Malaguti Commuter Help Part 2

I'll make it very simple...

Type: 78 Malaguti Commuter

Engine: Morini M01

Carburator: Dell'Orto 14.12

and finally...

THE Problem...I've been moved to install a Polini 60cc speed kit on this bike. It went smoothly with only a few obstacles: one being introduced to reed valves. The original cylinder was without this. The kit came with one that was perplexing at first to assemble. So after a a few modifications to the carb top, to allow the throttle cable to fit under the tank, I had everything together. It ran like crap really. The bike would only run when the choke was in. When I did give it full gas, allowing the choke to open fully, it just died get the point. Also, when i would let off of the gas, the bike would just rev up by itself. I wasn't sure about this....So I moved up a few jet sizes from the orignal 50 I had in there before I made the size change. With all these jet size changes, I could only test out the performance with the choke in. It was the only way it would run. I tried size 54 first causing it to fire up fine but still I could not just turn the throttle and take off smoothly. I'd ride, give it gas and it would bog down. So i let off of the gas and i would just take off on its own for a second or two then drop back down to normal rpms. I could only give so much gas or it would bog. This was no good. Shortly after I tried size 56 and 58 with the same results. I thought I was getting too much fuel. I took it down to a 50 again. This time it did run better. Much more smooth but still I had to run it with the choke in otherwise it would die. It still took off on its own at the point like previously mentioned with the practice of the larger jet sizes.. I went as low as 48 with similiar results as with the 50. I realizes the choke/air problem should be addressed first before I determine the correct size. So i have done the following: 1.Made sure the fuel flow was steady and no clogs or slow downs of fuel were found within the carb or fuel lines 2. I checked for a possible leak in the manifold and carb connection using a carb cleaner misted into the connection area checking for an change in the engine. Nothing changed. I retightened the bolts connecting the two anyways. It seemed air tight.

So i ask you moped guru, where do I go from here????????

Thank you.


My airbox was always intact.

Re: Malaguti Commuter Help Part 2

Chris MWH /

Check first that the cylinder base gasket is sealing using the same process as with the intake manifold. You might try to run the richer size jets and run it in a bit. Keeping an eye on the plug to make sure that it is not fouling. With the reed valve kits you do need to break the reeds in for a few miles before they will seal perfectly . This is what it sounds like. Stay away from those smaller size jets though.

Chris MWH

Re: Malaguti Commuter Help Part 2

Chris, I tried what you suggested and checked the cylinder base gasket. No change in the engine so I'm assuming its tight. I did check the reed valve by blowing through and sucking in making sure air did not escape when I sucked in. Could i need to rejet to a much larger size? Say a 62 or 64????? I just seems like i need to get much more gas since it will only run with the choke in. Thanks

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