What Did I Do To The Bombi?! 

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Tom is an asset. Thanks for saving his life, Matt!

If you are going to overfill the differential ... • Use 100% synthetic gear oil • Make sure you have a vent at the top of the differential • Add a rubber tube to the and run it about 2' HIGHER than the top of the differential (When the fluid get hot and expands it will just go up the tube. Worst case, put a burp tank on top.) Switch to SOFTER brake pads. Ceramic pads do not work well until they are hot. I don't know what type of cam sensor you are using, but if it is variable reluctance, the wires back to the ECU must be twisted. More twists are better. That should be adequate shielding by itself. If you want it to be shield, BUY shielded twist pair cable. Only ground one end of the shield ! (Counter intuitive, but trust me !)

I hope that Rhett realizes that moms kisses are the best. I don't have my mom here anymore and I miss her kisses... His mom seems like a sweet lady and Matt and awesome dad. Happy birthday lil' buddy and give some love to Amy she deserves it.

Hey Matt The real problem with your traction system is that you don't have a clutch that removes the power to the side where you want to turn. You need a system similar to the old bulldozer. we call this a setring clutch system otherwise you will destroy all your differentials. Ask heavy machinery mechanics and they will tell you the same thing the differential is not designed to turn in one direction with all the power of the V8. when you turn you therefore have the totality of the engine HP on the sun gear

One other tip thou, make sure Tom has a backup of the ECU profile so then if you BBQ the ECU, you can throw a new ECU in and drop in the profile and it'll minimise the pain of that

Matt, once again, a gm ls engine will start and run with the cam sensor unplugged. It is only used to tell the PCM when to start the injection sincqence it is never used after it's started. It takes a few extra seconds to start it unplugged but it will start. Plug a scanner in when it acts up, set it to rpm and see if you get a rpm signal, if no check crank sensor. Also verify that you have 5v on the reference wire, not 4.6v. 5v! Make sure you have ground straps on the body to the frame, from engine to frame and engine to body.

Katelynn & Matt installing the Control Lever Grips: Old Bike Mechanic trick... Spray some Hair Spray inside the grip before pushing it on. The spray lubricates to make it easier to install, then dries to help stick the grip in place. To remove, slide a long thin screw driver between the bar & the grip, & squirt (or spit) some water in. Work it around & the grip should then slide off relatively easily!

I think Rhett inadvertently came up with the perfect "guarantee" for shop repairs: "This should last the rest of its life."

We need 11% more Ed. None of us is around forever so we need at least 11% more Ed. And weather reports. Thanx😂

The thing about 80s cars is, you could watch them take an enormous jump, see the front end collapse when it landed, and the pristine machine continues as if it was built for it. Of course, 80s cars had turbochargers that made them leap into the air and fly staggering distances, so there's that. Happy (belated) Birthday!

At 36:51 you can see it in his eyes. I think Matt got a little offended when his kid messed around with the coconut again lol. A fan went out of his way to send a gift for them to enjoy, but instead is seeing how his gift is being tarnished. It’s like giving your high school crush a gift, only to see her afterwards throwing it in the trash while laughing with her friends. Mats emotional intelligence is at a very high level. 👏

1:22 I'm not one for giving advise but I know Matt loves his dogs so going to throw this out there. Dog beds, we've been through heaps in the last 32 years & they are all crap until I bought a Barney Bed, then I went and bought another for outside. Yeah they're a bit pricey but they are the most comfy, robust beds & I believe you can buy them in America too. I'm not an affiliate, just a bloke who forked out alot for my dogs comfort and its worth every cent imo. Maybe one of the editors or crew can try hit Barney Bed up for a freebie for when the new workshop opens, anyways its nice to see they have their little cosy blankets and beds in a dark warm place.

When you build a heat shield for something you do not attach it to the source of heat. If you do that that metal mass that you are calling a heat shield becomes a radiator for the heat and by radiator I do not mean a cooling device it will radiat the heat from the source. So that piece of metal welded to the exhaust will act just like the piece of metal in an infrared space heater. You need the heat shield from the batter to not be in contact with the exhuast or the battery.

Matt is the Joker, Tom is the Toker, Kaulin is the Midnight Stroker, and Peanut is The Gangster of Love.

4:44 fire extinguisher guy knows how supply and demand works! 😀 nice

To add my two cents, you might want to check out how the Ripsaw tank steers. Beefy 12 inch dif and two sets of disk brakes. One to engage side and one to brake track.

Matt, sometimes the tracks on Bombi get drawn in tight around the red drive sprocket - e.g. see time 32.17 in your “I failed” video - and I’m wondering if the track might have hit the brake caliper, and that’s why it broke off.

Here I am once again being ignored for the fourth time: Your problems all stem from not using a snowcat differential. IT has nothing to do with your brake system, it has everything to do with the forces involved in using a car/truck differential in a snowcat. The open diff design will eventually eat itself (as you can already see the beginnings of in this video). Put in a snowcat differential to eliminate the rest of your problems. Making bigger brake caliper brackets won't solve the problem of the extreme forces needed to steer a standard differential. I did an entire snowcat build series playlist on my channel and I covered this in depth during that build.

Tom looks like he could use a vacation, he looks exhausted there tuning the engine of the Bombie from behind the Bombie.

So excellent that the younger folks have opportunity to fabricate, TIG, and various other contributions. Makes memories, builds skills, and cements family. Priceless!

you can stick a castellated nut with a cotter pin on the end to keep the fan from rotating itself off with the inertial change - same way boat props handle that issue!

Those flying monkeys scared the crap out of me when I was a kid, lol....

An exhaust heat shield should be mounted such that the shield is some distance from the exhaust(1/2"-3/4") so air can circulate between the exhaust and the shield. You've welded the the shield directly to the exhaust pipe which partially defeats the functioning of the shield.

Happy Birthday Rhett! The day will come when you'll miss the Mom kisses. Don't take things for granted.

I highly recommend completing those fenders all the way, sand will always find a way to get around that design you made. Mud won't have any issues but soft particles need full coverage from your tracks.

something ive used often is exhaust heat rap. works great for keeping the heat from melting anything important.

A vehicle like this is where a diesel electric hybrid would be a good application for, especially now that electric motor tech has gotten so compact for the power. I feel like 2 separate electric motors would give this thing great control. And you'd just need a small battery as a buffer for burst loads. Or a little larger in case you run out of fuel and want a little range to get back. Or less of a walk lol. It would be expensive though. Hydrostatic would work too. Just being able to have independent forward and reverse control would really get you in tighter spaces.

During my time teaching in the Mechanical Eng Dept at Westpoint we used a TORSEN style differential. The unique thing about a torsen is any breaking action to one side transfers that torque to the other side. I think that style dif would work really well for the Bombi.

I saw a comment a few Bombi videos about the tipping point for the tracks. The dude sounded like he knew what he was talking about. Can the centre two wheels be lowered or the front and rear raised so when you grab a brake the weight should shift forward, take weight off the rear and need less brake force to turn. Let it pivot. When its stationary there'd be more weight in the centre and less fore and aft. It should also turn more easily at a stand still. Sounds logical to me.

Once you get the compound differential pumpkin installed it will steer correctly. If you loaded the Bombi in the trailer correctly instead of with all that tongue weight the Banana would tow just fine. I move my JohnDeere MC using one of my custom cars or a S10 Blaser.

Matt I noticed that the windshield fogs up really bad on Bombi. May I sugest instaslling a couple of small fans to blow air over the windshield to keep it clear of fog and frost.

New/old bicycle trick. When installing or removing friction grips, use an air compressor and small air nozzle at the open edge of the grip to provide clearance to move them on the bar. Ask Seth (Berm Peak) when he comes for the games.

It is not just a tool! It, along with the other vehicles, are family. When one watches it go from nothing to awesome episode after episode, it becomes way, way more than just a tool! All the time, effort, working with friends and family, having fun, hand fabrications, etc., that's putting heart into something and it means a lot.

PLEASE! At lease research a Torsen differential and their use in ALL brake-steer snowcats. An open standard diff is doubling the speed of the un-braked track, putting double the pressure and stress on the brakes. All of the Oliver-Clark differentials (what came in these cats) use a Torsen differential for this reason (and oil cooled band brakes but that is a different debate).

Kaitlin when you attach grips to a tube if you put a tiny bit of dish soup into some water and then use that soapy water to lube the rubber handle grips they will sli on realy easy and once the soapy water dries they will stick really well. This is how to attach handle bar grips to a bicycle.

Tip for hand grips, spay hair spay in them, when it's wet it will help slide them on, but when it drys the hairspray will help it stick

Matt: "This next section is really boring technical physics stuff" Me: "oh yeah, gimme the good stuff."

If you go back and watch the videos of the tracks spinning, or just higher speeds, you’ll see the tracks coming up from the bottom. I believe the track was hitting the caliper, and that is what broke the caliper.

Merely an observation about differential behavior: When one side of a diff drops to 0 rpm, the other side gets double the amount of output rotations, which cuts the output torque by half. If we consider that difference, you'd theoretically have to downshift the transmission (a lot) when turning to make up for the drop in torque. Since downshifting that much entering a turn isn't realistic, you're stuck with never having the right amount of torque to complete a hard turn. Even so, I don't think trading off for a more complex design will be worth it for Bombi. It's already built this way.

Tip for Kaitlyn, when installing handlebar grips even on a Bombi, a little bit of soapy water well, the grip to slide onto the handlebar.

Personal experience.... old organic brake pads offer the best "stickiness" when cold, semi-metallic are slightly less sticky but don't fade as bad when they warm up, ceramic are much less sticky when cold but don't fade as bad when hot as either of the others. I would probably look for the "softest" semi-metallic you can get your hands on for this.

Best part of the episode is Kaulin's (spelling?) obsession with the perfect coconut. Made me laugh, well done dude.

Watching Matt drive the Bombi reminds me of my 5 year old neighbor on his 4 wheeler. It's full throttle all the way on his 800 foot run. He comes back and asks, "Did you see how fast I was going?" It's no fun unless you can go full speed.

When I finally get off the parents estate and start heading easterly from Oregon, I think I need to stop by Matt shop and wire him up a proper ignition power switch and starter button. I probably even have new ones in my electrical box somewhere.

Your drive axle needs to be your primary braking power.. if your secondary brakes on non drive axle lock before your drive axle stops it will cause track binding hopping or worse.. good luck looking awesome

Consumer Feedback: The combination of your app seeking the Phone Identity permission and your Data Safety Policy stating you use phone numbers for Advertising or Marketing leaves me feeling like I don't want your app on my phone. That is all.

I learned about your channel from your interview with Derek Bieri. I’m really enjoying your videos. Unlike a big Utah based off road recovery company that has a channel your’s doesn’t have any added drama. You also seem to be very humble, and I appreciate that. You’ve gained a new fan.

I Looooove you guy's work environment. Working with your hands all day with a bunch of friendly, decent folks and getting lots of fresh air. I work on my computer all day alone. It pays well, but I get so bored and lonely. Glad I get to live a bit vicariously through these videos. Thanks for sharing.

I started watching Matt's off-road recovery few years ago. I stopped for a while because I didn't care for his lackadaisical (especially since a lot of you think he's a great role model for youth) attitude towards safety. Especially eye protection! There's no doubt that it seems a very tight family and the kids are getting experiences that most kids do not get. When I started in the trade in the early 1970s worker safe was a after thought. Guys were blowing brake assemblies off with compressed air. Fill in the shop air with the asbestos. We were idling V8 engines with four barrel carburetors in the shop and cleaning them with B12 while smoking cigarettes. Fortunately, I'm not a smoker. After 43 years is heavy duty truck mechanic. I look back on how safety measures have improved along with the safety equipment. Fortunately for me I had injuries, stitches and set her in my hands but never went to the doctor to get metal taken out of my eyes. A lot of my co-workers did. And most of them did all right after it was removed. Two of my co-workers lost eyes. One while pounding out a kingpin. The other one was in the back of a bobtail. The testing a paper shredder machine. He had eye protection on a piece. Broke off on the shredder blade. Went around the bobtail like a missile came back and hit him in the eye which he lost. Talk about workman's comp going up for the employer. It horrendous. Not to mention the loss of the employees eye. The job I retired from had a very simple safety policy. Adhere by our regulations and government regulations or go home! They provided all the needed safety equipment. Steel toe boots. Safety eyewear, gloves, welding jackets and gloves and whatever else was needed. Get caught without it three times and you could be terminated. And it was a union shop with a teamsters contract. They did not play If you watch Matt's face expressions when he's under a vehicle or around welding or grinding, he's squinting his eye all the time turning his head away from it. Someone was grinding something on the bombi Matt was holding the part squinting and putting his other hand in front of his face like he was going to stop a piece of metal or grinding material from hitting him in the eyes. One thing to say about that. Pure ignorance! No! That's not the right word. Matt's not ignorant about what could happen. I'd say pure stupidity! On the good side. Peanut is a very smart girl! She should make a great scene eye dog when Matt loses an eye! Just a matter of time. So much for being a great role model!

The most I've done on my Runner is change oil and swap the turn signal. Here's what a suggest next time for the Bombi. Take part "A" and put it where part "J" is. Take the weld and move it 3/16" to the left and then to the top of that thing you welded with the hose spicket. Then take the tires and put them on the other side and reverse the tracks. This way, back is forward and forward is back. I would also recommend taking the Flux Capacitor and turning it upside down. This way, you can just say we did it, although it most likely won't do anything.

Happy Birthday, Rhett! The Bombi is coming along great, good to see you all working together. Thanks for sharing!

"We don't fix it, we make it run", is that what's called a sledge hammer mechanic, pound it together, and beat it to fit? that was one of my dads' sayings. He was a machinist.

When the Bomb is moving, it sounds like the unlubed tracks on a WWII tank! LOL

Love all the nerdy details of y’all’s builds. Give us more!

Rhett dissin' his Mom like that!!! I feel your pain, Jaymie.

“I hate gittin’ blowed up” is the name of my hold my beer anthology that is now available as a pamphlet at an ER near you.

Tom at the very end 🤣🤣🤣 “ I’m falling out of the bombi “

Matt as he takes parts off: "That's not as terrible as I was expecting, that's not as terrible as I was expecting, that's not as terrible as I was expecting, ...Oh! This one is Terrible!"

My father was in the 8th Royal Tank regiment after WWII (UK) and he used to tell me that to steer the tanks the drive was disengaged to the relevant track, this meant when going downhill the steering was reversed which often had drastic consequences when teaching new tank drivers!

It's completely engineered different, but the ripsaw uses hydraulic disk brakes to drive the tracks and slips them when turning. So you are not basically riding the brakes the entire time the vehicle is moving. The Cleetus McFarland channel had a few detailed videos on how that setup works. It looked like it worked almost like a clutch on both sides.

Exactly right on a couple of comments. A Torsen differential is what is used successfully in all snow cats regardless of size or power. Stop messing around with automotive differentials and just install one of those. PROBLEM SOLVED!

Love the sound of the Bombi when you fire up, great exhaust system😊

I used to own a motorcycle shop. We always used contact cleaner to put grips on and off.

Reminds me of my 1982 Attex 6wheeler. Bend the sticks so they are in front of driver seat and put throttle on stick. Easy peasy and so much easier to drive.

For what it’s worth. I had a friend with long hair (usually in a ponytail) in a body shop. Working with a sanding tool the hair was caught up and before it stopped pulled out a large clump of hair. Yes, there was blood. His name, yes a dude, is Ray and he said he screamed in pain. Moral of this: Katelynn needs to obey this basic safety practice. Have Jamie or someone do something to protect her before something bad happens. Standard safety practice.

On ALL gasoline engines that use a "butterfly" throttle, throttle position (% open) is NOT LINEAR to air flow. (50% throttle does NOT equal 50% air flow.). The larger the diameter of the throttle body bore, the more non-linear it is. (Large throttle bodies will hit >90% air flow at less than 50% throttle opening.) To combat this, some engines that flow a lot of air use a throttle body with more than one opening/butterfly. "Throttle by wire" systems are designed to make the accelerator % position to match the % air flow.

I like the builds as much as the recoveries. leaning how you make it and why never gets old.

A big part of the issues with the brake-based steering system you're using is that it doesn't scale as well to higher power/torque; it was ok on the old power plant, but you've up-rated the engine so much that the brakes are having a tough time dissipating the much larger waste energy you're now demanding of them. In addition to running as large of rotors as you can as you mentioned (as well as investigating different materials for the pads/rotors), you could also consider adding water sprayers to cool the brakes/rotors. These are sometimes used on heavy haul trucks for large downward grades (more common in Asia seemingly) as well as on things like logging trucks. It's an open question whether you can find an existing system that will fit and could be adapted to the Bombi, but it would give you effectively unlimited brake endurance without fading as long as your water tank is topped off. Obviously freezing would be a consideration on a snow vehicle, but you can either heat the tank/lines or use a (hopefully environmentally safe) coolant mix with a lower freezing point as your fluid instead of water.

Lol 😂 Those grips just added a 100hp.

23:31 y’all did the “bear necessities, the simple bear necessities”

I just love the dynamic of an engineer and a derby dude

I understand your fix it style. You will get to it eventually. Life is too short. You will never get the change to enjoy life if you spend all your time fixing stuff. Oddly my search history led me to an old YT vid that simply suggested turning the cam sensor a quarter turn when your next shutdown occurs. The internal portion of the sensor looks like a linear slice of sensor electronics potted inside the main enclosure. Visually think about drawing a line from twelve o'clock to six o'clock. There is no way to see it inside before you install it. A simple quarter turn increases you chance of hitting the sweet spot on the sensor.. Drill the fan clutch and mount for a 1/8 inch roll pin to fix the fan. Easy to remove later with a drift punch. If it fails after that, the fan is not your biggest problem...

This is turned out to be one hell of a machine!👍

Those fenders turned out good. Awesome work fellas and Rhett

Thank you Matt and crew for the update on Bombi and lots of laughs !

Hi Ed! You make sure they get it right this time. Fun video on improving the Bombi and it looks like it is running great.

The Bombi is throwing frickin' rooster tails of sand! Awesome!!

Matt I know that diamonds are the hardest substance know to man, and woman too. With that in mind, to adjusted a kunavalve to .002 psi you need a Watson lug wrench. I know your thinking does it need to be a left or right handed Watson lug wrench? No body really knows, but I do know the grass is always bluer if you plant Kentucky blue grass with the point up. Glad I could help. 🤠

If you ever have to remove/ replace the grips on the steering brakes you might try a trick from the MTB world. Blow compressed air between the shaft and the grip while twisting to remove To install, pour a little alcohol (rubbing or denatured both work) into the grip and on the shaft. Quickly push the grip on while giving it a little twist. The alcohol will lube it up until it evaporates leaving a tight grip. 20:18

I totally agree with another comment. If you install the differential from a snowcat of any sort it solves all of your problems because they are made specifically for track vehicles, and you have put in an automotive differential!

14:06 "Like a Surgeon....yeah yeah....cutting for the very first time...." 😂

The fenders look great. The bombi keeps getting better and better. Now the only thing it needs is a snow shoe rack in case you need to walk out of trouble :)

Easy way to install the grips is to shoot some paint in them (aerosol) and they will slide right on. Once paint dries, they will not rotate. Or you can go to the local motosickle shop and buy some grip glue. Thanks for the video.

So while the Bombi did have brake steer before it wasn't the same.. The gear box from those would disengage the drive pressure to that wheel and then apply the brakes. this makes the work the brakes have to do significantly less. As you have explained in videos before a open differential applies torque EQUALLY. In you set up not only are you fighting the track from free wheeling forward but you are fighting all or the torque that it takes to move the other track.

A lot of times its forgotten that in an open differential, when one tire is stopped; the opposite is turning at TWICE the speed of the speedometer. This puts a lot of strain on steering brakes

Matt, I would try a switch to metalized racing brake pads. When they get hot the grip increases. You also need steering clutches at axles. Clut he's need to release before brake applies. This way while you are moving sometimes just releasing clutch will steer machine in finer increments. With the tracks you have so much ground traction and now much more horse power its difficult for brakes to stop or slow to steer.

Big Boyz n BIG toys! Great to see you enjoy your "work"! Thanks for sharing❤

Matt that fan problem I think you can solve that by drilling and tapping for a set screw in the attachment nut also counter sink the set screw .simple fix !!!

Open the inspection plate from the back of differential SPYDER gears. For open rear DIFF. It could use 2 speed axle from vintage maker like HEMINGWAY or Columbia 2 speed rear differential. The rear end could use maybe 6 inch ring gear in the carrier at front of the housing Tubings for BOMBI snow truck/cat.

I think what you really want is a force vectoring differential with clutch packs to completely disengage either axle. Bulldozers often have both a clutch pack and brake on each axle to reduce the strain the brakes. As you've mentioned in previous videos, the open differential applies the same amount of torque to each axle. It's possible to overcome this engine torque with brakes and stop one axle, but it seems you are asking too much from the brakes. These differentials are often called force vectoring. Some offer a drift mode option to electronically put 70% ~ 100% of the torque to a single axle. This allows you to drift even on AWD cars ... It's a much more complex and expensive solution than an open differential, but it would greatly ease the burden on the brakes. Audi is famous for this, but I believe Ford had one also.

Your filming made the Bombi look like an RC vehicle!

Hi Katelynn and Matt. Here is a little secret to putting on bike grips, use rubbing alcohol to lubricant the inside of the grip. It will slide on really easy and when it dries be grippy like expected.

Just a thought here Matt and crew, could you put a magnetic locker in the differential. Just in case you had to "snatch" something stuck, would not need to worry about steering (I believe) because a little tug would straighten itself out. All agreed, mention me please

No one's going to spit in your food for saving them a step in the preparation. Asking for no pickles only makes it easier for them and it's among the easiest modifications to make.

When rett moved away from his mom kissing him was upsetting for me cherish those moments. 2007 in high school century secondary now Westview in Windsor Ontario Canada i was 17 years old i got hand picked to do a water pump on the principles chevy. I was exited to prove my worth to everyone as soon as i opened the tool box my worst day of my life hit me. A lady in the office called on the PA speaker and said have will pack his things his father is here to pick him up. He picked up my twin sister my oldest and i and he broke the news that my mom suddenly passed away... was a blood clot to the knee to the lung. Moral of the story is that the very last memory at 6 am was her giving me a chocolate bar a apple and 5$ for the cafeteria and most importantly a kiss on my forehead😘 49 was young and so is rett enjoy those moments.

I believe it is a snow packing problem with the brakes. Snow plows bend and break parts all the time. Just moving snow. I do enjoy the use of all the shims and spacers.

@MattsOffRoadRecovery Cut the square corners on the cleats at a 45 degree angle to help turning. This won't reduce traction but allows the cleats to slide over catch points in turns.

Gloc and Carbotech will produce pads in any shape you want and they work PHENOMENALLY even when your rotors are red hot. Please do check in with them, they'll probably recommend their lower temperature compounds like in their "6" or 8" range. Their compounds range from "6" to like "18". Anything from either company will absolutely suit your needs wonderfully on this project

Alot of explanation in this one👍 I cannot wait to ride in the Bombi some day!