1983 xj650 maxim tach not working properly

Hey guys. This being my first post in here I hope some one can be some help. I just bought this xj after not riding since the mid 80's. My overall knowedge is very limited. Anyway. Here's my issue. Last week after having the bike sit for the winter I pulled it out and found that the battery was not strong enough to start the engine. So I boosted it from my car. Yes with the car running. Bad idea so I found out llater. Since then the tach does not run properly. It starts and runs normal. Everything works. Lights signals etc. I replaced the C.D.I. But still the tach reacts the same. Moves a bit but not like it used to or supposed to. Any and all help or ides would be greatly appreciated.

Thanks in advance

 

Which XJ are you working on?
Some of them are driven from the alternator stator coil. some direct from the cam with a cable. Jumping the bike from the car may have done something to the alternator. Do you have a meter to check the charging voltage, it should be around 13 to 14 volts at 2000 emgine rpm. We can start there.
I fyours is cable drive check the cable.

 

1983 xj 650 k. Oh crap you mean it could be the starter solinoid ?

 

You have a electric tach, I'm almost sure it is driven from the alternator. No its not the starter solenoid.
Can you check the charging voltage with the engine running? I bet it is not working properly.

 

So do I check the charging voltage on the battery wile the engine is running ?

 

Yes

 

Clean the Bushing-Bearings on the Tach.

Remove the Instrument from its Case.
Mark wiring.
Replace Bulbs (Red or Blue is cool)

Clean Bearing.
Flush while moving Needle.
Q-Tips soaked in Isopropyl Alcohol.

Lube.
Two. (2) -- Single Drops of Sewing Machine Oil
(Light Oil or HD Silicone Liquid)

Dip Darning Needle in Oil or Silicone.
Apply the drop to the Bearing.
Exercise the Needle through end-to-end movement.

:::: Apply the (2) Drops to the Outside Diameter of the Brass Bushing-Bearing on the Back-side of the Tach ::::

 

14.5 volts at apx 2000 rpm

 

Thats good, you charging system is still working. Check the plug connections for the tach behind the headlight. Then look into Ricks suggestion on cleaning the tach movement.

 

Ok thanks