Author Topic: rev counter  (Read 14830 times)

0 Members and 1 Guest are viewing this topic.

drcdb15

  • Super Member
  • ***
  • Posts: 506
  • Karma: 6
  • Location: East Grinstead, West Sussex
Re: rev counter
« Reply #45 on: May 29, 2015, 10:05:27 PM »
Cheers, Mintex.

sahin261

  • Member
  • *
  • Posts: 34
  • Karma: 0
Re: rev counter
« Reply #46 on: October 13, 2015, 11:31:17 PM »
Hello, I installed revcounter on my bis succesfully. I took rev counter from Fiat 125. I converted 4cyl tachometer for 2cyl. I even did a video.

https://www.youtube.com/watch?v=5VgMqtGOi7w

here link of video but all informations are in Turkish. I can translate if you interest :)
« Last Edit: October 13, 2015, 11:33:06 PM by sahin261 »

BHBASS

  • Member
  • *
  • Posts: 24
  • Karma: 0
Re: rev counter
« Reply #47 on: October 29, 2015, 10:27:11 PM »
Nice job, did not realise it was this problematic to source a rev counter for the little car.

Maybe this will help someone: type 'obrotomierz Lumel' into the search engine of your choice. There is a few models, see pics. I have got the round one, there are also two flat shaped ones (left side of the second picture), a dial one and a LED one. One in good nick should be no more than £40, but it is possible to get them for less. The flat ones must come with their 'foot', they are dashboard mounted with screws.

The round one is adjustable between 2 and 4 cylinders, not sure about the other two, but I would imagine they will most likely be as well. Practical reasons, the parts were not just available everywhere off the shelf back then, so the manufacturers' approach was a bit more universal.

« Last Edit: October 29, 2015, 10:47:56 PM by BHBASS »

drcdb15

  • Super Member
  • ***
  • Posts: 506
  • Karma: 6
  • Location: East Grinstead, West Sussex
Re: rev counter
« Reply #48 on: October 30, 2015, 06:05:28 PM »
In my travels trawling for a suitable tacho I've come across these few items, all labelled as being usable with two-cylinder engines. I take as my benchmark the model available for the 2CV, at £39:

http://www.ecas2cvparts.co.uk/tachometer-counter-52mm-diam-silver-bezel-white-face-engine-8000rpm-p-1964.html

So against that price these look interesting:

http://www.ebay.co.uk/itm/151702163952?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.co.uk/itm/400956680305?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

and this little item will show rpm AND hours of operation:

http://www.ebay.co.uk/itm/131577797096?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I recall many years ago noticing that a farm tractor had a "speedo" showing hours. When I queried this, the farmer told me you couldn't judge service intervals on a farm tractor by miles because the mileage it covered was tiny. So instead the servicing was judged by elapsed operational hours - makes sense...

And it also might make sense for something like a classic car like the baby Fiats. I typically only do 1000 miles or so each year in my classics, so on that basis one oil change would last nearly 10 years!!  On the other hand, do I really need to change the oil every year when the engine has not run under load for more than a few hours? How to judge? This item could be the answer. And at only £15 you can easily get one for each car you run.

Joe Webb

  • Super Member
  • ***
  • Posts: 138
  • Karma: 0
  • 1999 Fiat 126p elx, 1981 Matra Muren, 1971 Greeves
  • Location: Hove, UK
Re: rev counter
« Reply #49 on: April 14, 2016, 11:31:14 PM »
Hey, I know I'm bringing up an old thread, but would a tacho for a single cylinder 2 stroke work? given that there is a spark for every other revolution in each cylinder?

I'm not sure I understand how they work though so I could be asking a dumb question. Also it looks like the 2 stroke battery operated tacho seems to work?  ???
1999 Fiat 126p elx, 1971 Greeves Pathfinder, 72 Datsun 240z

mintex

  • Super Member
  • ***
  • Posts: 484
  • Karma: 5
  • Location: Wrexham wales.
Re: rev counter
« Reply #50 on: April 16, 2016, 10:04:12 PM »
A single cylinder 2 stroke would work i think as you say both plugs fire at the same time.

One if the battery operated tachos do work as i tried one for a bit but i found it was always jumping about a lot with the readings.
Dave

Joe Webb

  • Super Member
  • ***
  • Posts: 138
  • Karma: 0
  • 1999 Fiat 126p elx, 1981 Matra Muren, 1971 Greeves
  • Location: Hove, UK
1999 Fiat 126p elx, 1971 Greeves Pathfinder, 72 Datsun 240z

mintex

  • Super Member
  • ***
  • Posts: 484
  • Karma: 5
  • Location: Wrexham wales.
Re: rev counter
« Reply #52 on: April 16, 2016, 10:15:15 PM »
yes possibly, i did look at one like that myself.

just check with the seller that it will run on a single cylinder 2 stroke as most twin cylinder 2 strokes fire each plug independant and not the same time like the fiat  :)
Dave

mintex

  • Super Member
  • ***
  • Posts: 484
  • Karma: 5
  • Location: Wrexham wales.
Re: rev counter
« Reply #53 on: April 16, 2016, 10:17:05 PM »
The seller i asked said it was automatic at selecting and i was not convinced so never took the plunge. 
Dave

Joe Webb

  • Super Member
  • ***
  • Posts: 138
  • Karma: 0
  • 1999 Fiat 126p elx, 1981 Matra Muren, 1971 Greeves
  • Location: Hove, UK
Re: rev counter
« Reply #54 on: April 16, 2016, 10:46:20 PM »
yeah good point

I'll do some digging
1999 Fiat 126p elx, 1971 Greeves Pathfinder, 72 Datsun 240z

Joe Webb

  • Super Member
  • ***
  • Posts: 138
  • Karma: 0
  • 1999 Fiat 126p elx, 1981 Matra Muren, 1971 Greeves
  • Location: Hove, UK
Re: rev counter
« Reply #55 on: April 17, 2016, 12:02:08 AM »
I read that a lot of bikes use wasted spark ignitions anyway so a 4 stroke 2 cylinder or 1 cylinder should work as well

I also found some info on modifying tachos by changing their resistors

That way you could put a 4 cylinder tacho in, and halve the resistance of that circuit to double the rpm reading.
1999 Fiat 126p elx, 1971 Greeves Pathfinder, 72 Datsun 240z

mintex

  • Super Member
  • ***
  • Posts: 484
  • Karma: 5
  • Location: Wrexham wales.
Re: rev counter
« Reply #56 on: April 17, 2016, 12:44:52 AM »
Most 4 stroke bikes use 2 coils, even most 2 cylinder bikes have 2 coils (ive had bikes since i was 16) so keep this in mind before buying.


As for using  resistors i did read about this but never tried it out so sadly can't help you if it would work or not mate  :(


Dave

Joe Webb

  • Super Member
  • ***
  • Posts: 138
  • Karma: 0
  • 1999 Fiat 126p elx, 1981 Matra Muren, 1971 Greeves
  • Location: Hove, UK
Re: rev counter
« Reply #57 on: April 17, 2016, 02:06:00 AM »
I might give modifying one a go, find a cheap one and see how easy it is :P
1999 Fiat 126p elx, 1971 Greeves Pathfinder, 72 Datsun 240z

Xylaquin

  • Super Member
  • ***
  • Posts: 411
  • Karma: 8
  • Location: Orkney, Scotland
Re: rev counter
« Reply #58 on: April 17, 2016, 08:21:43 AM »
I use my ears as the rev counter. ;)

drcdb15

  • Super Member
  • ***
  • Posts: 506
  • Karma: 6
  • Location: East Grinstead, West Sussex
Re: rev counter
« Reply #59 on: April 17, 2016, 02:12:24 PM »
this looks like a good alternative then

http://www.banggood.com/Universal-Mechanica-13000RPM-Tachometer-Gauge-Motorcycle-p-929615.html?currency=GBP&createTmp=1&utm_source=google&utm_medium=shopping&utm_content=jude&utm_campaign=motor-uk

Although the price is attractive, remember you usually get what you pay for, and since most reasonable quality tachos are priced from bout £40-100, don't be surprised if a nine quid item looks (and performs!) like it came out of a Christmas cracker.

On a more serious technical note, to have any use other than being purely cosmetic, you want the tacho to match the rev range of your engine. I don't know what that is for the baby Fiats, but I imagine it's around 0-4000 rpm, with most of its life being spent around the 2000rpm mark.

That means that on a 0-13K rev counter the needle will rarely get above 14% of full scale. In other words, the needle will spend most of its time bumping around the bottom end, where anyway readings tend to have larger errors than mid-scale, and any information it might offer will be pretty much useless.

For the Fiat you really want a 0-5000 (-ish) range, not something designed for an ultra-high revving motorcycle.


 

SimplePortal 2.3.6 © 2008-2014, SimplePortal