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Spur gear problem on HPI Savage X 4.6

Old 12-27-2007, 05:36 PM
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motoxmax
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Default Spur gear problem on HPI Savage X 4.6

[size=2]Merry Christmas..........On the 25th we broke it in. On the morning of the 26th we took it to the hobby shop where we bought it and they set up the carb and gave it a check up before we started to run it hard. Later that day The spur gear broke. My son took it in and they installed a new one for $20. Today within the first tank it did it again. All the teeth on the gear shear right off. The hobby shop ordered a metal gear for $30 plus labor. I called HPI and the tech told me not to use metal, I am supposed to call them after January 4th and they will send a new plastic gear at no charge. He said my idle could be to high causing to much heat or the engine mounting may need to be adjusted. I was thinking if I use a metal gear what will break next. We also have a Firestorm but never had this trouble. Is this Savage X 4.6 motor to much for the drive train? Two gears in two days seems like somethings wrong or are we just lucky? Any input would be appreciated. ................... I just read the savage rtr post.[:@] I wish I saw it sooner. So anyway i guess i will say no to metal and install the new one myself
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Old 12-28-2007, 08:54 AM
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Parputt537
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Default RE: Spur gear problem on HPI Savage X 4.6

Welcome to RCU motoxmax. That RTR post is a good place to start. Getting the mesh on the spur and clutch bell can be a bit arduous, but once you get it right you will know the correct look/feel and your problems will be over. Another thing to look at is to make sure the brakes are not binding when the truck is in motion. I fried a new spur gear in minutes because my brakes were binding while driving. Make sure the mesh is correct, your clutch bell is spinning freely, and the brakes are not binding and you should be good to go.

Side note: A metal spur gear is not a major No No. You just have to get a hardened clutch bell or the metal spur will eat the clutch bell. In my opinion, a properly meshed stock setup is fine.
Old 12-28-2007, 10:40 AM
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Coastiebob
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Default RE: Spur gear problem on HPI Savage X 4.6

i agree about the brakes however i went to the robinson racing spur and clutchbell rather quickly and i love it. the looks of the pic it might be set too tight. ensure you have a little slop and read the link on hpi about setting it up (my bad they have deleted that thread with the revamping of the site). for the amount they charged to install the new gear you could've burned through one of two getting it close by doing it yourself... and getting an feel for it. just my $.02. it's tedious but don't get discouraged. happy bashing
Old 12-28-2007, 10:59 AM
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mortimersnerd
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Default RE: Spur gear problem on HPI Savage X 4.6

Check out http://www.savagehowto.com/?page_id=16 for some additional advice. The site is still being set up, but there is some info on the problem you're having.
Old 12-28-2007, 02:03 PM
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motoxmax
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Default RE: Spur gear problem on HPI Savage X 4.6

Thanks for all the advice. my son is going to get 2 new gears $3.50 each and we will try it. I will post the outcome a little later.
Old 12-28-2007, 02:14 PM
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X-ruler
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Default RE: Spur gear problem on HPI Savage X 4.6

I would also look into getting aluminum clutch shoes. The stock ones slip alot thus heating up the clutch bell and aiding in stripping the spur because of the heat. The aluminum grip alot better minimizing the slip.
Old 12-29-2007, 01:33 PM
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motoxmax
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Default RE: Spur gear problem on HPI Savage X 4.6

Well I installed the new spur gear and had to make a pretty big adjustment to the motor mount. the mesh was way loose and the bolt on the slipper clutch was set full on tight. When i replaced the gear i set the slipper bolt at half turn out. I was surprised how easy it was to replace. We are on our third tank of fuel, running in grass, dirt, pavement and jumping fairly hard ............no problems yet...[sm=thumbs_up.gif]
Old 12-29-2007, 02:48 PM
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Default RE: Spur gear problem on HPI Savage X 4.6

Good to hear. Now go have some fun!
Old 01-02-2008, 04:13 PM
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motoxmax
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Default RE: Spur gear problem on HPI Savage X 4.6

[:@]OK now I am starting to feel like I got my son an a F350 TD with a Pinto drive train......... I ran it this morning and the rear drive gave out, blew up disintegrated. It must be me.
i will call HPI amd see what they say.
Old 01-02-2008, 05:32 PM
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Default RE: Spur gear problem on HPI Savage X 4.6

Wow that stinks. I'v had mine for about 2 months and have only had the spur go bad and I think it was from my new brakes I installed. It took me three to figure out that you have to tightin it all the way. A half turn out with mine melted the slipper pad to the spur. Are you landing jumps full throttle? I was told that doing so would eat your gears up. Good luck
Old 01-02-2008, 08:46 PM
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Default RE: Spur gear problem on HPI Savage X 4.6

There isnt anything wrong with metal spurs but if you get one you will have to get a vented hardened clutchbell or the spur will tear the CB up. Getting a hardened vented CB and aluminum ****ch shoes will prevent your plastic spur from melting like it did though. As for your drive train im surpirsed it went out. I ran mine for 7 months mostly racing and I was hard on it before I finally blew out a bearing in my rear diff. My rear diff lasted longer then my first motor
Old 01-03-2008, 10:16 AM
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Default RE: Spur gear problem on HPI Savage X 4.6

I think you either got a lemon or don't have something setup correctly. I've had some broken parts (from 20+ feet jumps by a 9 year old) but we have well over a gallon on ours with no gear, or rear drive problems. Actually no problems at all, other than bad landings. I know people upgrade the engines with the stock drive train without problem, so I don't think thats the issue.
Old 01-07-2008, 01:55 AM
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Default RE: Spur gear problem on HPI Savage X 4.6

Quick Update........ It looks like the diff may not have been mounted correctly at the factory, The bearing on the ring gear side is bad,the outer cup has marks from being loose and there are teeth missing on my pinion gear. Is it possible my original drive train troubles stem from this? The truck is new and may have been binding up from day 1, that may have been the root of the spur gear problem..?? I will get with HPI I will post as soon as they give me an answer. I have been told that they do have good support.
Old 01-07-2008, 03:05 PM
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Default RE: Spur gear problem on HPI Savage X 4.6

My 0.02$ as well, I've read throught this post and it sounds like you
Haven't broken the motor in yet if your WOT at 1-3 tanks??????????
Old 01-07-2008, 11:45 PM
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Default RE: Spur gear problem on HPI Savage X 4.6

Could have been a badly mounted diff. I suspect they're separate problems. Some folks seem to have great luck with this stuff, others don't. I've smoked at least a dozen spur gears in two gallons of running. I've also had problems with the ring gear side bearing failing, esp in the rear diff. That said, I'm not the gentlest driver ever. Give HPI a call and they'll probably send you some free parts. They've always done a good job of taking care of me.

Justin
www.savagehowto.com
Old 01-11-2008, 03:44 PM
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motoxmax
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Default RE: Spur gear problem on HPI Savage X 4.6

I spoke to HPI support and they were very helpful. They are sending me all new parts at no charge. Because the bearing on the ring gear side of the diff went bad it could have easily caused the problem. I feel very confident after I install the parts the truck will be fine. BTW FOWLONE, Please explaine your comment. The only time we ran it hard was after it was broken in by the book and tuned by the hobby shop we purchased it from. I should have the parts soon and I will post the outcome.. thanks
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Old 01-11-2008, 03:48 PM
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Default RE: Spur gear problem on HPI Savage X 4.6

i had the same problem i installed a metal spur gear with A HARDEND CLUTCH BELL and neve rhad any troble since.
Old 01-11-2008, 04:56 PM
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Default RE: Spur gear problem on HPI Savage X 4.6


ORIGINAL: motoxmax

I spoke to HPI support and they were very helpful. They are sending me all new parts at no charge. Because the bearing on the ring gear side of the diff went bad it could have easily caused the problem. I feel very confident after I install the parts the truck will be fine. BTW FOWLONE, Please explaine your comment. The only time we ran it hard was after it was broken in by the book and tuned by the hobby shop we purchased it from. I should have the parts soon and I will post the outcome.. thanks
Cool, I just read through your posts and it said you were on your 3 thrid tank and already bashing.
Just thought you skipped the breakin process but if the shop broke it in for you and your on the third
Tank after that then bash away.
Cheers.
Old 04-30-2020, 10:47 AM
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Kjanora10
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I am upgrading my HPI into an electric car. All's I need to know is what the teeth on the spur are. Are they mod 1 teeth?
Old 05-01-2020, 11:58 AM
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yes, mod 1 pitch
EDIT: you are talking about the HPI savage right?
Old 05-01-2020, 01:09 PM
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Default Yes its the HPI Savage x 4.6

Ts

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