Tuning - help

[danci1973]

Hi there!

I have a 2000 GS (model year 1999) which has been restricted to 20kW by the factory.

Apparently, the restriction for a 1999 model was three ways:

1. the air filter with a small hole
2. blocking of the slider (hope that is the correct expression)
3. smaller jets (125 left, 115 right)

Now I got me a 'normal' air filter, I removed the plastic that blocks the slider and I installed larger main jets - 127.5 both carbs (Suzuki dealer said it should be 127.5 in the left carb and 122.5 in the right one - and I've seen him read it from a Suzuki spec- or datasheet).

However, with the stock exhaust, the bike works like sh*t at 6000-7000 RPM (in 5th it has problems getting over that, in 6th it doesn't) and doesn't go over 9500 at all (even in 1st, 2nd gear).

With aftermarket exhaust (which is pretty much open and LOUD) it feels very strong from ~4000 to 8000 RPMs. However, it still doesn't like going over 9000 RPM in higher gears.

What can I do to make it happy in high revs too?

Valve clearance maybe? It hasn't been done in at least 30000km (that's how long I've got the bike)?

Bigger main jets? I still have 130 jets I can try.

Maybe I should go with the asymmetrical jet setup?

Anything else?

Thanks, D.

PS: My top speed is ~90mph, and I think a GS should get over 100mph.

[MarkusN]

Try syching the carbs (or have them synched if you don't have the equipment). After major carburetor work, such as you have done that can't hurt.

It is normal for the GS to not rev up easily in 5th and 6th. It's a rare bike that has seen the red line in the 6th. But it shuld rev up to redline happily in the low gears, that's why I assume synching could help.

BTW, GStwin.com is not the best place to ask restriction questions, as the Americans rarely have this problem. As I have seen you over in gs-500.de as well, you probably find more expertise there. Just make sure you make clear you are talking about restriction of a late model, or you will be referred to the search function...