Mics info:

There are several types of tachs.    

The mechanical tachs will not work on our bikes without some heavy duty design and machining  work.

The more expensive direct wire ones hook up to the igition coil.  You connect to the small black (with stripe) wire that switches the coil on/off.   And to run the power to the tach, there is "switched" power under the fuel tank.  I believe it's the orange wire but you should double check a wiring diagram to make sure, for your year bike, the colors stayed the same.   The ground can be hooded up to the frame (I used the Ign coil mounting screws).

The universal digital tach use a wire wrapped around the sparkplug wire.   It should be noted that many of these small digitals have no power wire and run off a internal battery.  And most have the battery incased such that when the battery goes you just throw them out.  Life of the battery varies and could be related to how long the dealer  or distributor had it sitting on the shelf (called shelf life).  In theory they should go a few years......   in theory.....  

diamond jim wrote on 05/27/09 at 17:56:34:

gotta be 1 that'll work with 1 pulse per rotation of the engine, so an electronic one for a 2 cylinder 4 stroke with a distributor will work, or a cam fired 2 cyl... any will "work" but having to devide or multiply the reading aint so good....


edit: how about a scooter tach? crank fired singles mostly....

It seems like the package of one I read at the auto store said for 2 as well as 4, 6, 8 c ylinder engines.  Maybe I optimistically misread the package.  So would these show half the actual rpm?  

Never looked for a scooter tach.  Lemme see what I can find...

I found this post on a different thumper page (not LS650):

"... the two spark waste system will mean a different 2 cylinder or single cylinder 2 stroke setting. I hope my tach can do that, because it's for a single cylinder 4 stroke engine. And the fact that the CDI spark is too short duration for it to trigger a tach signal. Looks like I'm going to have to build a little gizmo like he did. I'm sure glad he supplied a schematic, as I'm pretty fuzzy on electronics."

In other words,  a lot of work like T Mack said above.

Edit: Looks like the tachs from Autometer, the ones designed for go cart racing, work and look like nice quality.  They'll put you back $150+ though.

and the savage isnt CDI... its battery excited induction.. check the wiring diagram... ignition hot lead goes to the coil... if it was CDI, that would sent a 300+ volt spike through the electrics... that wouldnt be so good... it's like a ford electronic iggy, for the most part..

diamond jim wrote on 05/27/09 at 22:52:45:

wasted spark... has too... the magnet passes the pickup every revolution, and no crank sensor....

edit: late night posts are bound to contain errors...lol  should be "no cam sensor".... and now back to your regular programming

All of the small cheap electronic tachs lag a second behind as they are averaging the nuts out of things to get a stable progression.  Some claim to only lag a half second behind, but big deal, it still lags noticeably.

You will have to get a "rapid response" tach which will cost you over $100 to get a "perfect response" to fast changes.

Here is some free advice -- don't bother putting a tach on an LS650.  
You will find out from any $25 cheapie electronic tach that:

1) You rev no more than 3,500 to 4,500 rpm doing what you normally do no matter how hard you twist your wrist.
2) You don't seem to be able to over-rev the motor even if you intentionally try to do so.


There is a great debate about this fact.  Although it is not stated as a "feature" anywhere in the Suzuki literature we do have a black box on our bike that runs an electronic ignition system.  We "may" have an unstated RPM limiter on the bike.   The Savage has always had a black box since the word "go" and we have always had a zero history of people blowing up motors due to over-revving them.

(letting them run low on oil is a different story -- that kills pretty quick)

We DO have a hell of a restriction on the input tract to the head and we also have another hell of a restriction on the exhaust side.  Apart from any black box electronic limiters, these restrictions are thought to be enough to flatten out the rpm increase above 4,500 rpm into a flat no gain zone.

Some folks have removed their intake and exhaust limiter zones by porting and polishing their heads.  Lancer has a bike that has been cleaned up and has a Lancer performance cam in it -- I will ask him at the end of next month (when we go on the Dragon Run) if he can go up & over 6,000 rpm with his bike which would disprove the electronic limiter in the black box theory.

I really like the Veypor, it does a lot of stuff, is accurate and reasonably priced.  Set up is easy, and the manufacturer provides free online downloads to update the device with new programs/improvements.  
It is easy to use on the road too.  You can install the wiring on up to 4 different vehicles ... 2 bikes (Savage and SRX, '08 Dakota pickup, and hotrod '71 Maverick for instance, or what ever mix you wish.  The device can be set up to store data for  4 vehicles of your choice.  Just plug it in to which ever vehicle you want to drive/ride, turn it on & go.  Get home, unplug from one and plug into another, turn on, select vehicle & go.

Accuracy ?  From http://www.veypor.com/veypor.html

Accurate RPMs

The built-in tachometer actually measures every individual engine spark with an accuracy of 5 millionths of a second. It then uses an adaptive algorithm to smooth out and average this value so you see the constant RPM of your engine, not values bouncing all over the place. This lets you get your engine speed exactly right before dropping the clutch and taking off.

I liked the Verypor so much when I got one that I applied to be a dealer for them.
The price of the unit has actually decreased from just under $200 to the current retail price of $159.99.

Anyway, that's my 2 cents.

Decided I wanted to add this list of basic features or the Veypor unit.

Features      Veypor/VR2
Full Instrumentation            
Portable Dynamometer with plots            
Full and Pro Tree 1/4 Mile Runs            
0-60Mph and Braking Test Timing            
Roll-on timing for any speeds            
Graph results for all Runs            
Save up to 8 runs            
Calculate Fuel Mileage and fuel level            
Separate Fuel Odometer            
Odometer and Resettable Tripmeter            
Metric or Imperial units            
Two maintenance hour meters            
Gear Indicator            
Lap Timer and Course Analyzer            
Full featured Rally Computer            
Store 4 separate vehicle setups            
Super bright dual-level shiftlight            
Programmable speed light            
Download all Run data to a PC      
(VR2 only)      
Drag Coefficient Calculation            
Rolling Resistance Calculation            
Full-time datalogging for up to 24h            
Programmable sampling rate            
View all logging sessions on a PC            
Time and Date with battery backup