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After experimenting and researching for months, I can happily say I have successfully unrestricted my LAMS SV650 2018 (2016-2018 is the same bike).
I bought a Bazzaz fuel tuner and it certainly smoothed out the throttle a lot but it did not unrestrict it.
I did some research and found out that our bikes come with secondary throttle valves. In each of the two throttle bodies, there are the primary butterfly valves which are controlled with your hand by twisting the throttle, and there are the secondary butterfly valves that are controlled solely by the ECU. The long rods on the right side of the throttle bodies under the airbox are contolled by the ECU and actuate the secondary valves. The power is limited by the ECU keeping these secondary valves closed more than they are on the full powered SV650. As we all know, more air = more power so by closing the secondary valves more on the LAMs version, there is not as much air being sucked into the engine compared to the full powered version.
These secondary valves are what also limits the max speed on the LAMS version... as you reach about 130kms/h the ECU completely closes the secondary valves so the engine can't suck in anymore air, therefore not making anymore power to go faster.
So what did I do? I took the airbox off the throttle bodies and (thankfully) the secondary valves are easy to access as they are at the top of the throttle bodies. Each valve has two screws in the top... I unscrewed them and removed the two valves. Unfortunately as much as I would like to remove the whole secondary valve actuator (long metal rods) to provide more space and get rid of useless parts, the ECU would throw an engine light as it would think they aren't working. So because I only unscrewed the valves, the system still works normally, trickingt he ECU, but there just aren't any valves to restrict airflow.
Did this work? YES :)
Without even trying, I sometimes accidently pop a wheelie in first gear. The bike now powers off with so much more force down the road.
My partner has the unrestricted version from 2011 and I can now take off just as fast as her whereas I couldn't before.
I have also gotten the bike up to almost 170kms/h before running out of road. Plus I'm sure the wind would blow me off the bike if I tried to hit 200kms/h considering there's no windshield but I'll still try someday ;)

Now, the con.... there is only one but I never notice it. The secondary valves on the full powered SV650 are there to smooth out the throttle response. What does that mean? Well it means that they help keep the air velocity into the engine at it's best. When you open the throttle fully with your hand, the ECU closes the secondary valves a bit to keep the airflow smooth. Imagine if the valves were fully opened in one quick turn.... there would be a huge bombardment of air that messes with the feel of the bike. Now because I have removed my secondary valves, if I open the throttle all the way in one quick turn, the bike feels flat and doesn't keep going faster until the engine revs catchup with the amount of air going in and starts utilising all the air, but this only lasts for a split second. Now I say that I don't notice this because I never just ram the throttle wide open. So this free and relatively easy way of unrestricting the 2016-2018 SV650 is the only one that actually works and as long as you aren't rough and violent with the throttle, it will work absolutely perfectly and smoothly. I am a smooth and fast, skilled rider so the split-second flatness of the bike never happens to me.
If you think you have the skills and tools to do this properly, go for it. You can always just put the valves back in if you don't like it but I've had mine out for about 2 months and I can happily say they are NEVER going back in.

An unrestricted ECU is about $1500 (yes I've asked from official Suzuki dealers as it is the only place you can get it). An ECU flash is really just a gimmick to do stuff you can do yourself yet charging you a fortune for it.
I think I've covered it all. Let me know if there's anything I need to clarify.







EDIT

Just an update on this.... The flat spot in the rev range I mentioned was because I have a short aftermarket exhaust that wasn't creating enough back pressure. I added a second baffle to my pipe and it has eliminated the flat spot and now I have the true, pure power of the SV650 V-Twin. This is an issue specific to me due to my exhaust so stock muffler should be fine regarding this issue. If you do this modification and have this flat spot issue, you need more back pressure. There are a few ways to do it but it depends on your setup so I won't bother going into it right now. If you do this mod and experience the flat spot, let me know and I can suggest some help to fix it.

Long term update........
I keep a close eye on my temperature and sounds from my bike to make sure everything's running as it should.
After about a month of taking out the secondary throttle valves, the engine temperature has not increased at all and the engine has been purring as perfectly as it should. I mention the temperature and engine sound because people will say that this change will make your bike lean. Lean running engines increase in temperature and are prone to pre-detonations in the piston that create a loud knocking sound. I haven't had a single issue at all
I have an sv650 AUl9 in the UK, assuming this is under Lams 47hp, I am thinking of this. Can you give me more of a guide?
 

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Though me personally if I didn't have a full license, I still would have bought the full powered SV, because the police don't know what bikes are LAMS or not, they might assume, but they don't know.
The police absolutely know if you're riding a LAMS model or not. Its registered as a LAMS model and the cops just need to check your license plate. They wont know if its a derestricted LAMS on the roadside but if they know bikes (like a motorcycle cop) they will know when its going twice as fast as it should be.
 

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I have an sv650 AUl9 in the UK, assuming this is under Lams 47hp, I am thinking of this. Can you give me more of a guide?
Hey, i'm also interested in this on my SV650 2019(EU). Is just removing the valves is OK ? or will it run the motor too lean ? Is there some sort of sensor that will compensate this extra airflow ? Everything is stock on my bike. (no fuel tuner or even exhaust)

Sorry for not perfect language, i dont natively speak English.
 

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The ECU calculates the fuelling based on how much throttle you give, the inlet air pressure & temperature, and the reading from the O2 sensor in the exhaust.

If removing the STV plates was changing the fuel mixture so much that it is outside the range that the ECU expects to see at any time, the ECU would throw a check engine light and fault code.

If Lovemtucken is not getting a CEL or fault codes, then it is likely that the STV restriction is activated by the engine RPM only. In other words, the engine mapping on a restricted motor will be the same as on an unrestricted full power motor, until the rpm at which the engine develops 47bhp. Then the STVs will close over to restrict airflow so that the engine cannot produce more than 47bhp.

Removing the STV plates but leaving everything else in place means that the ECU thinks it is limiting the power output because the STV actuator is moving and the STV position sensor is still working. But the restriction is gone, and the ECU is just doing its job of fuelling according to air pressure, temperature, primary throttle input and O2 in the exhaust.
 

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The STP restriction is based on RPM and throttle position. So if you're at 7600 RPM and 100% throttle your secondary plates are only open 43%.

The fuelling TPS is map is also really lean compared to an unrestricted bike. So you'll be running quite lean if you just remove the secondary plates.
 
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