PFI Aprilia SR50's

[xavi0n]

Can someone explain what PFI is and how and where the fuel is injected?

[Grenadiers]

PFI stands for Port Fuel Injection. Fuel is Injected via 1 or 2 Fuel Injectors that are positioned in the TBA (Throttle Body Assembly).

The fuel injection is controlled via a specially designed ECU that controls when fuel is injected into the TBA.

[MeepMeep]

E-mail me. I can't take on anymore work for a few months.

im glad its picking up, we need 2 of you. I may be looking to go a 180cc conversion but it wouldnt be until after the replica is done anyways......

[High-Gain SR50]

I would like to get mine all back together also but everyone else's comes first.
I'm taking a couple months away from College teaching then I will decide if I want to go back. It's a lot of fun and I could do it full time again.

[Grenadiers]

OK, the following pictures show’s what happens when you run a pre-mix T2 engine to lean…

At first look, I thought that the Cylinder was toast (I knew the Piston had packed it in)… I thought that the Nikasil coating had been worn away. But after sending high res pics to "Dr. Aprilia", he confirmed that it was more a case of the Aluminium from the piston that had been “deposited” on the Cylinder wall. The Nikasil coating is virtually bullet proof and can take a bit of abuse (but it still has its limits of course). So, I picked up a liter of Muriatic Acid to “wash” away the aluminium deposited on the wall. I spent most of Friday looking for a store that had some and while many had it, it came in 4 liter (1 gallon) containers! I needed all of a tablespoon!!!! Finally Canadian Tire had Muriatic Acid in 1 liter containers. So, purchasing the Acid along with a BOAT load of safety items (chemical resistance gloves and brushes, eye protection, a mask, Baking Soda to neutralize the acid, etc), I was all set!




In many ways, I was lucky. The result was a part of the piston overheating and, in essence, melting a part of itself onto the Cylinder wall. This caused the piston ring to be seated all the way into its track. Then, with the piston “melting”, it sealed it into place.





I applied just a drop to the locations with the Aluminium and the clear liquid turned black almost immediately!! A good sign as I knew that when acid comes into contact with Aluminium, it turns the clear liquid black. I waited about 30 seconds, then applied my water and baking soda solution to neutralize the acid. And inspect the work. It removed ALL of the smallest amount of Aluminium and reduced the other spots by at least 50%. So I did 4 more “treatments” and the results are in the picture below…





I think that I will do a couple more treatments to get the last of the Aluminium off of the cylinder wall later this week.

On a good note, I have found a way to get what I needed in order to get back up and running!! If all goes well, I'll have spare Pistons, Cylinder Kit, and hopefully spare Rings and Gaskets in the next 10 to 12 days!!! All thanks to a Member!

[NoNameForEver]

Aha! You got yourself a proxy.... Why did you run that new piston/cylinder with a lean mixture, was it by accident?

[Grenadiers]

Yeah... It was totally my fault.

The result of a few things... Over exuberant behavior on my part to want to get running, the lack of knowledge in listening to what the engine was “saying” to me and of course, not turning up the Fuel Pressure enough.

Lack of Fuel pressure in a PFI build means lack of oil to the Cylinder as we run a pre-mix… With a lack of oil, the results are apparent…

[NoNameForEver]

Over exuberant behavior on my part to want to get running, ......

Hm.... Could be as a result of hypoxia /altitude sickness after your long stay in Colorado... I would blame it on that..

[Rosscofat]

a little of both.. into the decompression chamber for you!

[Grenadiers]

LMAO!!

OK, sounds good! I'll go with that!

[captdan]

Greandiers- Did you sand/hone the cylinder at all or is that solely the result of the Muriatic Acid “wash?” Very cool.

[Grenadiers]

Just the Acid only, and only on the Aluminum transfer that was on the cylinder wall.

[Rosscofat]

Glad you are getting your parts you need! Can not wait to see to see the thing in its natural habitat

oh and if you have forgot.. Lots of pics and Vids! put that new camera to good use!

[Grenadiers]

That's the plan...

I have to tell you that the weather here for the last 2 weeks has been just great and the forecast for the next 7 days is sunny with temps between 28 to 31C (today we it 31 with a Humidex of 43c!!) and the road is just calling out to me!!

This is torture...

[Rosscofat]

rain rain here... yay