Sudden Loss of Power 1980 GS850 G

[FreeRadicalz]

Hi Everybody, I'm new to riding and have recently bought my first bike, a 1980 GS850 G. I love the bike, and it has been working quite well. Unfortunately, the other day something happened. I was driving, and there was a sudden loss of power. I was going about 60km/h at the time. I went to pull off the road, and suddenly she came back. I made it home with no other problems. I then took the bike out again about an hour later and it happened again at low speed, this time stalling out completely. no sputter, just died. The bike started again no problem, i went up the road and was pulled over on the side in first w/the clutch in when it stalled again. Had plenty of gas. I'm having a difficult time finding a garage in my city (Winnipeg, Manitoba, Canada) who works on older model bikes. Any suggestions as to what could cause this problem?

[7981GS]

Plugged screen in the petcock?

Daniel

[Tim Tom]

It is either a problem with fuel or spark. When the bikes dies does is smell of gasoline? If so that's an indication of a spark problem. I had a similar issue with my 850 last summer. It turned out that the coils were not getting enough volts to generate a nice fat spark. Its pretty easy to test, get a digital voltmeter and check the voltage at the coils. If it is below 12 V then you have an electrical issue.

Just my input, others here know vastly more than me. Basscliff should be along shortly with his mega welcome that is choc ful of helpful tips. You'll get it running right again, GS's are tough to kill.

[Dogma]

Sudden loss of power and sudden return of power sounds like a weak wire or connection powering the coils. My 850 had one of the power wires break right where it enters the coil. I lost half the engine like flipping a switch.

Inspect the wires leading up to the coils, clean (Deoxit) and protect (dielectric grease) connections to the coils (and the charging system, while you're at it).

Get used to nobody else wanting to work on your bike. On a lighter note, you have one of the easiest bikes to work on. It's more of a pleasure to ride when you've worked on it yourself too.

[1_v8_merc]

Yeah these older bikes are so easy to work on.

Yet, there's apparently this rumor that refuses to die, about how "complicated" they are, and you need all these "special" tools....

Everytime i'm at the parts department...I always hear the clerk pick up the phone and say something like, "ohh an 83 huh? Well it takes specific knowledge and bla-bla-bla-bla"

But yes I agree, I think you have something electrical going on...maybe coils.

[spyug]

Welcome aboard and sorry to hear of your issues. With an older bike you will need to forget about shops working for you and learn to look after it yourself, or if you do find a shop be prepared to be hosed.

Having been through similar happenings my vote is on an electrical issue too. I'll bet you have a coil issue or something related to it and I think you need to start looking there.

As mentioned, it is common for older bikes to have voltage drops from the battery to the various components, caused by resistance ( built up from crud and corruption...technical bike terms) at the connectors and contacts. Lowered voltage to the coils will cause weaker spark.So start by doing a voltage drop test. You will need a digital multi-meter ( Canadian Tire $20 or less). Fully charge the battery and test the voltage. It should be better than 12.5 volts maybe even into the 13s when first tested (it will drop). Now follow along to the coils and check the voltage at the connectors (orange/white wire touch with the red, i.e. positive lead, touch the black negative lead to the frame or the battery negative pole. You likely will have a drop of more than 1 volt which is common but not good. More than 1.5 volts is bad but in both cases you want to shoot for a good 12+ to the coil. so you need to clean-up and or replace all connectors in that circuit so you'll need a wiring diagram to help you figure where they are. Cliff will be along shortly to welcome you and provide you references to find manuals/diagrams on his site if you don't have one.

If cleaning doesn't improve things there is a "coil relay modification" with a how to on cliff's site that will sort out the issue for you.

In the manual, there will be details to check the primary and secondary wiring in the coils and you find that you have a wonky coil. Your description of the problem makes me think of this. Coils can seem to function, then quit suddenly then come back to life. There can be breaks in the wiring and when cold they touch and the coil works, then it heats up and they seperate the coil stops working. Let it cool down a bit and it starts again.

In addition to these issues, the plug caps and wires can have similar issues. On one bike I had, one coil was faulty as I described. On another I had a bad wire. They both caused the same run/die/run issue.

I know this seems like a lot of hassle and it can be a bear to figure out but you can do it, you just need some knowledge, some basic tools and the help of some good friends....like us.

Hope this helps a wee bit.

Let us know what you do and what you find.

Cheers,
Spyug

[FreeRadicalz]

Hey folks, well i must say that i am impressed by the quick replies to this thread; and very appreciative. Thanks everyone. I'll be sure to let you know how things turn out in the next couple of days. if anyone else has input i would very much appreciate it, as i will be checking-in regularly.

[49er]

You've got most bases covered here.

I suggest you do 2 checks on the fuel side first before attacking the electrics.

First, remove the fuel line from the petcock and turn the lever over to prime. Be sure to catch any fuel that flows out. If there's a steady flow, you can eliminate a clogged petcock filter from the list.

Next remove the filler cap and check that the breather hole is not plugged. If in doubt, try running the bike with it off, but take care. If the cap breather is blocked, a vacuum will form and fuel won't flow freely to the carbs.

[koolaid_kid]

If vou have to do the coil relay mod, I strongly suggest you get the Eastern Beaver relay kit (PC-8?) or make your own (like I did) once you understand how it works. You will be able to power lots of things: aftermarket horns, grip heaters, GPS, etc. It works; I built my own for my GPz and then discovered it was similar to the Eastern Beaver ready-made kit.

[nitro3custom]

I agree with 49ers suggestion first. And if you haven't already get yourself a manual. It's the most important tool you can own. Good luck

[koolaid_kid]

If you don't have a manual, you can get a PDF of it on BassCliff's web site for free.

[FreeRadicalz]

Hi Everybody,

Just a quick update: I had noticed that when these problems were occuring, the weather was hot/humid in my city (30+degrees Celsius) and i had been riding the bike all day. So i was hoping that the problem was only happening after she had been running for quite some time and the ignition coils or whatever is wrong were acting up when hot. I left it at home and took my car to work on tuesday (boring..haha). i then got brave and rode the bike to and from work on wednesday, with no problems. This morning i took it again. I wasnt on the road more than 10 minutes when she quit again. I pulled over and tried to start the bike. no response from start button. I waited a moment and then she started up again. i decide to ride home and park the bike. she quit several more times along the way. Once, while rolling, the bike started again after i downshifted and released the clutch. Another time, she just kept a rolling. again i pulled off to the side of the road. my lights and indicator lights were working, but no response from start button. I flicked the kill switch off and on a few times (i dont know why) and then she started again and i made it home. Long story short, i'm going to have my car mechanic (who knows some about motorcycles) help me on the weekend test the electrical as suggested by previous posts. i'm a real novice at this, so i'm assuming i have to remove the tank right? I have downloaded the manual from BassCliff's website (thank you). I'll keep you folks posted. Thanks to everyone for your input. I still love my bike! haha.

[BassCliff]

Greetings and Salutations!!

Hi Mr. FreeRadicalz,

There is still not enough information to properly diagnose your bike's condition. I know the igniter can sometimes be thermally intermittent. But it's usually something simpler. You have a 30 year old motorcycle that needs some TLC. You'll have to ensure that the carbs are clean, the intake system has no leaks, the petcock is functioning properly, all of the electrical connections are clean, the charging system is working as it should, etc. You'll find a couple of maintenance lists in your "mega-welcome". All of the tasks are pretty much critical to the proper operation of your motorcycle.

Anyway, let me point you in the right direction, dump a TON of information on you, and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed. I will put you on my prayer list.

Thank you for your indulgence,

BassCliff

[FreeRadicalz]

Thanks for the mega-welcome Mr. BassCliff, it was much appreciated. thanks for the links etc. by looking at some of the resources provided, i realize that my bike needs a lot of work/tlc!

This may sound very selfish of me, but the riding season in my part of the country is pretty short - 5 months or so. i hope that i can figure out this issue quickly so i can do more riding. then park her in my garage and fix her up good over our long winter so the bike will be in awesome running order for the start of the next riding season. but i'm not sure if thats what's best for the bike.

anyways, i will keep you all posted as to this issue. in the meantime, i have a lot of reading to do. thanks again!

[Tim Tom]

Well how'd the trouble shooting go? Any updates as to what the problem is yet?