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Main Area => General GS500 Discussion => Topic started by: pajazo on May 09, 2008, 11:30:51 AM

Title: Power loss
Post by: pajazo on May 09, 2008, 11:30:51 AM
Hi all

My girlfriend has a GS500E and we have noticed that it has been losing the low- and midrange power gradually in the two years she has had it. Last summer I checked the carbs and found nothing wrong with them. Today I measured the compression, it was some 150psi in both cylinders, so nothing wrong with that.

The machine is running fine except the lack of power. I have been riding a Fireblade for the last year, the feeling of power loss might have something to do with that :), but my girlfriend also thinks the GS doesn't run as well as it used to do. I have also checked the valve clearances and they are OK.

Now I decided to see if  re-jetting per the instructions found in gs500 wiki tables would help, and ordered the jets I need. As we live in Finland, we have only metric washers here. Could someone please measure the thickness of a #4 washer so I could find a metric one with the same thickness?
Title: Re: Power loss
Post by: ajaxgs on May 09, 2008, 12:02:56 PM
try sync-ing the carbs (balancing ) them , try to get the valves (especialy) exh on the low side closer to the .003mm
Title: Re: Power loss
Post by: ben2go on May 09, 2008, 01:02:56 PM
Adjust the valves before balancing the carbs.Here's a how to vid.It's easy.

http://video.google.com/videoplay?docid=-2015554469142545363&q=suzuki+gs500
Title: Re: Power loss
Post by: ohgood on May 09, 2008, 01:21:34 PM
#4 stainless washer:

ID = .125 " or 1/8"
OD = .312 " or 5/16"
THICKNESS = .032 " or 1/32"

metric:

ID= 3.175 mm
OD= 7.9248 mm
THICKNESS= .8128 mm

I'd bet you have some rust and crud beginning to clog the jets.
Title: Re: Power loss
Post by: beRto on May 09, 2008, 01:29:34 PM
Quote from: pajazo on May 09, 2008, 11:30:51 AM
I have also checked the valve clearances and they are OK.

My first guess would have been valves, but if you're sure they're in spec...  :dunno_white:

Quote from: pajazo on May 09, 2008, 11:30:51 AM
Now I decided to see if re-jetting per the instructions found in gs500 wiki tables would help, and ordered the jets I need.

Rejetting may help, but this may just be sweeping a problem under the rug. Especially considering that it ran well before with the existing jets. I would try and get to the bottom of this before introducing new variables.

A few thoughts come to mind:
FUEL
AIR
SPARK

Good luck!


Title: Re: Power loss
Post by: ben2go on May 09, 2008, 03:21:30 PM
GS's don't come from the dealer with a fuel filter.If you bought the bike used the PO(previous owner) could have added 1.Change it.Even if it's clear and looks fine.
Title: Re: Power loss
Post by: The Buddha on May 09, 2008, 05:38:00 PM
check oil ??? if its good, I guess look at airfilter, then at carb.
Cool.
Buddha.
Title: Re: Power loss
Post by: pajazo on May 10, 2008, 12:25:55 PM
The valve clearances are within spec. Last year I checked the carbs and the jets were clean. I set the float heights at the same time. The air filter is not new but it doesn't seem very dirty either.
Maybe I'm gonna check the cam timing when I take the tank off next time. Can't think what would have set the timing off though. I think I'll order a new air filter just to know it's not causing the problem.
Title: Re: Power loss
Post by: scratch on May 10, 2008, 07:53:31 PM
Have the carburetors been vacuum balanced or synchronized?
Title: Re: Power loss
Post by: pajazo on May 16, 2008, 02:47:01 AM
Yes, I did that also last summer. I don't believe that they can be yet out of sync, because the bike has seen only some 4000 miles after that.
Title: Re: Power loss
Post by: zenn on May 16, 2008, 07:22:52 AM
Years ago had an Olds Cutlass, started loosing power, similar to what you describe, even began to stall on my on occasion. After many trips to my mechanic. Turned out the muffler was packed solid. Replaced it, ran good as new.
Title: Re: Power loss
Post by: pajazo on May 16, 2008, 10:29:35 AM
I rejetted the carbs today. The original jets were clean. I didn't use washers as the needles appeared to have adjustable e-clips with 5 possible positions. The clips were at the middle position and I moved the clips one position lower.

Why do people generally use washers on the needles when they already have the adjustable clips?
Title: Re: Power loss
Post by: dgyver on May 16, 2008, 11:42:09 AM
Quote from: pajazo on May 16, 2008, 10:29:35 AM
I rejetted the carbs today. The original jets were clean. I didn't use washers as the needles appeared to have adjustable e-clips with 5 possible positions. The clips were at the middle position and I moved the clips one position lower.

Why do people generally use washers on the needles when they already have the adjustable clips?

US spec bikes do not have adjusable clip needles. Aftermarket DynoJet needles have adjustable clips as well.