I'm a noob

[mhodges]

I have a 79 GS750 that I bought a few months ago. I know that the bike is running rich and fouling plugs and so I think it needs a carb adjustment...the problem is I don't know if I should just synch/adjust the carbs or if I need to look at the jetting first and then synch/adjust the carbs.

When accelerating from a stop I have to open the throttle to get the bike into power range before letting out the clutch or the bike dies (I think due to the richness) and when running in mid range RPM's (~2500-4500) the bike is very jerky (again I think due to the richness)

I am at about 5k feet elevation.

Any suggestions would be appreciated.

[chuckycheese]

It would probably be best to start by taking off the carbs and giving them a good cleaning. If you do that, you'll want to take them completely apart and dip them. Don't cut any corners because, as everyone here will tell you, doing a thorough job is really important.

If your bike is stock, make certain that the jets are the proper size. Also, be sure to replace all of the "O" rings with one of Robert Barr's sets (do a search here on the forum for details).

Once you get them cleaned and back on the bike, I'm guessing you'll be very pleasantly surprised at how well it will run. Good luck and 'fire away' with any questions.

[Larry D]

+1
Clean,clean,clean them carbs and replace the o-rings.

[trippivot]

at 5K elevation you need less gas than every one else, I'd bet a silver dollar!!


air box or not?

4-1 exhaust pipe?

points or electronic ignition?

start with contact point adjustment if so equipped. may not sound right but you might be surprised.

move on to the idle mixture adjustment. lean it out some ride it around the block. check the plugs. if you get to the point where the screw is going to fall out get a smaller set of pilot jets. 1 size down at a time

keep repeating until the plugs show brownness not blackness at idle and very light riding. (0 throttle to less than 1/4 throttle )

next after you get into the"good" range is a moderate riding test to see how it responds to the needle clip setting (1/4 throttle ~ 1/2 throttle)and here is where you make a clip adjustment and ride it moderately and check the plugs clean them and retest over and over. leanning the needle out is done by putting the clip up to a higher groove with the point of the needle pointing down,thick end up

start with the pilot circuit FIRST
move on to the needle
and the last step -the very last I'm saying tune in the main jet. you might not need to change the main jet at all.

get rid of the fluffy black soot and chocolate brown is what you are looking for.

[twr1776]

If you do not have a good idea of the previous history of the bike you might also want to check the petcock filter and the inside of the gas tank to see what you have before putting you freshly cleaned carbs back on. I am sure Basscliff will be along shortly to give you the official welcome. He has lots on info, etc on his welcome.

[BassCliff]

Greetings and Salutations!

Hi Mr. mhodges,

I'm pretty much a noob too. But the folks here are very nice and I've been collecting the wisdom that they share. We'll start with your mega-welcome!

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 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)

Click here to visit BikeCliff's website.