Hello all,
The tach on my 1980 GS750E is very sticky.
Back story: About 5 years ago the idle became unstable. That was based on my hearing, not based on the tach movement.
I found a crack on the backside of one of the rubber manifolds between the carb and the head. Then things got out of hand.
With the help of the electrical gurus on this site, went through the electrical system, cleaning ALL connections (including the fuses/block), switches, etc., found/cleaned/resoldered the splice internal to the wiring harness. Have my SH775 R/R in hand ready to install.
Reset the valves, pulled and stripped the carbs, soaked them in Gunk, reassembled with the O-rings, set floats, etc.
So now I'm able to work on it again. Got new AGM battery, put a little fuel in a temporary fuel tank and hit the starter and it started!
But the tach didn't even move. And I need the tach as I'm ready to synch the carbs and adjust the idle mixture.
So I pulled the instrument cluster apart and extracted the tach. (Hopefully it will appear below.)
There seems to be something that reminds me of STP on the cup the magnet drives.
I flushed it off with a little brake clean and a q-tip.
Then chucked the q-tip in my cordless drill and spun the tach drive and it went up to about 2500 on the tach.
Reinstalled tach in the bike, added a splash of fuel, hit the starter and tach reved to ~3000 RPM, and as the engine died the tach stayed at 3000. :sorrow:
Pulled the tach out again, just *touched* the cup and it rotated back to 0 rpm.
What the heck is going on!
I can't see in the back of the cup to see if it is mounted in a bearing, but it must be.
And I don't dare try and unfold all the crimps that hold the tach frame together,
for fear it will never go back together with the correct shaft alignments.
Can anyone shed any light as to what's up with this?
Is there supposed to be some kind of syrupy lube on the cup?
Does the tack depend on vibrations to keep the cup from sticking?
Its only 60 degrees here today, but I know I have ridden in the high 40's in my younger days with no tach issues.
Should I just flood the cup and its supporting bearing with brake clean?
Thanks for any light you can shed.
(I wanna get this machine back on the road before they try and take my license away. :sorrow:
The tach on my 1980 GS750E is very sticky.
Back story: About 5 years ago the idle became unstable. That was based on my hearing, not based on the tach movement.
I found a crack on the backside of one of the rubber manifolds between the carb and the head. Then things got out of hand.
With the help of the electrical gurus on this site, went through the electrical system, cleaning ALL connections (including the fuses/block), switches, etc., found/cleaned/resoldered the splice internal to the wiring harness. Have my SH775 R/R in hand ready to install.
Reset the valves, pulled and stripped the carbs, soaked them in Gunk, reassembled with the O-rings, set floats, etc.
So now I'm able to work on it again. Got new AGM battery, put a little fuel in a temporary fuel tank and hit the starter and it started!
But the tach didn't even move. And I need the tach as I'm ready to synch the carbs and adjust the idle mixture.
So I pulled the instrument cluster apart and extracted the tach. (Hopefully it will appear below.)
There seems to be something that reminds me of STP on the cup the magnet drives.
I flushed it off with a little brake clean and a q-tip.
Then chucked the q-tip in my cordless drill and spun the tach drive and it went up to about 2500 on the tach.
Reinstalled tach in the bike, added a splash of fuel, hit the starter and tach reved to ~3000 RPM, and as the engine died the tach stayed at 3000. :sorrow:
Pulled the tach out again, just *touched* the cup and it rotated back to 0 rpm.
What the heck is going on!
I can't see in the back of the cup to see if it is mounted in a bearing, but it must be.
And I don't dare try and unfold all the crimps that hold the tach frame together,
for fear it will never go back together with the correct shaft alignments.
Can anyone shed any light as to what's up with this?
Is there supposed to be some kind of syrupy lube on the cup?
Does the tack depend on vibrations to keep the cup from sticking?
Its only 60 degrees here today, but I know I have ridden in the high 40's in my younger days with no tach issues.
Should I just flood the cup and its supporting bearing with brake clean?
Thanks for any light you can shed.
(I wanna get this machine back on the road before they try and take my license away. :sorrow:
