure the pistons weighed the same, and did the same on all of the related moving parts.
Balanced the crank.
When put back together and installed in the car the car easily achieved 90MPH

[Cranky]

[/quote]
Well, clearly all my work to build race winning, championship winning and lap record setting Royal Enfields has been a complete waste of time, as I clearly could have left the ports and everything else bog standard [/quote]

Now now --there is a big difference in porting and matching gaskets. The 500 UCE with a hemispherical combustion chambers is pretty good in that respect.

You did'nt go into details but I would think the UCE would benefit from exhaust porting. But you are not talking about the UCE are you.

[Cranky]

Probably the easiest way is to fit a smaller carburettor.

Could be. The yamaha V max fits smaller carbs for more torque. Big carbs dont force in more fuel it only supplies --if the demand is there.