Yeti XL kit finally done - first impressions

[SvdV]

It's finally done.



Setup: MMX / Neu-Castle 1515 2200kv / Hitec HS-8380 / Futaba 3PV / 3S Zippy 6200mAh 40c / XT90 connectors
Upgrades: GPM steering mount / GPM front body post mount / GPM rear upper and lower links
Mods: BHB pinion mod (of course) / Three bearing mod / Gorrilla taped tires / Epoxy driveshaft
Paint: PS-29 Gun Metal / PS-15 Metallic Red / PS-55 Flat Clear on top of the gun metal only, to keep the red bright and shiny.




Additional images one and two.

I started working on my kit early June, and took it slow. Having no tools nor previous experience in building RC cars, most time was spent figuring out I was missing something, ordering it, and waiting on packages to get shipped. Still provided plenty of fun tinkering each part together.

Strangest part was receiving two differently sized rear links. It had a 5mm difference, enough to not align screw holes. Axial responded quickly by sending new links under guarantee.

This morning I took it for a drive. What a beast! I won't have to tell you all how amazing the drive is. High speed drifting on loose sand and seeing the trail it leaves. Absolutely amazing.

What I didn't realize is that morning dew + loose sand = mud. The car got dirty, fast. For a moment I was worried to fry the electric bits, seeing thick water drops on the inside. That worry was replaced with a wheel coming off however. Those darn hexes won't hold tight. I think I have to either find adapters or go for the tiny-screw-to-hold-it-in-place mod.




Lucky enough I found the hex in the dirt. Sadly, the hex hub pin fell out. Time to clean up the mess, fix it, and drive again.

[Tzicul]

You can replace that little pin with the smooth end of a drill and fix it in place with a set screw. You probably forget to install it in the first place. Regarding the wheel nut you can use thread lock or use a second nut as a counter

Sent from my Sony Xperia Z5

[SvdV]

Thanks for the tip Tzicul. The pin was there, just not held into place by the lock screw. I did use thread lock, maybe not enough. Easy fix however, this thing will be back up and running in no time.

[Deckard]

Paint looks great. Very nice looking rig.

I put a ton of thread lock on the grub screw that goes into the axles to hold that pin. It's a biotch to get off but they stay on. Thread lock on the wheel nut is a must. I use a real socket wrench (not the one from Axial) on the wheel nuts and make sure they are tight. Let the thread lock dry a bit too. The stock wheels will most likely break or round out on you. They're awful wheels and there's not a lot of options that are light and strong. I run Pro-line wheels and haven't had a wheel issue since the change. I did have to trim the inside bead on the Pro-Line wheels. I also recommend switching to CI foams if you do a wheel change. Upgrades are for later though, enjoy driving it and just upgrade stuff as it breaks. Eventually you'll get used to driving it and you'll find yourself having a lot less issues.

Don't worry too much about that MMX. The ESC is waterproof but the fan isn't. I run one on my Bomber that gets submerged almost every weekend and haven't had an issue. I don't run the fan on the Bomber. If I had one my YXL I would run the fan though.

How are you connecting the batteries? Those plugs look interesting.

[SvdV]

Originally Posted by Deckard

Paint looks great. Very nice looking rig.

Thanks for the kind words, Deckard

I noticed the grub screw is still in place. The thread lock worked, I just didn't tighten it enough, expecting it to break if too much force is applied. Another lesson learned.

You read my mind about Pro-line wheels and CI-foam. That combination is high on my list. But, just as with the stock drive shaft, I have the steel one layoung around for the moment it breaks. Same goes for the wheels. I'll upgrade it once they're gone.

The MMX fan was on, and made a fair bit of noise. Maybe the logs give me some more info on temp, and if I can switch the fan off next time it's wet. Battery and engine were cool however.

Connectors I use is called XT90. There's a ton of info around, but it comes down to high amps, no sparks, and are easy to solder onto 10mm thick wires. Here's a picture showing my slightly oversized serial cable I fabricated.



And yes, that's my rear sway bar flapping about. The GPM rear lower links require a different set of screws to put it in place, and I don't have those lying around... yet.

[Lavaheadache]

Holy crap that was a long build. I was so excited to get mine going that I had it done within 24 hours of it arriving on my steps. Yours came out nice though. Happy driving.

[SvdV]

Small update after a three week holiday. I found some time to fix the wheel that came off. Upon reinstalling I noticed the inside of the wheel is ground out, but not enough to lose grip. The hex still fits, but it looks like it won't survive a few more rounds of bashing. Glad the kit came with a spare

Originally Posted by Tzicul

You can replace that little pin with the smooth end of a drill and fix it in place with a set screw. You probably forget to install it in the first place. Regarding the wheel nut you can use thread lock or use a second nut as a counter.

Created a pin from a drill bit, works great. I am a bit worried about the other pins however. They are all loose enough to take them out without any force. The set screws are completely tight, not sure what I can do differently.

Originally Posted by Deckard

Thread lock on the wheel nut is a must. I use a real socket wrench (not the one from Axial) on the wheel nuts and make sure they are tight.

I put thread lock on the nut, but upon putting them on, I can hear the plastic deforming. And that's with the little wrench from the kit. Can't believe you use a real one. How are your wheels holding up?

Brute force placed the set screws tight enough to lock the pin. The screwdriver handle broke in the process Hopefully I won't have to undo them anytime soon. I'm also observing some sand caught in the bearings next to the front pivot pins. The grindy noise tells me they will break in a couple of runs.

Fixes are done. Will take it out for a second run this Sunday and see if I can empty the batteries without breaking something.

First session, emptied my batteries. Only fix I had to do was re-glue one side of one tire. Other than that it ran perfectly. Took it out today for a second round of bashing. Didn't hold back and had plenty of rolls and crashes. Nothing broke. I consider this build a major success.

[Tzicul]

Have you done any mod on your diffs? I highly recommend the third bearing mod, with or without BHB's mod. Do this and buy a GPM rear shaft and you will never have any problem. Of course, if you tighten enough the nuts on your wheels

[SvdV]

Originally Posted by Tzicul

Have you done any mod on your diffs? I highly recommend the third bearing mod, with or without BHB's mod. Do this and buy a GPM rear shaft and you will never have any problem. Of course, if you tighten enough the nuts on your wheels

Thanks for the recommendation, you have in fact influenced my decision to invest in this. I indeed did the third bearing mod, and the BHB pinion mod. I also have the GPM rear shaft, but haven't installed it yet. First I wanted to see if/when the stock drive shaft fails before replacing it. Other than that, it's all in place and running smoothly.

Next changes:

• find some screws to mount the back sway bar
• a quick release for the back end of the body
• install the light bar set (haven't decided where to put it, the roof top seems too fragile)
• find a way to connect the Esc to my pc easier, those data logs are full before I can end my run, and the beeping to warn me about it is annoying...

[Lavaheadache]

I too have a mamba monster X. You can shut off the log full warning or have it do other things. I assume you have the castle link, just go in there and change the settings to something that suits you better.

[SvdV]

Originally Posted by Lavaheadache

I too have a mamba monster X. You can shut off the log full warning or have it do other things. I assume you have the castle link, just go in there and change the settings to something that suits you better.

Yeah, I should do that. I have the castle link, so will read out the logs to see what's in there. I am considering splitting the receiver harness, so I can connect the ESC without having to remove it. I know it only takes a few screws, but if the logs are full after every run, it gets annoying.

Not sure if anyone is interested in my updates, but in an effort to keep the community alive: I had a massive bashing session at a new spot. Top speeds, jumps, and a lot of rolls and tumbles. It was awesome.

About 30 minutes in, after a hard crash, I could hear the motor buzzing, but no wheels were turning. I was afraid the transmission gears were toast, but it turned out to be the motor pinion turned out to be loose. Lost connection, easy fix. I am surprised by the amount of sand inside of the transmission. Not that it's a lot, but just that it's there.

I love this machine.

[BarHarborBasher]

Ive found sand in my transmission because front the 2 speed plug fell out.. I glue them in now .

[pro mod steve]

I use the Castle quick link harness. It lets you connect to the esc without unplugging everything.

https://www.amainhobbies.com/castle-...079-00/p177606

[SvdV]

Originally Posted by pro mod steve

I use the Castle quick link harness. It lets you connect to the esc without unplugging everything.

https://www.amainhobbies.com/castle-...079-00/p177606

Guess I'm not the only one with this problem. Great to see there's already a solution. Definitely ordering it.

Originally Posted by BarHarborBasher

Ive found sand in my transmission because front the 2 speed plug fell out.. I glue them in now .

Good one, I'll double check that. And now that I'm at it, see how the pinion mod is holding up. Will take pictures.

[84yoda]

What I do is run a 3" extension so it plus the connection on the outside of the rx box.

[SvdV]

Originally Posted by Brinkman804

Any updates? Or pics

It's been a quiet few weeks YXL-wise, and an exceptional busy few weeks work-wise. It gets dark at 4pm where I live, and lots of rain lately. I have visited the US for work, and shipped back a number of items, including the Castle quick link. All parts are ready to be installed, just waiting for that golden combination of sun and time.

Todo: Get the quick link in of course, read out the drive logs as I haven't done that before, reassemble the transmission, lock the gear pinion, re-glue some parts of the tires, and then we're good to go for at least another 45 minutes

Appreciate the question. Motivates me to get going again.

[SvdV]

Dry forecast up until the weekend made me decide to fix the machine. I downloaded the logs, and found two particularly interesting bits. Apparently my motor ran over 115,000 RPM at a certain point. This is way above the 60k max that Castle suggests it should be limited to. Could it be that the motor ran over its max while being airborne? It doesn't seem to go this high constantly, but it does happen every other minute or so. I have to admit I have been pushing it with 3-second full throttle bursts.

The other bit I'm slightly worried about is the screws that hold the transmission casing. They won't tighten up anymore, leaving a 1mm gap. The housing stays in place, and will probably run for a few more sessions, but this will get worse and collect sand. Alu transmission, maybe?

[Tzicul]

Originally Posted by SvdV

Apparently my motor ran over 115,000 RPM at a certain point. This is way above the 60k max that Castle suggests it should be limited to.

You probably didn't correctly set the poles number in castle link

Sent from my Sony Xperia Z5

[cmbscx10]

Originally Posted by SvdV

Dry forecast up until the weekend made me decide to fix the machine. I downloaded the logs, and found two particularly interesting bits. Apparently my motor ran over 115,000 RPM at a certain point. This is way above the 60k max that Castle suggests it should be limited to. Could it be that the motor ran over its max while being airborne? It doesn't seem to go this high constantly, but it does happen every other minute or so. I have to admit I have been pushing it with 3-second full throttle bursts.

The other bit I'm slightly worried about is the screws that hold the transmission casing. They won't tighten up anymore, leaving a 1mm gap. The housing stays in place, and will probably run for a few more sessions, but this will get worse and collect sand. Alu transmission, maybe?

My XL2 logs said the same thing and said I put out 12.2hp before it popped the caps for a second time in my 1/5 scale. I can assure you the motor would grenade at double the RPM. There is fudge room but not double. I gave up on the XL2 but it is definitely a setting glitch like TZ mentioned.

1mm gap in the motor mount? Same here but 2 washers fixed it. Cheaper than a alum trans.

[SvdV]

First time I hear of setting poles numbers using castle link. Good to know it's probably not my engine about to explode

I'm not quite sure I fully understand what's going on however. Most search results talk about motor timing, and the castle link program doesn't show anything that seems to relate to this problem. Can you point me in the right direction?

Washers to fix the gap, brilliant. Why didn't I think of that... I did tape the gap in an attempt to keep dirt out, but your idea is better.