Anyone know tach ratios?

[memper]

Im looking to put an electric (not digital) aftermarket mini tach on my bike. What ratio should I look out for? Im seeing mostly 1:2 on ebay but my intuition is telling me that this is not suitable. Ideas?

('99 750)

[motoxmann]

the carbed engines trigger spark every revolution (wasted spark), not only on compression stroke. so you'd want a 1:1 tach, aka 1 trigger = 1 revolution

[memper]

Thanks so much!

[memper]

Ha! Too bad they're impossible to find. Seems my options are digital, and I hate digital. What would my read out be with a 2:1? Would 1000 rpm read 500 or something like that? I could live with it being off if I knew exactly how off it would be if in fact I can't find a 1:1 electronic dial.

[motoxmann]

if you used a 1:2 tach, it'd read double the actual engine speed. so if the engine is at 7k, the tach would read 14k
why not just get the ducati performance tach? it matches the stock speedo

[Howie]

http://www.spatechnique.com/product_pages/page.cfm?cat=3

They have one that will fit in place of your speedometer with a small digital speedometer and odometer in it.  Start measuring or maybe ducpainter can help you.   He has one in his bike.

[memper]

Thanks MM. Dont think I will be doing 2:1.
Howie, those are neat but for hundreds of dollars.....

I simply want a small basic tach. Guess I'll have to keep on lookin.

thx yall
*edit: went with a small round digital found on Amazon. Says its good for bikes, 2cyl, 4 cyl, 2 stroke, 4 stroke. I guess we'll see...

[Speeddog]

Here's a small tacho:
http://egauges.com/cyc_mult.asp?Type=2_5_8_Street_Tach_Black&Series=Pro-Cycle

[memper]

Here's a small tacho:
http://egauges.com/cyc_mult.asp?Type=2_5_8_Street_Tach_Black&Series=Pro-Cycle

Very nice but if I'm gonna spend $200+ I will likely put it toward better riding gear (like new gloves). I just needed something simple, effective and cheap. So I went for the digital universal one. But as they say, you get what you pay for...so likely it will malfunction riiiight after the warranty is up.