Returned to the workbench again today and got a few more bits onto the buggy
Steps 10, 11 & 12
Time to assemble and mount the suspension arms and hubs. Once again this car roughly follows the “Losissociated” style that has become the norm, although Yokomo have put their own twist on it. The top of the front steering knuckles hang below the caster block, giving the car a deceptively different look from the top, and the rear shocks are mounted behind the arms and feature kinked top links. Parts quality is again very good.
Assembling the front hubs is another opportunity to break into the Champions Pack, this time for the wheel hex adapters (for “Losi”-type fronts) and the optional aluminium kingpins. The wheel adapters are an easy fit, although I used some of the supplied black grease to hold the pins in instead of the suggested rubber cement (which might be a bit too permanent for easy maintenance). The king pins are unusual in that there are two ways of fitting them, which either lowers or raises the steering knuckle. I fitted them in the “up” position, mainly because it is the same as the kit pins and also because it is a bit easier to line up! Experience will show what effect this has on handling (in theory, the “up” position will create a higher roll centre at a given ride height, which will take away a little overall grip but increase responsiveness at the same time).
I did notice that the king pins actually have quite a lot of free play on them anyway, so I will consider a shim or two after the shakedown run.
The rear hubs accept the near universal “Losi”-type pin drive. I’m not a huge fan of this to be honest (nor of the small front hex), but it has become the de facto standard. If only Tamiya’s Top Force or Kyosho’s Lazer had been more successful, then we would have had a sensible 12mm hex like the touring cars do…
On the topic of pins, Yokomo supply a split pin for the drive – and as much as I hate losing standard pins, these will be impossible to get out in a hurry, because they were almost impossible to fit! Look carefully at the driveshaft and one side of the hole has a slight chamfer round the edge which makes it easier to seat the pin before you squeeze it in with pliers.
The suspension blocks that the arms hang from are adjustable – they can be turned upside down to alter the front kick-up and the rear anti-squat. I should have mentioned earlier that there are a couple of team driver setups at the back of the manual (including Neil Cragg’s Euro setup), and if you want to build your car with one of these you need to decide before you start, because the rear suspension mount that was fitted in Step 1 is also adjustable, and is well buried if you decide to change it now! I’m building mine to more or less kit settings.
The front arms are a very good fit but curiously the rear arms have a good millimetre of free play. Almost as if Yokomo forgot to include some spacers (there are plenty for the hubs). It’s another part I will look at shimming after the shakedown.
That’s enough words for now – here’s a nice picture!
Steps 13 & 14
Time now for one of those time consuming jobs in every car build – assembling the turnbuckles. Once again I am turning to the Champions Pack to pull out a set of seven titanium versions (although I suspect that the kit steel ones would be absolutely fine too, they are an almost identical thickness). The ball cups are a new design for this car, chunky and with an access hole in the top for quick unscrewing of the ball studs beneath. This should decrease wear from popping off the ball ends themselves.
Once assembled and set to the correct length (easier to do the final adjustment on the car rather than by hand), I noticed that the front upper links were rubbing against the shock tower, causing a tight spot as the suspension dropped. A quick examination suggested that the rearward sweep of the link was causing the edge of the ball end to rub, so out came the craft knife and a small chamfer was made. Result – smooth suspension travel again.
Steps 15 & 16
Now we come to the biggest reason people will have chosen the Champions Pack – the alloy shock absorbers. These have come straight from the BX (the previous Yokomo buggy) and are superb quality. Apart from threaded alloy bodies, they also include the famous Yokomo bleed caps, titanium nitride shafts and machined pistons.
They are easy to assemble (due in no small part to the quality of the parts), but I have a couple of tips.
First, use a little shock oil to lubricate all the o-ring seals as you assemble them.
Second tip is more personal preference than anything. I don’t compress the shocks fully to bleed them because what happens then is you cause a vacuum in the shock which actually pulls the shaft back in when you try to extend it. I don’t like this at all, so I set the shocks to rebound without pulling back in from full extension. To do this, push the shaft in only about 1/2 way before bleeding, the check that the shaft does not pull in at full extension. Also check that the shaft can be fully compressed without locking up from hydraulic pressure. Generally, this style of shock will squeak a tiny bit at full compression because it needs air bubbles to work, so don’t worry about it. In fact, I would rather hear the squeak than none at all!
The shocks are then fitted with the kit supplied black springs and spring bottoms, and mounted onto the car with some more newly designed parts. Thankfully these don’t seem as easy to crush as the old Yokomo ones (I’ve seen many a Yoke with dodgy handling because the shock mounting balls were crushed and causing major friction).
It’s getting late again – more updates soon!
fiveeight0sixsix 