Rev tacho needle jumping ? (speco 3cyl)

[Arctic Alto]

Hi all,

Just wondering if anyone knows why my rev tacho needle doesnt stay on a smooth movement.

It starts off smooth, but after about 5 mins, its starts to be erratic.

The plugs and leads arnt that old, and i've checked that their on properly.

Could it be the coil, the points or something else ?

Cheers
Craig

[Brayden]

Could it be the coil, the points or something else ?

Yep, coil, points, wiring or a dodgy tacho. (BTW: If you want a truly smooth reading you need a tacho with an air-core controller.)

[Arctic Alto]

I thought that the speco would have been a decent one.
I'll also have to check the points, how can you tell if the coils gone bad?

I know it wont be real smooth, but its also reading way off, it jumps from around 3k to 5k sometimes and is always jumping around a lil bit.

Thanks
Craig

[Husky]

I thought that the speco would have been a decent one.
I'll also have to check the points, how can you tell if the coils gone bad?

I know it wont be real smooth, but its also reading way off, it jumps from around 3k to 5k sometimes and is always jumping around a lil bit.

Thanks
Craig

I have a speco and quality seems good(6 months and counting)Check your points gap with feeler guage 0.4mm from memory also make sure points make even contact on each other(faces line up evenly)
Also check for good electrical connections on coil.

[Brayden]

how can you tell if the coils gone bad?

First sign is misfiring when the engine is hot.

Pretty sure someone else had a problem with an erratic Speco tacho, might be worth doing a search.

[supervan]

i also have the same problem in my carry but its a autometer guage

it does it the worst when backing of the trottle but also does it while driving does not do it at idle. i will be in fifth gear at about 3000rpm and then take my foot of the throttle and the shift light comes on for a blink and its set at 6000