Power loss

[pajazo]

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?

[ajaxgs]

try sync-ing the carbs (balancing ) them , try to get the valves (especialy) exh on the low side closer to the .003mm

[ben2go]

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

[ohgood]

#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.

[beRto]

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... 

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

• Maybe the float heights are off?
• Maybe the carb breather hose is partially blocked?
• Maybe the jets have gotten blocked since last summer?

AIR

• Maybe the air filter is old/dirty/mouse infested/otherwise constricted?

SPARK

• Maybe you need new spark plugs?
• Maybe the spark plug gap is incorrect (carbon buildup etc.)?

Good luck!

[ben2go]

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.

[The Buddha]

check oil if its good, I guess look at airfilter, then at carb.
Cool.
Buddha.

[pajazo]

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.

[scratch]

Have the carburetors been vacuum balanced or synchronized?

[pajazo]

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.

[zenn]

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.

[pajazo]

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?

[dgyver]

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.