My 81 GS750 won't start!!

[Alex M]

I just bought a 1981 GS 750 with 27k miles on it and I love it!

I rode it home (over an hour trip) and got it home and it wouldn't start the next day. It will turn over weakly but will not start. I got it to start after jumping it with my Jeep Cherokee but after idling for a while it died...

I like to do things myself, but I'm afraid I'm not much of an experienced mechanic. Any ideas? Any help is much appreciated!!

Thanks,
Alex

 

[SP-GS1000GL]

Hi there

Get yourself a multimeter, make sure you have a fully charged good battery and start working your way through "the stator papers"

http://www.thegsresources.com/gs_garage.htm

Steve P

 

[twr1776]

Welcome, I am sure Basscliff will be along shortly to give you the official welcome. His website contains most things that you will need to do to for a reliable bike. As far as the non starting goes there are a number of issues that could be involved. First thing is do is not jumpstart it from a running car, the larger cars charging system can fry many parts of your bikes electrical system. Since it is a new to you bike your best bet is to first verify your battery is in good condition, check and clean ALL of your electrical connections especially the grounds, and then do the stator papers to check your charging systems output. A lot of the wiring issues on these bikes are due to corroded connectors and bad grounds, I would not spend any money on new stator, R/R etc, until you do the tests. Good Luck, enjoy the bike.

 

[almarconi]

I got it to start after jumping it with my Jeep Cherokee but after idling for a while it died

It could be a dead battery but if you jump started it with your truck running you may have cooked your electrical system. The safe way to jump start a motorcycle is to use a car battery with the car turned OFF.

Check you fuses. What is the voltage reading on your battery. The charging system on your bike may not be working (you were able to ride home but the battery wasn't be charged).

I would check your fuses. Check the battery voltage, charge your battery if it is low. You can hook the car battery up to the bike with the car off..are you getting any power to the lights..etc? Pull a spark plug, ground it to the block and crank the motor. Are you getting a spark?

Check the basics first and report back,

 

[BassCliff]

Greetings and Salutations!

Greetings and Salutations!

Hi Mr. Alex M,

Yes, I'm the unofficial welcome wagon. I'm glad you found us.

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. Thanks for joining us and don't forget, we like pictures. Not you, your bike!

I concur with the suggestion about first checking your charging system using The Stator Papers. Most of the links you will need are on the mega-welcome page. Then check my website for a manual and maintenance tutorials. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[Go Mifune]

Alex is this your first bike? Did you pull the choke open or closed? Did you fiddle with the idle anjustment knob under the gas tank?

 

[Guest]

Do the stator papers. Sounds like a bad battery and/or charging system.

 

[Redman]

Alex,

Welcome to GSR.

Lots of folks here willing to help, and most of them speak from experience (har har). Yes, lots of folks here willing to help, and all that anybody asks of you is maybe to post a picture of the bike, and as you learn a few things about the GS then you can answer questions if someone else asks about that subject.

Good that you found a nice ol' GS, and good that you found the GSR.

Yes, like others said, you are going to want to have a multimeter (volts and ohms) to trouble shoot this situation. Find the stator papers and follow that. It is fairly detailed.
Or just start with: what is battery voltage with engine at idle (or engine off) and what is battery voltage with engine at mid rpms (4000-5000 rpm). That will give you a genral idea if entire charging system is functioning. Then follow stator papers to trouble shoot each componet and connection of the charging system.

Again, welcome to GSR.

Maybe you might mention where in general you are loctated, maybe located nearby to someone else. (If you rode home an hour, I quess nowhere near here.)

Tell us more what you find.

.

 

[81ZUKI75]

I resuscitated my 750 this summer after years of neglect (sorry to say, mine). I was amazed at the difference a NEW and FULLY charged battery made. I'm convinced I could not have taken the next steps in diagnosing problems without it.

Cranking and cranking was required while jumping from a car. With a fresh battery it would fire right up.

 

[twistedwankel]

I just bought a 1981 GS 750 with 27k miles on it and I love it!
I like to do things myself, but I'm afraid I'm not much of an experienced mechanic. Any ideas? Any help is much appreciated!!

Thanks,
Alex

Under the seat = Check the three bullet connectors and look for burned/melted plastic covers. Replace those connectors with spades if you get ACvoltage of 50+VDC @ 3000rpm across each of the three wires two at at time. Notice I said AC no ground 3 phase. Clean all terminals and connectors and grease with electric grease. Put a direct ground from the Rectifier (finned aluminum near fuses) to the battery terminal. Fully charge the battery and figure on replacing about every two year if you do Chinamart. Install a cheap volt meter or indicator to be assured of good charging system. 12.6VDC is a fully charged battery. If you have an open leg on the Stator (generator) you need a new one. A simple replacement while on center stand.

Follow links provided by others a life saver for lack of knowledge with these bikes. Ask two questions for every one repair attempt and you will be okay.

Good luck. My used once low miles 81-750EX has been bullet proof following this group's advice and will probably take it across the whole country this year if the economy, weather and gas are allowing. The charging system, adjust valves (check compression first to see if needed), drain/flush all carb bowls (I installed a gas filter after mishap), and synchronize carbs is all that's needed to have it reliable and fun. I had a local MC mechanic do the valves and synchro carbs for $125 including a new valve cover gasket as I don't have any factory manuals nor did I want to buy any equipment. Some people do these things routinely in their winter months. I live in FL so ride alot year round. That is the best thing for these bikes = never store them. I used to have to do that alot up N and it never seems to be as good as just riding them alot.

If you are lucky someone on this board will live nearby and be glad to help you resolve any issues. Or go on rides to parts unknown to cell phone service with you