Oil leak

[asetech]

Just finished my gs 850glt. Bought the bike with the head off. I removed the cylinder replaced cylinder base gasket and orings, replaced valve seals, dipped carbs and replaced o-rings, replaced intake orings, and head gasket. Did oil change then took on test drive. the bike runs great. But after it got warmed up noticed an oil leak dumping all over oil pan and exhaust. Found the oil coming from a hole in the crankcase in front of the shift indicator switch. on the other side of the webbing. Why is this hole there, whats its purpose and what is the source of the leak. Thanks for any input you can give me

[bwringer]

Mystery hole!

Ah, the Mystery Hole. It's been a while since we had a Mystery Hole thread.

Anyway, to fix your leak, simply replace the o-ring on the nose of the starter. Easy-peasy. You can get an exact replacement from any place that has metric o-rings, or order one from Suzuki if you have the time.


Now, I hear you ask... what's a Mystery Hole? BEHOLD!





Basically, it's just a drain hole for the starter cavity. I stuck a piece of blue tubing through the Mystery Hole to illustrate.

There's a void between the case castings -- the Mystery Hole doesn't drain into the interior of the engine. If you're riding in the rain, water can get on top of the engine and into the starter cavity, and it simply drains into the top Mystery Hole and out the bottom Mystery Hole harmlessly.

If oil is coming from your Mystery Hole, it's most likely escaping past the starter. You probably would have already noticed a big leak from the oil pressure switch or cam chain tensioner, but oil from these can also drain into the starter cavity.

[Dave8338]

Nicely done, Brian!! It don't get much better than that, just don't take it out of context...

[asetech]

I knew there was a reosonable explanation. Appretiate your help.

[bwringer]

No problemo! At least you seemed fairly calm about it.

Every once in a while, someone spots the Mystery Hole on their GS and has a very amusing overreaction -- AAAAAUUUGGHH! THERE'S A HUGE HOLE IN MY ENGINE! OMFGWTFBBQ!

[BassCliff]

Greetings and Salutations!

Hi Mr. asetech,

Now that Mr. bwringer has solved your whole mystery hole mystery, feel free to stop by my website and get in on all the 850G lovin' there. Here is 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.

[Larry D]

Mystery holes ?

Oh yeah, I've heard of those.....no wait....uhhmm..... nevermind. That was something completely different.

Great info, Brian !!

[ryonker]

That was great! Thanks Brian. Do all GS's (like my 79 750) have a Mystery Hole ?

BTW, thanks again for the wonderful tutorial on the Cam Chain Tensioner rebuild (gaskets etc). It worked great. Not a drip of oil now.

Rick

[bwringer]

That was great! Thanks Brian. Do all GS's (like my 79 750) have a Mystery Hole ?

Well, you could get down there and look...

But yes, the early 8 valve 750 has an identical Mystery Hole. The GS850 was basically a shaft drive development of this engine.

As far as I know, all GS models have a Mystery Hole -- the starter cavity is covered, but not sealed, so you have to have somewhere for water to go if you ride in the rain or wash the bike. It's probably not good if the starter sits in water, you know.