What changes occured in 97 GS to lower hp/tq?

[burnt_toast]

My question is, what was changed to lower the peak HP/TQ in the later model 97+ bikes?

These are the figures I found on wiki, and few other places were similar:

Horsepower: 1989–1996 52 hp @ 9200 rpm (38 kW).
              1997–2009 47 hp @ 9200 rpm (34.3 kW).

Torque: 1989–1996 30.4 ft·lbf (4.2 kg-m) @ 7500 rpm (41 Nm).
        1997–2009 29.5 ft·lbf (4.1 kg-m) @ 7500 rpm (40 Nm).

I'm pretty puzzled and been doing some searching with no avail.

[The Buddha]

The KOOL-AID ran out.
Cool.
Buddha,

[GAS]

Here the differences are attributed to:

-Catalytic converter;
-PAIR system - which required a larger exhaust pipe (in diameter)

[The Buddha]

Not till 2001.
Cool.
Buddha.

[GAS]

hmm really odd..

Here in Brazil specs changed in the same year those mods were made (2004 here, since we didn't have the 2001-03 models sold)

Maybe in the US they translated the specs from a country where the mods were made in '97 (Japan maybe). Is it a bad theory?

[FrenchGS]

In france it's different too. Bikes were 42hp until 1998 I think. after, they have 34mm carbs instead of the 33mm, and 47hp...

Weird!!

[adidasguy]

You're showing HP at 9200 rpm - pretty close to red line and I doubt I have ever had my GS's past 8k let alone much over 7k RPM. Difference in HP is about 10%.
Then you list torque at 7500 rpm with hardly any difference in torque.
What's the HP at a normal riding range - say 4k to 6k RPM?
Does it really matter? Or is it just curiosity?
There were so many different models of every bike depending on the country they were sold in. Europe generally had 2 models of GS's each year - the regular and the "U" suffix for "unrestricted". The HP was restricted in some models for licensing. If you were experienced and had the higher level license, you can buy a bike with more HP.
My 1992 is Canadian. Hence it has different emissions and jetting compared to the US models, where emissions were stricter. And let's not forget the California models with a completely different set of requirements and even a smaller gas tank (go figure?)

[gsJack]

Here we go again.     A stock GS500 has approx 40 HP as measured at the rear wheels on a dyno, always has and always will.

http://gstwins.com/gsboard/index.php?topic=50014.msg565940#msg565940

[XealotX]

My question is, what was changed to lower the peak HP/TQ in the later model 97+ bikes?

Suzuki finally purchased a dynamometer which could accurately measure HP that low...

[burnt_toast]

Lol, nice theories guys

I am very interested in purchasing a GS500 in the near future and was just wondering this so I'd know the better years to buy. I greatly prefer the naked look so not interested much in the 02/04+ bikes

Eitherway, I plan on upgrading the exhaust and intake so I figure that should round the bike out well

[XealotX]

The "better years" to buy are any bike in your price range that runs OK or can be repaired. I've never ridden a stock 1995 GS and a stock 2005 GS back to back but I would bet the performance difference is slight.

Also, the GS's were still naked in 02.

Will the GS be your first bike?

[burnt_toast]

The "better years" to buy are any bike in your price range that runs OK or can be repaired. I've never ridden a stock 1995 GS and a stock 2005 GS back to back but I would bet the performance difference is slight.

Also, the GS's were still naked in 02.

Will the GS be your first bike?

Thanks for you input, I agree as long as it meets price and condition criteria, I'm game

This will be my first official motorcycle. Been riding two wheels, scooters mostly for past 8yrs, check out my work here:
http://scootspecs.wordpress.com/showroom/

After lots of tiny engine tuning, I'm finally ready to enter into the moto world, soon as I find my GS that is  

Always been a fan of cafe style bikes, but want my first bike to be more modern so a naked GS seems like just the ticket I hope

[mister]

"More modern" and "GS500" don't really go hand in hand when you realise the bikes has pretty well remained the same since 1989 

I ride Naked twins, so am total retro baby yeah  me and twisted even had some guy approach us to talk about our Retro bikes - sweet.

Michael

[Toogoofy317]

Nah, Mister they were referring to you when they said RETRO 

Not sure what the differences is wanted to pick on Mister!

Mary

[burnt_toast]

LOL yes well in that case call me a sucker for retro hah Old school 70s 80s 2strokes are my thing, almost bought an RD400 and RZ350 few years back. But for actual commute riding, especially as a beginner I'd like something 4stroke and better than 30mpg 

My definition of modern bike: does it have CDI ignition? WIN its modern 

everything else can be replaced or modded in my eyes (even points to cdi, but just easier to start off with cdi)

[bombjack]

I thought it was commonly known that it was because Suzuki changed the carbs for 34mm to 33mm in 1997.
At least that's what everybody has been telling me.

Edit: I just checked the specs for 96 and 97 in a motorcycle catalogue and it confirms that the carbs changed in 1997.
Edit 2: Maybe that change was only here in Europe?

[gsJack]

The carbs were changed from 2 circuit 33 mm to 3 circuit 34 mm in 01.  This was a very significant change making the GS smoother and stronger thru the mid ranges in all around everyday riding.  I rode both my 97 and 02 GS's for a while and the 02 was much stronger all around thru the mid ranges but the 97 still felt a bit stronger on the top end only.  Both had the same HP and Torque as did all GS500/E/F bikes tested and reported on in the moto mags from 89 thru 04.  My 97 GS had Mikuni BST33 carbs.

Summary of all tests I've found:
http://img.photobucket.com/albums/v443/jcp8832/GS500tests.jpg

The 01-02 models were the best of the lot, older ones had the 2 circuit carbs and newer ones were fully faired GS-F models.

[mister]

Nah, Mister they were referring to you when they said RETRO 

Not sure what the differences is wanted to pick on Mister!

Mary

Michael