Won't idle, cold exhaust pipes

[allanbegg]

I'm working on an '80 (I think) GS850GL for my son, but am learning about this bike as I go. After the bike sat for 18 months, it was taken to a back yard mechanic, for a tune-up. When we got it back, it wouldn't idle. It would only run with a liberal amount of choke. I noticed that the #4 exhaust pipe was not getting as hot as the others. I pulled the spark plug and verified that I had spark, when the plug was grounded out. I decided that it was a fuel issue.

Not knowing what the guy did, I took all 4 carbs off, inspected inside and replaced the air idle screws, since we had a new set. Two screws were seized, when we got it back, indicating that the guy hadn't done anything with them.

Now, I can start it on the choke, but now, exhaust pipes #1 and #4 are cold, and I can not get it to idle. I have all of the air idle screws at 1 1/2 turns out from bottom, as recommended elsewhere on this site.

All jets are stock, I believe. I did a compression check and got 132, 130, 132, and 115. Any suggestions as to what is happening here?

Prior to the 18 month hiatus, the bike ran, but was a little rough. All carbs looked very clean when I took them apart. I did re-clean all passages and orifices including jets just to be sure. All floats looked to be at the correct height.

Also, is there an idle adjustment, other than the air idle screws on this bike?

Sorry for the long post, but am getting very frustrated with this bike. Any suggestions and assistance would be greatly appreciated.

Thanks, Allan
PS. Great site, by the way. Lot's of info here.

[greg78gs750]

how are the valve clearances? carb orings/intake orings? sounds like your mechaninc didnt really clean them, did you soak them or just spray em out? all this is the usual stuff....

[allanbegg]

Hadn't considered valves yet. Bike was running ok, before sitting for 18 months. I realize that the mechanic didn't do much, which is why I'm working on it. Not sure what you mean by O-Rings. Are these the ones under the rubber boots between carbs and intake? I hadn't pulled those boots off, yet. Was hoping I didn't need to mess with too much. I sprayed the carbs. They were very clean, so didn't feel the need to soak them. No varnish or anything inside, when I took them apart. Thanks for the suggestions. Keep them coming. Allan

[chef1366]

Do this and a valve adjustment and enjoy the bike.
Usually 1&4 cold would mean a bad coil. Double check the spark.

[BassCliff]

Hee Haw Howdy!

Hi Mr. allanbegg,

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)

[allanbegg]

Won't idle, cold exhaust pipes

Well, I'm learning a lot more about this bike than I had initially planned on.

I've done the carb rebuild, per linked instructions. Thanks for all of the info BassCliff. It makes me realize that I am not the first, down this path. I've also replaced the o-rings on the intake boots, since we had them in a gasket set. The old ones looked fine, though. The boots are still real soft, so believe them to be ok.

I'm ready to put the carbs back on the bike, but have one question first. I have all of the air screws set at 1 1/2 turns out from bottom. I have set all of the butterflies, to what I believe to be similar position, when the butterflies are slightly open. I realize that this will be fine tuned, when back on the bike. The part that I'm not sure about is the static position of the butterflies, when the bike is at idle. On this bike, the adjustment on the cable was such, that there was a little bit of slack in the cable. Therefore the butterflies are all closed. Is this correct, or should there be a slight amount of tension on the cable, to hold the butterflies slightly open?

Also, how do I adjust the idle speed, once I have everything back together?


I will be tackling the valve adjustment process, once the carbs are back on, but am trying to think a step or two ahead, as well as focus on the immediate task at hand.

Thanks in advance for helping a newbie.

Allan

[JTsGS650]

You will want to have a few mm of slack in your throttle cable. At the bottom of your carbs between carbs 2 and 3 there should be a largeish screw/knob that you can turn by hand. This is the Idle adjustment screw. After you get the carbs on the bike and get her started, use this screw to set the idle at around 1K RPM after the bike is at operating temperature. Good luck.