1150E tach refurbish

[Tazman001]

Well I took the instrument cluster I bought for my 1150E apart. It has some issues I need to address before I install it on my bike. First, the instrument illumination bulbs(Stanley 158s) are burnt out. So I went down to the local auto parts store to purchase some and a friend who works there said I should use LEDs to replace them. I went ahead an bought some 161 Sylvanias to replace them and started looking on the net for LEDs. I found these and wondered if they would cause problems with my bike's electrical system. Anybody know? Or has used these, or LEDs like them before?

Second, I've read the GSR and heard about problems with the tach needle jumping around and want to take preventative action on this by replacing the components on the circuit board before reassembly. Along this vein, I was looking at the back of the circuit card and was wondering if I'm right in assuming the labels on the back where the wires are soldered in mean what I think. The labels are: white wire -G (I take to mean ground), brown wire -S (I take to mean signal), and orange -V (I take to mean voltage or 12V). Also does anybody know what the signal is on the brown wire? Type of waveform, amplitude, cycle, etc. as I can reproduce about anything. I want to check for proper operation before I reassemble.

Third, I need to reattach a couple of the housing cover mounts and I'm thinking about using JB weld or some other 2 part epoxy. Anybody know something better? Thanks guys!!!

[TheCafeKid]

The tach is looking at a signal pulse from one of the coils... There is some debate about what it SUPPOSED to see vs what it actually does, and in turn what causes the problems they eventually display... Then, when it sees this signal, what it turns that signal into to move the tach... But, before you do ANYTHING, you need to be absolutely POSITIVE your charging system is in order. If its not working properly, especially if its OVER CHARGING...it will be quick to burn the chipset/board/caps out of your NEW stuff as wel...

[rustybronco]

I don't know if it will help any, but here is a post on the very same subject.

http://www.thegsresources.com/_forum/showthread.php?p=990175#post990175

do you have a Oscilloscope to check the wave form from the tach sender?

[TheCafeKid]

I don't know if it will help any, but here is a post on the very same subject.

http://www.thegsresources.com/_forum/showthread.php?p=990175#post990175

do you have a Oscilloscope to check the wave form from the tach sender?

Rusty did anyone ever track down a sufficiant replacement for the seemingly proprietary main chip on the board for these things?? I was hoping someone with serious electronic know how had, so perhaps we could order replacements, or better still, even design and produce replacement boards for the guys who have bad ones?? I have replaced mine once, and the "new" one is already starting to read incorrectly, about 500RPM high it seems..

[rustybronco]

Josh, no one has so far that I know of.

A replacement board for the tach is one of the projects that I would like to accomplish next year. I just have too much on the "front burner" at the present time; but it is definitely on the to-do list. (along with a float post repair write-up, a how-to on connecting a timing light inductive pickup to a O-scope, finishing the kitchen floor, redoing the hardwood floors, re-bushing a clock, finishing the '80, repainting the '82...)

[Tazman001]

1150E gauge package refurbish

Thanks TCK & Rusty for the reply. Yes, I have access to a oscilloscope, but the bike isn't running(got to do the carbs, and a whole lot of other things). I will definately check the electrical/charging system before installation. This instrument cluster has never been on this bike. My 1150 <--*clicky*! had the wrong instruments <--*clicky*! on it when I got it. They have been taken off now. I want to bench check this tach before I reinstall it in the gauge cluster. That's why I would like to know what signal is coming out of the coil pack, if anyone knows. I can guess, it would probably be something like a square wave, with a 1 to 3 volt amplititude, at about 4000 cycles per minute at 4000 RPM(about 66.6 hz). Or I could be wrong and the signal could look like a sine wave(however, unlikely) with a 12 to 14 volt amplititude(caps are rated at 25V), at 2000 cycles(two coils double the frequecy, DOH!) per minute at 4000RPM(heh, heh, jus' made a funny). I read some where the signal was off the negative (or ground) side of the coils, I suppose the signal could be a negative voltage. Possably a -1 to -3 volts? That's why I was asking if anyone knew what the waveform was. Has anyone tried the LEDs in place of the incandescent bulbs in the gauge cluster? I suppose I'll just use JB weld to reattach the housing support posts if no one has a better suggestion on that.

[posplayr]

Tach signals operate off of the negative side of the coils where the points are. This signal rises to the +12V nominal when the points are open and collapses to ground when the points are closed.
It will actually be a little more complicated than that as there will be a relatively high voltage spike when the points open but it will be moderated by the ignition capacitor. Electronic ignition should mimic this.

As far as what is required to drive the tach? Guessing a square wave which has a frequency related to RPM will suffice. Try a 0-12V signal. I was going to suggest you measure the voltage on your bike but see it is not running. On second thought maybe that should be a priority v.s. the gages.

[V84ME]

I used epoxy to secure two of the posts, and it's held together for over 15 years. But I am always very aware of not applying to much torque when assembling.

If you can't get your tach back in shape, I've still got a spare instrument cluster or two I'd let go for not much more than the shipping cost.

[UncleMike]

I used epoxy to secure two of the posts, and it's held together for over 15 years. But I am always very aware of not applying to much torque when assembling.

If you can't get your tach back in shape, I've still got a spare instrument cluster or two I'd let go for not much more than the shipping cost.

I'd be interested in one of those, mayhaps. My instrument cluster is actually in really good shape, other than a couple of dead flies hanging out inside and a broken post on the inside that makes the black cover on the back rattle at speed.