Derestricting

[Andybarber83]

Hi all, I'm new to the forum and just got my first bike which is 03 SV650s but I was told by the previous owner it is restricted du to him only having an A2 license. I've checked the ECU and seems to be the unrestricted version and there is no throttle stop fitted either. Does anyone know if there is another way it could be restricted and of so how to derestrict?

Many thanks.

[Seeker]

Welcome.

I don't know the answer although the subject has come up a lot in one form or another. A quick search of the site says that the K3-K7 pointy is restricted via an MGT061 ECU whereas the curvy uses a mechanical device.

https://forums.sv650.org/showthread.php?t=227483
http://forums.sv650.org/showthread.php?t=60163
https://forums.sv650.org/showthread.php?t=126474

Perhaps the previous owner was mistaken?

[Craig380]

I'm fairly certain the K3 - K7 bikes were restricted just by fitting a stop on the throttle body which only allows the main butterflies to open halfway.

I still have a set of throttle bodies I got cheap off eBay in case I needed them for my old K6. They have the stop plate fitted and the retaining screw is Loctited in place.

I recall seeing dyno charts of a K3 where the owner had done pulls at 50% throttle (from the TPS signal) as well as at wide-open. The 50% throttle run peaked at just under 50bhp.

[Andybarber83]

Thanks for the replies, I've checked the ECU which is the mt060 and apparently the unrestricted one. I've also checked if there is a throttle stopper plate in plate but negative on that too. I've read that removing the stva is the only other way but a bit dubious of this method due to the conflicting opinions.

[Craig380]

The quickest way to tell is to find a nice, quiet private road somewhere and give it the beans in 5th and 6th. If it pulls hard past 110 and keeps pulling, it isn't restricted

[Dave20046]

Originally Posted by Craig380

The quickest way to tell is to find a nice, quiet private road somewhere and give it the beans in 5th and 6th. If it pulls hard past 110 and keeps pulling, it isn't restricted

My thoughts exactly

I recall seeing dyno charts of a K3 where the owner had done pulls at 50% throttle (from the TPS signal) as well as at wide-open. The 50% throttle run peaked at just under 50bhp.

Isn't the point of restricting to limit it to 33bhp?
Mine was good to about 80-85mph, you then needed your chin on the tank to creep past 90.

[Andybarber83]

Originally Posted by Dave20046

My thoughts exactly



Isn't the point of restricting to limit it to 33bhp?
Mine was good to about 80-85mph, you then needed your chin on the tank to creep past 90.

Was yours restricted? I've contacted the previous owner who said he never bothered having mine restricted so should be fine as it is 🙂

[Craig380]

Here are those dyno charts of runs at 25%, 50% and 100% throttle (throttle opening measured by TPS voltage), for what it's worth:

http://forums.sv650.org/showthread.php?t=226401

[Dave20046]

Originally Posted by Andybarber83

Was yours restricted? I've contacted the previous owner who said he never bothered having mine restricted so should be fine as it is 🙂

Yes it was, I restricted it myself. An unrestricted one will pull to about 110-115 on the clocks and then creep from there.
If you are of an age/experience where you should be restricted I'd recommend restricting it for at least a year. It teaches you a lot more about the bike and riding than without IMO and it still has enough power to get out of trouble when needed.

[Dave20046]

Originally Posted by Craig380

Here are those dyno charts of runs at 25%, 50% and 100% throttle (throttle opening measured by TPS voltage), for what it's worth:

http://forums.sv650.org/showthread.php?t=226401

That's interesting though I can't see it mentions being fully restricted , only throttle opening %. My understanding was proper restriction was either a different ECU or a throttle stop and FI restrictors. Had a quick google and it's a bit conflicting but I found the below on this forum that might help AndyB - but it sounds like he's sorted anyway.
If the aftermarket restriction kits let you get away with 50hp and the law is 33hp there could be an issue with insurance but more interestingly it would make the SV really desirable to teenagers!

..possibly you have a full power ecu and the previous owner has installed an aftermarket restriction kit....(cheaper than a new ecu)

Quick check..lift rider seat....lift out ecu which sits behind battery.... check the part number( MT something something something)...if it ends in 60 its full power, and if it ends in 61 its restricted.

If its 61 then you need a replacement one for yer 70bhp or so....i got one second hand a month or so ago from england through a breakers i had to almost stalk over the phone .... they can be quite difficult to come by second hand for anything like reasonable money.

Drop me a pm if you need one and i'll see what I can do.



If its full power already and restricted through an aftermarket kit then im not sure...as you stated-possibly throttle stops and/or inlet washers...

Throttle.... open up throttle assy...2 screws iirc....check for anything that looks like its stopping full throttle movement.

Inlet washers,

lift tank, lift airbox....look for washers there...if none then lift throttle bodies....if no washers there then its not restricted.

Strictly speaking on the FI models there shouldnt be inlet washers for restriction....theres two sets of butterfly valves afaik..one controlled by the throttle, and the second controlled by the ecu in response to your throttle input and all the measured thingies that the ecu takes care of...so it would be "self restricting" if the throttle is limited.