2018 Aprilia RS4 50 Euro 4 Upgrade Project

[toratora]

I've not been able to find a workshop manual, or even any docs for the 2018 bike. The 2011 workshop manual is online in a pdf. Many things are similar between the two bikes. But the wiring diagram is of course going to be quite different.

[Berkeley]

The adapter finally came today and as I received news that the 14mm sensor was sent today I could fill in the hole with some high heat weld putty.



Bumped it again and was the same as yesterday, slowing down or pulling in the clutch it died if you didnt keep the revs up. The idle screw is almost all the way in.
So do i need to change any of the jets or other settings?its hard to say anything from my side about the right air/fuel mix etc as its not running correctly so i cant make the adjustments to verify.

I saw links to the 2011 manual too.. but nothing newer

[jkv357]

Bumped it again and was the same as yesterday, slowing down or pulling in the clutch it died if you didnt keep the revs up. The idle screw is almost all the way in.
So do i need to change any of the jets or other settings?its hard to say anything from my side about the right air/fuel mix etc as its not running correctly so i cant make the adjustments to verify.

I saw links to the 2011 manual too.. but nothing newer

The Idle Speed screw or the Idle Mixture screw?

If it's the Idle Mixture screw you need to determine if the adjustment is a fuel-bleed or an air-bleed. I would guess it's an air-bleed and being all the way in means it needs more fuel - so a larger Pilot Jet is required.

I'd confirm the type (air or fuel) of adjustment though.

[Berkeley]

Idle speed screw

[toratora]

Generally when running it in the bike is jetted a little rich, but spending a lot of time trying to get a perfect carb tune probably isn't worth while, because when you get it run in then you'll be re-jetting anyway.

So bump start it. Do the heat cycles. Get some run in time on it, and then fine tune the carb.

[jkv357]

Idle speed screw

Have you tried making adjustments to the Idle Mixture setting?

You shouldn't need to have the Idle Speed screw bottomed in order to keep it running.

I would look at the color of the plug for reference.

[toratora]

I did find the wiring diagram for the Derbi 125 4T. It's probably fairly similar to the later two strokes like your bike. There is a system that prevents the starter motor from spinning if either the clutch isn't pulled in, or the gear box in neutral. There is also a kickstand switch that will kill the spark if not in the proper position. I don't see any smog equipment that would keep the bike from running.

Also, I don't believe any of these items are your issue. My hypothesis is that currently the starter motor just cannot over come the friction and insertion to spin the engine fast enough to start it. Hopefully that will change once the engine is run in a bit.

[Berkeley]

Thanks Tora for the diagram.
Yeah I did Check multiple times of the above and it's not them.
Hopefully the temp sensor will arrive today so can run it in over the weekend without fear.
What's the max water temp it should be?

When i did the last start test the water feed pipe to the engine felt warm but the exit pipe on the other side of the engine/water pump felt luke warm /cold. I would have expected a constant temp on both sides now the termostat has been removed. So does the water pump always run or only kick in at a certain temp .This maybe nothing but something I noticed.

Below are just some observations that may give some more clues or reconfimations of the problem

When bumping the bike it takes a mate pushing it to get it going..to pick up enough speed then to turn it over fast enough to start. The choke is out and the throttle is open all the way for it to bring it into life.
Again normally a little 1 person bump should just be needed.

Putting the slide into the carb and connecting the wire to it I had to use the metal extension wire sleve of the old one. Without it there was too much slack. This meant that the spring was compressed quite a bit.. more than the old one fitting it inside the carb. Twisting the throttle the slide moved all the way up and releasing it it released back down and hit the speed Idle screw. Just checking that this is nothing.

Cheers

[kaldis12]

Temp should be between 60-80 celsius. I like the 65-70 celsius.

The water inlet at the cylindet and out at the pump. You should feel cold water at inlet and warm at outlet when the engine is warm. Otherwise when the engine is cold you can experience colder water at outlet. Because of the colder aluminium.

Mine needed 3 fukking people to gp start it. So dont underestimate anything.

[Berkeley]

Ok twat moment.
i filled up the cooling reservoir thinking it would fill the entire cooling system, only filled up one half ( the inlet side, even though its at the top of the radiator). so fixed that and temperature much better.
Bumped it this morning and ran better , still cannot idle low even though the idle speed screw is all the way in. I think this must be due to the friction of the piston rings and having an influence.
Or is this something else.. not sure.