Tachometer

A while back, I decided to add a tach to my bike, so I ordered a "Whizzer" tach online, and modified it to work on my bike. The wiring is fairly basic -3 wires for the movement - hot, ground, and signal, and two for the tach light - hot and ground. You need a 12v battery supply for it to work - I'm using a rechargeable lithium ion.
For the signal (trigger) I used the hot wire to the CDI.
To mount it, I had to fabricate a custom mount, and cut apart a stainless steel soap pump for the case.

 

[FurryOnTheInside]

Well my tachometer arrived today took all of two minutes to set up ! Seems my engine revs all the way to 4000 rpm hahah man that's bad !

That is interesting. You didn't intend to build a low RPM engine?
What is your top speed in km/h and what was your calculated engine RPM?

 

[zippinaround]

No I didn't intend for it to be so low , I haven't taken it for a spin yet because I need to change my back wheel , but top speed was ~28 mph which is ~45km/h , it has been sitting for a while too will change fuel and wheel later and take it for a spin.

 

[FurryOnTheInside]

No I didn't intend for it to be so low , I haven't taken it for a spin yet because I need to change my back wheel , but top speed was ~28 mph which is ~45km/h , it has been sitting for a while too will change fuel and wheel later and take it for a spin.

Oh, so it definitely seems accurate, and that was no-load RPMs? Eek. I am hoping to build a low rpm engine and don't mind limited no-load RPMs but I hope it will rev a bit higher than that!
I think you have your work cut out. Or to be more positive, you have found your fun winter project.

 

[KCvale]

Well my tachometer arrived today took all of two minutes to set up ! Seems my engine revs all the way to 4000 rpm hahah man that's bad !

You have it set to wrong mode, you are the mode where it only counts ever other spark.
Change the mode and you'll have your 8K normal rpm display, hence why I stressed reading the manual to set it up ;-}

 

[GreatScottt]

I am interested in how you modified the wiring. Can you explain or show pictures on how you did this? Also, do you think it would be possible to modify a motorcycle speedo/tach to work on motobikes?

http://www.ebay.com/itm/Universal-R...ash=item542dba9173:g:0tQAAOSwNKRXjIVg&vxp=mtr

 

[zippinaround]

I set it to rpm 1 I'm pretty sure , will check again but that would explain the lowness haha

 

[KCvale]

I am interested in how you modified the wiring.
Can you explain or show pictures on how you did this?

There is no wiring other than the single wire you just wrap around the plug wire.
It is internal battery operated.

Also, do you think it would be possible to modify a motorcycle speedo/tach to work on motobikes?
http://www.ebay.com/itm/Universal-R...ash=item542dba9173:g:0tQAAOSwNKRXjIVg&vxp=mtr

Sure you can use that, but you'll have to carry a 12V battery to power it as it doesn't have an internal battery.

I like a big old school analog speedometer/odometer over a tiny digital myself, especially in bright sunlight, a quick glance down tells me everything I want to know.

Handlebars are a big thing with me, always has been since I built my first bike and decided the kit grips SUCKED!

I usually just replace the grips with black BMX form grips as you can stretch them over the throttle barrel.
Some bikes I motorize however have great grips like the hand stitched real leather foam grips in the pic above.

But to get back on topic, anything you find for a Motorcycle expects you to have an on-board 12V DC power supply.

 

[zippinaround]

KC what setting do you set the digital tach to? I had mine set to 2 stroke 1 cylinder and it would only read half revs I think it might have been programmed wrong because I set it to 1 stroke 1 cylinder now it reads properly , I think my pipe might be stopping it at 7k (not complaining) , but would be interested to know what you set yours to

 

[KCvale]

KC what setting do you set the digital tach to? I had mine set to 2 stroke 1 cylinder and it would only read half revs I think it might have been programmed wrong because I set it to 1 stroke 1 cylinder now it reads properly , I think my pipe might be stopping it at 7k (not complaining) , but would be interested to know what you set yours to

Setting 2, a single cylinder firing on every revolution.
A 4-stroke doesn't need to fire every RPM, it does exhaust and intake on one 1 rpm, but the engines fire the plug anyway so 1 spark every revolution.