Problem with a part in Polini 2 stoke Direct Injection kits

[kevin55950]

It has been said on apriliaforums but I think it might be good to post it here as I got this problem and there might be some 49ccScoot members who owns/are looking for a SR50 and are looking for this engine that is way cheaper than the malossi one.
A small part in the Polini BBK for Morini (Aprilia DiTech) and Piaggio PureJet engines wears out REALLY fast ( I got time to start the engine, tried to take a ride and problems started...)



You see the black "valve"? It's made of plastic. There is a hard spring behind this part and on the other side, there is fuel pressure... It goes in the Polini fuel pressure regulator.

Well, the pressure on the two sides of this part is too much for a plastic part of this size. Scratches appears on the upper part of it and the plastic "valve" clogs in the part it goes in ( the part that goes to the fuel return line on the injection system), so the engine stops working. The engine will run on idle or on stand with a clogged valve, but will not while going for a ride. This makes the engine stalls while driving, it does a feeling near a soft seize. The engine starts right after you stopped the scooter but it will stop working after you've done around 1/8 to 1/4 mile.

To stop this problem, you have to find a machinist that makes a part that has the SAME spec as the original one but in aluminium (or brass). Personal advice: don't try to run the engine with the polini one, if it scratches, it will be harder to make the new one if you need the spec from the plastic one.

Here is a diagram I made:

[kevin55950]

Pics from the 2 parts was took on ApriliaForums.

[craisin]

very good

[bclivewire]

just a little off topic

are those Aprilia scooters realy worth that money ?

they are like over $3,000 for a 50cc scooter

[bclivewire]

mever mind --- I just googeled Aprilia scooters sr50

it have every modd you can do to a scooter strate from the factory

now I see way there worht over 3gs

[ryan]

they go over 50mph stock. some of the aprilias have 99mm variators with 124mm TD. ive scored some off ebay and craigslist they were stock also

[kevin55950]

Gearing is fun for high speed roads but you see it's far less peppy in the city. And F.i. saves a lot of gas while giving good performance, only bad thing is that they don't sound as good as carburetor 2 strokes and they don't respond well to mods more than an exhaust unless you have a lot of money to do everything at once. Piaggio SR50's reliability is not the best for the price you pay for.