Throttle springs - too strong

Adrian1 · Aug 3, 2013

Anyone know if they make different rate springs. The ones on my 900 series carbs are ridiculous. Can barely get the cable out. Btw the cables are well lubricated and correctly routed

Rohan · Aug 3, 2013

Have you pulled the springs out and looked at them ?
If they are something like twice the the length of the usual ones, you know someone has been at them...

Adrian1 · Aug 3, 2013

A fair comment but i don't know what the standard length is :cry:

Rohan · Aug 4, 2013

Measure them, and we will tell you if they are standard.

If they are too strong, then either they are not stock, or something is wrong somewhere else.
Not that there are many places for it to be wrong....

Adrian1 · Aug 4, 2013

Thanks. 72 mm

Rohan · Aug 4, 2013

Stock springs here are 74 mm even, with 10 coils.
Wire gauge is not easy to measure, but is slightly less than 1mm.

Do your slides slide freely with the springs out.
Do the carbs operate freely before you bolt them to the manifolds (if they are out and loose at any point).

Adrian1 · Aug 4, 2013

Thanks, yes the slides move freely. I noticed the spring on my other bike (Monobloc) is somewhat shorter and much easier

Rohan · Aug 4, 2013

They shouldn't be excessively strong like that.
Adding a quickaction twistgrip won't have helped, of course.

As someone said, you don't want the throttle slides to not return when you shut the throttle.
That can be lethal if your throttle doesn't shut off...

acotrel · Aug 5, 2013

Some of our guys used to fit much stronger springs to VM mikunis when they were fitted to four stroke motors . The increased vacuum could make the slides hang up when there is no guide pin, as in some carbs primarily intended for two strokes.

Throttle springs - too strong

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