"stage 1" performance upgrades

In order to put "racer" in the cafe-racer theme i wanted to increase the go instead of focusing on the show. Since i found out that the bike is running pretty decent i postponed my idea to do a full engine rebuild. This gives me the the time to source a second set of cylinders and head's since mine has cracked and missing cooling fins.

Warning, longest post jet!

When looking at the package there are 3 obvious area's to improve:

Ditching the points ignition for a CDI with curve
Improve the breathing of the bike (the stock air box is very restrictive)
Add Expansion chambers, for looks, sound and performance.

Ignition upgrade

So i started doing a internet research on what ignition alternatives where available. I quickly learned that it's not easy to retro fit a RD350 LC or banshee ignition. the player's in the market i found where:

VAPE
HPI
Dyna
Powerdynamo
Newtronics
Adapt a Zeeltronic or Ignitech

In the past i ran a HPI-progamable iginition on one of my projects and i had a lot of issues with the stator frying it self. The Dyna an Newtronics, just swap out the points for either Hall-sensors or light-ports, keeping timing fixed. Vape and Powerdynamo offer a complete swap, with a new stator & flywheel combo which eliminates the need for a battery and has a CDI with an timing curve that fits the RD. Many people rave about the quality. For me they both have a mayor drawback, it runs from only one ignition coil (with 2 leads) as the RD runs with 180deg firing interval it has to run with a wasted spark (sparkplug firing in BDP also) which could become a problem in the future if i want to run higher RPM's than 9K. Because the coil fires twice per revolution the dwell-time or charging time of the coil drops, lowering the spark-energy. Only the zeeltroninc or ignitech could fix that, but they would need a lot of adaptation and are by far more expensive. Also they include provisions for controlling YPVS valves and power-jet's i do not intend to run either one on a aircooled RD.

Fortunately i found "Bert van de Zand" on facebook, and he was looking for specific projects to complete, he quoted me a reasonable price (lower than the VAPE) for a digital CDI ignition running of hallsensors with dual coils and electronic rev counter. In order to fit this to my RD i made a timing flywheel, pick-up plate an coil mounts. Once fitted it ran almost straight up OK, the only real issue i had was that the old battery an mechanical voltage regulator couldn't keep up with the iginition causing voltage drops an ignition cuts. This was solved with a new battery and electronic (yambits) regulator (and properly sized feed wires with a hard ground).

The points ignition an stator removed to find room for the new componets.

The location of the orignal coils (these got swapped for modern car-type ones)

The placement of the new coils

A test fit of the timing fly-wheel

A test fit of the sensor plate

The control-box and one of the ignition coils, which run off constant 12V and receive a firing signal from the control box. This box holds 16! different timing curves. This box also monitors acceleration (by measuring RPM) if there is a steady RPM the ignition wil return to a fixed point. On load, timing will be applied as selected in one of the available curves. I'm runnig a Banshee "clone"-curve.

The timing flywheel fitted (with 4 magnets) they pass 2 hall sensors. So the control box can calculate the RPM and firing position of both coils.

Breathing

Getting fresh air an mixture in, with the standard air box it's to restricted. Probably to reduce intake noise. During one of my late-night internet strolls i found that keeping the Y-booth is sensible, just adding a K&N cone filter per carburetor was making tuning difficult due to unwanted reflections. I toyed with the idea of making a small Glassfiber airbox an fitting a big (banshee) pod filter to this, but i couldn't find room enough for that as i needed to keep the battery. I briefly tried to fit an alfa romeo twincarb oval shaped filter, but was struggling for room. So i opted to run a LARGE K&N cone from the standard Y-booth. The intention was to install YPVS intake manifolds with crossover-tubes and YZ85 Membranes, but i needed to modify the cylinders to much for that. So the membrane and manifold swap have to wait until i revise the engine.

The unwillingness of the alfa romeo filter to fit!

All the parts for the increase of breathing swap laid out, including cleaned carbs.

Showing the difference between the airfilters, when swapped out.

The Rover V-8 filter after installation. The intake noise is mad, when going hard on the gas it's almost deafening. But now the bike reacts to the throttle blips like mad, it barks!

Expansion chambers

The key to performance and engine trouble. I really like the sound a Twostroke makes when it's "on the pipe" or for lack of better words. Running in the powerband with an expansion chamber fitted. It's just pure power. So one of the first things i wanted to do is fit those. At first i wanted to make my own, i did for other project, made multiple to see wich design works best (suits the porting). So i started off on a internet stroll to find a lot of information on the German RD-forum. This i processed and merged with my own experience. and came up with a couple of paper models. The nice thing was that i could keep the center-stand, but i needed to remove the footrests and replace them in a more racier position.

But looking at the amount of cones needed, and knowing that "the first pancake is for the children" which is a dutch saying that translates to the first you make are not fitting and need to be adapted.

During this project i had alot of time consuming explorations, so i was in need of gaining some momentum in this project. So i looked in to purchasing a set of ready made exhausts, i realy want an old skool look to them, so the top notch Jim Lomas pipes with their separate mufflers were the first to be crossed of the list. and i Focused on purchasing a set of All-speeds. As budget always is an issue i tried to buy somthing used. And with a stroke of luck i found a set of RZ? or LC? im not sure pipes of a 350 in the netherlands. I bought them together with rearsets of an LC350. The seller asured me it was a straight up fit, but that wasn't the case. i Had to get flanges made to fit my cylinder stud pattern, and re-orient the pipes on the bends. Also reposition the exhaust hangers. during this proces i fitted Aluminium mufflers and made a TZ-style cable operated brake. I was able to retain the centerstand!

Edit: I just realized that i fitted : Higgspeed DS7-pipes based on pictures of their website and comparing that to what i have.

A paper model fitted to the bike in the early stages

First "mocking up" to see where it interferes

The "wrong" flange

In the middle the CNC-flange i had made, on the left the un fitting one. To the right a paper template.

Eyeballing how the headers line up, with the new manifolds.

I made a set of wooden rear sets to fit every thing at first. Once te exhausts where corrected, i made proper onces.

The headerpipes needed some adjustments to fit properly.

But in the end they aligned nicely.

Even the bump stop got moved, but became functional for the central stand.

All ready to go with full steel mufflers, ready for a shake down.

Once dialed in, the pipes sounded great. And when hitting the Power band in second, the little screamer would gracefully lift her front wheel of the pavement.

Rearsets

In order to be able to use the Kick-starter i had to use "folding" footrests, so i had to use the passengers footrests of the LC-rear set.

Here is shown the difference between a original footpeg and my lathed down one, which got screwed in to the shaft on the right. In order for the serrated bit to pivot.

Lenghtening of the passengers footrest, to make room for the pivoting of the pedals.

Machining vibration damping mounting holes

Again with the hacksaw and files, when does it end!

The wooden brackets, were copied in to aluminium plate, with a large hole for a rubber mount to hang the exhaust from. The rubber keeps it form vibrating it setself to bits.

The Lc-shift linkage bolted straight up.

This is the Cable operated brake lever, with an endstop. On the drum brake side, an extra return spring ensures the lever to retract to the endstop.

I swapped the reaction-beam for an aluminium one of a RM125.

The polished rearsets look the business.

And work, like a dream!

Mufflers

Just to make thing look nice, and have some show besides the go. I swapped the outside of the mufflers to polished aluminium. In that process, i fixed one of the tailpipes repacked the mufller and learned how to die form aluminium muffler end caps.