I dont know why forum members are suggesting you purchase a HRC card and loom to de-restrict your MC28!?

You can de-restrict your MC28 for around £30 :

A stock 28 will make around 40hp - you can take this up to 53hp by simply grinding out the 30mm restricting washers welded into the exhaust headers ( best to use a 40mm cone cutter or another option is a dremel and stone (2-3hrs each exhaust) - the stock exhuast is actually a good design and offers similar performance to the aftermarket options. Check the jetting after you do this - in my experience the stock bike is sold slightly rich and removing the washers does nothing more than to remove this rich margin - perfect.

The stock 28 has poor ignition advance and power delivery feels slightly wooly (soft) a MC21 flywheel advances the iginition by 2 degrees as a work around - another option is to purchase a 2degree woodruff key to use with your stock 28 flywheel - this mod will give you a nice crisp feel to the delivery and take the power up to 55hp.

If you want even more power then i suggest an airbox mod ( 4 holes in the front section of the lid ) - WARNING you will need to do a re-jet after this mod - this may give you a few more hp.

The sprockets supplied with the stock 28 acts as the speed restriction - the bike will only pull up to 112mph at redline in 6th. (stock gearing is 15front and 44rear) so if you de-restrict you may want to change the gearing to 15front and 38 rear which will allow you to hit 135mph in top gear.

Dont bother with the HRC card.

To de-restrict my mc28 cost me the grand total of £6.90 for the woodruff key (jap4performance) and £25 for the rear sprocket (Ebay)


steve