My Bike Just Died In the Middle of A Ride

[MadCapsule]

I was on my way home from work last night and my bike started to lose power like it was almost out of fuel. I switched the petcock over to the reserve position, but it continued to slow down and then just died.

I tried starting it again and got nothing. No lights, no sound.

I'm still new to all of this, but my first guess is that the stator or the r/r are at fault. I've read up on how to test the stator, which is great if the bike is still running and you have a multimeter. No joy on either for me at the moment.

The battery is brand new. Even if it was fried, it wouldn't have caused the bike to die while it was still running. I literally just went over all the connections and grounds on the wiring harness last week, which fixed a problem I was having with the headlight and taillight not working. This is why I suspect something in the charging system is amiss.

Any thoughts our input would be appreciated.

[MisterCinders]

If your stator and/or R/R are bad it probably wore down your battery. Check the voltage on the battery and hook it up to a charger to restore its power. Then you should be able to do the Stator Paper tests to find/confirm your charging problem.

Multimeters are pretty cheap. If you are in the city and need help, I have a charger, multimeter and a spare battery.

[mike_of_bbg]

Yes, in all likelihood either you wore down your battery or you blew your main fuse. Is anything working now? Headlamp, tail lights, indicators? You really should have a multitester. Not all of the tests in the stator papers require a running bike. For example, you could do the resistance tests on the stator or the diode tests on the r/r.

First check the main fuse. If it's blown that's probably because your charging system is shot and the bike is drawing too much current from the battery.

Is yours a sealed battery? Does it have the correct level of water? Most parts places will charge and test batteries for free. Just make sure they don't charge it at more than 2A (most parts folks know about that with MC batts anyway).

[BassCliff]

Hi,

Have you done any maintenance to your bike? Cleaned the carbs? Adjusted the valves? Sealed the air intake system? Tested the charging system? Is there rust in the tank? Do you use a fuel filter? Have you tested the petcock?

There are passive tests you can do on the stator and r/r (without the engine running). They won't tell you that you positively have a good part, but they might definitely tell you that you've got a bad part. Make sure you have a good, fully charged battery. It can be load-tested at an auto shop or parts store.

Let's assume that it is the charging system. Make sure you have a good battery and see if it will start. If so, test the charging system. We'll go from there. Keep us informed.


Thank you for your indulgence,

BassCliff

[MisterCinders]

I doubt he blew the fuse, since his power loss was gradual. The older GS750 has no "main fuse" -- it has a lone fuse. heh If he blew the fuse, the entire bike would go from running to dead immediately - don't ask how I know. :-(

It might have blown at the end or in the aftermath. He should double check it when the battery is charged, but my money is on battery run-down.

[MadCapsule]

If your stator and/or R/R are bad it probably wore down your battery. Check the voltage on the battery and hook it up to a charger to restore its power. Then you should be able to do the Stator Paper tests to find/confirm your charging problem.

Multimeters are pretty cheap. If you are in the city and need help, I have a charger, multimeter and a spare battery.

Yeah, I'm in Pilsen. I have a trickle charger that I'm going to throw the battery on in a minute here. Assistance with a multimeter and spare battery for testing would be greatly appreciated!

Shoot me a pm and we'll see what we can work out.

[MadCapsule]

Yes, in all likelihood either you wore down your battery or you blew your main fuse. Is anything working now? Headlamp, tail lights, indicators? You really should have a multitester. Not all of the tests in the stator papers require a running bike. For example, you could do the resistance tests on the stator or the diode tests on the r/r.

First check the main fuse. If it's blown that's probably because your charging system is shot and the bike is drawing too much current from the battery.

Is yours a sealed battery? Does it have the correct level of water? Most parts places will charge and test batteries for free. Just make sure they don't charge it at more than 2A (most parts folks know about that with MC batts anyway).

Nothing is working now. I'll have to pick up a multimeter with my next paycheck.

The battery is the type that came with a separate bottle of acid that needed to be poured over the plates through several little holes. The water level is currently correct.

Hi,

Have you done any maintenance to your bike? Cleaned the carbs? Adjusted the valves? Sealed the air intake system? Tested the charging system? Is there rust in the tank? Do you use a fuel filter? Have you tested the petcock?

There are passive tests you can do on the stator and r/r (without the engine running). They won't tell you that you positively have a good part, but they might definitely tell you that you've got a bad part. Make sure you have a good, fully charged battery. It can be load-tested at an auto shop or parts store.

Let's assume that it is the charging system. Make sure you have a good battery and see if it will start. If so, test the charging system. We'll go from there. Keep us informed.


Thank you for your indulgence,

BassCliff

I've had to tackle one thing at a time. Sealing up the intake system, cleaning the carbs and checking the valves are likely next.

There's no rust in the tank, no fuel filter and the petcock seems to flow freely in all positions. By this I mean it only flows when vacuum is applied in the "on" and "Res" positions and constantly when in the "pri" position.

I've got the battery hooked up to a Battery Tender Jr. right now and the light is indicating that it's charging. That would seem to imply that the battery was being drained. It seems strange that I didn't notice any sluggish starts or dimming lights though.

[Guest]

Check all your connections for corrosion or signs of overheating. These systems commonly produce too much voltage and boil the battery dry and in the process fry the stator. If your battery has normal levels it may be a connection issue burnt wires, bad fuse block, bad grounds or corroded switch contacts. General maintenance of all connections cleaning or replacement of overheated connections and coating them all with dielectric grease can eliminate a boat load of problems that have or are waiting to happen. It makes trouble shooting a lot easier

[MadCapsule]

Quick update.

The battery took about 14 hours on the Battery Tender to fully charge. I checked the fuse when I went to reinstall the battery and it was blown.

The previous owner left a spare fuse in the Vetter fairing that is identical to the one that was installed. I guess the first thing to verify is that these are the correct fuses to begin with. The package reads "AGC 25" and the end cap on the fuse itself reads "25A, 32V, 311". Does that sound like the correct fuse? I want to make sure before I potentially waste my time on another incorrect fuse.

Also, what should I be looking for as the cause of the blown fuse?

[TheCafeKid]

I seem to remember it only being a 15 amp fuse. A 25 probably wouldn't make much difference other than it protecting a severe problem that would have tripped a 15 maybe but if that were the case a 25 would prolly blow as well.
Your regulator may be faulty or your stator or both. Problem you'll run into here if the stator is bad is that as far as I have been able to tell, no one makes a replacement for the old 12 pole stators. Which means you'd have to change to an 18 pole which would also mean you'd have to get the charging rotor from an 80-81 850. Or maybe have someone re-wind your 12 pole. Or find a good used one.

Another thig to check. The holders for that silly glass fuse are prone to weakening and making an intermitant connection. I chased an intermitant open on one of these 77 750s for a few days until I figured that out. I then cut that crappy little buggar out, and replaced it with a blade style fuse holder and fuse. Even if it's not an issue, I'd suggest doing it for the future.

[SqDancerLynn1]

I have my reg hooked to a 20A fuse The main is 15A but you don't want it to blow the reg fuse if it is using 15 amps with the main fuse, Just a little reserve

[MadCapsule]

I seem to remember it only being a 15 amp fuse. A 25 probably wouldn't make much difference other than it protecting a severe problem that would have tripped a 15 maybe but if that were the case a 25 would prolly blow as well.
Your regulator may be faulty or your stator or both. Problem you'll run into here if the stator is bad is that as far as I have been able to tell, no one makes a replacement for the old 12 pole stators. Which means you'd have to change to an 18 pole which would also mean you'd have to get the charging rotor from an 80-81 850. Or maybe have someone re-wind your 12 pole. Or find a good used one.

Another thig to check. The holders for that silly glass fuse are prone to weakening and making an intermitant connection. I chased an intermitant open on one of these 77 750s for a few days until I figured that out. I then cut that crappy little buggar out, and replaced it with a blade style fuse holder and fuse. Even if it's not an issue, I'd suggest doing it for the future.

You had me worried about the stator, but the Electrosport piece appears to be a 12-pole, drop-in unit.

http://www.electrosport.com/street-bikes/suzuki/gs750-8-valve-models-76-80/stator-12-pole-suzuki-gs550750850-76-on.html

The price doesn't seem too bad either.

I have my reg hooked to a 20A fuse The main is 15A but you don't want it to blow the reg fuse if it is using 15 amps with the main fuse, Just a little reserve

I just have the one fuse for now. I'll have to see about possibly installing a fuse box for multiple fuses, since it sounds like I should be switching to blade style fuses anyway.

This makes me wonder if the previous owner was using the 25A fuse as a band-aid solution for a pre-existing problem. The spare fuse I found was in a package that held five and it was the only one left.

I've downloaded the pdf of duaneage's tutorial on how to modify a Honda r/r, but it doesn't mention which model bike(s) he was using for the donor r/r's. Does anyone happen to know which ones he was using?

[BassCliff]

Hi,

I've downloaded the pdf of duaneage's tutorial on how to modify a Honda r/r, but it doesn't mention which model bike(s) he was using for the donor r/r's. Does anyone happen to know which ones he was using?

There's a list on my little website. Look on the Electrical Odds and Ends page.


Thank you for your indulgence,

BassCliff

[MadCapsule]

Hi,



There's a list on my little website. Look on the Electrical Odds and Ends page.


Thank you for your indulgence,

BassCliff

Found it.

Thanks, Cliff.

[MadCapsule]

Another update.

I replaced the fuse and I've been riding the bike for the last few days and it hasn't died. I also have a blade-type fuse holder and fuse that I had planned on installing today, if not for the rain (I don't have a garage). I took the battery out today and put it back on the battery tender. It was fully charged in about an hour. I'm not sure if that indicates that the battery has been draining again or if that is a normal discharge rate after sitting overnight.

I have a Honda r/r on the way from eBay.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=290525697832&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_1730wt_1165

I'm debating on whether or not I should just buy one of the Electrosport stators for the peace of mind.