Slipping on GO!

Old 07-08-2010, 01:42 AM
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Default Slipping on GO!

Hi, just got my old Hornet out of storage (for the last 20 years!). Got a new battery and checked it out, regreased etc, all looks good. BUT it slips when taking off and just gradually speeds up, I can hear it is trying to go full speed straight away but something is slipping, what could it be? Motor?, checked the dif and all cogs are still good. How should I start troubleshooting?? ANY HELP APPRECIATED!

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Old 07-08-2010, 06:12 AM
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do you still have the old manual for your hornet? that would help you out to an extent. if you don't you can download it from http://lowclasscc.net/downloads/t/tamiya/

now that you have the manual you can see exactly how everything is put together. on other vehicles i would start out asking is the slipper clutch is tight enough.. then i would ask if the ball diff was adjusted properly. but in your case you don't have ether one of those.

in your case i would start out by inspecting the gears in the rear end of the hornet. make sure they are not striped and and working smoothly. i would also check the diff. i personally don't have experience with gear diff's like your hornet runs so i can't be anymore help than that.

but since you hear the motor spinning up and the car isn't going it would be something in the rear end assembly. also check to make sure that the pinion gear that is mounted on the motor is tight enough and not slipping on the motor shaft. if it is then you may just have to tighten a set screw on the pinion gear to fix it.

good luck on it and keep us updated on what you find out.
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Old 07-08-2010, 07:11 AM
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Could it be one of the roll pins in the rear axles is sheared, behind the hub that the rear wheels fit up to? Hold the wheels, see if the axles are turning.
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Old 07-08-2010, 08:07 AM
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Sounds like you re-assembled something incorrectly.
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Old 07-08-2010, 10:18 PM
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Originally Posted by alter_ego
Sounds like you re-assembled something incorrectly.
Hi, nope, pretty sure nothings assembled wrong as I've got the manual and have checked those obvious things out. I'll try some of the other suggestions and keep you posted. Thanks heaps everyone for helping.
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Old 07-08-2010, 10:35 PM
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those old buggies are pretty simple so the fix should be also. Is the pinion tight? Don't the axles "key" into the diff gear? could that be stripped out? What happens when you hold the buggy up and give it throttle?
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Old 07-09-2010, 08:29 AM
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Originally Posted by Dave H
Could it be one of the roll pins in the rear axles is sheared, behind the hub that the rear wheels fit up to? Hold the wheels, see if the axles are turning.
This would be my bet. If the roll pin is missing or the pin isn't keyed into the slot in the rim correctly it would cause exactly the issue you describe. Or the rim could be stripped out already. It would gradually get worse until the car will no longer move.
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Old 07-09-2010, 08:31 PM
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Originally Posted by RC Dad
This would be my bet. If the roll pin is missing or the pin isn't keyed into the slot in the rim correctly it would cause exactly the issue you describe. Or the rim could be stripped out already. It would gradually get worse until the car will no longer move.
I can't see a roll pin mentioned anywhere in the manual. The wheels are pushed over the shaft and locked on a plastic backing which in turn is locked onto the shaft with a pin. That is all locked correctly. One thing I have noticed is this - if I hold one wheel, I can still rotate the other one, this happens with both wheels, is that supposed to happen?

Think I may have found the problem! I took the wheels off again and I can rotate the tyre whilst holding the wheel! Surely that won't help because if there is any load on the tyre it will just slip. Hope its that simple, I have just glued the tyre to the wheel, battery is charging so I will let you know the result in a few hours!
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Old 07-09-2010, 09:57 PM
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Originally Posted by AlanH
I can't see a roll pin mentioned anywhere in the manual. The wheels are pushed over the shaft and locked on a plastic backing which in turn is locked onto the shaft with a pin. That is all locked correctly. One thing I have noticed is this - if I hold one wheel, I can still rotate the other one, this happens with both wheels, is that supposed to happen?

Think I may have found the problem! I took the wheels off again and I can rotate the tyre whilst holding the wheel! Surely that won't help because if there is any load on the tyre it will just slip. Hope its that simple, I have just glued the tyre to the wheel, battery is charging so I will let you know the result in a few hours!
That is the pin he is talking about. Does the buggy have the original tires and wheels on it? They should be a 3 piece design that would lock the tire onto the rim. Just like a current bead lock for you young guys out there.
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Old 07-09-2010, 10:30 PM
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Originally Posted by racer1812
That is the pin he is talking about. Does the buggy have the original tires and wheels on it? They should be a 3 piece design that would lock the tire onto the rim. Just like a current bead lock for you young guys out there.
Yep, everything is original It is a 3 piece design but it hasn't locked the tyre, I tightened it up as much as it would go but still not locked onto the rim, glued it now so heres hoping thats all it is. Hope to try it soon.

Just tried it, perfect now! Excellent, I'm so happy that it was that easy, p***sed off that I didn't look at that first though!

Thanks everyone for helping me out, night time here now but in the morning I'll send it through its paces!
Thanks again, great site, I'll definately be back

Last edited by AlanH; 07-10-2010 at 12:57 AM. Reason: Updating earlier post with a conclusion
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Old 07-11-2010, 01:21 AM
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Originally Posted by AlanH

Thanks everyone for helping me out, night time here now but in the morning I'll send it through its paces!
Thanks again, great site, I'll definately be back
OK, its official, I took it out todayand its just like I remember it from when I was a kid. My 4yr old son drove it today for his first time and ran it full speed straight into the kerb! It just bounced off and didn't brake anything, good tough old machine!
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