Total Loss Wiring Harness

[monkeystew0]

I am currently building an XTZ engined Supermono special (see Project Monkeystew's SZR Supermono in Projects section)

Need some help with the wiring....

Originally I was going to run a stock XTZ660 motor complete with Starter, charging circuit etc. and my original plan was to strip the lighting circuit out of the original XTZ harness and tidy it up a bit, BUT I have now acquired an ex race 790cc XTZ motor which has had the generator, starter and starter idler gears removed.

As such I only need a basic harness to get it running.

Anyone any good with wiring and can check my homework? I have a specific question about one wire out of the CDI I need to resolve.

Here goes. Original wiring diagram looks like this:

Having studied it I have boiled it down to a total loss harness that looks like this:

In summary:

Battery provides power through a fuse to an ignition switch (wanted something that lit up when its all switched on so I know when its"live")

Ignition switch then provides power to coil and through the kill switch to the CDI to charge the capacitor (red and white)

CDI has output to the coil to tell it when to fire (Orange)

CDI has 2 inputs from the igntion pickup (blue/yellow and green / white)

CDI is earthed

CDI also has a black and white wire which originally connected to the starter cutout relay set up (Details below:)

Here is my question

As I have no starter motor, starter relay, ignition cut off relay, Clutch switch, neutral light or side stand fitted...What do I do with this Black and white wire???

Earth it or remove it?

Can anyone work it out and let me know. I don't want to guess and wreck the CDI for the want of asking what might be a silly question....

Anyone help work it out for sure??

[chrisexup]

First of all let me say, electrics are pretty baffling to me.

Now that's out of the way, let me also say that the circuit you have shown looks similar to my TDR250

The black and white wire is basically the kill switch. Once it is earthed the engine will not spark.

if the TDR won't start because the sidestand switch or similar is acting up disconnecting the black and white wire from the CDI enables the bike to run.

as i said, i'm far from expert so check this advice out before you act on it

[thorlz]

If I am reading the diagram correctly. Then the black/white wire is there to go down to earth, and thus allowing the safety circuit relay coils to energise (providing a netural circuit in many ways). This in turn allows power to be transfered through the relays and to the starter motor.

As you are not running a starter motor (this bit does confuse me) am am not sure 100% sure, but i don't feel it will make any difference if it is earthed or not.

Earthing it shouldn't blow your CDI as that wire goes to earth anyway eventually in the original wiring.

I sure someone with more knowledge will be along soon to tell you properly.

Question, how are you starting/turning the engine without the starter motor?

[thorlz]

At first glance the diagrams / diode direction looked fine to me.

Then you got me thinking (whilst trying to get sleep, cheers Mille , bad habit of mine, just as I fall asleep my head says "ok what do you want to talk about now")

Anyway, correct me if i am wrong but diodes allow the flow of current in one direction only, and current flows from - to +.

My suzuki and Honda manuals all show the diodes in the same way as the diagram above, I thought maybe it's just the way that the japanese draw their schematics.

A quick google search gave me the answer, see link below:

http://www.allaboutcircuits.com/vol_3/chpt_3/1.html

It appears that diodes on some diagrams are actually draw arse about face to the way they actually work, as such I think the diagram is correct and the interlock will work no problems.

Sorry if I am teaching you to suck eggs, not taking the piss, your previous post have already shown that you definately know more about this kind of subject than I do.

Monkey: as Mille says, just earth it and it should be fine.

I do like little brain teasers like this, does that make me sad/ a geek?

[monkeystew0]

Thanks for your help chaps. I love a brain teaser too, except when the wrong answer could cost more money!!!

Looks like I got it about right then with the wiring and that wire can be either state as it connects to nothing now. I assumed the logic of the starter interlock was to either prevent the starter relay energising or grounding the capacitor in the CDI to stop it firing....Couldn't fathom exactly which.

On the subject of starting it.....No idea!!! I can't decide between reinstalling all the starter motor system thats been removed (motor, idler gears, relay , engine side cover etc etc), or sorting out a roller starter MotoGP style setup.

I like the idea of an electric start but the starter motor fouls the oil return take off on the crankcase, the rotor etc will all have to come off to reinstall the gears etc (which i am am not sure I have). Bit of a faf.

And making a roller starter from a car battery, starter motor and rollers sounds like fun (today anyway) Might even draw up some plans and sell them to make some cash back....

Head full of ideas me...

Anymore feedback on the harness welcome too

[bazdude]

Thorlz I thought electric current flowed from pos to neg unless noted that it is 'electron flow' of which it is in the reverse direction.

[thorlz]

Thorlz I thought electric current flowed from pos to neg unless noted that it is 'electron flow' of which it is in the reverse direction.

I suspect that you are correct. Can't remember alot of the science behind it.

Put it in the never to use again part of my head. Along with most of the stuff i did in college. Calculus- wtf. Done it. Never used it. Never had a reason to think about it, now forgot it .

[monkeystew0]

A bit of an old thread resurrection but I need help.....

Having got all the rest of the bike sorted i'm ready to get it running......and I have got no spark!!!

The bike is wired up as per the total loss harness diagram above. It has a new battery and spark plug.

Having no starter (ex race engine, all charging and starting bits removed) I'm having to put it into gear, turn the rear wheel over by hand while the Mrs holds the plug against the head and looks for a spark..

So far I've checked the following:

1. ignition switch illuminates when swithced on so power is going through there.
   
2. 12.34V across the battery terminals so battery fully charged.
   

Using my fluke multimeter i've been checking that all the connections are sound and i'm getting power where I expect to :

1. -ve meter lead on battery -ve , +ve lead on +ve connecttion of the coil and i'm seeing just over 12V so power is getting to the coil
   
2. -ve meter lead on battery , +ve on Red/White connection of the CDI i'm seeing just over 12V also..
   
3. Flick the kill switch to OFF and the CDI voltage drops to 0 so Kill switch is working.
   
4. Orange signal wire from CDI to coil -ve. Checked for continuity and buzzer sounds so connection is good
   
5. Black CDI earth connected direct to battery-ve
   
6. Both signal wires from igniton pick up checked for continuity and also OK to resistance test as per the Yamaha manual.
   

I've checked the coil by measuring the winding resistance between -ve and +ve and secondary winding between +ve and the end of the HT lead - At 4.2 ohms its in the 3.6 - 4.8 spec and the secondary checks out too so Coil should be fine.

Plug cap also checked out as per the Yamaha manual, as does the igniton pick up.

Ive got a spare CDI, coil , plug, HT plug cap and pick up and swapped them all out. Still no joy.

Ive connected the Black and White wire from the CDI (orignal sidestand ignition cutout) to earth and also left it unconnected. No effect either way

I've run out of things to check. Either my circuit diagram is wrong or I'm missing something (earths perhaps??)

Any ideas anyone?

[RonniB]

There usually a minimum revs limit, before the cdi sparks. It's about 700-1000 rpm on most bikes.

So you need to the bike over faster ( by hand) or make a make-shift rollerstarter

[BudgetBoy]

+1 to what RonnieB say's.. You wont make it spark by turning it over by hand mate. Try bump starting it as this is much better for a fitness point of view. (Or make a roller stater as already said)

[monkeystew0]

Thanks for the replies guys.

Ill check the engine earth strap as that is something I have overlooked in the checking process...

I have got a "starter" set up. A modified minimoto to spin the back wheel up. I shall get that running and maybe try that to get it turning over a bit quicker also.

Ill keep you posted..........

[BudgetBoy]

Rubbish - no such thing.

You think a starter motor, or even a bump start, get's the engine turning over that quickly?

@Monkeystew - have you checked the engine earth strap?

I was always led to believe that a starter motor tuns the engine over at about 250-500 rpm, and that a bump start give a boost at about the same rpm in a quick hit like,.

If you can make the bike spark by turning it over by hand (all pugs out) then this is worth knowing IMO.Personally i did not think this would work due to the CDI/ECU's on bikes nowaday's.. I know you can do it on old cars and bikes with points.. Seriously i am interested as this would save some time in the workshop if i ever need to use it so please explain how it works so i know.Cheers

And yes a bad engine to frame strap can do it as well.

[monkeystew0]

Update;

Replaced the earth strap today with a direct connection from battery -ve to the engine block, and added a second from the engine block to a coil mounting bolt.

Engaged first gear. spun the rear wheel by hand, flywheel spinning but still no spark. Next step, get the remote starter running and spin the engine over faster to see if it makes any difference.

I need to work out how to check the signal from the ignition pick up is working....

[monkeystew0]

This is the flywheel and crank sensor set up:

As I bought the engine second hand some time back I assume its a stock flywheel, stripped of the charging rotor and stator set up. Its certainly a standard crank sensor as it is the same as that fitted to a spare stock engine I have. I've not adjusted the backplate but have swapped the sensor for the spare.

I need to double check its aligned with the flywheel triggers . I have already checked the resistance as per the Yamaha manual. Any idea where I can get my hands on an Oscilloscope for the purposes of checking the crank sensor output and how to do it?

Next immediate job is get the remote starter running and drag a willing assistant out to the cold garage to try turning over at a higher speed:

If that fails its back to the drawing board and multimeter.....

[monkeystew0]

Finally got a willing volunteer to man the starter while i troubleshooted the ignition circuit. It took a few attmepts to get a spark but after swapping the CDi, coil, HT, plug and coil we still had no joy....until i remembered the wire from my first post in this thread. Connected the starter interlock earth wire to earth and a big juicy spark appeared.

Seems the circuit was fine all along. Just needed spinning up in top gear connecting the second CDI earth and away it went.

Very happy now.