GS500 wobbling in high revs

[mrboazz4]

Hi fellow gs riders,

My 1993 GS500 is acting up after trying to give it some love haha

I did the following things:
-Change oil and oil filter
-Change air filter
-Change headlight from double headlight to the more original single headlight

Now when I am riding it rides like a charm up to 5000/6000 revs, after that it it buckles and shocks lightly and stops accelerating like it suddenly has no power or torque left.
Does anyone know what could be the problem? The air filter I put in looked the same as the old one and is, according to the site where I bought it, also compatible with my bike.....

Thanks in advance,
Kind regards Boaz

[The Buddha]

Wont rev past 5/6 K - sounds like a rip in diaphragm.
Cool.
Buddha.

[mrboazz4]

2 questions:


Why would suddenly the diaphragm be torn after installing only new spark plugs, oil and filter, and air filter?

If it is actually the diaphragm, how much work is it to fix that? (I think its enough to buy a carburetor revision kit right?) and how bad is it to drive my motorcycle while it is not fixed yet? (I have driven it with the problem a couple times already)

Thanks in advance

[The Buddha]

Carb "revision" kit ? Yea after you buy that, then you should go to the Suzuki store and buy the diaphragm and then throw away the "revision"  kit.

OK OK I'm kidding, you can keep the "revision" kit - just don't install it.

I will trouble shoot first.
Air filter etc etc - no idea - the one and only time my diaphragm died back in 1998 - I have no idea why, just not revving up - especially as load increases that was the symptom. So in 1st you'd make 8-9K, 2nd 7-8, 3rd 6500-7500 and so on. Revs dropping with increase in load.

Cool.
Buddha.

[herennow]

Lets look at what you changed. 99.99% of time its there..

To me the airfilter is the likely culprit. Did you change like for like or an OEM for a K&N, etc. If you search the forum there are a few warnings of this kind of behavior when moving to HIFlo filters, although I tried them and they were fine.

Have a very close look at the airfilter, the symptoms sound just like friend who had a leaf block a part of the filter area.

[Bluesmudge]

Have had a similar problem around 5 - 6k rpm when I had the K&N drop in filter without the restrictor ring + V&H exhaust. Had a really hard time getting past 5500 rpm but it was fine above 6,000 rpm if you could get there by down shifting.
Switching to the Dyno jet kit with a uni foam filter mostly solved the problem but still acted a little weird around 5,500 rpm. You could see the HP & Torque dip in the Dyno graph at 5,500 rpm but no idea how to tune for some quirk that small. 500 rpm. Finally also switching from Vance & Hines exhaust to Jardine solved my issue. Must have been some flow issue related to open filter and open exhaust or shape of the Vance & Hines but just around 5,500 rpm.

Long story short: Just go back to stock Suzuki everything to avoid this whole mess. If your filter, airbox, jetting and exhaust is all stock then ignore everything I said and get ready to rebuild carbs.