So What Broke?

[SavagePhil46]

It was so nice outside this weekend and got a few bash sessions in. Finally got my Big Joes on and went to my local spot. Realized I dont like the Joes for heavy bashing or high speed runs, they shake way too much. Wound up stripping my servo horn so replaced it and went out again to a local park and big dirt hill and fried my slipper clutch pad I am pretty sure. It started acting funny like the engine was revving but the truck would barely move. Sounded similar to bad mesh but both gears were gripping and nothing was stripped but I saw some smoke coming from around the spur gear engine area. Have not unbolted anything to asses it yet but I am sure it is that.

Anyone else go bashing? Anything break?

 

[Racer 1966]

Congrats on getting in some fun bashing time. Def sounds like you smoked the slipper,you'll be lucky if you didn't ruin the center of the spur gear too.

 

[SavagePhil46]

Congrats on getting in some fun bashing time. Def sounds like you smoked the slipper,you'll be lucky if you didn't ruin the center of the spur gear too.

Thanks! I'm thinking I am going to just pick up a 52T spur as well while I am at it to move those Joe's. Anyone know if the big joe's shaking all over could have caused the slipper to burn?

 

[Ern510]

If its just like my electric ( new to nitro ) its toooo loose .. I like mine on my savage for bash'n cranked all the way then back off about a half turn or trying to race out of a corner and take the lead of the guy next to you without spinning out of control then I back it off about 3/4 turn so you can can control the take off .. Good luck .. Just grab a few there cheap

 

[SavagePhil46]

So I took the Savage apart and I pulled the spur and it is a lot worse than I thought. When I had put my new spur on I tightened the spring all the way and then backed off about 1/4-1/8 of a turn. Now I see that it was way too tight. The pad isn't just melted to the back of the spur but it has caused the slipper plate to fuse to the pad and the spur making one burned heaping mess. Also the little brass bearing inside the spur is also fused to the plastic. I purchased a new 52T spur and 14T Ofna vented bell to replace my current set up but I think I need a new slipper clutch as well. Here is a pic of the damage:

 

[HPI-Killer]

Nothing yet I'm still building...

 

[SavagePhil46]

Lucky ^ I have been breaking this thing a lot lol

 

[Metalhead Matt]

It wore from being too loose, not too tight. It slipped to the point of melting.

 

[SavagePhil46]

It is supposed to slip i thought.

 

[SavagePhil46]

More pics of the issue now that I have pried the slipper plate from the spur gear. Still cannot get the little brass bushing out though. Look at that wear pattern on the slipper plate looks like it was not spinning around the proper point. Also should I try and scrape the burnt plastic off that plate or get a new one?

 

[HPI-Killer]

Lol always something small that gives up the most fight!

 

[Metalhead Matt]

Not to the point of melting. It should only slip for the first 2' of full throttle take off. Just enough to absorb drivetrain shock. I'd replace the whole setup.

 

[SavagePhil46]

I see, any upgrades to the slipper clutch that you recommend or is stock good enough?

 

[SavagePhil46]

So I went to my LHS and picked up a new slipper plate, the ofna 14t vented CB, and a 52t spur which turned out to be for the 21 so I exchanged it for a 49t foe the x. Now I can't seem to get the 49t to fit. It is HPI77094 but when I put it on, it is a different shape from stock so the washer and spring go on but they leave a gapfor the spur/slipper to move around. Am I missing something or this also the wrong part.

 

[battyone]

had that happen only once and after seperating the molten mess i just ran a wire wheel from bench grinder to gently scrub off any of the spur gear plastic gave it a light sand with 120 grit wet n dry and replaced with a new spur gear n pad. usually after 3 or 4 tanks of fuel ill take off upper tansmission assembly and pull it all apart and inspect it as it is a major slipping /wearing component that needs to be cleaned and checked and not wait for it to melt down. while tranny case is open ill either fine tune 3 speed and check condition of bearings as well

 

[bifft it]

spur gear part # should be 76939 and should have come with 1 pad not 2.and have re-inforcements on the back and not a spot for another pad

i ordered a spur gears from ebay a few weeks ago(actually 5) part #77094 and it turnds out to be for some dual pad slipper clutch set-up that i cannot find parts for. they are thinner and dont have re-inforcements on the back, instead you put a pad. and it seems you need a hardenened clutch bell with these.tried to put 1 on truck and just couldnt get it to work.

it seems hard to find 49t spur on ebay. and if ya do find em, they expensive. 2X the price of 47t part# 76937

 

[TaterX]

spur gear part # should be 76939 and should have come with 1 pad not 2.and have re-inforcements on the back and not a spot for another pad

i ordered a spur gears from ebay a few weeks ago(actually 5) part #77094 and it turnds out to be for some dual pad slipper clutch set-up that i cannot find parts for. they are thinner and dont have re-inforcements on the back, instead you put a pad. and it seems you need a hardenened clutch bell with these.tried to put 1 on truck and just couldnt get it to work.

it seems hard to find 49t spur on ebay. and if ya do find em, they expensive. 2X the price of 47t part# 76937

Try this place. The price for the spur gear is the same regardless of teeth.
http://www.advantagehobby.com/30279/HPI76939/

 

[SavagePhil46]

spur gear part # should be 76939 and should have come with 1 pad not 2.and have re-inforcements on the back and not a spot for another pad

i ordered a spur gears from ebay a few weeks ago(actually 5) part #77094 and it turnds out to be for some dual pad slipper clutch set-up that i cannot find parts for. they are thinner and dont have re-inforcements on the back, instead you put a pad. and it seems you need a hardenened clutch bell with these.tried to put 1 on truck and just couldnt get it to work.

it seems hard to find 49t spur on ebay. and if ya do find em, they expensive. 2X the price of 47t part# 76937

That is the exact part I got. I installed it with one pad touching the slipper and put the brass bushing from the stock spur on, to serve as a spacer outside the spur, as well to clear the space that the washer will not reach. Now it all bolts up and the mesh is set fine. Hopefully this setup will work for me but I will let everyone know. If not I will be trying to get another 49/52t spur.

Off topic but I am in need of a new roto start shaft now that I have the XL tvp's. Does anyone know they length of the xl roto start shaft? Is this the part?

http://www.amainhobbies.com/product...ucts_id/32706/n/HPI-Starter-Shaft-with-O-Ring

 

[bifft it]

how did you keep the spur from sliding along the longer bushing? i think i tried that with the gears i got. i recon a person could washer the bushing so they wouldnt slide on it

 

[SavagePhil46]

The new spur I got has a smaller inner diameter than the stock and comes with a much smaller bushing to sit inside so it spins freely on the shaft. Then I put the stock large bushing up against the back of the spur and because it is bigger it just sits there. Then goes the washer, then the sprin, then the nut. I fired here up yesterday just fine but then she didnt cut out and my roto start battery was dying so I couldnt restart it to test.

Will keep everyone posted.