2018 Aprilia RS4 50 Euro 4 Upgrade Project

[toratora]

Raimu adds safety gear to Hane's SuFour
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E-clip enabled Euro2

Hane would approve the extra safety gear!

Do you think the crash had to do with the starter failing? Since it was covered under warranty were you able to bring in the starter to the dealer to swap it out, or did they want the whole bike to do the swap?

For gearing on kitted bikes I will run either a 14, or 15 up front with a 52, or 53 in the rear. The rear sprocket is generally chosen based on what comes with the bike. The front sprocket has to do with where I'll be riding.

If it's hilly then I'll want the 14 to be able to get out of the tight uphill corners. If I need more top speed, say for some quick sprints on the freeway, then the 15 is quite useful.

It would probably be good to have a selection of front sprockets, and just use an E-clip to make swapping them out easy. The Grom uses the same front sprockets as the Derbi so it's easy to get front sprockets for these bikes.

You keep asking about other things to get for the bike! It's pretty much endless. Again look through the project threads for ideas. I would probably ditch the stock tires and fit Sava/Mitas MC50s on there. That's what I did with both of my bikes that have the same type wheels.

I'm also a fan of more gauges. A water temp gauge would be easy to add. EGT would be a little harder, but those are nice too. They probably aren't super important on this build, but get the water one. The Koso I have on the DRP would be nice.

[Berkeley]

Thanks Tora.
Didn't know about the tyre upgrade..although have read your posts many times over.. missed it maybe?

The crash may had something to do with it but it wasn't a high impact one and it didn't get hit..so I doubtful it was??? I had to convince the shop that it was the starter, as didn't bring the bike in. They ordered a new one and said to bring the old one in as they have to send it off. Glad it was that else would have looked a little silly.

If I run a 14/53 then should the 132 chain be ok still with Just the back wheel moving fwd a bit? Or will have to get a 134 chain?

Also looking at the air filters.. I see many different types including some venturi effect ones? Carbon covered ones, long foam ones,short wide ones.. have you tried these and any good or should just pop on a std polini one? https://www.maxiscoot.com/polini-air-fi ... 082-3.html.
Or just a k&n filter as you mentioned?
https://www.amazon.com/RC-2320-Universa ... B00062YOXQ
Thanks

[toratora]

K&N Style Air Filter for the Air Box
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132 Link DID ER 420NZ3 Chain

Filters
Basically those are called pod filters. They have their place, but not on your bike. You want to keep the air box. Removing the air box on these bikes is generally a very bad idea. The air box makes it easier to tune, quieter, less susceptible to environmental conditions, and other things. When you replace the air box with a pod filter you create a total nightmare of bad possibilities.

The K&N Style
What you need is a cleanable air filter that goes inside the air box. K&N makes them, but probably not for this bike. So look for something like this one in the image to the right. These have to be oiled to function properly. But the stock air filter in the bike should be fine for quite a while, unless you do a lot of off road riding stirring up clouds of dirt.

Adapters
Like I mentioned previously you’ll need an adapter from the carb to the air box, so measure the nozzle coming from the air box so that you can get the proper adapter for the carburetor.

Chains
I’m not sure what combo of things you got for your chain—I’m running this chain with a 16/53 sprocket combo on the Red Rocket. If 132 links works for that you shouldn’t have any issues with it on your bike running a 14/53, or 15/53.

[Berkeley]

thanks tora,
.... most helpful

I took the bike out for a quick test drive and still have the issues of it dying when on occasions I let off the throttle, or when i come to a stop. I set the idle so it ran at 2500 rpm.. i tried to tweak it down but theres no little response either revving high or back down to 1250 but it happened again. Once its died it very hard to start again. Only when you bump it down the road, then use the stater motor does it fire back into life.

Is this dirty fuel? a blocked pilot jet, damaged idle valve,a damaged float as you said before or running too lean? ( at the moment about turns out on the mix)
When I took it apart last time everything seemed to be fine.. no obvious damage so im wondering what? If anyone has some other ideas or stages to diagnose it then would be glad to hear it.. all the videos on you tube just point to increase the idle speed..

I also noticed on this test run that when im changing gear in the power band +7500 rpm, in the next higher gear it jumps back down to 7000 rpm, just below the power band which it never used to do before.. just wondered if these were linked in any way?

any light spread onto this would be great thanks

[jkv357]

If there is any possibility the fuel is not good I would replace it before doing anything else. It will never run right, no matter what you do, if the gas is bad..

What is the idle mixture set at now? Did you set it to get the highest RPMs when hot, then adjust it back to the correct speed with the idle speed screw?

What does the plug look like?

If it's anything like mine, it's just starting to get good about 8000, and shifting is best around 10,000 or slightly more. How much it drops back down when you shift depends on the gear you are in and the overall gear ratio.

[Berkeley]

Ok cool I will start with the fuel first.
I set it up with 2 turns of the air fuel mix screw out and left it at that last time.

Yesterday I tried doing the procedure but just warming the bike up it died... then hard to start.. so stopped the procedure.
Will give it another go tonight.

Before the bike was like yours and could always change gear above the power band and be in it on the next gear up so maintaining the acceleration
....let's see
Btw I ordered every thing for 70cc upgrade last night.. but would be good to do the change with a healthy bike first.

[Berkeley]

Hi there,

Changed the fuel, Adjusted mix screw, about 3/4 turn out for it to be revving the highest. idle set at 1500 rpm, much better above 7000rpm when changing gear.. so looks like it was running lean in the previous setup.

However bike still stalled when slowing down. Also when it's in the garage idling, the bike will just die after 2 mins or so........again very hard to restart again.

The plug looks like this and looking at the charts I believe its fine???

Next ideas??

Cheers

[jkv357]

If it idles fine for a while, and then dies, usually that means there is a fuel delivery problem like a plugged fuel filter or gas tank vent.

[kaldis12]

Whaaaat, what kinda sparkplug is that? Just stick a normal NGK B(R)8ES plug in there. You should get the BR type because of the resistor. But maybe the normal B could work too.

[jkv357]

I can't say I've seen a plug quite like that either.