[Mike flanagan]

Has anyone any knowledge of effective performace upgrades for the 500 sport twin,aka meteor minor? I taking down the motor now.I wouldnt mind a little more power(33hp)respectively.Any practical too?thanks in advance.

[grumbern]

I dont know about adaptability, but I suppose you could use Connie- or Interceptor-cams, es well as the double manifold of the Connie using two carbs. Higher compression pistons should ad some torque.
Andreas

[Dantheman]

Has anyone any knowledge of effective performace upgrades for the 500 sport twin,aka meteor minor? I taking down the motor now.I wouldnt mind a little more power(33hp)respectively.Any practical too?thanks in advance.

One thing, would be to fit the 700 crank assembly, barrels and pistons... might make a fun project depending on how far you want to go.

[Kevin Mahoney]

There is probably no one that knows more about the viability of your project than the folks at Hitchcocks Motorcycles. I would encourage you to contact them.

[Mike flanagan]

Yeah,ill be contacting Hitcocks with my list,still tearing down to see whats good.I know engine parts interchage,not sure of the extent.Nothing better than insider knowledge.

[Adrian II]

I wouldn't be too hasty about a capacity hike, whether fitting the parts to make it a 700 engine, or even fitting an Interceptor 750 lump in there. There's always the notion that the original 500 twins were much sweeter than the larger ones that followed. A conventional tuning job on that 500 might give you all the fun you want. If not, just buy a Series 1 or 1A Interceptor.

A.

[Mike flanagan]

Thanks for the heads up,im of your mind on this too.im hoping my crank ,rods and tranny are good,new pistons and a bit of porting,tuning may be the ticket.

[Mike flanagan]

Trying to get the barrels off slowly.Look at these domes on these pistons.

[Adrian II]

Those pistons are actually one of the primary tuning mods for a 350 Bullet!

A.

[ace.cafe]

Roller rockers.
Not cheap, but can be done. Long waiting time involved.

If you prefer no external adjustment ports for more original appearance, it can be done, but a bit more work to adjust the lash because the adjusters are on the pushrod side of the rockers.

It solves the big drawback of low lift on all Enfields, and can significantly improve flow and valve train performance and reliability.

I am the sole source, and they are road proven in a performance 700 twin shown in the photos.

[Mike flanagan]

That looks like a bit of machinist sorcery.I would have to wonder what a proposed 33 hp twin could obtain hp wise with this setup.

[ace.cafe]

That looks like a bit of machinist sorcery.I would have to wonder what a proposed 33 hp twin could obtain hp wise with this setup.

It depends on the state of engine tune in terms of port flow, compression, rpm target, etc.
On the 700 Super Meteor we did, 84hp at the engine was estimated with full race tune. The heads ended up on a street bike, so we don't know exactly how much hp it made on that bike. We did get a road report from the owner that it hit over 110mph on the street without any fairing, on pump gas.

[Mike flanagan]

Man,thats alot.I would be very happy with high 30's or adout 40.I want to run old style parts,might be the most affordable option.Your rocker tuned head and a little higher compression pistons might get me close to 40.My year model supposedly had better cam(s) than previous.

[ace.cafe]

Man,thats alot.I would be very happy with high 30's or adout 40.I want to run old style parts,might be the most affordable option.Your rocker tuned head and a little higher compression pistons might get me close to 40.My year model supposedly had better cam(s) than previous.

A key factor would be how much flow you can get from your ports and valves. I haven't done any heads from a 500 twin, so I don't know what could be gotten from them for flow.
If you only want 7 hp, you should be able to get that without getting radical mods done. I would suspect that a compression increase, a bit of mild porting, and some Interceptor R cams would probably do it.

[Dantheman]

Roller rockers.
Not cheap, but can be done. Long waiting time involved.

If you prefer no external adjustment ports for more original appearance, it can be done, but a bit more work to adjust the lash because the adjusters are on the pushrod side of the rockers.

It solves the big drawback of low lift on all Enfields, and can significantly improve flow and valve train performance and reliability.

I am the sole source, and they are road proven in a performance 700 twin shown in the photos.

Very nice upgrade by the looks of it, the access points appear to be integrated really nicely into the heads with the setup 👌