RC10Talk - The Net's Largest Vintage R/C Community

Very interesting build!

Quick question from someone who has never owned or even seen a Yokomo in person: is the adjuster in the picture used to set belt tension? Or is that to tune chassis stiffness? Something else?

If I may answer you (someone who has never raced this device or even seen it racing) Well, after reading and thinking about it, I sum it up like this: This adjuster debuted 1996 in YR-4-II touring car to increace front grip particularly at low grip surfaces by supporting chassis flex. 1997 this adjuster was part of a YZ-10 upgrade kit, as used by Team Yokomo during 1997 Worlds Warm-Up. Next it appeared at 1998 launched successor, the MX-4. Then it disappeared forever. While flexing belt tension decreases. Front belt tension becomes random in dependency of track surface. Let me mention, in detail there are differences: in YR-4 II there is no support between upper deck and chassis, so huge chassis flexing is taking place between front bulkhead and motor mount. Low forces leads to big bending. In YZ-10 1997 the back part of upper deck is bolted the chassis, so flexing takes place only in the front section. In MX-4 its the opposite, the front part of upper deck is bolted to chassis, so flexing is limited to the middle zone inbetween front upper deck support and motor mount. This solution flexes almost nothing at all.
In 2003 I joined racing again with the MR-4, so the adjuster was dead for a long time. It was popular to loose the front screews of upper deck a little bit. This increased front grip too by allowing transversal bending without longitudual bending = much less affection to belt tension.
In my opinion this adjuster is senseless bullcrap. But it looks like a million dollar through the YZ-10 body - just my 2 cents

MX-4 vs. YR-4 adjuster. Same part (except the spring, it is black at MX-4 and silver at YR-4) but very different bending characteristic

GrePo wrote: ↑Wed Nov 20, 2024 5:37 pm
In my opinion this adjuster is senseless bullcrap. But it looks like a million dollar through the YZ-10 body - just my 2 cents

Thank you for the explanation and I agree, it does look awesome!

I have a touring car with a provision for tuning chassis flex. The screw holes for the upper deck are slotted, so loosening the screws allows flex in one direction. It is a clever design but doesn't have the visual appeal of the Yoke mechanism.