Retrofit tacho to A7 Star Twin

[pdg]

Hi,

Does anyone know if it is possible to retrofit a cable-driven tacho to an A7 Star Twin?

I've seen timing covers with the requisite hole (assuming everything else fits?). Am I right in assuming that the tacho is driven off the magneto pinion nut and if so can the non-tacho nut I've got be replaced with one onto which a cable can be attached?

Many thanks, Peter.

[muskrat]

G'day Peter.
 Is yours a long or short stroke? I'm not sure of the long stroke but the short stroke isn't a problem if you have manual advance. The extended nut is available, the g/box's and covers are getting pricy.  With auto advance the drag of the tacho/cable/g/box would restrict the unit from advancing, and you'd have to modify the nut.
Cheers.

[pdg]

Hi Muskrat,

Many thanks for your reply. I have auto advance but am thinking of getting rid of this with an electronic ignition upgrade. Do you know the part number for the extended nut?

Thanks, Peter.

[wilko]

You will need a reverse drive 1:1 ratio drive to suit any 2:1 tacho.As long as the tacho itself isn't reverse driven And just to confuse you, a 4:1 tacho can be used if you use a 2:1 drive.

[a10 gf]

Hello, have fitted a tacho system to my A10, made my own 'extended nut', and you'll need a tacho-ready timing side, or find a way to do a nice machining job on a non-tacho one.

[muskrat]

G'day Peter
67-713 = 67-0713
http://www.a7a10.net/forum/index.php?topic=3260.0
http://draganfly.co.uk/index.php/accessories-a-misc/product/14717-
Cheers
PS. I'm a electronic ign convert. Boyer on my 3 A's.

[pdg]

Many thanks. Does this simply replace the existing pinion nut?

Regards, Peter.

[muskrat]

Yes

[pdg]

Brilliant. Many thanks.

Now I just need to find the timing case .... 

[pdg]

Does anyone have a picture of the tach drive that bolts on the outside of the timing cover, please? Does it have a circular base plate the fills the entire recess in the timing cover or is it an elliptical shape that just covers the area between the 2 screw holes (whilst of course filling the hole in the timing cover)?

Many thanks, Peter.

[muskrat]

http://www.ebay.co.uk/itm/new-TACHOMETER-GEARBOX-DRIVE-BSA-GOLDSTAR-65-9164-made-in-England-TACHO-DRIVE-/360493772547?pt=UK_Motorcycle_Parts_13&hash=item53ef1a6f03

[pdg]

Many thanks - again!

[terryg]

See also http://www.nsamotorcycles.co.uk/65-9164-bsa-gold-star-tacho-gearbox-drive-6539-p.asp, for comparison.  There are presumably others with stock too.

For example http://www.ebay.co.uk/itm/like/291284479092?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108, who claims to have both 1:1 and 2:1.

[pdg]

Many thanks. Have found a timing cover, so the process to completion has really started now.

[chaterlea25]

HI All,
I have found that the 1:1 tacho drive in goldies gives the rev counter mechanism a hard life
A  2;1 drive and recalibrated or 4:1 tacho is a lot more reliable
My 2 cent opinion
The 3:1 tachos driven from the oil pump are scarce and (even more!!) expensive 

Cheers
John