Yokomo YZ870C First Run

Here's a video of the car's first run. Boy was I impressed. The car tracked straight, accelerated hard and steered really tight. I dare say in the right hands this car will stand a good chance making it to the A Main in the local races!

enjoy!

Yokomo YZ870C - all ready to race!

Finally my Yokomo YZ-870C is ready to run, finished up some final mods and also a body shell for the car.

Here's a shell that the used car came with. Gave it a good wash and trimmed up some of the cracked areas and it actually came out looking like a decent basher shell. I was told by a friend this looks like a "Eagle" shell from Parma. It looks like it was purpose made for this car given the way it fits with the under-tray.



I like the design of the shell very much although the paint on this one could have been a lot better. Funny thing is, "cab-forward" buggy designs were present even in the vintage era - though I must say the execution seems so much more aesthetically pleasing than the current crop of Bulldog and Punisher shells. lol


As I gave the car a once over I noticed quite a bit of slop in the suspension, particularly where the hingepins go through the bulkheads. I thought of machining some front and rear hingepin braces to take up some of the slop, but the wonderful guys at RC10talk.com suggested this solution - longer hingepins, a couple of balls and a turnbuckle. Nice!


Here's a pic of the car ready to run with lipo batts and a black can motor (requirement of our local vintage event). I also wussed out and changed the elegant stock bumper for a larger RPM one which offers more protection.


Okay so the nice basher shell comes off and here's the car with the Protech shell it's supposed to run - done up in the same paint that I run on almost all my race cars. I got this shell from Mr Lexan and I must say his work is very good - lexan seems to be of excellent quality and the body is well made with proper overspray film too.


Fresh paint, JC tires to fit 2.2" JConcept Caliber tires, RPM bumper, vintage AE gold shocks...


One more pic to go!


Drop me a comment if you like this restoration project.

YZ-870C update - lipo trays, body shell...

The last 2 days have been very unfortunate ones with regard to my tools... for some strange reasons, accidents have resulted in 1 broken carbide end mill, reamer and machine tap... and 1 messed up drillbit as well.

At least through it all there's been some progress on my 870C. Slow and steady she goes!

Manage to mill out new lipo battery trays as well as stand offs for thumbscrews to hold down the batteries. The tray on the right of the car can be flipped over to swap the battery position for weight adjustments.




Batteries mounted. Barely visible is also the servo mount plate that I made. I didn't want to drill any new holes to mount the servo so I used the existing holes in the chassis originally used to attached the chassis "spine".



Also trimmed out the shell and undertray. Took a bit of fiddling and trimming to get it to fit right especially with the new top-deck mounted. Here's a pic with the shell and Pro-line Caliber tires all round. Starting to look like an 870C now!



Gonna mask up the shell and get it painted.



Some stuff still to finish... wingmount wire, cut and paint wing, glue tires, rebuild shocks, install electronics.

If time allows I'm going to try to mount a rear brace to the hingepins also, not to strengthen it but to remove some of the slop. lol!

Finally a top deck for my YZ-870C

One more car to finish up for the vintage event and that's my Yokomo YZ-870C. Some of the great folk over at RC10talk informed me that the front bulkhead was prone to breakage especially where the front shock tower was attached. Their advise? Fashion a top deck to support the back of the tower to take some of the load off the bulkhead in the case of impact.

Took quite some time to measure up everything carefully but I'm very pleased with how it turned out!




Front of top deck with shock tower support. :)

Mudblaster and Yokomo 834B shells...

So it appears white is the new black. lol!

Short post with quick pics.

Mudblaster with painted shell... she's ready for the vintage event!



And here's the stickered up 834B. It's a basher shell so just trying to get it to look a tad cooler...

Yokomo YZ834B RPS SE Track Test

Here's how the car looked at the last vintage event held in October...



Although it started life as an RPS SE I had returned it to stock 834B specs for the event with the twin-monoshock suspension setup too.

I had a blast with the car but it was far from competitive. The stock wheels/tires combined with the monoshock suspension just couldn't handle the rutted track very well. For the upcoming event in December I wanted to go back to a dual-shock rear setup. So here's the car back in RPS trim.



Basher shell



With the rear independent suspension and the larger, more "modern" 2-inch wheels and tires the car was certainly transformed! It's still no TRF511, but it did much much better. Rough track handling was improved and the car was a lot more settled. There were some wierd steering characteristics but I attribute that to the limited steering throw (leading to a lack of steering) and the front one-way-bearing design (leading to the occasional breaking of rear traction resulting in too much "steering").

I did have problems with the king-pins though. The design of the car uses grub screws in the knuckles to hold the kingpins but because the kingpins are totally cylindrical there really isn't much for the grub screws to hold onto. Coupled with the soft plastic the knuckles are made of, this resulted in the kingpins coming undone easily.

Solution? I machined new kingpins with notches on the surface for a firmer hold. This way, the grub screw doesn't need to tighten all the way down to secure the kingpin, the notch will hold it in... that's the idea anyway.

Here's a pic of the new kingpins (I know... not much to see till I take pics of the pins removed) but they should work well and will be tested soon.