Reed Valve

Hi All, I am considering converting my P200 malossi to reed valve. Just wondered if anyone has fitted it and if so can tell me if the
power increase is really worth all the hassle.


I fitted a Malossi reedvalve and 30mm carb to a tuned Px166 and it made a massive difference. Worth doing but a lot of work.

Just for your info, I run :
Malossi 166 kit with modified exhaust port (Taffspeed).
Head modified for compression ratio (needs to be run on super unleaded or octane booster).
Malossi reed-valve, Dellorto 30mm PHBH (132 main, X5 slide) and Ram airfilter.
Welded, ported and polished cases.
Taffspeed expansion pipe.
Denso W27 Platinum tip spark plug (BH9).
Timing retarded to 16* from 18*.
Lightened flywheel (1.8kg).
P200 primary drive, T5 4th gear, Cosa clutch with 23t drive and Malossi clutch springs.
Throttle pulley on handle bars modified to allow 30mm carb to open fully.
Standard crank.
I always use Silkolene Pro2 premix at 3% and Silkolene Pro4 in the gearbox.
On the Dyno it put out 18.5 HP and is jetted for reliability not maximum power.
On the road the powerband in 4th starts at 70mph and top is 85mph on the flat (providing there’s not a high wind in you’re face).
Oh yeah, nearly forgot, a petrol-can for when I open it up on the motorway, at full throttle motorway speeds you’ll never reach the next petrol station.

Hope this helps,

Thanks Martin for the info.
You’re set up sounds really impressive. I have had a couple of 180s Pinasco/Polini but they were just bolt ons with the casings done, both made a big difference though.

With the reed set up I heard that 45mpg is about the best you can get[taking it easy], and that it aint hard to only get about 35mpg. Would you agree with that?
Also, do you manage to run without a fuel pump? As I heard that you can get fuel starvation problems as the fuel gets lower in the tank.

Thanks again


I first went from 20mm to 24mm with standard cases and kit which was ok for a while. Then later I got cases welded at the transfers (clutch side only needed done) to open the transfer ports fully for the 166 kit and got the inlet opened for the reed-valve. The inlet didn’t need welded to get it big enough for my needs. I can get 3 fingers in the inlet without the manifold in place, so that gives you an idea of the size of the inlet compared to normal. I run the reed-valve with a 30mm carb and a Ram air filter and fuel consumption is very good on motorways but not as good in town.
Standard cases with a kit : OK
Welded ported cases with reed-valve and a kit : Awesome
Spend time getting the carburation, timing and comp ratio set right as the engine will generate a lot more heat.
My scoot was on the Taffspeed dyno for 3 hours to get it to run some decent miles without exploding. £35 an hour but money well spent.


Thanks for taking the time to reply.
Did u go from 20mm standard carb?
Did you weld the inlet?
Thanks : [:smile:]