Aprilia Rs 125, Which Power Valve should i choose?
BC Enginering Valve Kit CNC
It's an interesting one.
I'm not familiar with the latter system, but understand the Pneumatic system.
I want to start off by saying both systems are inferior to the RAVE 2 System Developed by Rotax.
RAVE 1 can be found on earlier Aprilia Futura AF1's way back in the late 80's early 90's.
This system is somewhat similar to the Italkit system. It's a pneumatic system that uses a spring and exhaust pressure to actuate the exhaust port height.
The problems with the system is that it required the engine to be making enough exhaust pressure for it to open. For town riding and general cruising, it was found that the oily nature of two stroke engines gummed up the actuation system, increasing the pressure required to actuate the valve, or causing it to stay closed. The result was that the system required to be cleaned more often, and proved unreliable. It's also a reactive design, I.E. it requires the exhaust pressure to build to open, rather than it just being open the moment you need it open.
Then came Aprilia's Solenoid Solution. This system used a separate ECU in conjunction with a solenoid to precisely control the opening actuation of the port. This resulted in the port being opened in a controlled manner, and not reliant on the exhaust gases to push the valve. The solenoid is strong enough to over come the gummyness of the engine, but often finding the weak point being the cables fraying and snapping.
The drawbacks of the Aprilia's solution is that it's an expensive alternative to the RAVE systems. It requires more parts. It's also not as easy to configure unlike the RAVE's pneumatic solution, where by the opening of the valve is controlled by the preload spring pressure.
You said to me you're looking at a Zeeltronic. If that's the case then Aprilia's System should be your only choice for consideration.
Zeeltronic systems allows you to fully program the solenoid system, controlling precisely the RPM's that you want the Valve to open at, as well as the amount to open by. The Zeeltronic for the RS also comes with the ability to add in a Throttle Position Sensor. I haven't tested it, but it might also be possible to tie this back into the system to allow the port to close at certain throttle openings. Although don't quote me on that.
If your tuning requires it, you could have the valve open at 50% by 10'000 RPM, and 100% by 10'001 RPM. This is simply not possible with a Pneumatic solution. The reason why RAVE still exists in various forms today is likely due to the the Rotax Max engine still being produced for racing Karts. In Kart racing, you are on or off the throttle, with little various inbetween states. In other words, the exhaust port is either to be fully open by 8K RPM at Wide Open Throttle, or it is closed.
Even then, you could argue the Aprilia's system is simply a more elegant design. Race engines are not only thrashed, reducing the gummyness of the valve, but also regularly maintained and rebuilt. Therefore the pneumatic valve is cleaned.
The Aprilia's system is more expensive and older than Italkits design. But is the best solution. Even more so when you are running a Zeeltronic.
@pedrobatista10 I've actually looked into this quite a bit. @Calum is very knowable on these bikes and his comments are spot on. I would add that there's not a great deal of difference between the two, one is pneumatically operated and requires air to move it. The other uses a solenoid to push a rod to open and close it. Both are about the same performance wise with the pneumatic kit requiring less maintenance, which most owners do not keep up. However the Rave Solenoid kits are more controllable and can be set to open and close at chosen RPM's, as they have their own stand-alone ECU. Both kits you have quoted are pneumatic and both will require a hole to be drilled in the head and also both use an aluminium blade which is less durable then the older stainless steel blades, which can still be found and are well worth seeking out. Plus the ali blades need regular maintenance to keep em in tip top shape.
Most upgrade kits for the power valve aka rave valve are designed for race bikes, which get stripped down, parts swapped and engines rebuilt weekly, so durability is key for a road bike. Ultimately it's all down to personal preference and whether you want to spend more time riding or more time maintaining your bike? The Rave solenoid kit seems to be the top choice for most owners looking for top performance from their bikes. And is indeed what Aprilia went for when the updated the bikes, so I guess that was from R&D feedback they received from the race teams. Also there was actually a recent discussion on this very topic one of the RS Facebook groups, well worth a read and joining the group.
@NINJA Not heard about the blades being week between older and new ones. Pretty sure original Rotax blades are Ally as well. I sold them and bought the Titanium Coated one.
I don't know, but I didn't think the blade wears, since they're made of a similar material to our DT powervalves. But I heard the housing is prone to crack, and the bit that retains the cables fail. But the new moto-R ones should address this.
When it comes to performance, real world performance, I'll admit there won't be any difference. But closed lab, dyno print outs, you can make more power on the RAVE 2 system.
I think the RAVE 1 system suffered reliability for teenagers way back when. Only the pneumatic systems require the hole drilled in the cylinder, this is done on the 140 kits.
@Calum "WEEK" LOL
OEM blades are made from stainless steel, which explains why they cost twice as much as the Ali replacement one's. Any blade will wear over time as it's being pushed back and forth in a slot, as well as the carbon build up if it's not being maintained properly. Plus if the top end goes Ali blades will fail quicker than a steel blade. Race teams will replace blades frequently over a season, so hence why an Ali blade is more cost effective over time.
Granted there's not much ultimately too choose between the two, but as the OEM item in a SS unit, I would personally go with that.
I'm not thinking of RAVE 2, I'm talking purely about the Solenoid solution. I thought that was RAVE 2, but I was wrong. RAVE 2 is still Pneumatic. The Solenoid solution was created by Aprilia not Rotax, and it's Aprilia's Solution which is the superior one. Not the RAVE 2.
@Calum Thankfully my MX came with the solenoid version, so I'll be sticking with that. I take it that with the Zeeltronic you remove the Rave ECU and let the Zeely control everything???
I think that the 11KW version had an Aluminum valve blade and this was uprated to a Stainless Steel blade for the full power 34Bhp models. Which probably explains why there are 2 different types of blade materials in operation?
@NINJA He's getting a Zeel anyway, I got two sets of Solenoids for less than £50. I kept an eye out for bargains.
The later restricted models did not have a powervalve, instead it was blanked off. But Standard Italians left the wiring loom in for the ECU. Good lads
Which probably explains why they'd be aluminium, since they don't move. I can't imagine the Moto-r ones really being troublesome? But a you say, it's half the price of the OEM unit. And sorry to say this, but Aprilia don't scrimp.
Having had a few Aprilia motors in my time, I rate them above KTM. Just because they are so CHEAP in comparison! The KTM might be a better spec, but you pay for it. The Arpilia's are just so well priced for the spec. Someone commented on my DT Project saying how it looks like a Aprilia MX, to which I said thanks. Cause they're well spec'd for the money!