ALTERNATE TACHOMETER

The tachometer failed on my 98 EV during a recent trip across Nevada. I don't know how or when, I just looked down and it was sitting at zero. I took it to Palo Alto Speedometer, normally a reliable service firm. They reported that the internals were totally fried and not available at any sources, and that they had broken the face clamping bezel upon removal. Thus, I couldn't even use it as a broken dummy to fill the hole in my dash panel.

A new replacement from Guzzi is nearly $300 and will be the same crap that the bike came with. Lots of people have had failures.

After a bit of searching, I came across a new, aftermarket tach. The IEQUUS #8068. Mine came from Auto Barn at http://www.autobarn.net/ieqper338tac.html , but it is available at various net resources and on EBAY. $70 This is the only cheap, normal replacement tach that I could find which had optional use of “inductive pickup” for the spark speed signal. Just clamps onto the spark wire like your inductive timing light does. Most tachs require a direct connection to the low voltage primary circuit. They are hard to find or install in a way that works for a two cylinder motor. On my EV, the spark coil signals come directly from the ECU. I didn't want any chance of a wayward signal going back to the ECU. Ask Tim Crump what happens when a tach shorts and sends voltage back to the ECU. The inductive system simply clamps around the secondary spark wire. Doesn't care if you have a single cylinder or a V12. It just counts the one cylinder.

The original box came with a big mounting clamp to install this tach on a steering column or on a dash panel. I tossed all that and simply put a clean bead of silicone on the body behind the dash face. I can always scrape that away for future removal.

My goal was to find something that mostly matched the original appearanc, was easy to install, didn't require ANY modification to the bike so that I could always go back to the expensive, unreliable original if necessary. I think this meets most of those criteria.

This is a test, so we'll have to see how it holds up under vibration and weather. I'll keep you posted.

What was right?

It was all very easy to install. Yes, I had to lathe some parts, but those modifications were quite simple and could be done by any friend down the road who has a lathe or a mill.

I was able to use ALL original wiring and connections so that nothing was cut, damaged, spliced into, etc. It is still a completely stock bike.

Installation and adjustment instructions were very complete.

What was wrong?

The tach body is about .020” bigger diameter than the dash hole. I was able to carefully mount it in my lathe, run the lathe rotation slowly by hand, and shave off the excess. I could easily have ground out the tach hole (which is actually cut pretty crude at the factory), but that might have precluded return to original at some future point.

The outside face bezel is quite a bit larger diameter than the tach body. No way to reduce that diameter without damaging the bezel. It interferes with the chrome, idiot light face plate. I lathed up a simple ring, 3/8” thick to hold the tach out away from the dash panel face.

It is visually close, but does not really “match” the speedo.

The old tach swept from 8:00 position to 4:00 position with normal cruise 4,000 rpm up vertical at the noon position. This new tach is based with zero at the 4:00 position and 8K at the 2:00 position and normal cruise 4,000 rpm with the need level pointing level left at 9:00 position. I could rotate the body by 90 degrees so that the arc was similar to original, but then the numbers and product name would all be sideways and would look weird. I contacted the company and they do not have or intend to manufacture a face with the 90 degree right orientation. I could have someone remove the face and repaint all the graphics, but that sounds VERY expensive. I'll learn to live with this for awhile.

The lighting is substantially brighter than the speedo. Perhaps I can remove the bulbs and dab on some spot of black paint to reduce the glow.

The tach body is too big to fit inside the chrome cosmetic housing from the old tach. It is now simply exposed behind the stock windscreen. So, perhaps this thing will not be weather protected enough? I'll be searching for some standard, aftermarket body cup to try and duplicate the original installation design.

The Pictures

The dash panel that I see when I am riding.

http://home.comcast.net/~pehayes/tach/tach1.jpg

Showing the 3/8” standoff ring and the silicone bead installation behind the dash panel.

http://home.comcast.net/~pehayes/tach/tach2.jpg

Showing the “inductive clamp” on the right cylinder secondary spark wire.

http://home.comcast.net/~pehayes/tach/tach3.jpg

If you think this option may work for you and you have any questions, don't hesitate to ask.

Patrick Hayes

Fremont CA