2018 Aprilia RS4 50 Euro 4 Upgrade Project

[kaldis12]

Seems to me that when you start it up the float bowl is full of fuel. After a while it runs out. This could be because: 1, there is something in the carb, clean it out everywhere.
2, is that the float height is too low. I cant remember that it is settable on the CP carb or not. Tora will definetly know this. But now we knoe that this should be fuel related.

[jkv357]

How accurate do you think the jetting on the new carb?

Was it off of a particular model or was the jetting set for a specific engine?

[kaldis12]

Yeah jetting could be an other thing. I had this issue when my carb bowl couldnt fill up all the way because of a little dirt. Cleaned it and all good. I think there should be something at the bowl. Im sure the jetting is not even right because he didnt start it up once so thats propably bad too. You could try setting on the air but I doubt that would help. Check the needle height and the idle jet too.

[Berkeley]

Hi guys,

The jetting was a complete guess. The 19mm carb came with a 40 90 setup. I changed it for a 46 96.

This was from the uk dealer:

'No as far as i can see all you have is the electronic choke and a water pipe for warm up purposes….

Can’t see any throttle position sensor…..the only electronic thing in the carb is the choke.'

This was Looking the standard carb.. nothing mentioned about the electronic sensor.

Inside the new float bowl there was a black plastic cap inside that circulated the main jet. I didnt see one on the old carb . or ever have before on any other ones . Could this be there just for protection and needs to be removed?

I would have taken some photos of this but everything was covered in petrol.

[jkv357]

Hi guys,

The jetting was a complete guess. The 19mm carb came with a 40 90 setup. I changed it for a 46 96.

This was from the uk dealer:

'No as far as i can see all you have is the electronic choke and a water pipe for warm up purposes….

Can’t see any throttle position sensor…..the only electronic thing in the carb is the choke.'

This was Looking the standard carb.. nothing mentioned about the electronic sensor.

Inside the new float bowl there was a black plastic cap inside that circulated the main jet. I didnt see one on the old carb . or ever have before on any other ones . Could this be there just for protection and needs to be removed?

I would have taken some photos of this but everything was covered in petrol.

The connector was for the electric choke then - so you should be fine.

I have seen a plastic ring around the Main Jet before on dirt bikes. I assumed it shrouded the jet to make it less likely to intake a gulp of air if the gas in the bowl sloshes around - or something like that.

[kaldis12]

That plastic cap should be okay there if I remember correctly. It was a few years ago when I worked with this carb. I'm pretty sure that your issue has to do something with the carb settings if your fuel is flowing freely to your carb. Clean it out completly just to be sure. For me this is hard to tell it from distance you know. Tora will know Im pretty sure.

[Berkeley]

the connector, he was referring to was on the old carb as i sent him a pic of that. he didnt remark about the sensor that we are all questioning... maybe tomorrow ill get some answers??

will clean it out , maybe try with a bigger pilot jet?? will await answers from god before doing anything.. thanks for all of your inputs.

[toratora]

These carbs come jetted nearly perfect. I've even put them on the bike, and not had to change a thing. I would try putting the jet it came with back in it.

Do you have a link to the 2016/17 manual? I don't think I have those it and I might be able to find some info in there. Also, ask the dealer if he can send you a wiring diagram.

[kaldis12]

Tora, if that was the problem I rip my fikking pants off xD I can tell a littlebit without seening it in real life and now you are on the way to fix the problem from like propably thousands of km. Dudeee you are proo I hope what Tora said will fix it but ohh maan

[Berkeley]

Oh... so I wish... Tried it today and still the same. Tried with an 8 spark as well. A bit ill at the moment will try bumping it tomorrow to compare how it ran before.
Thanks for all your input!!!

Re the sensor...

The dealer said 'this is a valve for gasoline vapors you can disconnect it'