The new life of a 72' XS II - Build thread

[GLJ]

I finished my my masters degree, with a pretty cool project, according to me, in collaboration with Yamaha Scandinavia, on making their CP3 platform more inclusive for female and shorter male riders, by introducing an adjustable subframe - a lot more complex than it sounds.

Anyway, I figured I had to get my motor back on the road as I had to give back the MT09 Yamaha let me borrow for prototyping.
I soldered and glued the regulator and the rectifier, to hopefully avoid any costly un-rattling in the future.

I also made a bracket to hold the air filter boxes, to get stress off the intake boots.

Connected a new battery and there was power throughout the system, but no spark…

I think I might have fright my Boyer ignition…

I am reading 12 V on the wires going into the blue ignition box, but nothing happens when I kick, when I try to join the stator plate wires going out of the ignition unit, I get nothing.
View attachment 353210View attachment 353212View attachment 353211
This could be because the coil might be toasted with an extra side of coal, I am reading 0.6 ohms on the primary side and 8.39 k ohms on the secondary side (17,5 k ohms at caps), when it should be 2.7 K ohms as far as I read.

But I guess there’s no way to know if the ignition box is OK without buying a new coil…
Though I fear I might need to replace both, what a great way to start unemployment hahah

Congrats on getting your Masters and getting to work with Yamaha.
Your coil is fine, it's a current coil. They are different than a voltage coil.
I checked a new blue box coil I have and it reads .7 ohms on the primary and 8.54 K ohms on the secondary.

 

[GLJ]

Check your pick-up should be around 142 ohms.

 

[Jan_P]

So you are able to read ( hahah .. a only Joking ) congratulation

There are fault finding procedures

https://vintagebikemagazine.com/technical-articles/boyer-trouble-shooting/

 

[GLJ]

So you are able to read ( hahah .. a only Joking ) congratulation

There are fault finding procedures

https://vintagebikemagazine.com/technical-articles/boyer-trouble-shooting/

The coil specs in Jan's post are for a red box Boyer system (voltage coils).

 

[Heinz Ketchup]

Congrats on getting your Masters and getting to work with Yamaha.
Your coil is fine, it's a current coil. They are different than a voltage coil.
I checked a new blue box coil I have and it reads .7 ohms on the primary and 8.54 K ohms on the secondary.

That’s great news!
So potentially only the blue box unit is broken, which is just over 100 euros from Heiden - will need to check.
And thank you

Check your pick-up should be around 142 ohms.

I will as soon as I’m back from vacation,

So you are able to read ( hahah .. a only Joking ) congratulation

There are fault finding procedures

https://vintagebikemagazine.com/technical-articles/boyer-trouble-shooting/

Well only sorta, I’m dyslexic heheh but thank you.
That fault finding guide is way better than the one Boyer has on their website, thank you!

 

[GLJ]

That fault finding guide is way better than the one Boyer has on their website, thank you!

Keep in mind that is for a red box Boyer system.
Disregard the coil tests.

 

[Heinz Ketchup]

I’ve tested the system according to the guide, it appears that the only thing that’s not working is the blue box, the control unit.
With the amount of problems I’ve had, I am now considering investing in the vape system instead, which would also allow me to run without a battery, and rest assured both the charging and ignition won’t fail on me any time soon.

I have looked at similar systems like the one from electrex world, but even though I’m not using an electric starter, run indicators and use LED, 55 W might be a bit to low.

 

[Heinz Ketchup]

Damnn, wasn't sure I'd do it, but ordered the VAPE kit with a capacitor from oldtimershop-dresden.de for 650 eur, pricey but hopefully worth it, I'll try to sell some of the old parts to make back some of the money.

Very excited to try something new

 

[Heinz Ketchup]

Received the VAPE, currently sorting all the wires, removing a lot of the wires not in use, simplifying everything.

Most of the install is pretty straightforward, the most time consuming part is probably making the wires and parts fit nicely and organized.

Though I did spend some time trying to figure out how the killswitch relay was supposed to wire up, only to discover I didn't need it and the killswitch needs to ground at the off positions when not using a battery with the VAPE system.

Unfortunately the rear light is also done for, which is several SMD LED's, I'll try to measure if they're all cooked, or I could potentially bypass or replace broken ones.

 

[Dunc]

Make sure you locktite/tension the 3 bolts in the backing plate before fitting.

 

[Heinz Ketchup]

Make sure you locktite/tension the 3 bolts in the backing plate before fitting.

I made sure they were tight, (read the post about the one that wasn't tight, broke and VAPE didn't wan't to cover) but I didn't remove the bolts and put locktite on - wonder if that might be necessary, my unit does have a record of vibrating - now that I think about it, maybe I should make sure the Crankshaft is within spec one of the coming winters.

 

[Heinz Ketchup]

All the wires are tucked away now, not perfect but okay, the wires to the Daytona speedo and analog to digital sensor takes up some space.
under the side cover, things are manageable - I love all the extra space the battery frees up, will be great to be able to have a spare tube and maybe more tools always on the bike.
Unfortunately the ignition switch only turn the lights and electrics on/off and not the new ignition, therefore I have to use the killswitch to turn it off - I'll circle back to this at some point.



Youtube link (

)
A video of the second start, it already sounds healtier than with the Boyer, despite me not tightening the carb clamps and the rotor moving out of tune, the following day on a test run - I then pulled the rotor (checked the backing plate) and repositioned it, used locktite and someone recommended 51 NM torque, so tried that to fasten it down.

My taillight and headlight bulb broke when the wire unplugged from the regulator and sent 20V through the system, frying my Boyer Blue-box.
I spotted that a small 210 Ohm resistor in the taillight was burnt, when bypassed the LED lit up, but there was no difference between the brake and normal rear light, so I went looking for a small resistor.
After a little search around the garage I found and LED strip which had 270 Ohm resistors on it, so stole one from it and sure enough now the taillight works.



While I was at it I also replaced the brake pads, the old ones where beginning to squeak with just a few mm left on them.

 

[Heinz Ketchup]

Bash plate mounted and tested, it reflects some of the sounds from the engine which I will have to get used to, but looking forward to testing it for real!
It also doubles as an oil pan heheh - it doesn't drip too much any more, but the new oil pipe with cooling fins from Heiden has some fittings at the banjo bolts which are a bit too large, and therefore doesn't fit seal proper with just one washer, as the fitting hits the engine head - silly...

Have been out testing the bike with the new VAPE ignition on the roads for 300 km and the list of things I need to figure out is shorter than before:
But first off the ignition works great!

• My Speedo "Velona" from Daytona doesn't like the drops in power at low rpm at red lights, shuts off till the RPM rises, deletes the current trip distance = annoying as I use that to estimate fuel consumption and km left
  • I will probably install a very small battery somewhere just for the speedo
• I still get fake air between carb and intake, despite of new intake rubber (seems to happen when the engine gets hot)
• The jetting is close, but from ¾ throttle it sorta stutters, which I'm understanding to be too rich - lowering the needle helped a bit, but not enough.
• 2. gear... I have been annoyed with 2. gear since I first assembled the bike, it jumps out to neutral when accelerating
  • • Tried changing shift fork
    • Tried different springs for the gear star wheel retainer wheel
    • Tried adjusting the gear arm position on the star wheel
  • Only thing left is to take the gears out again and measure washers and sorts I believe?
• The light switch has a loose connection internally (the internal plate with connectors broke years ago, but with some glue has worked until now), for now I just bypassed the switch, to turn on with the ignition, but will need to either fix it or replace.
• The bike over heated when the electronic ignition went out of adjustment and might have popped the valveseals...

 

[Heinz Ketchup]

Did an other 300 km test run and what a difference, did some fire roads, green lanes, a hill climb and obviously some km on pavement - did a burnout at a garage party so I’ll have to get a new rear next season…


Lowering the needle did almost remove the stutter, I’m stunned it made such a big difference, next I’ll try lowering it one more to see the effects (it was in the middle position to begin with..)

I’m also considering a different culprit for the 2nd gear popping out - the dogs on the shift gears, but no other way of finding out than opening her up again.

 

[Heinz Ketchup]

Did a small adventure out to a nearby lighthouse, slept in the forrest all because I ran out of data and it made me realise I needed to get proper offline:

I made the video in danish for my little nephew to see, as he loves to follow my different adventures - but to ease things here’s an English version for non Scandinavians.
Bike still performs wonderfully, still need to try a different jetting, fix the 2nd gear and all the other odd bits, but it’s great to get out there, even when it’s 5°C at night.