Results 1 to 13 of 13

Thread: 2-cylinder shop tachometer?

  1. #1
    Registered User lmo1131's Avatar
    Join Date
    Jan 2010
    Location
    Pismo Beach, CA
    Posts
    2,923

    2-cylinder shop tachometer?

    Slash 5 owner here. My tachometer is basically useless under about 2,000 rpm. I'm not even sure it is accurate at that speed.

    But try to synchronize carburetors to anything remotely near 1,050 rpm is virtual guess work.

    Is anyone familiar with a tachometer capable of working with a 2-cylinder engine? I don't want to mount it, just have it in the shop.

    "Ear-balling" just isn't working for me....
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  2. #2
    Administrator 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    12,430
    I know that the TinyTac product works reasonable well on /2 models. However, the update rate might not be sufficient to really be accurate down that low. There are probably tachs that are used for Harley's might work.

    What about something like this? I used this to synch the carbs on my R69S, which has no tach...made a big improvement.

    http://www.dealparts.com/product/43-5712-0.html

    Jeff Dean shows them in use on his bike on this page:

    http://bmwdean.com/personal_challenges.htm
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  3. #3
    neanderssance man sedanman's Avatar
    Join Date
    Jul 2011
    Location
    Beacon, NY
    Posts
    472
    You need something like this, ( not my listing, just answering the question)

    http://cgi.ebay.com/ebaymotors/Elect...item5d2a23c2b1

    It doesn't matter how many cylinders, it measures sparks per cylinder. it is adjustable for # of sparks per revolution , 2 cycle is 1 every revolution, 4 cycle is usually one every two revolutions ( depends on ign type), etc.
    Paul
    "Friends don't let friends ride junk!"
    2011 R1200RT

  4. #4
    Registered User
    Join Date
    Oct 2005
    Location
    NW PA
    Posts
    129

    Thumbs up

    The Harmonizer sync tool includes a tach feature. The tach displays with the balance indication so you only have to look at the Harmonizer.
    http://www.advrider.com/forums/showthread.php?t=701625

  5. #5
    Registered User stanley83's Avatar
    Join Date
    Oct 2009
    Location
    Somerville, MA
    Posts
    269
    Quote Originally Posted by Railbender View Post
    The Harmonizer sync tool includes a tach feature. The tach displays with the balance indication so you only have to look at the Harmonizer.
    http://www.advrider.com/forums/showthread.php?t=701625
    +1 on the Harmonizer. Recently purchased one to replace the $4 synch tube. I like it better than the Twinmax and it includes a tach.
    Justin in Somerville, MA
    _________________________
    76 R75/6, 78 P200E, 63 VBB
    Lots of bicycles

  6. #6
    Registered User lmo1131's Avatar
    Join Date
    Jan 2010
    Location
    Pismo Beach, CA
    Posts
    2,923
    I have a Twin-Max and have to say, it's been a disappointment. Too "delicate" in it's adjustment... at least I find it to be.

    I was just getting set to build the $4 synch tube, but it still left me with "no tach".

    The Harmonizer looks like a complete package.
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  7. #7
    Registered User stanley83's Avatar
    Join Date
    Oct 2009
    Location
    Somerville, MA
    Posts
    269

    Twin-Max

    My big issue with the Twin-Max is that it's really easy to hit the zero knob. I tried on at a tech day and i kept hitting the zero knob, forcing me to start over again.
    Justin in Somerville, MA
    _________________________
    76 R75/6, 78 P200E, 63 VBB
    Lots of bicycles

  8. #8
    Registered User lmo1131's Avatar
    Join Date
    Jan 2010
    Location
    Pismo Beach, CA
    Posts
    2,923
    My big issue with the Twin-Max is that it's really easy to hit the zero knob. I tried on at a tech day and i kept hitting the zero knob, forcing me to start over again.
    Same experience.

    It's just too sensitive ... it seems to lose it's set point just being strapped down to the seat while I'm using it. I'm no EE, but I would have thought that they could have selected a potentiometer that wasn't sooooo sensitive.
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  9. #9
    Registered User lmo1131's Avatar
    Join Date
    Jan 2010
    Location
    Pismo Beach, CA
    Posts
    2,923
    Just ordered the Harmonizer... incredible feedback on it and especially on it's developer on advrider.

    We'll see.... the lowest price tach is could find was hovering around $60, so I figured a replacement for my Twin-Max, AND a tach. Win.
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  10. #10
    Cam Killer marchyman's Avatar
    Join Date
    Jun 2008
    Location
    SF Bay Area
    Posts
    3,305
    Quote Originally Posted by stanley83 View Post
    My big issue with the Twin-Max is that it's really easy to hit the zero knob. I tried on at a tech day and i kept hitting the zero knob, forcing me to start over again.
    A second issue with the twinmax is that sometimes you could appear to get things in balance, but if you swapped the vacuum tubes to verify it would show up as out of balance. I got rid of my twinmax long ago.

    The Harmonizer is very nice. Not only for the tach feature, but because it tells you how much out of balance you are. The spec for my '05 GS is anything less than 25 mbar at idle is OK. Since the only way to sync that bike at idle is to re-adjust the valves knowing the actual out-of-balance amount is important. Last service the Harmonizer told me there was a 14 mbar difference. No worries!

  11. #11
    Registered User lmo1131's Avatar
    Join Date
    Jan 2010
    Location
    Pismo Beach, CA
    Posts
    2,923
    My Harmonizer showed up this morning.

    A bit surprised that no instructions were included... but it looks like the first page on a advrider link will suffice.

    Smaller than I thought it would be.
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  12. #12
    Cam Killer marchyman's Avatar
    Join Date
    Jun 2008
    Location
    SF Bay Area
    Posts
    3,305
    Quote Originally Posted by Lmo1131 View Post
    A bit surprised that no instructions were included... but it looks like the first page on a advrider link will suffice.
    The label attend to the front has most of the instruction you usually need. Yesterday I found that it also works quite well with my R69S that had vacuum nipples added. The bike was running nice. It's now running nicer.

    Looks like my Morgan Carbtune is no longer needed.

  13. #13
    Registered User lmo1131's Avatar
    Join Date
    Jan 2010
    Location
    Pismo Beach, CA
    Posts
    2,923
    WOOO HOOOO!!!! that Harmonizer is absofreakin'lutely the simplest, coolestest... mostest accurate-est tool I have!!!

    I'm going to balance everything again tomorrow just cause it's so much fun!!!

    Thanks for turning me on to guys!


    edit -


    Thanks for turning me on to guys!


    I'd gotta pay more attention to proof-reading.. . . .
    Last edited by Lmo1131; 11-06-2011 at 05:04 PM.
    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •