Absolute necessity wiring

[jwhite2]

I have a silly question.  What is the absolute minimum I would have to do with wiring to get the motor to start?  I am not sure what needs to be connected so that it will run.  Yesterday I had to cut all the wiring out.  It was in baddd shape with everything in a tangled mess.  Rewiring is required.  I intend to purchase a wiring harness and get everything going but at this point I would like to see if it will run.  If it doesnt then I would like to avoid spending any money on it till I can figure out what needs to be bought to get it running.  I also need to bypass the key if that's possible.  I dont have a key for it.  Or a battery.... oh gosh this may be hopeless.

Any suggestions?

[Toystoretom]

Wow.  

I guess the best course of action would be to visit the appropriate service manual for your bike and look at the wiring diagram. What you will need is the circuit for the points and coil, because you will need spark to get it running. This will involve a battery since you will need to power the coil somehow. You could skip wiring in the generator at this point and just use the battery as a constant loss system just to simplify things.

Really... the better way to do it would be cutting to the chase and see if Richard has a wiring harness for your bike. It sounds like you need one anyway. I know you want to do it on the cheap but you could spend a lot of time on a custom harness and if you don't get it right the bike may not run.

[jwhite2]

Its not that I am trying to do things cheaply, but I dont want to spend money on a wiring harness if the bike still is not going to run.  If it needs some other major part, I would rather go for that and THEN get the wiring harness.

Basically, I am married and I have to SLOWLY spend the money. No dropping 500 bucks on a truckload of parts right now.

I have the service manual from here but I am not great at reading the wiring diagram.  I will look into just borrowing the battery off my Vespa and see if I can get anything out of it.

Thanks

[OldSwartout]

On a 175/200, you need to supply voltage to the coils and a ground to the frame/engine. The wire supplying the coils is blue coming from the ignition switch, which connects to double blue wires going to the coils. You can jump your hot wire into that somewhere (I think the double connector is under the gas tank).

[jwhite2]

My problem is I dont have a key so going through the ignition will be problematic.  Also, nothing is wired at the moment.  Its all been cut free.  I am just wondering what I will need to run to get the engine to start. 

I am kind of new to wiring so be as simplistic as you can.  I know the coils are the things under the gas tank that run to the spark plugs but what are points?

[Richard Clark BS parts]

I hate to plug my parts, here in the forum, but I do have pre-cut original keys, pretty decent price at 15$, post paid, need the three numbers off face of ignition.

Questions? or need Bridgestone parts? call:

Richard Clark
812-944-1643  8am-6pm EST Weekdays

[reed]

Jwhite2
I have a question for you, where do you live maybe a member can help you out, if he lives near you!
Thanks.
Steve.

[jwhite2]

Near Little Rock Arkansas.  I do intend on buying the key at some point Richard.  Right now the name of the game is "Prove to my wife that the bike is worth spending ANY money on."  The bare minimal that I can spend to see if it will run or not is what I intend to do.  Once I know that its a decent runner, then I can invest a little more to fix it up and make it a road worthy bike. 

Just the wiring harness, battery, key, and cables I will need will run me a pretty penny.  Maybe some of you out there have some used parts but I will post an add in classifieds.

Still, to "hot wire" a MKII RS?  What exactly do I need to hook up?

[Toystoretom]

You are going to have to design this yourself to a certain extent, but here are some basics.

The ignition circuit is just that, a circuit. Current flows into the coils and it creates a magnetic field inside the coil. When the points opens this field collapses and it induces a high voltage current in the secondary windings inside the coil, which then travels down the spark plug wires to the spark plugs.

You will need to run a wire from the positive post of your battery to the positive side of the coils. It might be a good idea to put a switch in this wire so you can turn the bike off if it starts.

You will need to run a wire from the negative post of the battery to a good ground connection on the engine.

You will then need to run wires from the negative side of the coils down to the set of points that belongs  to that cylinder. You can study the wiring diagram to figure this out or go on the theory that as a piston nears top dead center that particular set of points should be close to opening.

If you don't have the correct set of points matched with the correct cylinder the bike won't start. If you don't have the points set up correctly the bike won't start. If you do all of this in your garage and have fuel leaking and a stray spark due to hotwiring this you will burn your house down.

If you have no experience with electrical circuits and points ignitions possibly you have a buddy who does. This stuff is pretty straight forward and somewhat universal, it could be done.

[jwhite2]

Thanks!  That was exactly what I was looking for!  Luckily, im in a detached shop so it would be the only thing that burns down... still not good though.

I will try this out this week and see what I get.

[jwhite2]

Got to working on this today.  I basically set it up exactly how you told me.  Ran one blue wire from the positive post of my battery to the two blue wires leading to the coils.  Then connected the black and white wires from the coils to the dynamo thingy.  Ran two wires from the negative post to each cylinder and tried to get a spark.  After kicking it a few times and seeing nothing, im assuming that im doing it wrong.  Anyone have any suggestions?

[scrambler]

Your ground to each cylinder, how is it connected. You really only need one ground wire from battery to engine. That sounds about right for the rest of it. Have you had a look at your points? They could be terribly corroded.

[jwhite2]

Took a look at the points.  They were pretty nasty.  Took them out and cleaned them.  I was able to get spark off of one spark plug after that!  Getting closer.  The other point was really gummed up so I took the little lever apart and cleaned it and it moved a lot better.  Put it back together but I still cant get spark on that side.  I notice that when touching that left point that doesnt work with a screwdriver, I dont really get any sparks like I do on the right point.  Where the little points come together, no sparks.  Noticed that when rotating it, no sparks either.  Weird thing is, when touching it with a screwdriver before I took it out to clean it, I was getting little sparks all over.  Did I put it back together wrong?  It looks just like the right side that is pretty electric.

[scrambler]

You need to make sure you installed the points wiring correctly. If you put the wire on the wrong side of the fiber washer you will have no spark. Look at the side that has spark and look at the side with no spark. See if you notice a difference in where that wire is in relation to that insulating washer.

[jwhite2]

Heres how I have it now.

nut
regular washer
fiber washer
Flexible thingy
Points bracket
Fiber Washer
Wire
Regular Washer
Bolt

Would putting that fiber washer first effect it?  I looked at the right side last night and thats where I thought it was at.  Maybe my eyes deceived me!

[scrambler]

What you describe sounds correct.

[jwhite2]

I guess ill just have to check again.  Make sure all the wires are matched up.  Just seems weird that it would work before but now now!

[paul25g]

jwhite2,

I've got a used wiring harness you may be interested in...I sent you a PM...let me know if you don't get it.  Thanks!

Paul