Eating the spur gear

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Zep71

Zep71

Well-Known Member
Messages
161
Location
Ray City GA
I put a new motor in my savage 25 motor runs great its the Dynamite 2.8. i have tried many times to get the mesh right and so far no luck it eats the spur gear. where am i going wrong? its good to half throttle after that truck stops moving, and the spur is stripped.
 
Most likely your mesh is off, too tight or too loose, if you having alot of trouble setting mesh double a piece of binder paper and run it into both gears, tighten the mounting screws and then pull out the paper, it should be pretty close after doing that....
 
Also, check everything around it. If the chassis is off at all it will cause your gear mesh to have issues and strip gears.
 
its been an uphill battle with this old dog ordered 5 more spur gears today. i am going to figure this out if it takes 100 gears lol
 
Zep71 said:
its been an uphill battle with this old dog ordered 5 more spur gears today. i am going to figure this out if it takes 100 gears lol
Click to expand...

A better option is to go with the robinson racing spur and bell combo and have that part of the drivetrain be tougher and able to withstand the heat generated by a nitro truck... I have the steel spur and bell combo 48 spur and 16 bell on my Savage and it stands up very nice to the stresses generated....

http://www.robinsonracing.com/catalog/savage21-25.html

It says at the bottom it is for the 21/25 trucks but it will fit any of the savage line perfectly and requires nothing to install except the gears...
 
i second going with metal gears!!! mesh them with the paper strip folded in half and once you done take out the paper hold the clutch bell and with the other finger try to move the spur gear... you should get about 1/16th play. just enf to have space between the two gears.
 
i have to agree with you guys i just had no idea i could get steel spur gears for this. but now i know and knowing is half the battle.. thank you very much guys its nice to get good info..
 
Zep71 said:
i have to agree with you guys i just had no idea i could get steel spur gears for this. but now i know and knowing is half the battle.. thank you very much guys its nice to get good info..
Click to expand...
Also if someone else hasn't said it, upgrade clutch bell to hardened steel one. Stock one doesn't hold up long, not even a tank for me lol
 
Post a photo of a few of your fried spurs. Will help us get an idea what's not right.

Mesh is an issue whether your running steel or plastic. Steel is just more expensive.
 
Hey Guys i am back at it had a lot going on after Irma tried to blow us away.anyway i am trying to post picture of the gear so maybe you can tell me what is going wrong.going to get steel gears but it seems mesh would still need to be correct.
 
Tough to see on my phone. It looks like the mesh was well centered in the spur gear. Looks like it wore away the tips of the gear teeth, likely that the mesh was too loose.
 
I always prefered the plastic spurs, cheap so I could have 2-3 different sizes and easily swap them out. I always set the mesh so there is just a tick of play between the spur and clutch bell. Hold the clutchbell with you finger and move the spur, if you have just a little tick your good. No tick its too tight, a big tick and its too loose.

Its hard to say what caused the spur failure from your pic but if the mesh was good then 9 times out of 10 heat was the problem. Excess heat can be generated from several places including,

-Slipper nut too loose. I run with it tightened all the way.
-clutch bell not spinning freely. Should spin pretty much friction free. If not check bearings and somtimes worn clutch shoes will mushroom and hang up on the clutch bell. Worn slipping shoes themselves can also create excessive heat. Make sure the shoes have some life left and the springs are not contacting the clutchbell trying to do the work instead of the shoes.
-Also a long shot but make sure you have the tiny hex shaped washer installed just before the spring on the outside of the spur gear. Without it you will have failure almost immediatly everytime. Years ago I misplaced this little washer and thought it was just a regular round one but many spur gears later discovered that it is not. Lesson learned.
 
LeroyX said:
I always prefered the plastic spurs, cheap so I could have 2-3 different sizes and easily swap them out. I always set the mesh so there is just a tick of play between the spur and clutch bell. Hold the clutchbell with you finger and move the spur, if you have just a little tick your good. No tick its too tight, a big tick and its too loose.

Its hard to say what caused the spur failure from your pic but if the mesh was good then 9 times out of 10 heat was the problem. Excess heat can be generated from several places including,

-Slipper nut too loose. I run with it tightened all the way.
-clutch bell not spinning freely. Should spin pretty much friction free. If not check bearings and somtimes worn clutch shoes will mushroom and hang up on the clutch bell. Worn slipping shoes themselves can also create excessive heat. Make sure the shoes have some life left and the springs are not contacting the clutchbell trying to do the work instead of the shoes.
-Also a long shot but make sure you have the tiny hex shaped washer installed just before the spring on the outside of the spur gear. Without it you will have failure almost immediatly everytime. Years ago I misplaced this little washer and thought it was just a regular round one but many spur gears later discovered that it is not. Lesson learned.
Click to expand...
it does not have a hex shaped washer i got the truck used now it had a round washer and it came with 3 or 4 spur gears that were stripped. where can i find a correct replacement?
 
Zep71 said:
it does not have a hex shaped washer i got the truck used now it had a round washer and it came with 3 or 4 spur gears that were stripped. where can i find a correct replacement?
Click to expand...
ok Found it on ebay part number 87042b
 
That looks to be the right part #, it might come with the spring as well. That should keep you going, a round hole washer will cause the whole assembly to come loose and burn up the pad/spur gear almost immediatly.
 
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