Idling eats spur gear???

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pitbull14218

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Ok, so today i get my savage 25 going put a BRAND NEW SPUR GEAR in it, lock tight'd the mount bolts, did the fold the sheet of paper spur gear mesh trick, then also checked with my fingers to make sure it had slight play.

Drove it around had a blast, thanks to finally getting it tuned decent enough in the 23 degree weather. Drove great! I was very pleased with it. I have a Fail safe on it, so i turn my controller off and it applies the brakes. I let it sit there idling for maybe 2 minutes because my hands were freezing and i didnt feel like pulling the body off to pinch the fuel line to shut it off. So i go inside to look for gloves real quick, then i came out side, 2 seconds from pulling the body off to shut it down, the rev JUMPS!!!! Rev's up very very very high!!! so i pinched the fuel line, engine shut off, and i look down my spur gear only in one spot was chewed up.........................................................

Now this was a brand new spur gear, and i just drove it for a whole tank of gas, everything was fine, but i let it sit outside idling with the brakes on and the spur gets chewed??????? what could i have done wrong? Maybe it would have been fine if i didnt let it sit?
 

samrsnow

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Check you're motor plate. It could be cracked. That or you're slipper was way too tight.
 

pitbull14218

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Check you're motor plate. It could be cracked. That or you're slipper was way too tight.

Maybe it was too tight of a slipper, when i pulled the spur gear off the metal piece was stuck to the clutch material, and i use a flat head to pop it off, it didnt take much force but i guess that could be it.

Funny thing is the reason i had put a new spur gear on is because the last one i didnt tighten the slipper clutch enough, and it got eaten up from slipping so much............

But it was Idiling!!!! Wouldnt there have been a problem when i was driving it more then just idling? I was driving on snow though.

This is what the spur gear looks like........



IMG_0397.jpg


IMG_0398.jpg


IMG_0399.jpg
 

ohmygahitscoby

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It could be the heat that was transferred to the clutchbell while it was idle, making the spur melt.
 

pitbull14218

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It could be the heat that was transferred to the clutchbell while it was idle, making the spur melt.

Yes i thought that could of been that too...

Now has this happened to anyone else before? I mean this is WINTER.... 23 degree's and the heat from idling was enough to soften it up and let it get eaten?

Does anyone else out there let there truck idle for longer then 3 minutes?
 

KbigO69

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dude thats weird your pic looks IDENTICAL to what mine looks like i swear its like you took a pic of mine and put it on here. mine also got eaten up just from doin a few slow runs. i just heard a grinding noise everytime i hit the gas. If you never messed with the slipper what could cause this?
 

ohmygahitscoby

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Yes i thought that could of been that too...

Now has this happened to anyone else before? I mean this is WINTER.... 23 degree's and the heat from idling was enough to soften it up and let it get eaten?

Idk, I was just thinking around.

My second idea was that there may have been a way that the whole tranny was locked in that position, and the revving from the engine caused the spur gear to eat away those teeth.
 

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Only one thing destroys a spur like that, the clutch dragging and overheating the CB. I'ts why i run 1.0 springs and al. shoes on my bashers. The stock clutch engages too easily and creates a ton of heat.
 

pitbull14218

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Only one thing destroys a spur like that, the clutch dragging and overheating the CB. I'ts why i run 1.0 springs and al. shoes on my bashers. The stock clutch engages too easily and creates a ton of heat.

I guess that could be possible, but i wouldnt know what springs, and i dont know what Al. Shoe's are. I hope its not expensive. But it was still like 23 degrees on that day.
 

MadKawi650

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If your Revs jumped way up when the spur let go, then you must have been holding it back quite a bit with the brakes on. Like the guys said, the CB probably heated way up do to the higher idling engine, melted the gear enough to let the CB strip the teeth off of the Spur.
 

pitbull14218

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If your Revs jumped way up when the spur let go, then you must have been holding it back quite a bit with the brakes on. Like the guys said, the CB probably heated way up do to the higher idling engine, melted the gear enough to let the CB strip the teeth off of the Spur.

Well, before i buy a new part, i like to try to learn about how it works and what i should get. So if i get springs that dont engage the clutch as quick, will it hurt take off performance? Are there popular kits i should consider or look at? I'm at work so i dont really have time to go search. Thanks
 

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If you have a 3 shoe clutch, I'd just replace the shoes with HPI Teflon shoes/springs and bearings in the CB. If it was heat related, most certainly your bearings are cooked as well.

If you have a two shoe setup, then I'd suggest upgrading a bit to a 3 shoe:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXGWY3&P=ML
Been running those shoes for many years with no failures yet. I replace them once a season just because. Run them in my savage and aftershock (with an LRP28).

Could have been just a rock or something got in the spur and the teeth came off while you were bashing. As soon as you stop, the spur spins a bit to the spot where it doesn't make contact with the bell, then when you try to go, it just spins. Mine did that not too long ago when I jacked up 4-5 teeth in a single area on the spur.
 

pitbull14218

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If you have a 3 shoe clutch, I'd just replace the shoes with HPI Teflon shoes/springs and bearings in the CB. If it was heat related, most certainly your bearings are cooked as well.

If you have a two shoe setup, then I'd suggest upgrading a bit to a 3 shoe:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXGWY3&P=ML
Been running those shoes for many years with no failures yet. I replace them once a season just because. Run them in my savage and aftershock (with an LRP28).

Could have been just a rock or something got in the spur and the teeth came off while you were bashing. As soon as you stop, the spur spins a bit to the spot where it doesn't make contact with the bell, then when you try to go, it just spins. Mine did that not too long ago when I jacked up 4-5 teeth in a single area on the spur.

I probly have my idle up a lil too high too though, i think its a two shoe clutch. i was lucky to have just walked outside right when the spur failed because i had to ripp off the body and pinch the fuel line, it pretty much reved up to its limit, I'm lucky it didnt explode!
 

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I don't think I would ever walk away from a running truck for that reason. What if it revved up and took off on ya and hurt someone?
 

pitbull14218

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I don't think I would ever walk away from a running truck for that reason. What if it revved up and took off on ya and hurt someone?

fail safe was on, and it was facing a fence. pretty much right against the fence. Let alone it was snowing out, so it would of just dug deep in the the snow and would of got stuck.
 

MotoGod

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hehe I do the same thing. Face it towards a barrier. I do need to buy a failsafe still though. Ugghhh
 

pitbull14218

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Well i put a new spur gear in it, i lowered the idle just a tad, but it still moves forward ever so slightly, i feel if i lower it more it will die, or hesitate.

But it did run great again, but my buddy's tmaxx would destroy me if he got traction in the snow.
 

scoobydoo2u

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Lower the idle until the clutch bell is no longer chattering.

The clutch bell should be still and the trucks tires should not be spinning if you pick it up off the ground while off the throttle.
Takes a little playing with it to get the idle right, but then again it could be like they suggested, worn springs in the clutch.

And about leaving it sitting with the fail safe engaged, I'm not sure about this, but IMO it could be damaging for the servo to hold all that load of full brake for a extended period of time.
A fail safe if meant to be a save your truck type deal, not a parking brake.
Like I said thats just me, I very well maybe full of it.
 
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jathom

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ok something similar happened to me, and it was a big fault n my part cause i totally forgot to tighten my motor mount bolts all the way the day before when i broke it down and just totally forgot about it lol... what happened is i was just doing some cold weather putts around my road and i turned left real hard and it just starting accelerating uncontrollably, the motor had moved to the right holding it at wot and came up off the spur gear and wearing a nice groove in it, so might be a mixture of something like, loose motor mount (broken also) not tight enough against the spur gear (just barely) or a hot clutch bell etc... doesn't look like it was melted at all though, just brutally grinded against imo...make sure to lock tite ur motor mount bolts and the ur spur gear doesn't really have any play against that other gear, but that a thin peice of receipt paper will still barely make it thru without ripping... hope this helps :)
 

cptvkirk

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can someone fill me in on the paper guide for setting spur/pinion lash? I pulled my gears and held them together to see how well and where the gears line up and from what i could see, they will set pretty deep and bite well so long as there is SOME lash, as in not bound tight. I line mine up fairly snug and tighten eng mounts down right side first then left to avoid futher movement and once i release pressure, gears are close but just enough room to hear a tic if you held one still and moved the other. I don't know that paper in there would be the same space or not. Just looking to expand my knowledge base any info would be helpful.
 

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