Digital "tachometer"...has anyone correlated the tick marks to RPMs?
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 16
Like Tree23Likes

Thread: Digital "tachometer"...has anyone correlated the tick marks to RPMs?

  1. Top | #1
    mike01's Avatar
    Join Date
    Mar 2017
    Last Online
    Yesterday @ 09:58 PM
    Location
    NY
    Posts
    1,229
    Thanks
    33
    Thanked 155 Times in 101 Posts

    Digital "tachometer"...has anyone correlated the tick marks to RPMs?

    My first X758 didn't have the digital dashboard, just two analog gauges (temp and fuel) and an hour meter (it was a 2015). This one has the fancy digital panel, and there's a tachometer of sorts there. I was wondering if anyone had worked out exactly what each mark is analogous to. So, for example, say three tick marks is 1200RPM, five is 1800, and so on.

    So...anyone work this out yet? Perhaps someone with an add-on tachometer can make the correlation?
    2019 X758, 54" Autoconnect deck
    2018 2032R, 220R Loader, dual rear SCV, hydraulic top link, SB1164 Snow Blower, RC2072 rotary cutter, BB5048L box blade, 42" Titan forks, BB2060L back blade

    Owned in the past:
    X570, X758 (2015), 1025R, X590

  2. Remove Advertisements
    GreenTractorTalk.com
    Advertisements
     

  3. Top | #2
    jgayman's Avatar
    Join Date
    Jul 2012
    Last Online
    Yesterday @ 10:49 PM
    Location
    Central Pennsylvania
    Posts
    9,239
    Thanks
    352
    Thanked 1,483 Times in 1,126 Posts
    My understanding is the tach display is not that accurate. The tick marks only give a generalization of the engine RPM. In other words, if 10 tick marks are displayed the engine is running faster than if 5 tick marks are displayed. Then again, your ear will usually tell you the same thing.

    You guessed it... it's pretty much just a gimmick. :-)
    mjncad, DRobinson and PJR832 like this.
    2012 2720 -- 200CX Loader -- 54" Quick Attach Snow Blower -- Frontier LR5060 Rake -- Land Pride RB1660 Blade (Hydraulic Angle) -- Artillian 42" Forks -- Ken's Bolt on Grab Hooks -- Fit Rite Hydraulic top-link -- 2013 X500 for mowing duties

  4. Top | #3
    mike01's Avatar
    Join Date
    Mar 2017
    Last Online
    Yesterday @ 09:58 PM
    Location
    NY
    Posts
    1,229
    Thanks
    33
    Thanked 155 Times in 101 Posts
    I don't know...if the readout is repeatable based on throttle position (meaning, it always reads say 5 ticks when the throttle is exactly in the middle), then a correlation can be established.
    2019 X758, 54" Autoconnect deck
    2018 2032R, 220R Loader, dual rear SCV, hydraulic top link, SB1164 Snow Blower, RC2072 rotary cutter, BB5048L box blade, 42" Titan forks, BB2060L back blade

    Owned in the past:
    X570, X758 (2015), 1025R, X590

  5. Remove Advertisements
    GreenTractorTalk.com
    Advertisements
     

  6. Top | #4
    etcallhome's Avatar
    Join Date
    Jan 2011
    Last Online
    Yesterday @ 09:15 PM
    Location
    Preston County WV
    Posts
    13,038
    Thanks
    3,151
    Thanked 2,298 Times in 1,509 Posts
    The x738 has the digital tach like you I have no idea. For the gas version I was told run wide open all the time , no matter what you are doing or where you may be going.


    Just know , to engage mower at wide open throttle on x 738 and at idle when operating my 1025r.


    Like others I've noticed the x tach doesn't seem to be accurate.
    mjncad, DRobinson and PJR832 like this.
    Gene

    Have fun and be safe !!!
    USAR 8yr 8 mo SSG 99th ARCOM
    JD 1025R, H120 FEL 54" bucket, 54" mmm Auto Conn, 54" Front blade, JD back hoe ,JD IMatch, 48" Bush Hog tiller, Middlebuster from MF dealer, used King Kutter 5' rear blade, a new 47" JD Front blower and Original Tractor cab w/heater.
    We have a Red Honda Pioneer 700-4 (4 seater) w/soft top , doors, and winch.

  7. Top | #5
    jgayman's Avatar
    Join Date
    Jul 2012
    Last Online
    Yesterday @ 10:49 PM
    Location
    Central Pennsylvania
    Posts
    9,239
    Thanks
    352
    Thanked 1,483 Times in 1,126 Posts
    Quote Originally Posted by etcallhome View Post
    The x738 has the digital tach like you I have no idea. For the gas version I was told run wide open all the time , no matter what you are doing or where you may be going.

    Just know , to engage mower at wide open throttle on x 738 and at idle when operating my 1025r.
    I can see needing to use a lot of throttle with a belt driven mower deck and electric clutch but it just makes no sense at all with a shaft-drive deck.
    DRobinson, mike01 and PJR832 like this.
    2012 2720 -- 200CX Loader -- 54" Quick Attach Snow Blower -- Frontier LR5060 Rake -- Land Pride RB1660 Blade (Hydraulic Angle) -- Artillian 42" Forks -- Ken's Bolt on Grab Hooks -- Fit Rite Hydraulic top-link -- 2013 X500 for mowing duties

  8. Top | #6

    Join Date
    Jul 2018
    Last Online
    Yesterday @ 08:11 PM
    Location
    South Eastern, Connecticut
    Posts
    296
    Thanks
    3
    Thanked 42 Times in 38 Posts
    Quote Originally Posted by jgayman View Post
    I can see needing to use a lot of throttle with a belt driven mower deck and electric clutch but it just makes no sense at all with a shaft-drive deck.
    Its all about the Torque curve of the engine. The V-twin gasser needs high RPM to develop the torque needed to get the mower blades moving from a standstill. Less than 3/4 throttle and you risk stalling the engine when you engage the mower deck.

    My machine runs 3/4 to WOT for any work being done. The generally equates to the right below or in the little highlighted grass cutting RPM range marked on the top of the digital tach gauge.

    As for what that digital gauge is telling you, I would say the bars are roughly equal to throttle position. The digital gauge is measuring engine RPM directly though, what each bar means in terms of rpm is anybody's guess.
    etcallhome and PJR832 like this.
    X738, 54HC deck w/ auto connect, 3PH
    Woods GBC48 box scraper
    Day dreaming of a 54" snow blower

  9. Top | #7
    Keeper of the GTT Cookies dieselshadow's Avatar
    Join Date
    Nov 2011
    Last Online
    Yesterday @ 08:25 PM
    Location
    Joelton TN
    Posts
    19,510
    Thanks
    1,048
    Thanked 4,153 Times in 2,521 Posts
    Quote Originally Posted by jgayman View Post
    I can see needing to use a lot of throttle with a belt driven mower deck and electric clutch but it just makes no sense at all with a shaft-drive deck.
    Torque transmission has virtually no difference in how much torque is produced. The only real difference would be how much made it through. Between belt and shaft it would be very close in efficiency. Within a few percent at least. The gearbox would eat up most of the losses in either system.
    - Jason

    GreenTractorTalk.com Rules, Policies, and Terms of Use

    Subscribe to dieselshadowman on YouTube

    2720 w/ 200CX FEL
    , Ken's weld-on hooks, Fit Rite Hydraulics Top and Tilt kit, Artillian forks.
    1954 60 - getting full restoration, 1964
    110 round fender in the shop for crustoration
    Ferris IS3200Zzero turn mower

  10. Top | #8

    Join Date
    May 2018
    Last Online
    Yesterday @ 02:16 PM
    Location
    Rexton NB Canada
    Posts
    399
    Thanks
    104
    Thanked 28 Times in 28 Posts
    Quote Originally Posted by mike01 View Post
    My first X758 didn't have the digital dashboard, just two analog gauges (temp and fuel) and an hour meter (it was a 2015). This one has the fancy digital panel, and there's a tachometer of sorts there. I was wondering if anyone had worked out exactly what each mark is analogous to. So, for example, say three tick marks is 1200RPM, five is 1800, and so on.

    So...anyone work this out yet? Perhaps someone with an add-on tachometer can make the correlation?
    Bring a Garmin or equivalent GPS based street navigation . . . many tell you the speed you are traveling . . . at least mine does
    Auguste . . . a blue collar guy working in a white collar world
    Rexton, New Brunswick, Canada

    JD Tractor aka Bucky
    2018 1025r ~ New in April 2018

    Accessories ~ Front End Loader ~ Backhoe ~ Mid-Mounter Mower ~ Box Blade ~ Fork Lift ~
    Roto Tiller ~ Chipper ~ Mulch Kit ~ Sub-soil Conditioner ~ Ballast Box ~ Plug Aerator ~
    Thatcherator ~ iMatch Quick Hitch ~ Landscape rake

    Modifications Completed by Me ~ LED lights on roll bar ~ Mirrors ~ Shortened Rollbar to fit in Garage

  11. Top | #9
    jgayman's Avatar
    Join Date
    Jul 2012
    Last Online
    Yesterday @ 10:49 PM
    Location
    Central Pennsylvania
    Posts
    9,239
    Thanks
    352
    Thanked 1,483 Times in 1,126 Posts
    Quote Originally Posted by CJadamec View Post
    Its all about the Torque curve of the engine. The V-twin gasser needs high RPM to develop the torque needed to get the mower blades moving from a standstill. Less than 3/4 throttle and you risk stalling the engine when you engage the mower deck.
    Actually, even on my X500 the faster engine speed seems to only be required when the mower deck is cold. Once the deck has run for a bit you can easily engage it at less than half throttle and it will not stall the engine and there is almost no belt screeching.

    My point is... the manuals for the various tractor models don't always give sensible information. And they don't always distinguish between engine types. Example... the X700-series manuals for both gas and diesel models all contain the same information telling you to engage the mid-PTO at wide-open throttle. Which of course makes no sense. Whereas the 1-series manuals advise to engage the mid-PTO at less than 1500 RPM and then increase engine speed to operational speed.
    2012 2720 -- 200CX Loader -- 54" Quick Attach Snow Blower -- Frontier LR5060 Rake -- Land Pride RB1660 Blade (Hydraulic Angle) -- Artillian 42" Forks -- Ken's Bolt on Grab Hooks -- Fit Rite Hydraulic top-link -- 2013 X500 for mowing duties

  12. Top | #10
    jgayman's Avatar
    Join Date
    Jul 2012
    Last Online
    Yesterday @ 10:49 PM
    Location
    Central Pennsylvania
    Posts
    9,239
    Thanks
    352
    Thanked 1,483 Times in 1,126 Posts
    Quote Originally Posted by dieselshadow View Post
    Torque transmission has virtually no difference in how much torque is produced. The only real difference would be how much made it through. Between belt and shaft it would be very close in efficiency. Within a few percent at least. The gearbox would eat up most of the losses in either system.
    I agree. The difference seems to be the deck itself. On my X500 when the deck is cold (hasn't been run for a while) you need to have the engine at WOT or else it will stall when the PTO is engaged. This usually results in a lot of belt screeching. However, after the deck has run for a while and is "warmed up" you can easily engage the PTO at an engine speed around 1/3 throttle with almost no belt screeching.

    Almost all lawn and garden tractor manuals always instruct to engage the mower at WOT. Which seems to be a CYA move so you don't have Johnny Homeowner calling the dealer and complaining because the engine always stalls when he tries to engage the mower. All SCUT/CUT manuals always instruct to engage the mower at a low engine speed (less than 1500 RPM).
    2012 2720 -- 200CX Loader -- 54" Quick Attach Snow Blower -- Frontier LR5060 Rake -- Land Pride RB1660 Blade (Hydraulic Angle) -- Artillian 42" Forks -- Ken's Bolt on Grab Hooks -- Fit Rite Hydraulic top-link -- 2013 X500 for mowing duties

  13. Remove Advertisements
    GreenTractorTalk.com
    Advertisements
     

Page 1 of 2 1 2 LastLast

Similar Threads

  1. 54" Snowblade Install on a 1025r & Tim Marks.
    By LoneStranger in forum Implements & Attachments
    Replies: 1
    Last Post: 12-29-2016, 10:45 AM
  2. KT17 Series II Cam and Crank Timing Marks
    By steppinthrax in forum Vintage Lawn & Garden Tractors
    Replies: 4
    Last Post: 11-22-2015, 11:24 AM
  3. RPMs go up/down after engine has warmed up fully
    By steppinthrax in forum Vintage Lawn & Garden Tractors
    Replies: 11
    Last Post: 08-08-2015, 02:06 PM
  4. John Deere L&G Marks 50 Years
    By T-Mo in forum Vintage Lawn & Garden Tractors
    Replies: 0
    Last Post: 12-04-2013, 08:05 PM

Bookmarks

Posting Permissions

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