Technical Information:  Common DiTech Choking Problem
This article addresses the problem that many people have with their DiTech scooters choking out. It is not a very common problem, but it does happen to a large amount of people it seems. I was one of those people. My scooter was running great, then one day on the way home from work, it just seemed like it lost power. Then it started getting a little worse as time wore on.

Well I have read a lot of articles on this topic trying to figure out what it might be. One topic that seems to be popping up a lot is that it is the 2-cycle oil... Mainly MOTUL 600 fully synthetic. But then you hear others make comments that it isn't possible, how can this be when so many others are running the same oil and they run great?

Well I think I might have stumbled across the answer to everyone's questions. I discovered this when I was installing a big bore kit on my DiTech scooter. Everything was going along smoothly until I took my injector off...
Around my injector was this white milky substance. It didn't look like oil, and it didn't look like gas... So what is it then?

Well for any of you that has ever worked on motors before, you know that a white substance in your motor along with oil can only mean one thing!!! WATER!!!

Well I took apart my fuel filter and air supply assembly and this is what I found in there!  Lots more of the white milky substance!
My first thoughts were the cooling system, maybe I had a leak somewhere.  But I really didn't think this was the problem because it wasn't in the cylinder and there really wasn't any way for water from the cooling system to get where it was... So I decided to pick up the phone and make some phone calls...

I called MOTOTEK, AF1 RACING, and 2 of my local dealers to get some info on possible causes. It turns out that this isn't a very common problem, but it does happen. You see there is a small air compressor on DiTech scooters that pressurizes air and injects it into the cylinder with the gas. Well for any of you that own an air compressor, you know that moisture can build up when humid air is pressurized. The dealers I talked to all said they have only had a few cases of this happening. And apparently, IT IS OIL RELATED!!! Apparently synthetic oil actually has a moisture content which lets the moisture condensate and collect in the oil. This collection of water in the oil is actually a water/oil emulsification which only occurs with the presence of synthetic oil.

I also learned that Aprilia does know about the problem and is trying to figure out why exactly this is happening. Apparently Aprilia has put out a "Quick Fix Kit" that involves a trap on the delivery line to catch water particles. Evidently the "Quick fix" doesn't really fix the problem very well. Most dealers I talked to said the easiest and best fix is to go to a semi synthetic or pure petroleum based oil instead.  Eliminating or reducing the amount of synthetic base in your 2-cycle oil will help reduce or eliminate the water emulsification.

So then I took everything apart, the air injector, air line, the entire injector delivery assembly and cleaned it all out with gas.  I used a pipe cleaner and pushed it through the delivery hose and I was amazed how much crap was in there also!
To be on the safe side, I was curious as to whether there was any water in the crank case. So I removed the compressor unit and took a look inside to be sure. Thank goodness, there was no water in the case.  Which would actually make sense since it is only found in the air AFTER the compressor compresses it.

But the compressor itself was full of water. So I took the compressor completely apart and cleaned everything really good with gas.

I reassembled everything after it was cleaned.  Then I drained the fully synthetic oil and replaced it with a semi synthetic oil.  After running for about a month with absolutely no problems, I suddenly started having a relapse of my old problem.  I tore my injector apart, and low and behold, there was the milk again.  I just recently switched to running a pure petroleum based oil with no synthetics.  I am also now looking into other possible remedies, such as putting an in-line compressor filter on the delivery hose.  I haven't ridden long enough to report anything, but so far so good.  I will update once I am confident I have found a good cure for this problem.
This is what I have going right now.  I bought an in-line compressor filter and also decided to add a pressure gauge.  I needed a T to split the line so I could add the gauge
This is what I ended up with.  The hose pointing up goes to the injection head, and the hose to the right goes to the compressor.
This is what the gauge looks like once I got it installed.  The red arrow is pointing to the filter.  It tucked up real nice under the farings.  I really like having the pressure gauge there.  It looks cool, and it is real nice to see what the pressure is doing.

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