TOPIC:

Hi I bought a grasshopper and having some great fun with it. I want to upgrade the motor to the 540. I have bought one and a 18t pinion as per a lot of advice from some forums. I've tried to fit the motor but it doesn't touch the gears to engage. When I look at the old motor to the new it seems to be offset. Have I bought the wrong motor, wrong pinion or do I need to change the gear cog that the motor engages.

You might have the wrong holes with the Mount screws.

Just checked the manual, did you build as shown? Without the adapter that goes onto the 380, did you get the correct 18T pinion. The standard tamiya are mod.6 the grasshopper needs a mod.8 and has a bigger diameter.

I haven't done a whole lot with these type of gearboxes, But should there be an offset adapter plate that helps with pinion alignment

Oh what motor do you got, one with 2 holes or 4 for mounting, that can offset the motor as well.

andyaus wrote:

But should there be an offset adapter plate that helps with pinion alignment

That's only for the small motor, Andy. A 540 should fit straight on without it...

One can have a look at the Hornet manual for it.
A 0.8 mod pinion like waterbok mentioned is of course essential as well.

Welshwaters78 wrote:

Hi I bought a grasshopper and having some great fun with it. I want to upgrade the motor to the 540. I have bought one and a 18t pinion as per a lot of advice from some forums. I've tried to fit the motor but it doesn't touch the gears to engage. When I look at the old motor to the new it seems to be offset. Have I bought the wrong motor, wrong pinion or do I need to change the gear cog that the motor engages.

You either have the wrong pinion, or are doing something wrong when it comes to fitting. Count the teeth on your pinion & measure the outside diameter, if it's not 18 teeth and a gnat's under 16mm OD then you have the wrong pinion.





If the pinion is correct, then you're fitting it or the motor wrong. This is the section from the Hornet manual (same chassis, 540 motor).

Wow thanks guys for all the info will have a look and get back to you. Thank you again

Just measured the pinion and it's 1.2mm wide.
So wrong pinion will order a new one now

You should probably go for a steel Robinson pinion then. Or this one, it's rather nice too :

In any case, don't get tempted to use a 32dp Traxxas one...
My Grasshopper sounded like a coffee grinder with it, even though it should've theoretically been alright.