Dry Lakes Racers Australia

have a 14000rpm AutoMeter tach, driven via a ARC-2 (Dynatek) on my Kawasaki ZX12, the thing works fine until full noise in 5th or top (6th), the needle "bounces" really bad between about 10 & 14 grand, ,, has anyone experienced this with AutoMeter tachs, is there a fix,

thats an odd one Ronnie, did you wire the autometer to the std tach wiring?? I wonder if its a coil pulse interferance issue but you wouldnt think so when running coil packs. I will look into it tomorrow and see what we can come up with.

is it a vibration issue or electrical ??
some of the aftermarket boost gauges i have used are useless due to the bikes vibration level
needs a liquid filled gauge to work in that case , just wondering if your seeing a similar issue

Spoke to a lot of bike guys this year doing licensing runs, who were at either end of the allowable limit for a particular license.
I'd ask them why, and the answer would be;
Tach not accurate or unreadable at speed
Don't have a speedo or a tach fitted
Could not read GPS (usually because it was somewhere where they couldn't see it)

Would definitely be interested in your comments on being able to monitor your instruments on the salt.
How can we improve this?

Probably just need to calibrate there speedos and allow for some wheelslip as speeds increase
a chase vehicle on a return road can give you an accurate speed indication and you only need multiply it out to figure what your speed would read at various licence levels

other option would be to standardise a gps mount , but even then the change in focal distance from concentrating up track to just in front of you can cover quite a few meters , dials are easier to read than digits


SCTA has more leeway, 150 lic would be between 125 and 150 , preferrably in the 135 or so range , and your only likely to repeat if your been a smartass or they have some concerns

Back in my circuit racing days we used to rotate our instruments so that the normal or ideal range put the needle at 12 o'clock. A quick glance at just the needles was all that was needed. All vertical, keep your foot down. Perhaps if the speedo or tacho was well shrouded from sunlight and was backlit, with the maximum wanted speed set to vertical it might help. It should also be angled so that in the crouching position the rider is able to look square at the face of the speedo/tacho/GPS.

As for vibration, perhaps mount the instrument panel on small rubber isolators. That might only change the vibration frequency, not stop it, I'm wondering if holding the panel (gently) to something solid with a light spring might calm it down.

Gotta get on top of this problem as the bikes off to Bonneville later in the year and i depend on a target rpm for top speed, my performace at the lake suffered this year as it was a guessing game,

Shane, the tach is wired directly to the tach output in the ARC-2, im hopeless when it comes to electrickey, but am wondering if there may be a lot of noise(interference) at those revs, would a resistor in line help ,,(the ECU, ARC-2, PC3, Ignition Module and Wego are all in the ducktail yelling at one another, ,,

Greg, vibration, maybe, this old girl gets a bit of a rattle up at those revs, however knowing that, i had the tach rubber mounted, maybe vibration, not sure, ,,

I always set my guages in the line of vision, so it only takes minimal eye movement to monitor them,,, at speed especialy at 200+ one shouldnt be searching to check a gague reading, ,,,

I have a used a Trailtech Vayper in the past that feeds off the spark plug lead - I am NOT recommending the Trailtech (it was a bad product) but something similar might help. The reason it might help is that it gives you a second opinion and you can set shift lights. I think I could set it to blink orange at one rpm and red at another.

Perhaps a digital tach. just to see if it is vibration or interference related. Im not saying that you should keep it, it might help with the fault finding. http://www.ebay.com.au/itm/Tacho-Hour-M ... 733wt_1393

Dave

Ronnie .... is the tacho playing up in lower gears at those revs? ....at max power/ rpm your coils will be drawing the most current so noise could be an issue.... is it waste spark ? what is your dwell time ? ...... or as Greg said it could be vibration. I went to liquid filled fuel pressure gauges due to vibration/pressure fluctuations
I had one of those veypor things pos never worked especially the reading of rpm hahaha. Hope you track the problem down.
Gary

Hey Ron
With most of my sidecars I used a tacho off any 12v bike with the correct rpm range.
As long as it is from a NON injected bike you should be able to use it. They only have 3 wires Red -- pos. Black-- neg. and another colour which
is the trigger from one of the coils.
I would get a busted dash , take the tacho out and make another housing.
If you got one off a 250 , 4 cylinder you would have some rpm to spare. I would love to hear a 12 @ 17000 revs.
The damping should be ok as it came off a bike
cheers Bones

Bones, people were comenting on how this thing "wails" at full noise, take it to 17k me thinks the only noise would be tinker,tinker, and i would be wailing, ,,

As for what the tach needle done in other gears, i only take it to the top of the torque curve one thru five and the needle climbed smooth and steady, , however, sometimes i suffer real bad from 5th gear syndrome,

Thankyou to all for your imput, am looking at all options, digital would be good, but, i have to concentrate too long to see where its at, for me a line on the tach glass that corosponds with target revs is easier to spot at a glance, ,,

Our tach died early in our second run this year...500 single...isolation mounted Scitsu tach. Looking at the on-board video it was bouncing around a bit. Wasn't a problem in 2010.

Have heard of some other ones failing on big singles, so maybe I shouldn't be too surprised. It's a pain without it for gearing choices etc. though.

So maybe don't get a Scitsu...

SR 832