Speedo Issues!!!!

[mercman]

Wondering if anyone with a still stock setup on an 04 gs500f can give me there speeds relative to tach per gear....Speedo is bouncing all over and cant tell actual speed...gonna order anew speedo gear to hopefully solve problem.....

[gsJack]

GS500 gearing has been the same since the beginning of time, this is from the first GS road test in Cycle Mag:



So 11000 x 60/140 = 4714 rpm @ 60 mph

and 11000 x 70/140 = 5500 rpm @ 70 mph

etc, etc

Slightly different from the 4730 rpm @ 60 they listed but close enough.  Your speedo and tach errors may vary a tad from theirs.  Both my GSs showed between 47-4800 rpm on tach at 60 mph when new.

Try lubing your speedo cable first, a dry cable is frequently the cause of a bouncing needle.

[mercman]

U da Man!!!!gonna go do the lube thing now

thx dude

[beRto]

Here's an alternative interpretation of the same info gsJack gave you:

km/h


mph


Details available at:
http://cgi.stanford.edu/~sanjayd/gs500/Main/GearingCalculator

[ben2go]

Usually a bouncy speedo is caused by a sticky cable.I remove my cables,hang them up with a clothes hangar,put my oil change drain pan under it,spray lube in the speedo end.I do it every 10 minutes until it runs out the other end of the cable.

[mercman]

Upon further inspection of speedo cable I noticed the outer plastic jacket has worn through in several spots...Think 'll just replace...about 20 bucks I think???

As far as the speed charts...Rode behind my friends car.... at 50 mph on his speedo I was at 4500 rpm and 60 mph showed 5500 rpm on the bike..His speedo is within a 1 or 2 mph devience at 60 according to the police rader....dont ask...So I,m a bit confused....counted teeth on front and rear sprockets 16 and 39 and tires are stock sizes.....

Any thoughts?

Thx

[gsJack]

Those would be close to the right rpm's for 5th gear.

50/124 x 11000 = 4435 rpm

60/124 x 11000 = 5322 rpm

[ben2go]

Your gearing is different than that of a car so his rpm for a given speed will be different.If it's an auto it will be way different.

[dgyver]

Indicated speed will vary with the tire diameter. Different brands will have different diameters and as the tire wears, its diameter will change as well. Different tire pressure will a contributing factor as well.


Sprocket sizes do not matter with a bike getting the speed from the front wheel.

[gsJack]

Different sprocket sizes will give different engine speeds for the same indicated mph so it does matter if your tying to use the tach for a speedo which is what mercman wanted to do because of a malfunctioning speedo..

[dgyver]

The varying conditions of the front affecting the indicated speed are the same for the rear tire and rpm at a given speed.