Technique and elaborations Tue 03 April 2018

How I transformed my Yamaha

My interpretation of enduro is to overcome any obstacle along the trail using one’s own abilities. In this sense enduro is somewhat like a level: you can get to the top of an obstacle using more than ten different techniques, from the flawless one of the trialist to the self-made … and make it anyway.
For me enduro should pull out the best abilities one naturally has, may it be combativeness, stubbornness, pure technique, speed or else. And sometimes, at the end of the day, the determination of the amateur equals the talent of technique which may lack energy in some situations.
A love to create, adapt, understand how things work and modify them to my requirements. Therefore, I feel like I am doing enduro even while I’m thinking of or making a modification I deem useful or necessary.

This Yamaha Special is borne slowly, over the span of years, using it every Sunday and continuously maturing new ideas and modifications.
I purchased the motorcycle in 2012, with the express intention of buying a frame universally considered as valid, and the all Yamaha anomaly of a 2005 designed bike that is still sold identical (only a few aesthetic updates a few years ago), I think proves the success of the frame design.
The single beam aluminum frame, an excellent balance between torque rigidity and required flexibility, was an incentive. Another reason for buying the Yamaha was its manufacturing quality and reliability, besides the engine characteristics that, even if cross, has a great pull even at low revs.

First step: the gearbox. Yes, the motorcycle comes with cross spacing, and even if the first gear isn’t very long, (as that of the Hondas for example), but is all in all usable, (there is still the problem of a short fifth gear), I bought the bike only after I learned that I could mount the enduro gearbox of 4-stroke Yamahas, generation 99-2000.
To have the right gears for enduro is the first thing to worry about in my opinion, and I think that the goodness of the bike doesn’t make up for a gearbox handicap.
Incidentally, the famous X version of the YZ marketed in 2016 combined cross first and second gears with enduro fourth and fifth gears.

Second step: installation of a hydraulic clutch command, handmade radiator protections and VERI expansion. My previous experience with other bikes led me to make my own protections using an 8 mm stainless steel bar.
For the expansion, I mounted a standard carbon protection externally surrounded by a sort of roll-bar made using the above mentioned stainless steel bar, fixed to the frame on the top and to the aluminum skid plate on the bottom. In this way, during falls the weight rests on this roll-bar instead of totally on the expansion. Maybe not brilliant aesthetically but very functional.

Third step: fairing or, better, updating its early 2000s style and lowering the seat to facilitate hard area riding. The evolution on which I worked all these years led to the current look, i.e. tail unit and filter box replaced with the 2016 model, creation of a handmade aluminum tank with a carbon cover which can carry the more modern conveyors of the 2010-12 4-stroke Yamaha.
This tank, besides giving it a newer look, has the advantage of lowering the front of the seat, since the tank cap area is much lower, as the post 2010 bike trend requires, to facilitate the forward movement on the seat when curving. Another advantage is that it lowers the center of gravity since the liters of fuel lay lower. Total capacity: 8.1 liters, enough to cover the same mileage of other 2-stroke bikes that carry 9.5 l, thanks to the efficiency obtained by modifying the engine (that I will illustrated later).

Fourth step: installation of the PowerCDI control unit. A vigorously pursued installation, since the YZ was not included in the manufacturer’s list of supported bikes. To do it I had to modify the bike wiring and ask the manufacturer to carry out a specific study on the electric parameters of the Yamaha stator, that in theory shouldn’t have been able to work on the PowerCDI electronics, but with the right settings/parameters (this engine control unit is completely reprogrammable/reconfigurable) it turned out to be perfectly compatible. Later, the manufacturer has also created a simple adapter that allows the use of the original wiring of the bike.
This electronic upgrade allowed the mechanical setting of the engine to be configured (squish, carburation, valve adjustment, ignition timing) for maximum efficiency and performance. A carburation so clean would be useless on an engine without electronic dynamic controls, as would a greater squish (which lends combustion efficiency).
It also grants low consumption and high performance, this obviously compared to similar motorcycles.
The YZ engine is already designed to house the gearbox sensor, which however is only used to signal the neutral to the control unit, but if you install the sensor of the 4-stroke models (identical and compatible) you can make the most of the considerable advantage given by the PowerCDI of having ignition and Dynamic Power Control mappings customized for each gear. Specifically, I preferred, for example, a control on rpm increase tightly connected to the gas control in first gear. Practically, in this way, there is no need to use the second gear together with the clutch on slow and slippery ground, since the first gear (that I could never use before electronics came into the picture) is already soft and not nervous.

Fifth step: installation of the 300 Athena kit. I personally love torque and easiness of use, and the increase in displacement helps these two aspects. Once again, thanks to the PowerCDI, I was able to set this 300 in an otherwise unimaginable way: squish at 1.1 mm.
Therefore, promptness (when you hit the gas), combustion cleanliness and reasonably low consumption. However, this rather compressed setting amplified a problem I already had: no electric starter which is indispensable on any high-powered 2-stroke enduro.
I’m short and the force needed to kick-start the bike was too much to be able to start it in precarious situations.

Sixth step: electric start installation. The idea originated from the electric start of the GasGas, A rough measuring of its dimensions indicated that it could probably be housed even near the crankcase of the Yamaha without requiring considerable modifications.
And that is how it was added. I cut the GasGas crankcase, welded a dedicated adapter-flange shaped for the crankcase of the Yamaha, added a weight I created with a lathe above the flywheel of the Yamaha to which I could fix the sprocket.
The start is powerful and never fails. To prevent wear (suffered by this type of start), the two main axes, that originally move on the aluminum crankcase, have been equipped with self-lubricating sintered brass bushes embedded in the crankcase using a CNC milling machine.

The final result is a through and through true enduro with all the characteristics, comfort and devices set by European specs, which still has stability and accuracy in its DNA and excellent weight and maneuverability. Its overall sturdiness granted me thousands of riding hours with a bike always relatively “fresh”.
The constant evolution is like changing your motorcycle for a new one, even if on a smaller scale. Above all I like to ride and not to set up my machine only to admire it parked in the garage. But even changing fairing and stickers every now and then to satisfy my vanity is part of this hobby.
My riding companions, who quintessentially are the first critics with one another, keep telling me that dealers sell ready to ride enduro bikes.
They are right … so much so that the motorcycle I’m working on goes far beyond what I did until now!
I will call it Honda Crr300!

Text by: Andrea Niccolini
Photo by: Courtesy MB fotopress

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