When you install a tach on a 2 stroke Sport 400, does it require the use of a battery, because I removed my battery and was wondering if I need to buy a smaller one just to run the tach?
Thanks!

 

No it doesn't require a battery.

 

What about a tach for a 4cyl car, I have been told they will work, would I need a battery for it?

 

A tack for a 4 cycle will read twice the actual rpms if it is used on a 2 cycle.

 

I remember a while back some guys were running a Sunpro automotive tach on their 400's. The tach needed to be set up for a 4 cylinder engine to run correctly. I think it has something to do with there being 4 magnets on the flywheel.

 

Thats the same thing I heard WIscrambler, thats why I was wondering, did everyone you talk to or read about say they worked fine, everyone tells me thats the way to go. Thanks for the input.

 

i have one of those sunpro tachs on my quad...

 

16polaris-
I don't recall anybody having a problem with the Sunpro tach. They are only about $35 at Autozone or Advanced Auto. I searched the forum about a month ago on this topic and there was a complete write up on how to install the tach. Here's what Mudmaster250 wrote:

this is the post i used to help me wire mine up, hope it helps. in step number ten it says cut the 1 ft section of wire. dont do it unless u have two headlights. i have pics of mine mounted but if u need more i can get some next weekend when i go to ride. and if u want a picture of the wiring i can get the pretty quick.

It was a SunTach I got from Autozone. There's not too much to the install but if interested how I did it, I found this post I did quite a while back. So ignore it if it bores you. So here it is.
The Tach is a Sun Supertach II which I purchased from Autozone for about $35. There's a black faced one that's the same for about $29. The choice is yours. You will also need to go to radio shack and pick up a pack of red wire splice/coneectors to connect the wires off the tach to the bike(it actually comes with 4 in the package but you actually need 5. You also need to pick up a pack of wire conectors(yellow I believe). I'm not sure what the proper name for these are. It's the type of connection that you use to join 2 wires together with a crimping tool. Both of these together probably won't cost you $3. While your at the shack, also pick up a tube of clear silicone with the long pointed end on it if you want to add some additional element protection to it.

#1. Remove the front cowling(hood) off of the bike and disconnect the battery cables in the back of the bike.

#2. Take the mount that comes with the tach and put it in a vice and smash the bottom of it till it's flat and not curved anymore(you'll see what I'm talking about when you look at the mount). Do not flatten out the concave part of the mount that the tach actually mounts on to. You need to flatten the bottom of the mounbt because you will be mounting it onto one of the bolts holding the handlebar in place. You will have to take a bolt off of the handlebar mount (one of them on the front side of the bike)and drill out the hole on the bottom of the tach mount big enough to slide the bolt through.

#3. Use the silicone and apply some all around the inside edge of the face of the tach and use a shop towel(or a rag with little grain to it) to force the silicone into the inside edges of the face. Do the same thing to the bottom side of the tach. Now make sure and slide the protective wire covering all the way up and into the tach housing and then slide the rubber grommet all the way up the wires till it is at the inside edge of the tach housing. Then take the wires and slide then through the tach mount and slide the plastis tach housing securing cap onto the wires all the way up to the tach and tighten the tach onto the mount.

#4. Use some more silicone to fill up the area around the wires coming out the back of the tach and let dry. Make SURE and put the switch on the back of the tach to the 4 cyl setting!

#5. Now mounthe tach by bolting it down onto the front side of the handlebar mount.

#6. Sit on the bike in your normal riding position and gently bend the tach towards the front of the bike until you are able to see it the way you want to.

#7. You will need wire cutters/strippers/crimping tool now. Connect the green wire to the Yellow/red wire coming off the rev limmiter switch located right behind the oil tank on the right side using the red splicing connectors that come with the tach.

#8. Connect the black wire to the brown wire coming off of the headlight wires(connect it as far down as you can so it won't be visible when you put the hood back on the bike).

#9. Connect the red wire to the Red/white(should be able to use the one off the ignition switch although I believe any Red/white would work) off the ignition switch.

#10. Take the wire cutters and cut off a 1' section off the white wire and take the 1' piece and cut it in half. Then twist the 2 pieces together and stick the end into the wire splicing connector and crimp it. Then taqke the white wire coming off the tach and put it into the other end of the crimp connector and crimp it together so that you now have 2 white wires, one of each to connect to the green wires coming from each headlight(that way your tach will be illuminated at night no matter whether you have the light on dim or bright)

#11. Here's a bit of advice: Before you snap the red connectors closed, Coonect the battery back and turn the ignition on and use a power probe to check and make sure that you indeed do have the tach properly grounded and to make sure that you have power to it when the ignition is on and no power to it when the ignition is off. I'm sure this is a cake walk for you as you are a electrical engineer as I think I remember. If everything checks out, turn the ignition switch on and the tach needle should jump to 0. Then fire the bike up and see if it works(it should).

Sorry about the long post and I can't be 100% sure that I didn't leave out a detail, but if i did and you have a question, just let us know and I'm sure either i or someone else here will come up with a answer. Best of luck.

 

THANKS ALOT WIscrambler, thats ALOT of good info, I think i'll try to pick me up a tach tomorrow, is there anything that I need to look for other than the 4,6,8 cylinder settings?

 

I don't have a tach on my quad (yet), but I think those instructions should get the tach installed. I'll be picking up a tach myself this coming week but won't have my Scrambler running for about another month. [img]i/expressions/face-icon-small-sad.gif[/img]