yz125c electrics

[mainline]

ok, so I rebuilt the 125C and tested the original electrics to the best of my ability and the resistance readings on the coils were (I thought) within specs.

Given that all the original cabling was immaculate (it'd spent it's life wrapped in a split garden hose and then taped up) and all the original 3 and 2 pin plugs were perfect, I thought I'd get away with not forking out cash to rewind coils etc.

So, I finished putting in together just in time for CD8 and started it - wouldn't rev, just sat and idled. When you tried to rev it, it'd gurgle and die. I figured it was a carb problem seeing as the spark looked really strong and I'd already stuffed up something else when I put the carb back together. Got it up to CD8 and no-go. A guy camping nearby (who rewinds coils for a living) came over and said the problem sounded electrical. So it got parked for the weekend.

Then yesterday (while I should have been doing my tax) I was thinking about it (and the kill switch which also didn't work) and decided to pull all the electrics apart and start again. I cleaned up all the old connections and disconnected to kill switch alltogether.

When I got home this arvo I had another go at starting it and it started first kick and revved to the moon. I had to pull the plug lead to stop it.

So, any ideas?

BTW, the killswitch i have is a yamaha 2-wire and there's only one wire to connect to on the NOS loom I picked up for that section of the wiring.

 

[Freakshow]

Sounds like you need another $5 kill switch. there is an earth leak in there somewhere or a bare wire no doubt that arcs when its running.  Bin it and try another kill switch and wire back to coil and also check the earth has good contact.

[YZ250H]

You know how I said Ted was the winner of the trophy this year.... Guess what 
At least you found the problem without spending a fortune 

That is definitely sh1t happens 

Did it rev uncontrollably or 'cause you had no kill switch you couldn't stop it. 

Where you relieved or pissed off 

[mainline]

You know how I said Ted was the winner of the trophy this year.... Guess what 
At least you found the problem without spending a fortune 

That is definitely sh1t happens 

Did it rev uncontrollably or 'cause you had no kill switch you couldn't stop it. 

Where you relieved or pissed off 

bugger that, the "shit happens" award would only have applied if Ted had casually strolled over and pointed out the problem   Actually, I think the award should go to Vandy for cracking the sads when his bikkies got wet

It revved uncontrollably and with the killswitch disconnected the plug lead was the only thing I could think of besides a hammer. I'll let you know if I'm relieved when it all works properly.

Sounds like you need another $5 kill switch. there is an earth leak in there somewhere or a bare wire no doubt that arcs when its running.  Bin it and try another kill switch and wire back to coil and also check the earth has good contact.

Cheers freaky, should I be picking up a single wire killswitch while I'm at it instead of the 2-wire job?

[YZ250H]

Sorry Champ - taking an awesome resto to CD8 and not being able to ride it on the pre 78 track then getting home and finding the problem takes the cake over:
1) driving from Sydney to look at your own bikes all week-end or
2) getting the poops over soggy chocolate biscuits 

I believe it is also more impressive than buggering up your gear level position, although the feelings of dread when it happened would have been very similar 

I'll get your name engraved on it this week-end .

[mainline]

you may want to wait till it's actually sorted, otherwise your eagerness to share the love around might see you back on the trophy anyway

[YZ250H]

OK - Jury remains out for now (briefly) .  1) above is definitely up there with the best.

P.S. - you have looked at the wiring diagram right    What's the go with the kill switch ? 
Electrics shouldn't make it rev uncontrollably (??)  The amount of fuel available controls the revs 

[mainline]

I don't know, all I know is:

1. I have a 2-wire killswitch and only 1 wire available to plug into it. It didn't work no matter how I connected it ie. one wire to earth the other plugged in.

2. The bike wouldn't rev at all before today's experiment, and now it won't stop revving

[Woody]

Mainy
I have this one stashed away in my glory box that I could part with (bugger owes me a little though)



SWITCH,HANDLE 1

1973 Yamaha MX250
1973 Yamaha MX250A
1973 Yamaha SC500
1974 Yamaha MX100A
1974 Yamaha MX125A
1974 Yamaha MX175A
1974 Yamaha MX360
1974 Yamaha MX360A
1974 Yamaha SC500A
1974 Yamaha YZ125A
1975 Yamaha MX100B
1975 Yamaha MX125B
1975 Yamaha MX175B
1975 Yamaha MX250B
1975 Yamaha MX400B
1975 Yamaha TY175B
1975 Yamaha YZ125B
1975 Yamaha YZ250B
1975 Yamaha YZ360B
1976 Yamaha MX125C
1976 Yamaha TY175C
1976 Yamaha YZ100C
1976 Yamaha YZ125C
1976 Yamaha YZ125X
1976 Yamaha YZ175C
1976 Yamaha YZ400C
1977 Yamaha TY250D

[vandy010]

Sorry Champ - taking an awesome resto to CD8 and not being able to ride it on the pre 78 track then getting home and finding the problem takes the cake over:
1) driving from Sydney to look at your own bikes all week-end or
2) getting the poops over soggy chocolate biscuits 

I believe it is also more impressive than buggering up your gear level position, although the feelings of dread when it happened would have been very similar 

I'll get your name engraved on it this week-end .

i reckon you should cut the guy a little slack Tony for the bike not running properly as he really did make an effort towards that result.
However, if anyone was to ask Ted what the track was like? i very much doubt his answer would hold any truth
and with all respect to the said "soggy chocolate biscuits",
well the chocolate ones weren't mine anyway.
but basically for those that are not sure what all this is about,
please allow me to explain,
it was raining on the tarp over our camp,
water was pooling in the tarp and Gav seemed to have it all under control by pushing upwards on the tarp in a particular way as to allow the water to run off in a safe place.
when our mate Mainline decided to offer his assistance,
well,
lets just say his efforts lacked any real thought as the water ran off the tarp
and all over our previously nice dry bickies.

[Davey Crocket]

Bastard.....its all I can say Mic....but would you have expected anything else from the muppet? ....you forgot to pick up your gearchange cover aswell.....Have you got the TY fixed yet....could have been sabotaged you know!!!!

[IT400C]

Mainy
I have this one stashed away in my glory box that I could part with (bugger owes me a little though)



SWITCH,HANDLE 1

If Mainline isn't interested, I would be - I have a second hand one (and of course there are the readily available red MCS ones), but it would look good onthe NOS(ish) IT400C I'm putting together..   

[Mike52]

....Have you got the TY fixed yet....could have been sabotaged you know!!!!

The TY was running and looking better than when he bought it.
Needs a new tank tho

[Freakshow]

Bastard.....its all I can say Mic....but would you have expected anything else from the muppet? ....you forgot to pick up your gearchange cover aswell.....Have you got the TY fixed yet....could have been sabotaged you know!!!!

that wouldnt be my second one would it ?? sent you 2 up and only one came back ?  thought you where just still working on it... do you want me to bring your bush tool with me to the DT nats if you going to be there ......

[Davey Crocket]

Yes to the DTN......your 1st housing cracked.....only have about a 70% sucess rate getting the old bush out.....have you fitted it yet?