Based on the archives I've installed a Sun Pro II tach on my scrambler 400. For those that have used it:

Are they accurate? I'm set on 4 cyl but feel my reflected RPM idle is a bit high. The service manual suggest my idle be set @ 600 rpm. I don't think it'll run at an idle as low as that. The tach shows a 1000 rpm idle right now and as low as it seem to run smoothly... Porting is stock


Do they hold up to the bouncing and elements?

Thanks guys.

dan

 

Dan, I cant help you on the idle speed, my race mod wheeler idles at 2400-2500rpms, and without a battery, it starts fluctuating below 1500. It does hold up to vibration well,though. You better remove the faceplate and clear silicone it, then silicone all other places to keep water out. Condensation killed my first one quickly. My second one has been on it for a few months without a problem. Bubba

 

Glad you checked in on this bubba. I suspect the much suggested "set it in 4 cylinder" is wrong. I get an idle speed that is simply too high. I need an idle of about 1,100 before I feel its happy. Service manual says 600 - 800. My bike dies before it gets that low. So I suspect the readings are off. Yet, we get 2 impulses per rev (magnets on both sides I guess) which should look like the coil of a 4 cylinder 4 stroke...

You should hear the BS the actron tech support guy slings. I finally told him "you don't really know how it works either do you?" He finally acknowedged that he was trying to quote what he'd heard others explain but maybe needed to have an engineer talk to me. sigh....

Any chance the hpd mid-range pipe I've got alters the required idle speed? hmm... That seems likely doesn't it. hm... another damn call to hpd. Maybe higher compression affects it to.... What do you think?

Any others w/input?

 

my bikes idled between 1000-1100 rpm with stock porting and LRD pipes. They both idle higher than that now hope that helps.

Jack

 

My Xpress idles at about 1000-1100 rpm's. Like Bubba said, silicone any and every hole you can find. The first time mine sat out in the rain, it quit working right. I had to take it apart and let it dry out. Once I put it back together it was working fine. I sealed it all up and didn't have any more proplems with it. The vibrations didn't seem to hurt mine. I even left it on for the first couple of races that I ran this year. Worked flawlessly. I took it off a while back. The biggest reason I had it on was to work on my clutching. Until I change my clutching, it will stay off.

 

Thanks all!

 

I tried this weekend to put a sunpro tach on my banshee. The banshee uses a two pulse system. I have a battery mounted on the bike to run my shift light (works through the dyna ignition). I hooked the tach up to the battery and coil, and when turned on, the needle zeros. When I start/rev the bike, nothing happens. Do you think the total loss mag system doesn't produce enought voltage to the coil to trigger the tach? It is set on 4cyl.

Bubba, I lost your number and need to talk. I am needing the 350 ported. Please e-mail me at Sandric@go.com

Thanks,
Richard

 

I don't think it will work. Certainly the number one warning on those tachs and related faq's is against attempting to use it with a magneto based system. I've always considered the banshee, CDI and all, a magneto based system.

The issue, I suspect, is while the 'she does use two pulses, I don't think the voltage amount or duration matches what is needed. In fact, I suspect at upper rev's it will butn out the unit.

The diagnosis of @ power-up the needle goes to 0 is important as we now know ground and power work.

While much maligned, I think a spark based pick-up (lik tiny tach) is needed. To help it become accurate I'd swap wires over to resister based and plugs too. I suppose you could hope the radiated noise from the she was keeping the sun from working, but given the dire warning all over the box, owners, manual, etc... I'd suggest it ain't gonna happen.

I'd pursue it with you but I've no real need for a tach on my 'she. Nothing I'm doing requires tuning via rpm.. Out of pure noiseness, is this a need one or a want one for you? You know about the mechanical RD400 tach option right?