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Denmark
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Discussion Starter #1
Been wanting a analog rpm for a while, and was about to pick up a CBR954RR tacho cheap to try and make it work, but got sold right in front of me.

Going through ebay I came across the SC57 tacho, which looks pretty cool. What kind of problems could one expect trying to fit it? Ive read some old threads about 2 cylinders VS 4 cylinders giving wrong speed, half or double, but wouldnt the Speedohealer be able to easy fix this?

 

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A chap on the Superhawkforum put one just like this on his VTR so there's no reason it won't work on an RC. It's a simple matter of matching up the wires.....
 

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Possible? Yes.
Easy? Most likely not.

The instruments are possibly programmed to accept different signals from the various sensors. Something like a speedo healer might be able to help, but it might not have the range. The Jim ahlman unit only goes up to 30% correction, but the ones from healtech go up to 100x, so that would be your best bet. You possibly might be able to use one for the tach signal also. Otherwise you might have to make something yourself.
 

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Go to the Superhawk forum (SuperHawk Forum) and ring up a chap named Tweety. He can give you the info you need. It can, and has been, done.
 

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TOP GUN Instructor
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HUMMM Correct IF I'm wrong... BUT A "SpeedOHealer" has Nothing to do with RPM's... It is for Speed Only, eh...;)

Peace Jeff
 

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Denmark
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Discussion Starter #9
Thanks for your answers, mark thats also a pretty sweet cluster, but properbly also quite another price-range.

Im already running a Healtech speedohealer, but maybe the RPM will be strange, ill try the other forums.
 

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I have also been looking into running an analog tach for a while and from what I have been told the biggest problem you are going to face is the signal sent from the cam pulse generator. *if I recall correctly.

Apparently the signal sent for an analog tach is 1/2 the required signal for a digital tach so it will alway read either 50%+/- of what its supposed to.

I have been told that the HRC ECU is set up to send this correct kind of signal but if you want to run one with an OEM ECU you need to do an electrical engineering project to covert the signal to the correct one.

Stunna

Been wanting a analog rpm for a while, and was about to pick up a CBR954RR tacho cheap to try and make it work, but got sold right in front of me.

Going through ebay I came across the SC57 tacho, which looks pretty cool. What kind of problems could one expect trying to fit it? Ive read some old threads about 2 cylinders VS 4 cylinders giving wrong speed, half or double, but wouldnt the Speedohealer be able to easy fix this?

 

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Member (Large)
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HUMMM Correct IF I'm wrong... BUT A "SpeedOHealer" has Nothing to do with RPM's... It is for Speed Only, eh...;)

Peace Jeff
Well yes, but all that a speedo healer does is take an incoming signal and modify it for an output. I don't know if the two signals are interchangeable or not though.
 

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Let's try this again:

Go to the Superhawk forum (SuperHawk Forum) and ring up a chap named Tweety. He can give you the info you need. It can, and has been, done.
 

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Let's try this again:

Go to the Superhawk forum (SuperHawk Forum) and ring up a chap named Tweety. He can give you the info you need. It can, and has been, done.
Or talk to Damon Stewart.

Heres what he told me specifically about what Id need to convert mine:
"Its very possible to build a divide by 2 or dubber circuit as needed to
get the correct tac pulse. Any college student in electronics could
do it, maybe using a 555 timer IC."

555 timer IC - Wikipedia, the free encyclopedia
 

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Denmark
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Discussion Starter #15
So Ive talked to Tweety who is actually local so me, pretty cool coincidence

He says the tacho is pretty much plug-and-play once you match the wires. Only problem is the temp which need the sensor from the CBR to work, but it should screw in directly, so easy swap.

So looks like it shouldnt be too hard.
 

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RC51 only 4stroke I liked
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168 Posts
Isn't that sensor necessary for your ECU to function properly? A different sensor would send the wrong signal and mess up the map.

The baro sensor sends pressure and air temp, right? The SP2 engine temp. is fed into the ECU. The SP1 has a thermal switch for the fans and a different one for sending to the ECU...

Just a thought! The VTR has carbs so it may be a different sensor from the CBR but the CBR's may be compatible.

So Ive talked to Tweety who is actually local so me, pretty cool coincidence

He says the tacho is pretty much plug-and-play once you match the wires. Only problem is the temp which need the sensor from the CBR to work, but it should screw in directly, so easy swap.

So looks like it shouldnt be too hard.
 

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I'm not too sure how much help I'll be, but I spliced in a CBR 1000RR Gauge set like the one that is pictured at the top of the thread to my VFR 750. Yes, I know it's still a 4 cylinder machine, but the firing order is a little different than an in-line 4. It wasn't too difficult, just a bit of wiring cutting and splicing. I cut off the factory VFR harness at a good point, and matched up the wires, and slpiced in the CBR wiring harness. Took a ahlf of a day to do. I did need a speedo healer though, as the speed indication was waaay off. Installed the speedo healer, and it works just fine. I did have to install a different water temp sending unit, but that was also easy to do. I did it to save weight, and for the shift light, as my VFR is my track bike.
 

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RC51 only 4stroke I liked
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I am not familiar with the VFR, an other EFI engine right, or were the older (80s) ones with carbs?
Is the temp. sending unit//sensor feeding into the ECU? I think this is significant not for the gauges but how the engine runs. The fuel ratio changes by the ECU depending on the engine temperature. This is why these engines don't have a real choke but a high idle lever, the rest is handled by the ECU. This is also why you shouldn't fiddle with the throttle while it starts and warms up as the fuel mixture is rich and you risk fouling plugs.
 

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RC51 only 4stroke I liked
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168 Posts
As I understand temp. sensors, they are just a variable resistor that is affected by a range of temperatures and varies the resistance of the current going through them. If 5v is fed into them they may go from 0 to oo resistance from the bottom of the range to the top of the range (or maybe in reverse). I would put them in the same spot with the same ambient temp and measure resistance, then warm them up (maybe a small cup warmer/hot plate) and remeasure to see if they are different.
 
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