New to me '80 GS750L dead after 80 miles...

[streetlightpoet]

Which is mainly my fault I am guessing for not taking care of some of it's issues before I put on those 80 miles. Here is the rundown so far:
I bought this bike last week as my first motorcycle. With the age and the price I assumed that I would need to put some work into it but was hoping that it would run reliably until later this fall. I have been lurking here for a bit now and trying to learn as much as I can about how these things work in general and especially anything I may need to look out for in mine.
So far on mine I have come up with this: The bike is definitely getting too much air (not a hard revelation considering the airbox is currently pressfit against the misshapen manifold/aircleaner on the carbs.) This is what I was assuming caused my high idle once the bike was warmed up, (whenever you would back off the throttle/pull in the clutch the bike would rev to 2-3k, rode fine when in gear.) That's where I was and was hoping to stay while the weather was warm, however the other night she seemed to die for good.
I noticed on the way home that my throttle seemed to have a dead spot, you would twist from fully closed and get response for a half inch or so then nothing until about 1/4 open. I tested it in all gears and it seemed to be across the board. As soon as I established this was happening I turned onto my street and halfway through the turn the engine shut off. I coasted to a stop on the side of the road and tried to restart it, it would turn but not catch. Tried with choke and it would start, rev, then die. I did this a few times (as I said, still pretty new, wasn't sure I was working the clutch right) until it got to the point that the engine won't even turn. Tried again the next morning figuring it may just need to cool off, still nothing.

[streetlightpoet]

Sorry for such a long post! Anyway, here is where I am at currently:
I know my air situation needs to be fixed, so I'm trying to source a new airbox and potentially aircleaner/carb manifold. I will definitely be replacing all the rubber boots regardless of success finding the boxes.
Question 1)What is the proper method for checking for spark? I would like to go ahead and get this out of the way so I know it is not the main cause of my issue. I pulled two of the plugs and they appeared how they should according to everything I've read and my buddy who is quite a bit more experienced than I with mechanics. I know I need to ground the plug on the engine and try to start it, but do I just do one? Do I need to do all four individually?

Question 2) I've been told by everyone that I talked to that the air issue shouldn't have caused it to die and that I most likely have a clogged carb. From what I gleaned from the previous owner it was about due for a cleaning/overhaul anyway. My potentially stupid question is this: Even if one carb were completely clogged, wouldn't the other 3 hypothetically still be running?

3) Am I on the right track so far to get it running again by trying to fix the obvious airleak and cleaning the carbs? What else should I be keeping an eye out for that might be keeping it from running?

[BassCliff]

Hee Haw Howdy!

Hi Mr. streetlightpoet,

Let's hope you didn't burn a valve, or worse. Here is a bunch of stuff, that perhaps you should have done, in your own mega-welcome!

Dear fellow GS rider,

Let it be known that on this day you are cordially and formally welcomed to the GSR Forum as a Junior Member in good standing with all the rights and privileges thereof. Further let it be known that your good standing can be improved with pictures (not you, your bike)!

Perhaps you've already seen these, but I like to remind all the new members. In addition to the carb rebuild series, I recommend visiting the In The Garage section via the GSR Homepage and check out the Stator Papers. There's also a lot of great information in the Old Q&A section. I have some documentation on my little BikeCliff website to help get you familiar with doing routine maintenance tasks (note that it is 850G-specific but many tasks are common to all GS bikes). Other "user contributed" informational sites include those of Mr. bwringer, Mr. tfb and Mr. robertbarr. And if your bike uses shims for valve adjustments, send an email to Mr. Steve requesting a copy of his Excel spreadsheet that helps you keep track of clearances, shim sizes and other service work.

These are some edited quotes from one of our dear beloved gurus, Mr. bwringer, with ideas on basic needs (depending on initial condition), parts, and accessories.
***********Quoted from Mr. bwringer************
Every GS850 (and most other models) has (or had) a set of well-known issues that MUST be addressed before you have a solid baseline for further troubleshooting. It's a vintage bike, and it's quite common (as in, every single GS850 I have had contact with) that there are multiple problems that have crept up and slowly gotten worse over the years. It's not like a newer vehicle, where there's generally one problem at a time.

These common issues are:

1. Intake O-rings (install NEW OEM or Viton only - common nitrile O-rings will quickly deteriorate from heat)
2. Intake Boots (install NEW -- these cannot be repaired)
3. Valve clearances (more important than most people think)
4. Carb/airbox boots
5. Airbox sealing
6. Air filter sealing
7. Petcock (install a NEW one)
8. On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)
9. On all models, it's fairly common to have problems with the spark plug caps. These are $3 or $4 each, and often worth replacing if you're keeping the stock coils/wires.
10. Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.
***********************************
Carburetor maintenance:

Replace the intake boot o-rings, and possibly the intake boots. Here's the procedure:

http://bwringer.com/gs/intakeorings.html

Here's an overview of what happens with this particular problem:

http://cycleorings.com/intake.html

You'll also want to examine the boots between the carbs and the airbox. There's a good chance these are OK, but check them over.
And finally, if things still aren't exactly right, you'll want to order a set of o-rings for BS carbs from the GS owner's best friend, Robert Barr:

http://cycleorings.com

Once you receive these rare rings of delight, then you'll want to thoroughly clean and rebuild your carburetors. Here are step-by-step instructions that make this simple:

http://thegsresources.com/gs_carbrebuild.htm

***************************************
OEM Parts/Online Fiches:

I would definitely double and triple the recommendations to use Cycle Recycle II and Z1 Enterprises as much as possible. These guys are priceless resources. Z1 tends to have slightly better prices, CRC2 has a wider range of goodies available. If you're near Indy and can bring in an old part to match, CRC2 has a vast inventory of used parts.
http://denniskirk.com - Put in your bike model and see what they have.
http://oldbikebarn.com - seems to be slowly regaining a decent reputation, but it's still caveat emptor. They don't have anything you can't get elsewhere at a better price anyway.
http://www.babbittsonline.com/ - Decent parts prices. Spendy shipping. Don't give you part numbers at all. Useful cross-reference if you obtain a part number elsewhere. Efficient service.
http://bikebandit.com - Fastest. Middlin' prices. Uses their own parts numbering system to obfuscate price comparisons -- can be very confusing for large orders. Cheapest shipping, so total cost usually isn't too bad.
http://flatoutmotorcycles.com - Slow. Cheapest parts prices, crazy shipping costs. Don't expect progress updates or much communication. Real Suzuki part numbers.
http://alpha-sports.com - Exorbitant parts prices. Different type of fiche interface that's quite useful at times, especially with superceded part numbers. Real parts numbers. Shipping cost and speed unknown due to insane, unholy pricing.

Stainless Bolts, Viton o-rings, metric taps, dies, assorted hard-to-find supplies and materials, etc:

http://mcmaster.com - Fast, cheap shipping, good prices. No order minimum, but many items like bolts come in packs of 25 or 50. Excellent resource.
http://motorcycleseatcovers.com - Great quality, perfect fit (on original seat foam), and available for pretty much every bike ever made. Avoid the textured vinyl -- it's perforated.
http://newenough.com - You DO have riding gear, don't you? Great clearances, always outstanding prices and impeccable service.
***************End Quote**********************
Additional parts/info links:

GSR Forum member Mr. duaneage has great used upgraded Honda regulator/rectifiers for our bikes. Send him a PM.
New electrical parts:
http://stores.ebay.com/RMSTATOR or http://www.rmstator.com/

http://www.ricksmotorsportelectrics.com/index.php

http://www.electrosport.com/

For valve cover and breather cover gaskets, I recommend Real Gaskets (reusable silicon):

http://www.realgaskets.com

Carolina Cycle

http://www.carolinacycle.com

Ron Ayers Motorsports

http://www.ronayers.com

MR Cycles

http://www.mrcycles.com

Moto Grid

http://www.motogrid.com

Salvage/Used

http://www.ricepaddymotorcycles.com

http://www.ozpowersports.com/

If all else fails, try this:

http://www.used-motorcycle-parts.org/

Used bike buying checklists:

http://www.amadirectlink.com/roadride/Riderresc/checklist.asp

http://www.clarity.net/~adam/buying-bike.html

Lots of good info/pictures here:

http://www.suzukicycles.org

http://www.cyclechaos.com/wiki/Motorcycle_Wiki

http://www.bikepics.com
Basic motorcycle maintenance/repair:
http://www.dansmc.com/mc_repaircourse.htm
Online Clymer manuals:
http://search.ebscohost.com/ Click on "Small Engine Repair" then "Motorcycles". User=library, password=library. Note: This link may not work if you are on a school campus.

Thanks for joining us. Keep us informed of your progress. There's lots of good folk with good experience here.

Thank you for your indulgence,

BassCliff
(The unofficial GSR greeter)

[almarconi]

You probably have multiple issues with your bike.. none of which can easily be solved until you go through the entire bike and see whats wrong with it. Get yourself a repair manual and start going through each system to make sure everything is in order. I know on my 750L, I had to rebuild the carbs, replace the intake boots, replace the airbox/filterbox because it was missing, replaced rubber hoses, cleaned the gas tank, replaced the petcock, clean/rebuild the brake system, new battery, tires, chain and sprockets, cleaned/replaced burnt electrical connectors, ..etc..etc..etc. This is pretty normal for a bike that has been neglected or sat for a number of years. I know you are in a hurry to ride but it's best to fix your bike so that you have a SAFE and reliable machine.

[slowride]

When replacing your intake boots, don't forget new o-rings. Mr. Robert Barr can help you with those (refer to BassCliff's site for info and address). Be patient and good luck. GSers here will help you get it going!

Ed

[Kbecker3]

I have an '81 750L and if it is anything like the '80 it shouldn't have o-rings in intake boots, the rubber boot just slips over the cast aluminum on the intake.

what i did to remedy my air propblem:

i know when i was going through the wiring on my bike, if i had the air box off it didn't run very well. but as long as nothing is cracked you should be able to seal it. i used foam weather stripping around the lid since the foam that was there originally was gone, and mine had a slight wear mark with a hole in it on the corner of the airbox, so i bought a fiber glass repair kit, and roughed up the surface and it seamed to work great. also make sure to get a stock air filter if you dont have one already. otherwise just make sure the clams are all on and tight and none of the boots are cracked.

[almarconi]

The 1980 GS750L does not use o-rings on the intakes.

[streetlightpoet]

Well so far I have replaced the battery, air filter and oil filter. I will be going to order the parts today to replace all the boots for the carbs and airbox, as well as picking up a new inline fuel filter. Pulling the carbs last night I took a look at the filter and it was clogged with what looked to be a decent sized chunk of Kreme or whatever tank sealant the PO used.
I also need to get ahold of the PO and ask about the jetting because I keep forgetting that it has a Mac exhaust instead of the stock one. Does that affect the jetting on a 4 stroke like it would on a 2 stroke?

[Kbecker3]

weird that it would have something in the fuel filter.... the petcock on mine has a screen inside the tank. so a chunk of something should not have gotten that far.

mine was set up with an inline fuel filter also but the p.o. ran it with slightly longer hose than it needed to be, and i think after riding for a while it warmed up the fuel hose slightly and it would kink slightly. there is supposed to be a spring over the hose to prevent kinking. so when that was happening to me, it would start run for a little and then stall out, the kink would starve it for fuel. so you may want to look that over...

just figured i would start at an easy place to look for problems... as soon as i put the spring over the hose, i haven't had a problem since.

[slowride]

I stand corrected. Thank you.

Ed