[HydeWhyte]

Ok, does anyone know the truth about this story's subject? Does the 299/186 limit actually restrict the speed of motorcycles, or does it simply restrict the speedometer from indicating higher speeds while the bikes will go faster? I have heard both from various sources. My question regards stock bikes, not ones with ECU's that have been flashed to remove restrictions and/or increase performance.

Here's Why Your Sport Bike Is Restricted To 186 MPH (msn.com)

 

[Yellow Submarine]

AFAIK know the bike was actually restricted to not accelerate past the given speed of the “agreement”

I had a riding buddy who has since sadly passed away who had an early unrestricted ‘Busa and a later restricted one.

I rode both and the unrestricted one would definitely make you “pucker”. The later one while still no slouch by any stretch was not quite as violent in acceleration.

 

[Chuckster]

Not sure about the agreement, but I do know the speedo will not count above the limit. I put a hex nut on my dremel and slowly ramped it up on the speedo sensor. About half way up, it got to the 186mph.... adding more speed didn't change it. So, the limit is not only in the calculated engine speed/gearing from the ECM, but it's programmed in the speedo encoder as well.

 

[JCW]

I've read the Panigale R dash goes blank after 186 but continues to accelerate.

I believe there was an attempt... and it held for a while. now it's more loosely followed.
I think most japanese bikes are electronically limited by the ecu.

 

[MadisonMotorsportUK]

As far as I am aware, the agreement is still being followed, it's been in effect since the early-mid 90's. I seem to remember a bit of a fuss being made regarding this when the 'Busa arrived but Suzuki relented in the end and started restricting them. I think they were just trying to prove a point. However, I don't think that Italian manufacturers really took much intentional notice of the agreement, it was more of a Japanese thing.

There have been several bikes that are more then capable of 200mph+, the Kawazaki GTR1400 is a good example, but as said above, they are restricted within the ECU.

There are also 90's bikes that can do those sorts of speeds with minor mods. My Thunderace had a book top speed of 186mph but I could get it to bend the needle off the top of the 190mph clock after fitting a 6 speed box and it was a 'Busa killer. I believe Yamaha intentionally fitted a 5 speed at the factory to keep it within the agreement, sources told me some years ago it was originally intended to have the 6 speed box but testing proved it could do over 210mph.

 

[QRO]

Ok, does anyone know the truth about this story's subject? Does the 299/186 limit actually restrict the speed of motorcycles, or does it simply restrict the speedometer from indicating higher speeds while the bikes will go faster? I have heard both from various sources. My question regards stock bikes, not ones with ECU's that have been flashed to remove restrictions and/or increase performance.

Here's Why Your Sport Bike Is Restricted To 186 MPH (msn.com)

It's a rev limit in top gear.

FWIW, MCN reported that the GSXR 750 doesn't have the limiter, so the stock bike will actually go faster than the 1000.

 

[Ghost020]

Reportedly (I watch You-tube too) the Ducatti Panagali V4 and Yamaha R1 at least can do over 200 mph stock, but won't show the speed past 186 mph. That's just like the old 1st gear speedometers GM at one time put in high performance cars. (SSHH, don't tell anyone the tachometer still works and some bikers can do math!)

 

[HydeWhyte]

I haven't tested this out on the roads and the fastest (indicated, not GPS) speed I've ever caught showing on any of my GoPro vids was 178 mph (actually it was a friend that pointed it out, I hadn't noticed). She felt like she had more there but I don't recall what the tach was reading at the time. My ECU has been flashed to include removal of the restriction but I'm not really curious enough about it to spin-up the Woolich Racing tuner to reflash back to stock in order to find out. Maybe one of these days if I'm bored.

 

[Ghost020]

I haven't tested this out on the roads and the fastest (indicated, not GPS) speed I've ever caught showing on any of my GoPro vids was 178 mph (actually it was a friend that pointed it out, I hadn't noticed). She felt like she had more there but I don't recall what the tach was reading at the time. My ECU has been flashed to include removal of the restriction but I'm not really curious enough about it to spin-up the Woolich Racing tuner to reflash back to stock in order to find out. Maybe one of these days if I'm bored.

Coincidentally that seems to be Suzuki's officially listed top speed for the 750, but it's limited by horse-power, gearing and air resistance, not electronics.

 

[HydeWhyte]

Coincidentally that seems to be Suzuki's officially listed top speed for the 750, but it's limited by horse-power, gearing and air resistance, not electronics.

Since speedo's are made to display ~10% faster than actual speed (to meet the regulation that they can't show less than actual speed) it's likely I was really only doing around 160 when the 178 was caught by the GoPro.

 

[Yellow Submarine]

If you were running stock gearing anyway. I regeared the yellow submarine with 2 up on the rear sprocket.

It allows me to run 3rd gear at 30 mph without all the drive line lash I got with the stock gearing. I was always between 2nd & 3rd before the swap. 2nd the engine rpm was too high for continual riding at that speed (Yosh exhaust) and 3rd was too tall so I got a ton of driveline lash and bucking from riding at near idle.

The consequence is the speedo error increased so 35 indicated is now 30 actual (I get to check it daily against radar) and the error increases with speed. 72 Indicated is actually 63 mph. I couldn’t tell you what the error is at 100 mph but Cycle World (I think) tested it at 10 mph off at 100 indicated back in 2004.

I suppose I could just get a speedo healer but it isn’t like I care that much. I’m not out doing 100 on a daily basis.

 

[QRO]

Is that due to the fuelling for that year, or the exhaust, do you think? FWIW, I can, and occasionally do, ride the 750 L0 with 10% 'increase' in gearing with no noticeable driveline lash in 5th gear, just over 2k rpm. 6th is OK if steady but can shunt slightly if on and off the throttle at or below 2kprm.

It's this amazingly smooth behaviour at low engine speed that I occasionally refer to when I say I am amazed at the amount of low speed torque this puts out.

(For reference, it has the 'stock' factory yoshimura option, the exhaust valve is disabled and set wide open, and I set 25mm mid-way deflection on the chain.)

Obviously, 3rd or 4th are more suitable if it is a series of decels and accels in traffic, 2nd or 3rd if I am lane filtering in town.

 

[Yellow Submarine]

I’m fairly confident it’s a gearing issue. My Aprilia and Ducati are similarly geared down. Both are +2 on the rear sprocket. The Aprilia was similarly “low speed challenged” before the gearing change.

The Ducati, even with +2 on the rear is still super tall geared. It will however roll comfortably in 2nd in the low speed environment of the installation where I work. In 3rd, it too will experience drive line lash and really doesn’t like how low the RPMs drop for 3rd at the 30mph limit.

Since all three exhibited the same behavior, I presume it to be gearing related. As I’ve had the reduced gearing on the yellow submarine for several years now and no longer experience the lash & bucking associated with the OEM gearing, I think my presumption is proven correct.