My son's first ride was a bust

[fritalian]

So, at 10 years old, I decided that my son was ready for his first ever ride on a motorcycle. It was a beautiful evening. We changed out of our shorts and put on some jeans and riding jackets. We practiced in his school parking lot a little so that he could feel the movement of the bike and we could talk about what he could expect while we were riding. We spent about 20 minutes on the back roads near our house enjoying the scenery and having fun. I turned down a side road, realized it was a dead end and promptly did a u-turn to get back on the main road. I gave my son two or three leg taps, as discussed in our pre-ride briefing and opened the throttle. I felt his body tighten up behind me. At the top of first gear the bike revved and popped, almost like backfire, something I had never heard before. At first I thought I missed 2nd and was in neutral but soon realized that the engine was sputtering and non-responsive. After 3-4 seconds, the engine stalled and all electronics went out. We were dead in the water, in the middle of nowhere. There were no fluid leaks, no smoke and visually, everything looked fine. Gas and oil levels were fine. Thank goodness for CAA.
I'm thinking this might be an electrical issue and there may have been a lack of spark that contributed to the stall. Then again, I don't know what I'm talking about. The battery charger at home showed a full charge this morning but there are still no electronics.
I just had the carbs disassembled, cleaned and replaced the 0-rings and needles. She was running so well.
Any ideas as to what the problem might be?
I know that the R/R is an issue with these models but the PO mentioned that he had replaced it already. Can anyone tell me if the photo below is the original R/R? If it is the original, how can I accurately diagnose a bad R/R? Can I just swap it out? I've checked out the R/R forum but was hoping for feedback before moving forward.
Btw, my son still loved the short, but fun ride. Now if can just get her running again, we'll both be much happier.

 

[bccap]

Read the below link, fully charge your battery and perform test 0. Report back with the results....

http://www.thegsresources.com/garage/gs_statorfaq.htm

 

[tom203]

I don't care how new that R/R is, it's too tiny. Do some testing- simple one here
http://www.thegsresources.com/_forum/showthread.php?p=1272192#post1272192

Seriously consider a series R/R- a SH775 can be had for about $70 usa

 

[ptexotik]

cool Dad !!!

 

[spyug]

Sorry to hear about the curtailed trip but did the lad enjoy the little bit of a ride?

Definitely you are looking at an electrical issue and from experience with my 550 I think you can look at the ignition switch or kill switch as I had almost the exact same thing happen last year. In my case it turned out to be a bad connection in the ignition switch. If there are no signs of life and no lights it is undoubtedly the ignition switch.This is the inside of the switch which is found on the bottom of the ignition key. The contacts were corroded:

If you had full battery voltage when testing it is nothing to do with the R/R so don't waste time worrying about that. It is much more likely to be dirty or corroded contacts somewhere.

In order to fault find an electrical issue you really need to use a digital multimeter and a circuit test light. The test light is especially useful as it allows you to follow the flow of electricity from the battery to where ever it is needed. It will quickly help pinpoint where you have a problem.

You also will find the wiring diagram to be very helpful so hopefully you have a manual to refer to. If not check Cliff's site for one.

I'd start by cleaning the contacts in the right handle bar control as power comes into and goes out of there and they do tend to get gummed up over time. Becareful when you work on it as there are little screws and contact parts in there that can easily be lost. If that doesn't fix things then move to the ignition switch.

Electrical issues are the bugbear of these old bikes and while they may seem daunting at times, just take your time and think things through. Eventually you will figure it out.

Good luck with it.

spyug

 

[fritalian]

Read the below link, fully charge your battery and perform test 0. Report back with the results....

http://www.thegsresources.com/garage/gs_statorfaq.htm

I wasn't able to perform anything beyond testing the battery with ignition in the off position and in the on position since the engine won't run.
My multimeter has a DC pre-set dial at 10, 250 and 500 volts. At the 10v setting the needle spiked and buried at 10v with the key in the off position. The same for when the ket was in the on position in the ignition. I don't want to make assumptions but, based on this information and the battery charger showing "charged", it looks as though the battery is good.
According to the stator papers, the bike needs to idling and revving in order to test the complete circuit properly.
Is there any way to diagnose a bad stator without the engine running?

 

[spyug]

I forgot to mention that in the ignition circuit the power lines are the orange with white tracers. It can get a bit confusing as they run from the fuse area to the ignition switch across to the kill switch then back out and down to the coils.

With good contacts and the key on you should be able to follow power from the fuse block all the way around this circuit to the coils. so as I mentioned above, with the key on, you should see power in the kill switch/starter button area. If not, then the ignition switch is the problem.

Good luck.
spyug

 

[fritalian]

Sorry to hear about the curtailed trip but did the lad enjoy the little bit of a ride?

Definitely you are looking at an electrical issue and from experience with my 550 I think you can look at the ignition switch or kill switch as I had almost the exact same thing happen last year. In my case it turned out to be a bad connection in the ignition switch. If there are no signs of life and no lights it is undoubtedly the ignition switch.This is the inside of the switch which is found on the bottom of the ignition key. The contacts were corroded:

If you had full battery voltage when testing it is nothing to do with the R/R so don't waste time worrying about that. It is much more likely to be dirty or corroded contacts somewhere.

In order to fault find an electrical issue you really need to use a digital multimeter and a circuit test light. The test light is especially useful as it allows you to follow the flow of electricity from the battery to where ever it is needed. It will quickly help pinpoint where you have a problem.

You also will find the wiring diagram to be very helpful so hopefully you have a manual to refer to. If not check Cliff's site for one.

I'd start by cleaning the contacts in the right handle bar control as power comes into and goes out of there and they do tend to get gummed up over time. Becareful when you work on it as there are little screws and contact parts in there that can easily be lost. If that doesn't fix things then move to the ignition switch.

Electrical issues are the bugbear of these old bikes and while they may seem daunting at times, just take your time and think things through. Eventually you will figure it out.

Good luck with it.

spyug

Mon son loved the experience and wants to get out right away. He just has to wait for dad to find a solution to the problem... which might take a while.

Since the battery is good, I suppose starting with the power switch on the handle bar then moving to the ignition afterwards sounds like a reasonable trouble-shooting plan.
However, I'm concerned about removing the front fairing because there are some cracks in it and I don't wanna damage them. If I remove the side panels and front fairing, will this be enough to access the relevant electrical circuits for testing with a multimeter?

 

[chuck hahn]

I rode the 77 750 to work one day and it rode fine till TURNING into the store lot and going over the storm drain grate. It stumbled and then blacked out gauges and lights and rolled to a stop.

My problem was that the red wire had fallen off the soldered connection point on the bottom of the ignition.
I had to wire the two wires together inside the bucket to get it live and get back home. Resoldered the wire on and was good to go.

Also check the wire connections in the back of the fuse panel, the connections in the headlight bucket too.

 

[fritalian]

I forgot to mention that in the ignition circuit the power lines are the orange with white tracers. It can get a bit confusing as they run from the fuse area to the ignition switch across to the kill switch then back out and down to the coils.

With good contacts and the key on you should be able to follow power from the fuse block all the way around this circuit to the coils. so as I mentioned above, with the key on, you should see power in the kill switch/starter button area. If not, then the ignition switch is the problem.

Good luck.
spyug

Good advice, thanks Spyug.
Got the Clymer manual out, the laptop on and my fingers crossed. Gonna start with the fusebox.

 

[fritalian]

Main 15A fuse is fried.
Now the question is why?

 

[chuck hahn]

Check behind the panel, under the tank, and anywhere else you can think of where wire could get pinched or rub itself thru the insulation for a short.

 

[fritalian]

Check behind the panel, under the tank, and anywhere else you can think of where wire could get pinched or rub itself thru the insulation for a short.

Thanks Chuck Hahn, gonna plug in a new fuse and keep a spare in the "toolbox." If it fails again, I'll know there's a bigger problem somewhere.

 

[spyug]

Well you got lucky there. I assumed you had looked at the fuses first so didn't mention that...silly me. At least now you know there is a shorting issue some where so as Chuck mentions , you can begin the search for a bared wire.

You will need to remove the fairing to get to the bulk of the wiring in the harness up by the headlight. All the forward control lines plug in there. As Chuck says it more likely to be under the tank but you need to check every where.

As far as the cracks in the plastics, they are easily repaired with the ABS slurry solution. Do a search for more complete details but it is essentially pieces of ABS plastic (Lego blocks, drain pipe etc) dissolved in Acetone. You can make it as thin or as thick as needed by adding plastic. A consistency of toothpast or honey is what you want. Use it like glue but it is actually a liquefied version of the plastic so it bonds with the original better than any glue. Here is a piece I fabbed up for a Katana chin fairing to give you an idea:

The end piece in white is made from sheet ABS and you can see the slurry used to bond it to the original.

Its easy to use and is as fully workable as the original plastic.

Good luck finding the problem and let us know what it turns out to be.

Cheers,
Spyug

 

[Redman]

Not stock R/R.

Main fuse blowing could be result of short circuit to ground in the red wire from fuse block to the ignition swtich, or the orange wire from ignitikon swtich back to fuse block .... or ... the R/R itself.

If you replace the fuse and it blows imeadiatly before even turning on the ignition key; then disconnect the R/R, and try another another main fuse. If that fuse holds, then you have pretty good idea the R/R itself is were the dead short to ground is. If main fuse does blow when turn on key, remove the head fuse the ignition fuse and the signal fuse and try another main fuse, and turn key on, if main fuse blows then know problem is in wiring from ignition swtich to the fuse block or IN the fuse block.

Oh, main should be 15A, and the other 3 10A. If ther is a 5th fuse for Auxilary, that should be no more than 10A either. So you probably are going to want to go buy some 15a spares and somw 10a while you are at it. Those combo packs are about not that usefull, don't have enough of what you need, and more of what you don't need.

You can go a long way without an R/R.
(do you have a small battery charger?)

Tell us more what you find.

How did you decide your 10 year old was ready for ride?
My criteria (for kid to ride on back) was that kid had to be big enough to hold on and have legs long enough to stand up on pegs (not just touch them with his toes). Good that you had some parking lot instructions first.

And now you can also teach some troubleshooting skills har har har
.

.

 

[fritalian]

Tell us more what you find.

How did you decide your 10 year old was ready for ride?
My criteria (for kid to ride on back) was that kid had to be big enough to hold on and have legs long enough to stand up on pegs (not just touch them with his toes). Good that you had some parking lot instructions first.





Replaced the fuse and she purrs like it was 1983.

I decided my son was ready when, like you Redman, he could comfortably reach the pegs, he was strong enough to hold on during hard acceleration and when I felt he was able to listen to instructions.
I'm using a passenger riding belt with him so that he has a good grip with both hands and he can sit comfortably on the bike.
He has only fallen off twice so, not bad I guess

 

[Redman]

.
.
Replaced the fuse and she purrs like it was 1983..
...

Hum.
THe picture of the fuse looks like it blew due to an overload or dead short. Does not look like it just because the fuse itself failed because of fatigue.
So, I suspect it is going to happen again. Maybe rarely or maybe with increasing occurances.
Carry some spare 15s with you.
One way to trouble shoot this is to wiggle around wiring harness until it happens and then look in more detail at what you were wiggling.

But good to hear you are back on the road.

.
.
.
He has only fallen off twice so, not bad I guess

I assume the happy face means you are jokeing.

.

 

[fritalian]

Hum.

I assume the happy face means you are jokeing.

.

Yes, absolutely.

 

[850 Combat]

You can remove the stator and the R/R and the bike will run just fine while the battery has a charge. They are unrelated to running problems UNLESS the battery was allowed to run down due to faulty charging.

A bad R/R CAN cause overcharging and too high of voltage which will smoke parts, but it is not directly related to providing spark or starting.