I am installing an MC28 engine in my 21 and have found that the MC28 does not have the carb boost bottles that the MC21 has.

A bit of research on the site tells me on the 28 these are part of the airbox. Given I won't be running this airbox, am I safe to assume I need to fit the MC21 boost bottles?

Bike is race only, but I'd rather have them if they make setup easier...

Boost bottles make it a better road bike.

If it was my race bike I wouldn't bother with them.

nxrsr20 wrote:Boost bottles make it a better road bike.

If it was my race bike I wouldn't bother with them.

What's the reasoning behind that?

It's supposed to smooth out throttle response at the lower openings. I don't understand the theory behind it but that is what I was told.

What gearbox are you using ?

Neal wrote:What gearbox are you using ?

MC28...

Ok, so what constitutes lower RPM? I.e. is it relevant for track work?

As a guess anything under power band is lower rpm , plug them off , less clutter

Read the specs on the gear ratios , there are better options than the 28 gearbox

Neal wrote:As a guess anything under power band is lower rpm , plug them off , less clutter

Read the specs on the gear ratios , there are better options than the 28 gearbox

I don't mind the clutter, they aren't really in the way. I'm more interested in doing what is best for power and rideability...

Ok thanks for that, are there any guides for gearbox removal/changing gears? That's something I haven't done before...

The complete gearbox comes out as 1 unit and you swap it for either a mc21 unit or whatever you can get etc .
The site recommends to remove the boost bottles for track/ fast riding