TW200 Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
762 Posts
Discussion Starter #1
I just had me the pleasure of buying and mounting a Trail Tech digital battery-operated tachometer. Mini-battery for display; wrap the spark plug lead with the sensor wire.

Now, I'm not sure it's working properly. There's adjustments with a calibration button; the button is on the back side, inaccessible after I glued it down. Peeling it off is not a good option...doable but not advisable.

Yup, I tested it before using the shaped double-stick foam pad. Seemed okay...started and showed an idle of 1200rpm. About right.

NOW...it's showing an idle of 1500 rpm. Granted the engine was cold at first test; but I wonder if some sort of calibration slip or some other strange digital bad-input kind of thing.

In 5th gear, I'm showing about 6000 rpm at 50 mph. (I'm drawing from memory from a half-hour test ride) Seems a little fast, again.

Finally, what is the redline supposed to be? Someone said 10250 rpm?
 

·
Registered
Joined
·
762 Posts
Discussion Starter #3
Thanks.

Yes, the gearing is stock. I wanted to wait and see how I did with the gearing and what I used this bike for, in the end, before changing out gearing.
 

·
Registered
Joined
·
3,549 Posts
Gearing Commander is a little more flexible as you can see three different ratios at one time and do other stuff. According to it, at exactly 60 TRUE mph, you should turn 7750.....pretty close.
Hint: you can make the speed box in any particular speed and RPM read an even speed value by adjusting the "minimum Speed to display" box.

At exactly 50 TRUE mph, it says 6460 RPM. This is close to your inexact memory. ;) Remember, tire pressure will have a large effect on your speed at any given RPM, so pump them up to 26 psi and try again. Most likely the tach is right on....they are very simple counters. 100 spark impulses per second equals 6,000 RPM, for instance ( just a guess!)

Your speedo is useless for this calibration unless it has been compared to a GPS readout many times. Figure it is likely to be 5 mph fast at 60.

And finally, these gearing applets are mathematically derived... MANY other real world circumstances can make them look inaccurate. I would be happy if they were within 50 RPM of an actual scientifically tested value. They are still the best way to play around with ratios before making up your mind. Then you can use this to find chain length: REBEL GEARS CUSTOM MADE MOTORCYCLE SPROCKETS ANY SIZE

BTW, redline is 9,500 RPM.
 

·
Registered
Joined
·
762 Posts
Discussion Starter #5
Okay...I'm getting the idea of how much this thing winds up.

I thought it might be double-counting, or some weird one-point-five count, but it seems I'm spot on the money.

Not a bad deal for $38. Took exactly five minutes to install.

Amazon has it cheaper....
 

·
Registered
Joined
·
2,516 Posts
The TTO tach you have is a good unit , I've had mine on for a few years now......nice . Trail tech also sells a mounting bracket for it , kinda fumbly but it works .
 

·
Registered
Joined
·
3,519 Posts
Certainly beats the tach. that I have on my bike now. Some of you might also be interested in the temp gauge that Trail Tech sells as well. Around the same price and design. Gerry

 
1 - 7 of 7 Posts
Top