Need advice on electric for 1980/1981 Yamaha

[Colt]

So first of all, let me tell you the story.

This last week I received three bikes from a friend, the deal was that if i fix his I get to keep the other two. (we had done the same deal except i got a truck for fixing two other bikes) the main problem on any of his vehicles is he uses them, the tags expire, and they sit, and sit, and sit... so naturally there is A LOT of varnish in the carbs and gas tanks, which is no problem, a few hours a piece and you've got them running. This time is different.

The bikes i received are as follows

1980 Yamaha 400 Special II (blue)

1980/1981? (the bikes are essentially the same, just a little different on certain parts) Yamaha 400 Special II (blue)

Unknown year Yamaha 125 Enduro (red)

The two big bikes are a matched set (sort of) sad to see them split, since he wants to keep his original bike and give me the rest.

Now... Im fixing his to give back before i work on mine, naturally, I've cleaned the carbs, and oiled and greased everything, but there is a major problem, no spark, no lights anywhere on the handlebars, no headlight, no turn signals, nothing.

Here's what i have done to fix the problem so far, I've checked all wiring connections and ends for corrosion, they all look good, all fuses are good, ignition is perfect inside.

After doing that i put it all back together and turned the key on, still nothing, with the exception of the license plate light and the brake light , which is now stuck on as soon as the key is turned on (I have no idea how that works, none of the brakes are engaged, so all the switch contacts are loose and open, does it get dimmer after the bike is started?)

So here is my question, is there any way to figure out what is wrong with the electrical, is there anyone who's had the same problems?

I plan to check the whole system with a continuity light soon

any tips are greatly appreciated.

Thanks, -Colt (a 15 year old boy who knows more mechanics than anyone he knows, minus his dad)

P.S. the bikes are in no way mint condition, there is mouse pee everywhere so the bikes are practically all rust, I'm planning a complete rebuild for my bikes, take off all the parts down to the frame and sandblast and repaint (they were stored in an old shed since 88)

[slice]

Hi Colt, Check the battery then the fuses then ALL of the earth points (clean & grease) brake light might just be that the switch is stuck open so give it a tap to see if it will go off if not take it apart and regrease it, check that the bulbs in the instruments are actually working it might be that just cos the Ignition light don't come on that it's blown and does in fact work ok, In the USA I believe the lights come on when you turn the ignition on so the REAR BRAKE light MIGHT be in fact the side lights or running lights, hope some of that helps mate, plus STAY AWAY from the MOUSE PISS it is toxic and can give all sorts of diseases WHILES DISEASE for one which is very nasty and can kill if untreated, give all the bikes a thorough wash down with soap and a jet washer BEFORE you start work.

[dt502001]

Washout that mouse piss imedatly as MMR pointed out that stuff can make you realy sick

1St the rear brake switch are bad for sticking so follow the wires up and un plug them that should put the light out if not do the same with the front.No they don't get dimmer when running. the switches don't ground the light they power it Ie cut the power wire and place a switch in line.

2nd the front of the bike is grouned under the tank and the rear is grouned at the back so I'm guessing that it's the front ground, but also check to see you have power comming to the ing. switch. headlight turns signals dash coil and cdi are all feed from the ing switchSo get a paper clip and back probe the ing switch to make sure the contacts realy are sending power out all but the black wire should have power with the key on of course.

If you get the light's up and still no spark check the kill switch first inside the housing the you have 2 bikes so start swaping parts cdi coil 1 at a time tillyou find the problem.

Good luck young man you should get it sorted out

[Colt]

hey, thanks for the help, still havent figured it out, i'm a little busy today but managed to get some things done. Instead of starting to swap parts from my bike to his, i just took the battery out and put it in mine, only to find out... mine has the same problem

BUT I'm pretty sure his has somthing to do with one or two of the amazing electric... i dont know what there called, but they always break, the little shiney boxes that resemble like, resistors or somthing (im killing myself talking like this) be ause if the brake lights turn ong that means there is power to the ignition, so its gotta be somthing after that, ive got some pictures that i took and will post soon.

The guy i got these bikes from is famous for his quick fix remedys and frequently uses two longer wires bolted to the main battery wires as jumpers to a full size car battery, which he did to this bike... none of the fuses were blown, but could this have broken any important electronic components because of too much power? (im not good with DC electricity)

Fixing these bikes is like inheriting his problems...

[Colt]

Okay here's some pics-

this is his bike im working on

this is one of the bikes i keep

this is the other bike i get (haven't looked at this one very thoroughly yet)

Rust an those "shiney little boxes" i was talking about, im more worried about the main one the the positive on the battery hooks directly to

does anyone know the purpose of this wire... both bikes have it, but its not hooked to anything... is it just a universal wiring harness and these wires didnt need to be used for this bike?

all that snazy rust and varnish in the tank on my bike...ugh

okay...so suddenly after i check all the main wire connections... these lights work, but just wont turn off unless i turn off the key, so i know somewhere a switch for the brake light is messed up.

Hope these help (: