tachometer inop

Well, hopefully my carb flooding problem is fixed. so on to the next thing. the tach doesnt work correctly. it comes up to about 1000 rps at idle. when revving it comes up some more but not accurately. this problem seemed to happen when i washed the bike for the first time a few weeks ago. i thought i remembered it working before that. it may have been a coincedence. Tach runs off one of the coils right? what other componants could be a factor- besides obviosly the tack itself.

 

I was researching tach parts on ebay to find that there is a tack drive and cable. apparenty this guage is mecanical and drives off the cam somwhere? I havent had a chance to look at the bike yet to see how its set up and troubleshoot it.

 

Look at the front center of engine and you will see it.

 

I found some good threads-Ill figure it out. Thanks.

 

Mechanical tach in '83?
I'm thinking spider webs inside. If it's electrical, there's another connection inside the headlight shell (I think, there was on the Seca)

Remove headlight and tank,
Pull and re-plug all related wires that have an orange and a grey.

 

Dang spiders. You would not BELIEVE how much webbing and carcasses I pulled out of my instrument cluster this weekend. Brutal!

 

Tack drive is off the front right of engine (at least on the 650), but you location may be different. It picks up the engine speed from a set of gears in side. This is transmitted to a rotating disk inside of the tach via the cable. Inside the tach, the disk (magnetic) spins inside of a "bell" (magnetic). The interaction of the two magnetic fields causes the bell to be twisted. Since the bell spin is countered by a spring, the travel is limited. The faster the spin the further the bell can pull the spring. There is no contact between the bell and the disk!

If you got water (or anything else) in the tach housing, they could interfere with the magnetic forces or spring. Wouldn't normally expect it to suddenly go bad.

Try the following. Pull the cable of and check the ends for damage, then lube it. (I use 3-in-1 oil, but any should do). Reinstall and see what happens.

If that doesn't fix her up, then pull the head cover and check that end for excess wear. (not likely).

 

Ill check that out. I need a new headlight anyway. I am gonna check the cable with a drill and make sure its turnig the tach sufficiently too. it maybe the transmission as well. Soon as the wife gets home to watch the rugrat, im gonna scope it out and run the hell out of it some more. i originally thought the tack ran off the coil- mechanical guages are easy.

 

Well then there are many cool after market gauges if you need them also. I just put some from MikesXS on and dumped the old and warning light thingy (now part of speedo). Next up is shrinking the head light (I think).

 

I looked at the tach. its not mechanical. I havent taken it apart yet or checked the wiring. but would guess my guage is bad. there is a crack in the housing from PO laying the bike down. i bet water got in there and $#@% it up when i washed it. Ill keep yall posted with what i eventually find.

 

Still, plenty of cool after market gauges.