Starting issue

[purpleflamingskulls]

Hello all, what a great website. I recently bought a 1978 gs750 (I think it's an "L" but it's got custom paint and the title doesn't say) It had been sitting for 5 years but for 400 dollars who can complain. I got new plugs, gas, and battery like they say you should and after driving the neighbors insane with the starter for 5 minutes I got it started. I found that if I let it sit for too long it needed the same starter-burning routine to get it going again. I cleaned the carbs, rebuilt the petcock, replaced the gas line, checked the vacuum line, am pretty sure i've got the carbs synced, and have driven it hundreds of miles without any problems while running. However, the thing still won't start cold until I've drained the battery and run it down the street (very embarrassing on dates). Could this problem be caused by leaks around the airbox, my less-than-perfect air filter, or the little rubber/alluminum connection pieces between the carb bodies? (they looked a little worn) Thanks for any suggestions.
-Don

 

[BassCliff]

Hee Haw Howdy!

Hee Haw Howdy!

Hi Mr. purpleflamingskulls,

Have you adjusted the valves? It is typical of the 8 valve motors to be hard starting cold when the clearances get tight. Here's your mega-welcome! :dancing:

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)

Click here to visit BikeCliff's website.

 

[GQROD]

Check and adjust your choke cable as well as your valves.

Hope this helps.

 

[purpleflamingskulls]

I might be an idiot

I might be an idiot

I'm sitting here in the garage with the carbs apart (again) and I see that valve #2 is the one with the vacuum port that goes to the petcock. I had it on #3. This will solve many problems, no? Also, I got cone air filters to replace my airbox and now I see the air hose that comes off the top of the motor and I wonder if I need to get a filter for this or if the cones won't work. Please advise.
Thanks,
Don

 

[BassCliff]

You are NOT an idiot

You are NOT an idiot

Hi Mr. purpleflamingskulls,

By "the air hose that comes off the top of the motor", I think you mean the breather hose. This, on a stock system, gets connected to the airbox. With pods ("cone filters") you will need to install a breather filter (another little "cone filter"). Just use a short piece of breather hose to connect the breather to the filter. Something similar to this:

<<The picture is click-able. This is a 1/2" model. You may need a 3/8". Denniskirk.com and others also sell breather filters.

Yes, the vacuum port from carb #2 supplies the vacuum to the petcock. Other ports between 1 and 2, and between 3 and 4, are for carb vent hoses. Click here for some carburetor port and hose locations.

Why don't you visit my website, find a manual to download, and look at all of the information there? A lot of it will help you get familiar with your motorcycle. Read up and be prepared. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[SqDancerLynn1]

On the VM carbs used thru 79 the petcock vacuum line goes to the #3 carb !!! 80 up uses the CV carbs vacuum port is on the #2 carb

 

[Steve]

Just remember that, regardless of year, the carbs are numbered from left to right.

That is, from clutch hand to throttle hand.

All references to left/right, up/down, front/back are done as if you are sitting on the bike.

.