The latest Yokomo Bmax III Factory kits are shipping with some of the latest hop ups. The most notable in my opinion is the inclusion of the Lightweight Short Chassis kit, a $95 value! On top of that there are updated shock shafts, shock pistons, steering bellcrank brace, nice aluminum rear hubs and updated springs. I also once again chose a full set of Protek RC titanium screws for my build.
The chassis went together without issue, just be sure to follow the supplemental instructions. Building the diffs was up next and they come somewhat pre-assembled. Now don’t cut corners here, take them apart. You’ll need to remove the anti-rust oil from the outdrives with some motor spray. Remove the 0-rings and lube the diff housing, o-rings, and outdrives with some high speed/temp grease. Don’t go overboard, but don’t skimp here either. The rest of the diff build is straightforward with none of my parts requiring any hand fitting. The instructions have you assemble the diff housings and drop them onto the chassis. Here’s where most guys make a mistake. The instructions show a few shims one one side. This is a “guideline” and may not be the ideal fit for your diffs and housings. In my case I needed a smaller shim to get the side to side diff fitment correct along with the proper “lash” on the ring and pinion fit. The kit doesn’t include them so make sure you pick up some extra shims. You won’t free spinning diffs but you do not want a lot of “lash” or free play on the ring and pinion fit. You also don’t want there to be any rough or harshness on this fitment. Take your time, and get it right the first time. Doing so will give you long life and quiet drivetrain. I lube my ring an pinion gears with some Lucas Oil “RED ‘N’ TACKY GREASE.” It sticks to the gears, doesn’t slow the action down, and is easy to find at your local auto parts store or speed shop. I pack the ring gear, work the drivetrain by hand, and remove the excess.
Building the front and rear hubs was next up and they go together without issue. The included aluminum rear hubs are very easy on the eyes. Bearing fitment is excellent, snug but not too tight. Again Avid bearings are the product I choose. Don’t forget the rear axle spacer between the two bearings. The CVD’s come pre-assembled, but again take 5 minutes and take them apart. They don’t appear to be lubed with anything other than an anti-rust agent. I don’t use a lot of grease on my cvd’s and prefer to use a lightweight oil such as Tri-flo or similar product.
Shocks shocks shocks! Yokomo has and still does make some of the nicest shocks to ever be bolted to a r/c car. The fit and quality of the aluminum parts as well as the molded plastic parts means very little if any fitment is required. Take your time here and it will pay off in dividends and lower lap times. I’ve already showed you the O-slip o-ring lube I use on my shocks and how I put them together on the Bmax2 build. One thing I didn’t show in that write up was measuring the shocks. You must measure your shocks overall length once you build them. They need to match left to right to eliminate any “tweak” you’d build into the car if there was a length variance. What does that mean? Well if you have a left front shock that’s longer than the right front the car will have more down travel on that corner. What can this do? It can make the car turn differently left to right, it can cause the car to jump sideways ever so slightly, and it can cause the car to land funny. The list can get very long in potential issues to be honest, so take 60 seconds and assure the shocks are the same length. Josh Alton from Alton Designs sent me these really nice turnbuckle wrenches which I use quite often as a regular wrench, for example snugging up the shock bushings here. I chose to ditch the stock nuts and use some of the new Avid RC blue aluminum lock nuts to complete the “Factory” look.
I’m a huge fan of ditching the stock wing body clip/nub mounts and going to wing buttons/screws on all my cars. It’s easy enough to do. Simply use some sharp side cutters and nip off the nub, making sure it’s flush when done. Use the wing to line up holes and mark them to be drilled. I use a 2.5mm drill bit to drill out the holes, and tap them with a 3mm tap. Some Avid RC wing buttons in “yok” blue and we’re all done.
Wrapping up the build is mounting up my Tekin electronics. I chose the Tekin RSX esc and Redline 6.5T motor. I also dropped in my trusty Ko Propo RSX2 servo using a Ko Propo black aluminum servo horn and Ko Propo aluminum servo bushings to keep it all centered and secured.
Last but not least will be mounting up the bodies and taking the buggies out for the maiden voyage to tune them to my driving style. I’ll be posting setups once I’m happy with their performance which I’m sure won’t take too long.
As always, Good Racing!
