Author Topic: Engine losing power during fast acceleration  (Read 853 times)

0 Members and 1 Guest are viewing this topic.

beagle

  • Neophyte
  • *
  • Posts: 18
  • Karma: 0
Reply #15 on: February 22, 2019, 08:04:58 pm
Also, do a quick check the air filter isn't clogged up a bit and the fast idle lever is off.
Drink now....avoid the Xmas rush.


gashousegorilla

  • Grand Gearhead
  • *****
  • Posts: 4,284
  • Karma: 0
Reply #16 on: February 23, 2019, 10:59:58 am
   If your in first gear and you take off and get on that throttle HARD and rev the snot out of the motor,  and it starts to stutter... your getting into the soft cut on the rev limiter.   If you continue to rev it at that point, it will go into a hard cut with the rev limiter and the motor will cut out completely.  UNTIL... you back off on the throttle.  This  most likely will happen in first, second and third gears if your revving the hell out of it.    In fourth and and fifth gears, this is unlikely to happen because a stock bike does not have the power to hit the rev limiter in those higher gears.   A Tacho installed on the bike would tell the tale...
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


Bert Remington

  • Grease Monkey
  • ****
  • Posts: 378
  • Karma: 0
Reply #17 on: February 23, 2019, 09:03:20 pm
I collected some information on the MMB tachometers here https://forum.classicmotorworks.com/index.php/topic,26258.msg302777.html#msg302777

Of course you want to pair it with a Smith's Chronometric Speedometer here https://forum.classicmotorworks.com/index.php/topic,26963.msg307324/boardseen.html#new and here https://smithsgaugesusa.com/chronometric
2016 RE Classic 500 CA version Fair-Weather Mountain Bike
2012 MG Norge 1200GT 8V roller lifters All-Season Freeway Cruiser
2000 BMW R1100RT "Ride Not Taken"


9fingers

  • Grease Monkey
  • ****
  • Posts: 255
  • Karma: 0
  • From the New Hampshire part of New Jersey
Reply #18 on: February 25, 2019, 05:31:46 am
I collected some information on the MMB tachometers here https://forum.classicmotorworks.com/index.php/topic,26258.msg302777.html#msg302777

Of course you want to pair it with a Smith's Chronometric Speedometer here https://forum.classicmotorworks.com/index.php/topic,26963.msg307324/boardseen.html#new and here https://smithsgaugesusa.com/chronometric
Bert, do those MMB tachs work with the UCE engine and EFI?
2016 Classic Chrome Maroon
Beta Rev 3 270
Honda TLR200 custom
Honda TL 250 TMI custom frame
Honda TL 125
Yamaha TY350


Bert Remington

  • Grease Monkey
  • ****
  • Posts: 378
  • Karma: 0
Reply #19 on: February 25, 2019, 10:50:13 am
Yes they would.  The RE uses a Kettering ignition so you would connect the MMB tachometer Green wire (Positive input) to the RE ignition coil trigger wire (ECU Pin 18 IG, White/Red as I recall) and the MMB tachometer Red wire (Ignition power) to the RE ignition coil power wire (ECU Pin 1 IGP, Brown as I recall).

Since I last visited the MMB site, the prices seemed to have gone up about 20 Euros and the installation PDF not longer seems available so I attached it.
2016 RE Classic 500 CA version Fair-Weather Mountain Bike
2012 MG Norge 1200GT 8V roller lifters All-Season Freeway Cruiser
2000 BMW R1100RT "Ride Not Taken"


dickim

  • Grease Monkey
  • ****
  • Posts: 290
  • Karma: 0
Reply #20 on: February 25, 2019, 03:28:20 pm
I have the mmb unit waiting to be fitted (needs hole to be enlarged slightly) but works on testing before getting dremel out 😀


SquadronROE

  • Neophyte
  • *
  • Posts: 10
  • Karma: 0
Reply #21 on: February 27, 2019, 05:06:16 pm
   If your in first gear and you take off and get on that throttle HARD and rev the snot out of the motor,  and it starts to stutter... your getting into the soft cut on the rev limiter.   If you continue to rev it at that point, it will go into a hard cut with the rev limiter and the motor will cut out completely.  UNTIL... you back off on the throttle.  This  most likely will happen in first, second and third gears if your revving the hell out of it.    In fourth and and fifth gears, this is unlikely to happen because a stock bike does not have the power to hit the rev limiter in those higher gears.   A Tacho installed on the bike would tell the tale...

Incredible. You folks figured it out.

It turns out that I really am used to cars and engines with much higher red lines than this bike, and without a tach I couldn't recalibrate my brain. I took the bike into the garage just to make sure everything was ok and they told me basically the same thing: There is a soft cutoff prior to the actual rev limiter being hit. So it will starve the engine of fuel instead of destroying the engine.

So ultimately it really is that I need to accelerate more gently. Which is certainly a habit I can form.


gashousegorilla

  • Grand Gearhead
  • *****
  • Posts: 4,284
  • Karma: 0
Reply #22 on: February 28, 2019, 06:38:19 pm
   Hehehe ! Glad you got it figured.  We are here to help ... sometimes we get it and sometimes we don't ?   Sometimes it's difficult to figure out  through a forum and not getting your hand s on a bike.  And having Tach really helps on these bikes, or any bike for that matter.  But anyway... I believe what is going on with the rev limiter, and from what I have seen , is that... It cuts spark first , on every other engine revolution.   Which causes a miss , or your " soft cut " at around 5250 rpm's.   You can actually hold your throttle right on the edge of that soft cut and feel it sputter.   At around 5500 rpm's  it will go into a HARD cut , were it cuts off the fuel.   The valve springs have a pretty lite seat pressure as well , so if you go much above that RPM range... give or take.   You could start floating the valves , which would kill power and pump a lifter temporarily.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gizzo

  • Grand Gearhead
  • *****
  • Posts: 1,831
  • Karma: 0
  • Live slow, die whenever
Reply #23 on: February 28, 2019, 08:11:15 pm
     You could start floating the valves , which would kill power and pump a lifter temporarily.
Happened to me on my CGT once when I missed a gear. It ran like snot and I thought I might have killed it but it bled back down and came good  ;).
simon from south Australia
Continental GT
Pantah
Monster
DR250
Honda C90
TRX850
DRZ400SM