The fastest CB500 engines in UK

Honda CB500 Race Engine Tuning

Thundersport 500/EMRA/Scottish Legal Engine Build

Are you racing at Thundersport, EMRA or the Scottish 500 class and finding your down on speed? Or find other bikes you are racing against are faster than yours? The problem with racing CB500's is that most of the engines come from commuter bikes with many seeing over 50,000 miles. This means the engine will be very worn out for racing terms and a worn engine means a loss of power. Also, with these engines being mass-produced and not built for racing, the machine tolerances vary on many engines, this also causes a loss of power. A refresh which is done correctly and rebuilt to the correct specifications will restore the power you require to be competitive at Thundersport or EMRA.

Your engine will be stripped, every single component will be measured and assessed for any damage or wear, you will then be given a quote with all the required parts on and total cost. You can then choose to go either go ahead with the rebuild, or if you don't want to, pay a £50 strip down free and have your engine back. All engine oil and valve seals will be replaced regardless.

  • Full strip, measure, clean, replace and rebuild

  • Cylinders honed 

  • Bearings resized for reduced friction

  • All valve seats cut, valves replaced or refaced

  • Cam followers finished with a diamond rouge for minimal camshaft friction

  • Crankshaft micropolished

  • Valve clearances checked and re shimmed

  • Engine built to spec within 0.001mm 

  • 20% Discount on all genuine parts, usually just 5% more than cost. ( I pass all parts savings on to the customer)

  • Possibility of free delivery and collection anywhere in the UK

  • Full build sheet provided

£500 Labour plus parts

60+bhp Engine Build

Over the past couple of years, I have developed different aftermarket performance parts for the CB500 engine that no other engine builder can offer you. I have modified some of the standard engine components which can now be used to give you more performance. I have tried many different mods to find the perfect set up which I can now pass onto you within a reasonable budget. I can cater for any budget, just send me a email and I will assist you the best I can. 


  • Full custom BCR Performance cylinder head port 

  • 3 Angle valve seat cut and valve reface 

  • Camshaft modification and degreed to suit your riding style

  • BCR Performance Crank shaft modification 

  • Cylinder re-bore with a choice of aftermarket lighter pistons 

  • Choice of different connecting rods, depending on power output

  • Engine casing modification

  • Total loss system if required (+ 3/4bhp increase)

  • BCR Performance Ignition modifcation

  • Crankshaft, Connecting rods and Pistons dynamically balanced

  • BCR Performance inlet tract modification, depending on power requirements

  • 20% Discount on all genuine parts, usually just 5% more than cost. ( I pass all parts savings on to you)

  • Possibility of free delivery and collection anywhere in the UK

  • Full build sheet provided

As well as the full engine work, we are currently developing new velocity stacks for the standard carbs which will work specifically with BCR Performance race engines which will soon be for sale. You can see a photo of these on the right.

It is common practice for 'engine tuners' to just run a carbide burr and a cartridge roll through to get rid of any rough castings and to open the port for 'smoother / faster gas flow'. This however isn't the case, as the standard 500 carbs can only flow a maximum amount of fuel mix, if the port is to big, the velocity that the mix travels at is very slow. The correct way to do a 500 head is by adding extremely high quality epoxy to the port which is drys into a special resin that can withstand heat and petrol, as well as the vibrations of the engine. Once the epoxy resin has hardened I shape the port for more velocity and faster gas speed. It is also used to alter the power for torque or peak power depending on what you want. After lots of testing, I have found the perfect flow rate for the 500 engines for different applications. Have a look below at our gas flowed head rates. Our cylinder head gas flowing alone can increase power by up to 10bhp.

If you have any enquiries or want some advice please use the contact page. 

£700 Labour Plus Parts

Bolt On Power Upgrade Package

Understandably you may not want to pay the high price of a full engine rebuild and may just want some cheap modifications that give a great boost in power. If this is the case, this package will be perfect for you. 

I have developed the 500 head to work with my own spec high lift cams, meaning on average you gain around 15 / 20% over what you currently have. Even if your engine is tired below the head, you will still gain a nice power increase. The image to the right is a before and after of this package. As you can see it takes it from 48bhp to almost 57bhp. 

  • Updated BCR spec Gas Flowed Head (see below)

  • BCR High Lift Cams

  • Cylinder Head Skim for boost in compression

  • Valve Clearances checked and re-shimmed

  • Cylinder Head Service with stem seals

  • All valve seats re cut to 3 angle for better flow and seal

  • BCR Performance flywheel - 800 Grams lighter 

£900 All In



Gas Flowed Head

Send your head to us to have the inlet and exhaust ports gas flowed and matched. Gas flowing helps the engine breath far better by allowing the fuel mix to enter and exit the combustion chamber much faster. The standard 500 cylinder heads can be improved so much with port work purely because the ports are so poorly designed and cast. You will tell us where you want your power in the rev range so your head will then be custom flowed to your riding style. It takes a while to do one of these heads properly, usually around 8 hours in total but the lead time is usually around 2 weeks. This option also includes new valve stem seals, all valves lapping in and all valve clearances checked and adjusted if required. I would also highly recommend going for the BCR high lift cams as this gives you a much better gain overall as they are both made to work together. A lot of my customers choose to have a gas flowed head with cams. 

Gas Flow Only - £350

With Cams - £650

CB500 Machining Prices
  • Cylinder Head Skim                                   £40

  • Barrel/Block Skim                                      £70

  • 3 Angle Valve Seat Cutting        £8 per seat

  • Cylinder Rebore                                          £80

  • Flywheel Lightening                                 £35

  • Crankshaft Lighten & Balance             £100

Cylinder Head Refresh

Are you finding your bike is becoming harder and harder to start? Do you find your engine is blowing smoke out the exhaust when you are off the throttle? This is more than likely down to a tired cylinder head and worn valve stem seals. A simple cylinder head service can help restore power and general starting of the bike. We will fully strip, clean, vapour blast (extra cost) and check your cylinder head components we also re shim the valve clearances and re lap the valves which we will then vacuum test to ensure they are sealing correctly. 

All you have to do is post us your cylinder head. 

Head Refresh - £180