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  1. #1
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    Burning smell coming near motor

    So I just added new steel rear axles(eBay cheap version) and big foot wheels so itís much bigger and wider then stock. I test drove it hard in my garage for about 5 minutes and I get a burning smell near the motor. Does anyone know what is burning ? How bad will my car damage from this? Thanks in advance for anyone who can help.

    -Slash 4x4 vxl on 3s

  2. #2
    RC Qualifier Calebs0615's Avatar
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    The biggest mistake I ever made was buying monster tires...

    To answer your question, you need to gear down to compensate for the rotational mass you added with metal shafts and bigger tires.

    The burning smell was likely one of the wires going to or from your motor to or from your esc. But if it still works, it should be fine.

    You should invest in a temp gun. I got one at harbor freight for like 40$. Dont operate your truck if your motor is over 150 or 160 degrees.

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  3. #3
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    Can the wires be replaced? I have a temp gun the motor was only 112 after 5 minutes. I’ll be going back to stock wheels and return the axles. I recently snap the stock stub axle right after a new 3s battery. Would the oem Traxxas steel drive shaft have less weight and problems?
    Last edited by Slashn4x4; 08-13-2020 at 12:07 AM.

  4. #4
    RC Qualifier GotNoRice's Avatar
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    How bad was the burning smell? I mean it's normal for electronics to smell a bit when they get hot, and a motor can certainly get very hot. You said 112. 112F or 112C? 112F is not hot enough to make anything smell like burning though, and certainly not hot enough to burn a wire. Maybe if something was wired poorly, and you have arcing somewhere.

    You should not worry about the heavier tires or axles. Plenty of people run monster truck tires on their slash. Gearing down is a good recommendation. Long-term, you should probably consider a bigger motor. For example, in the new Hoss 4x4, Traxxas paired your same VXL-3s with the larger motor from the Maxx.

  5. #5
    RC Turnbuckle Jr. Squeegie's Avatar
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    Was it an electrical smell? If not, could it have been your slipper? It may be too loose for your changes. If it was, you should probably take it out and check it for glazing.

    Good luck!
    Creativity is intelligence having fun. -Einstein

  6. #6
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    Gear down, You must.
    Or just do a 1/8 motor and esc

    If you only drove the truck for 5 minutes in your garage (probably 72-80įf) and it got hot enough to smell, how would it do outside in the heat?
    "Speed and power solve many things"

  7. #7
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    It smelled like burning rubber or some type of burned fluid. It was 112f on my temp gun. This truck is new so I ran it about 3-4 times everything is stock besides cooling esc/motor fans, rear steel axles and larger tires. Could it be the wires heating up or slipper clutch glazing?

    I think Iíll replace the tires with the stock. Is there a tire/wheel slightly taller but stock width that would work on the slash and not have problems?
    Last edited by Slashn4x4; 08-13-2020 at 09:30 AM.

  8. #8
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    If its the slipper clutch you could hold the ruck still and the motor should still spin
    "Speed and power solve many things"

  9. #9
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    I held the truck the wheels spin normally. What am I looking for? The smell only happens when it’s being driven

  10. #10
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    Can a bad bearing make a liquid smell? Im guessing

    Theres not many liquids in the slash 4x4

    But i know a motor can make electric smells and burning smells AND liquid smells sometimes.

    I cant tell if it might be one of your fans blowing around a smell from the esc?

    And also i meant a burnout ish thing see if when the tires have a load they still try to spin
    Last edited by cooleocool; 08-16-2020 at 01:32 AM. Reason: merge
    "Speed and power solve many things"

  11. #11
    RC Qualifier Calebs0615's Avatar
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    Quote Originally Posted by Slashn4x4 View Post
    It smelled like burning rubber or some type of burned fluid. It was 112f on my temp gun. This truck is new so I ran it about 3-4 times everything is stock besides cooling esc/motor fans, rear steel axles and larger tires. Could it be the wires heating up or slipper clutch glazing?

    I think Iíll replace the tires with the stock. Is there a tire/wheel slightly taller but stock width that would work on the slash and not have problems?
    You might want to be checking different spots on the motor cause the top could be 120 when the barrel its self is like 180.

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  12. #12
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    Yes around the motor and the back of the motor also the highest I got was 112. Could it be the 3 in 1 oil I put in all the axle bearings burning?

  13. #13
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    Hmmmmmmmmmm

    Check this bearing
    https://www.flickr.com/photos/189146...posted-public/
    [IMG] 20200813_115024_2.jpg[/IMG]
    Last edited by LargeCar1999; 08-13-2020 at 11:37 AM.
    "Speed and power solve many things"

  14. #14
    RC Qualifier Calebs0615's Avatar
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    Quote Originally Posted by Slashn4x4 View Post
    Yes around the motor and the back of the motor also the highest I got was 112. Could it be the 3 in 1 oil I put in all the axle bearings burning?
    I dont know, I wouldnt think theyd get that hot.

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  15. #15
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    I will check that bearing tonight. Does it usually
    Burn up when installing bigger wheels and not gearing down.

  16. #16
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    Im not sure but i know that that one bearing can do some crazy things

    Also its the second fastest moving bearing so if its damaged something could happen

    Ive never had anything happen to that bearing before though

    Nor have i heard about it smelling

    But ive had one cease and i couldnt even hear it
    If you have the stock bearing there, could it heat up and burn up the rubber seals?
    Last edited by LargeCar1999; 08-13-2020 at 01:30 PM.
    "Speed and power solve many things"

  17. #17
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    I need to do some research on install and reinstall of that bearing to check it. I did put on the original wheels ran it no burning smell. Then I put on the bigger wheels and I get a burning smell after a short run. The car is a lot slower with the bigger wheels also .
    Itís not worth doing a monster slash until I have more Info on what needs upgraded. Has anyone done a 4x4 vxl monster slash successfully?
    Last edited by Slashn4x4; 08-13-2020 at 08:32 PM.

  18. #18
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    Dont check that bearing, you dont need to if the smell stopped, its not that bearing. But i fear it IS the motor or the esc.

    One of those things do crave a lower gearing
    Maybe a pinion gear with 3 less teeth

    The bigger wheels put alot of strain
    Last edited by LargeCar1999; 08-13-2020 at 08:20 PM.
    "Speed and power solve many things"

  19. #19
    RC Turnbuckle Jr. Squeegie's Avatar
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    Did you check your slipper? Is it loose?
    Creativity is intelligence having fun. -Einstein

  20. #20
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    Quote Originally Posted by Squeegie View Post
    Did you check your slipper? Is it loose?
    Not yet because of time. Hopefully soon. Did you have a similar problem?

  21. #21
    RC Turnbuckle Jr. Squeegie's Avatar
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    No, I upgraded my slipper system when I went to the larger 2.8 wheels/tires.

    With increased rotational mass, the slipper would need to be tightened from stock settings to compensate. Worth checking. If you don’t want to take it apart, just tighten it and see if it makes a difference. Just keep in mind that it may have glazed your pads over by now and you may have to take them out and scuff them up.

    Good luck!
    Creativity is intelligence having fun. -Einstein

  22. #22
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    I haven’t taken apart the car yet but I pop off the cover and the smell it’s definitely the slipper clutch pads. The surface of the disc looks shiny still but the pads look a little deteriorated. Is it time for a rebuild yet if the truck drives fine? What other parts should I upgrade. I hear the bushing and bearing should be replaced because they go bad quickly .

    https://flic.kr/p/2jwo19U

    https://flic.kr/p/2jwsrsk
    Last edited by Slashn4x4; 08-14-2020 at 09:34 PM.

  23. #23
    RC Turnbuckle Jr. Squeegie's Avatar
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    You can get new pads if you want (I like the aluminum ones) and upgrade to a metal bearing adapter.
    Just remember to tighten it up a bit. Test test test...

    Have fun!
    Creativity is intelligence having fun. -Einstein

  24. #24
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    Thanks Squeegie. U we’re right the whole time!

  25. #25
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    For me, that seems like a high pinion gear ratio for big tires.
    But if it works it woks lol

    Also when something goes wrong in your truck, just keep digging around until you find whats wrong

    And also if theyre not the aluminum pads, they should be scuffed right?
    Last edited by cooleocool; 08-16-2020 at 01:32 AM. Reason: merge
    "Speed and power solve many things"

  26. #26
    RC Turnbuckle Jr. Squeegie's Avatar
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    No problem! I’m just glad the source of the smell was found and that it is a free (if sanding/scuffing) or cheap (if replacing) fix!

    Have agreat weekend!
    Creativity is intelligence having fun. -Einstein

  27. #27
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    It’s the original pinion gear. The extra pinion gear that came with the truck is that the lower gear pinion?

  28. #28
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    Quote Originally Posted by Slashn4x4 View Post
    Itís the original pinion gear. The extra pinion gear that came with the truck is that the lower gear pinion?
    I think thats the speed pinion gear that is a higher ratio

    Thats not good for big wheels 8(


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