Speed Limiter Removal on a 1200 ?

[bstard]

Hi
The Japanese model GS1200SS I have has a speed limiter that cuts in at 180 kph.
So how do you remove this limiter or even better how can I make up a switch to switch it on and off.
This is definitely a speed based limiter as when you disconnect the front sprocket sensor you seem to disable the limiter but you lose your speedo as well.
Any Idea's ?
Thanks
Richard

[Red01]

The B12 doesn't have that "feature" but in some markets it has a wire that controls output in lower gears.  IIRC, it's to meet some sound requirement.  In those markets, that feature can be defeated by snipping a wire in the harness for the sensor.  So your mission would be to find out which one of those wires in your harness does that.  Do you have a wiring diagram for the SS?

[Chris H]

I read that you can get a TRE de-restriction box to remap some Suzuki models, d'nt know if they would derstrict a speed limiter as they are for the power side, but worth looking into, you could maybe email the company.

[bstard]

Hi
Thanks for trying to help but those TRE's wont do it.
But I am slowly gathering info on how to do it...but it is painful 
Just about ever GS1200SS here in NZ has had the Speed Limiter removed but do you think anyone will tell me how to do it !!!
I cant believe that every single bike here in NZ had it done by some bike shop and they are all keeping the info to themselves.       Someone must have done it themselves.
I think I have found out enough info to remove it.It involves cutting a wire from the gear position switch and connecting it ...thru a 1.5 K ohm resister...to earth.
Once I have tested it and confirmed that it works I will post the info here and on my own web site.
Just so the next poor bastard doesn't have to go thru the trouble I am at the moment.
Thanks
Richard

[Chris H]

No way cannot beleive Suzuki still do this, i have a Jap 400 and they all use this form of restriction, look in the 250/400 blog there will be loads in there. On the B4 ther are two wires from the gear sensor, one of them (green/yellow i think) feeds a resistance reading back to the cdi, in the low gears you get 1.5Kohm and full power, you disconnect this then put a 1.5K resistor between the cdi wire and ground and leave the other end the one to the gear selector loose, this is for a B4 but you sound similar.

[bstard]

I read that you can get a TRE de-restriction box to remap some Suzuki models, d'nt know if they would derstrict a speed limiter as they are for the power side, but worth looking into, you could maybe email the company.

Hi
Sorry Chris but it seems you were correct about the TRE. If you look here you will see a proper writeup on what a TE is and does. Thanks to Jim Cotter for his great web page.
http://www.maxlean.com/motorcyclepages/tre.htm
Although the GS is not fuel injected they still use the change in resistance that occurs in each gear to tell the bike that once your in 4th gear or above then bring in the rev limiter once 180kph has been reached. Still not sure precisely how it is done as the speed sensor on the front sprocket is not connected to the ignition at all.Just the speedo.
But however they do it... the way around it is to cut the pink wire coming from the gear position sensor and connect the CDI side of it to a 1.5K ohm resistor then connect that to earth.
This fools the bike into thinking it is in 3rd gear all the time.
Don't just cut the pink wire as that will cause the CDI to move the rev limiter down to 7000rpm in all gears.
Hope this is of help to anyone with a Japanese model GS1200.
Thanks for your help Chris.
Richard

[Red01]

Although the GS is not fuel injected they still use the change in resistance that occurs in each gear to tell the bike that once your in 4th gear or above then bring in the rev limiter once 180kph has been reached. Still not sure precisely how it is done as the speed sensor on the front sprocket is not connected to the ignition at all. Just the speedo.

My guess is they use RPM and gear position... so if you changed gearing, the rev/speed limiter would be faster or slower than 180kph - depending on which way you went with the gearing, but at the same rpm as with the stock gearing.

[Chris H]

Glad to hear you nailed it!!
It must be the same for all the home market Suzukis using different resistance for each gear, its a bit simpler on the B4 as we only get 3 resistances, lower gears, neutral and higher. If you find which restrict on your GS, you could play around with the other values and find if one gives a nice power curve cause how the TRE reads they are also changing the timing for different resistances, its usually to give good emissions for non Jap countries, you may be like me and not get these as we run Jap only models!!
I looked at some of the Jap websites for your bike using babelfish to translate and there are some very nice parts available for your GS.
All the best
Chris.

[bstard]

Hi
Just a little update on my speed limiter removal.
It worked fine.
Yesterday I ran the bike at a small drag meeting and although their timing gear was not the best I have gone from doing 11.9s @ 114mph to consistent 11.6 .I'm not sure on the speed as the timing gear was a bit inconsistent.
I will be down into the  11.5s on a properly prepared track.
The changes I made from my stock standard bike...that ran consistent 11.9s....are

Removed speed limiter
Down one gear on front sprocket
Slotted pickup plate and advanced ignition 3 degrees
Dyna Coils and Leads.
Adjusted TPS closer to standard spec's

I am racing ,in our first National competition meeting for this new season, next weekend and should have some better info after that.
Richard