MicroSquirt.com read only forum (Jan.15,2018)

thanks for the reply's gents, I installed a dyna 2000 and hooked the tack out sig to the optn+ and grounded the optn- and IT READS!!!!!!!!!!! it reads 1/2 what the bike is reving at and when i switch it to the other tach output on the dyna box it reads at a 1/4 so im hoping that i can change that vea tunerstudio to read correctly.

Good stuff!

I did some digging and browsing and googling, and I came up with this pic for a pulsing rotor for the older ZX9R: This is the 1-long + 3-short trigger pattern so beloved of the Japanese OEMs in the 80s and 90s for use with their edge-detecting circuits. Unfortunately, because of the long trigger tooth, the uS and MS with their zero-crossing detector circuitry are effectively unable to make heads or tails of this wheel. This link gives a very good explanation of how VR sensors work, and why long teeth confuse the heck out of zero-crossing detectors (about half-way down the page). This error is unpredictable and constantly changing; when the trigger can occur anywhere in a 30deg span, it's unusable.

Fortunately, a clever lad going by Matt_GSXR figured out how to build 1) an adaptive circuit, and 2) a code patch to use that circuit; the link is here - note that this uses the MSExtra code, and if you want to discuss this possibility further it'll have to be on that code's forum.

dontz125 wrote:...This link[/url] gives a very good explanation of how VR sensors work, and why long teeth confuse the heck out of zero-crossing detectors (about half-way down the page). This error is unpredictable and constantly changing; when the trigger can occur anywhere in a 30deg span, it's unusable..

+1
and I just like to add, that it's not just MicroSquirts that are affected by long teeth and simple VR sensors. Using a Hall effect sensor with discriminatory circuitry can overcome this. I have been using an Opel crankshaft sensor, that is positional sensitive, so if you have the rotation one way, and the sensor in one position you get two edges detected with a short or long tooth, but if you rotate the sensor 180º or reverse the shaft rotation, you only get one pulse for the first edge. This gives a very good trigger arrangement that seems to be insensitive to speed of rotation, so that it'll work off a kick start and also at 20000 rpm.

As some have noted before, these can be bulkier, but they are getting smaller all the time in the automotive world. I am not up to speed with latter day motorcycles OEM equipment, but I believe the Yamaha R6 had a Hall effect cam sensor, which was smaller. The Opel part number is 9174621 and is on fleaBay with a search, mine cost under £10 each inc P&P.

I still think a little effort to change the trigger wheel to a 36-1 is the best way to go and then use the stock VR sensor.

Mine has worked a treat from day one.



Its just the smallest universal one (51mm i think) from triggerwheels.com and worked great all the way to 12500 redline. Never had any cranking or starting issues with it.

Slingy88 - Good stuff, but in fairness, your initial post was a little vague ; had you indicated that a nearly bolt-on solution was available, this thread would have been a lot shorter!
What mods were needed to fit that wheel?

I started with the origional suzuki trigger wheel which looked VERY similar to the ZX9 rotor picture earlier in the thread and turned it down as close to the centre boss that sits on the back and locates in the crank as i thought was safe. Then i bored out the triggerwheels.com wheel to be an interference fit and then pressed together. But i made a little jig out of scrap first to aid in setting the possition and remarking TDC on the new wheel as below. But in all honesty, a simple crad or paper reference would have been just as good.







Once the 2 pieces were pressed together i had to turn down the outer diameter by about 0.7mm as it was just fouling the VR sensor.
So abit os simple lathe work was all that was required. Less than an hour all up. I am in australia but happy to help out with my services .

slingy88
someday I would like to step up to the hole package and run timing with the micro as well but just to start out with fuel will be ideal for me right now. I am how ever really digging all of your pics and your great how to on how you fit your wheel

Blue eyes - true enough, but I think you're going to need some sort of mod even for fuel only, be it a toothed wheel or the extra code with a filter circuit, or something.

Have to aggree with Dontz125.

Microsquirting a bike is quite easy realy but i see many people having issues with crank triggering, cam sensors etc, when there is no real need.
To my mind the trigger wheel is probably the MOST important thing to get right. Throttle bodys, injectors, sensors, ect are all easy and cheap to source used and can be easily moddified to most situations, but the one thing that all of this relies on is a good cranking signal and this is where most problems seem to lie. For example,to few teeth and poor cranking timing is experianced.
I really believe if more people spent the time when they did the install/convertion, building a decent 36-1 triggerwheel setup, the time spent would be more than made up for with all the fettling trouble shooting later on.
With a 36-1 wheel and waisted spark, no cam sensor is needed making the install alot easier.
My setup pn a 1988 GSXR750 is as follows.

triggerhweels.com 36-1 trigger wheel on modded suzuki wheel.(new)
stock suzuki VR sensor wired straight into the VR shielded input. (secondhand)
Ford EDIS4 coil and 8mm silicone leads (secondhand)
gpz1100 tbs and tps sensor.(secondhand)
4 Mazda RX7 460cc high Impedance injectors (secondhand)
GM coolant sensor .(new)
gpz750turbo IAT sensor (secondhand)
GM copy 3bar MAP sensor.(new)
Innovate wideband sensor.(new)
Pierburg efi pump.(new)
SARD adjustable FPR (new)

The other little tips i would share are to make a vaccuum manifold and plumb a vaccuum point from each TB into it, then from this to your MAP sensor or anything else you need to run a Vac reference to. Mine is a bit of ally pipe with BSPT threaded bungs in the ends and using 0.6mm MIG welding tips as pipe nipples as these act as restrictors and further help smooth out the pulses coursed by the individual tb's. The final tip is to use a small fuel filter as a further baffle chamber betweeen the Vac manifold and the MAP sensor. This all REALY helps smooth thye MAP signal and dosnt seem to course any delay in MAP sensor responsiveness. Piccys below.







Running tunerstudio and the Extra code with 16x16 tables, alpha-n with MAP Multiplication on, and it all just works so well together