Speedo Drive Gear

[J86]

Yet another thread as I have more and more questions having fun learning my GS450...

I think the speedo drive gear on my bike (1981 GS450T) is bad, as the speedometer does not work and I have (1) replaced it and (2) the cable looks OK. Is there any easy way to test the unit itself? Also, I am considering buying a used one online, but want to make sure if I buy one off another year or model 450 it will be accurate to the bike I have. Are the drive gears from say 80-82 450s all compatible? Thanks.

 

[Guest]

pull the wheel off, see if you bent the metal tabs on the drive that engage the slots in the speedo gear. straighten them up and make sure they engage correctly when you put everything back together

 

[Guest]

Lift the front wheel off of the floor and with the cable removed spin the wheel and see if the drive pin is turning. Put a screwdriver in the drive slot and spin the wheel to see if the worm gear is still driving and the drive pin isn't broken.
On second thought the slot may be on the cable. In which case hold the drive tab with needle-nose pliers.

 

[Gorminrider]

yes the slot is on the cable. Just do as amk sez-lift the front wheel, spin it slowly and either look in with a flashlight or even maybe stick your little finger or a qtip in the cable hole to feel it. If nogo, take the wheel off per smilin'brads post and check those two drive tabs he mentioned.
Putting the cable on is tricky. There's 4 ez ways to do it right...but however you do it,you need to get the housing's knurl nut(?) threaded all the way in or the slot is not engaged with the drive . You will see very few threads-to-go when it is correct..AS A RULE (here anyways), it goes all the way in easily using just fingers without using vice-grips! if not, the slot is not engaged... This is important because if it's not threaded in all the way, it effectively makes the housing longer than the internal cable, so the speedo won't go.