79 GS850 - Shooting for cross country reliability on a college budget

[Lunchbox88]

I bought a 79 GS850 recently for $500 with the goal to take a trip with some friends across the country at the end of the semester. I knew my current single cylinder supermoto wasnt up for the task, so after some research I decided on the GS850 for its brick reliability, decent access to parts, and cheapness. My original budget goal was to get a bike around a $1000, but hopefully with the $500 bike I can keep the whole project under $800.

Current Issues:
-Turn signals need to be rewired
-Two valves with clearances out of spec (gap < .04mm)
-Rear rotor is shot
-Needs new pads all around (Ordered)
-Seat needs new foam and cover, or I need a new seat.

-Fix and seal airbox (It was definitely on fire, and the air filter doesnt seal. Anyone know if I have the wrong filter or just a broken airbox)

-Fix gear indicator

Work completed
-New throttle cables installed, old ones were trashed.
Will someone check my cable routing, Im not sure if I got it right.

-Oil changed with new filter
-Ripped terrible custom turn signal wiring out from PO.
Before

After

-Started tearing apart the gauge cluster to fix the gear indicator

My roommate bought a 81 cb750 the same day I got my bike and its a race to to see who gets street worthy first. With your guys help I believe I have a fighting chance.
Heres the two bikes:

As a reward for reading this lengthy post, heres a video of the bike starting up.
http://s667.photobucket.com/albums/vv39/Lunchbox_reloaded/gs850/?action=view&current=047.mp4

 

[Buffalo Bill]

You got time? I dunno?

You got time? I dunno?

Welcome Lad!
Looks like it needs a lot of detail work. That's the biggest time eater.
Try to not be sucked into a detailed restoration at this point, but make sure you do reliable electrical repairs.
Yes, the seals on the airbox need to be done, weather strip foam. That filter looks correct to me.
For that seat, you can buy some excellent cover fabric from a fabric store at just $15 a yard.
You should be prepared to do a roadside replacement of the stator and rectifier/regulator during your trip. Read up on testing, and replacement. Be sure you got a good ground to the battery.
The fuse box might have to be replaced, check that.
Some gaskets might seep, not a worry.
Bill

 

[Nessism]

You are doing well. Keep going...

Your spark plug wires are misrouted; the cables should exist the coils and do down between the frame rails, not around the outside of the frame rail (the cable appears to have been pinched by the gas tank. Check the photo below...


As far as what should be done, I'd rebuild the carbs properly with new O-rings inside and on the intake boots. The intake boot O-rings are sure to leak if the are originals.

 

[BassCliff]

Hi,

To get your machine safe and reliable again, you must address every item on the maintenance lists in your "mega-welcome", plain and simple. Don't skimp by not doing things like rebuilding brake calipers and replacing tires. Good luck.

Thank you for your indulgence,

BassCliff

 

[850 Combat]

Nice. I agree with your choice of motorcycles. Its hard to beat an 850G on a dollar to capability basis.

Hopefully, you will have a great trip.

 

[Steve]

Your spark plug wires are misrouted; the cables should exist the coils and do down between the frame rails, not around the outside of the frame rail ...

I noticed that, too, as well as the fuel filter. Unless that is a filter made for a gravity-fed fuel system (most filters at the auto parts store are NOT), it might create more problems than it solves.

I also agree, good choice of bikes. (Check the bikes in my sig.)

If you might be interested in a bucket-type seat VERY CHEAP, let me know.

.

 

[850 Combat]

Goodness, that is clean. I would have to wash my hands before I work on that.

You are doing well. Keep going...

Your spark plug wires are misrouted; the cables should exist the coils and do down between the frame rails, not around the outside of the frame rail (the cable appears to have been pinched by the gas tank. Check the photo below...


As far as what should be done, I'd rebuild the carbs properly with new O-rings inside and on the intake boots. The intake boot O-rings are sure to leak if the are originals.

 

[Lunchbox88]

Welcome Lad!
Looks like it needs a lot of detail work. That's the biggest time eater.
Try to not be sucked into a detailed restoration at this point, but make sure you do reliable electrical repairs.
Yes, the seals on the airbox need to be done, weather strip foam. That filter looks correct to me.
For that seat, you can buy some excellent cover fabric from a fabric store at just $15 a yard.
You should be prepared to do a roadside replacement of the stator and rectifier/regulator during your trip. Read up on testing, and replacement. Be sure you got a good ground to the battery.
The fuse box might have to be replaced, check that.
Some gaskets might seep, not a worry.
Bill

The filter looks like the right size, but nothing is holding it to the top and sealing it. Air can just go around it. Thanks for the advice on the stator, I will research them later tonight.

You are doing well. Keep going...

Your spark plug wires are misrouted; the cables should exist the coils and do down between the frame rails, not around the outside of the frame rail (the cable appears to have been pinched by the gas tank. Check the photo below...


As far as what should be done, I'd rebuild the carbs properly with new O-rings inside and on the intake boots. The intake boot O-rings are sure to leak if the are originals.

Thank you, this picture will help alot! I went through the carbs a couple days ago and found a broken pilot fuel screw in one of them(Know where to get one?), but most of the o-rings looked good. I may order replacements anyway.

Hi,

To get your machine safe and reliable again, you must address every item on the maintenance lists in your "mega-welcome", plain and simple. Don't skimp by not doing things like rebuilding brake calipers and replacing tires. Good luck.

Thank you for your indulgence,

BassCliff

Yes thanks you, your site has been awesome. Brakes will be torn apart soon, and the tires are actually fairly new and god condition.

Also thanks 850 Combat and Steve, I believe it will treat me well. Also Steve I will PM you about that seat.

 

[850 Combat]

The filter looks like the right size, but nothing is holding it to the top and sealing it. Air can just go around it.

There is suposed to be a foam seal glued to the face of the metal on the filter housing. Yours has rotted off, which is common. That is one of the places where you put the weather stripping. It helps, too. The bike will run lean without it.

 

[TitanNeil]

Looks like you are making good headway, keep it up and you will have a rock-solid ride.

You mentioned checking the o-rings in the carbs, which is a good idea, but the troublesome ones are not in the carbs but hidden behind the intake rubber/metal flanges that bolt directly to the cylinder head. You would remove the carbs, then unbolt the flanges from the motor to get these out - they sit in a groove machined into the back of the rubber intake. They're about 1 1/2" in diameter. You can order them cheaply on this site and they are a MUST-DO REPAIR, if you do not replace them the bike will never run properly. Due to the engine heat they will have hardened and split years ago, permitting air leaks that will make tuning impossible. I didn't think this was a common problem until I found it on all 3 GS bikes I have - the o-rings fell out in chunks when I removed the intakes. Search this site and buy the rings, they're cheap as dirt and will save you a worlds of headaches.

Have fun on the trip!

 

[TitanNeil]

The airbox should have some grooves on the inside near the top that the filter assembly tucks into as you slide it in. The tab that you hold while pushing it in locks onto a metal tab hanging down from the top of the airbox. Look closely with a flashlight, you should see what I mean, unless the previous owner broke them off or damaged them somehow.

 

[DanTheMan]

All your carb o-ring needs, cheaply, cycleorings.com.

 

[Lunchbox88]

Looks like you are making good headway, keep it up and you will have a rock-solid ride.

You mentioned checking the o-rings in the carbs, which is a good idea, but the troublesome ones are not in the carbs but hidden behind the intake rubber/metal flanges that bolt directly to the cylinder head. You would remove the carbs, then unbolt the flanges from the motor to get these out - they sit in a groove machined into the back of the rubber intake. They're about 1 1/2" in diameter. You can order them cheaply on this site and they are a MUST-DO REPAIR, if you do not replace them the bike will never run properly. Due to the engine heat they will have hardened and split years ago, permitting air leaks that will make tuning impossible. I didn't think this was a common problem until I found it on all 3 GS bikes I have - the o-rings fell out in chunks when I removed the intakes. Search this site and buy the rings, they're cheap as dirt and will save you a worlds of headaches.

Have fun on the trip!

Ok Im going to go ahead and order new carb and new intake o-rings. I know I have the VM carbs but just to double check I need the 32mm intake ones right? Also if anyone know where I can get a pilot fuel screw for the same carbs, the only one I can find is in the Z1 carb rebuild kit.

 

[Nessism]

Please check to make sure the tip of that fuel screw isn't stuck inside the carb body. As for where to get one, that rebuild kit is the only place I know of other than posting in the Parts Wanted forum here.

 

[Lunchbox88]

Please check to make sure the tip of that fuel screw isn't stuck inside the carb body. As for where to get one, that rebuild kit is the only place I know of other than posting in the Parts Wanted forum here.

I will definitely check that out, thanks for the reminder.

Can someone confirm that the orings I need for the intake boots that meet the head are the Viton Intake boot O-ring set, small (32MM) $3.30 from http://cycleorings.com .

Today I removed the cams to get easy access to the shims to check sizes. I know there are less invasive ways but this just gave me access to everything at once so I just did it. My clearances and shim sizes were as follows:
Cylinder 1 2 3 4
Clearance (Exhaust) .06mm .08 .05 .05
Shim size (Exhaust) 2.75mm 2.70mm 2.75mm 2.75mm
Clearance (intake) .05mm <.04mm .04mm <.04mm
Shim size (intake) 2.70mm 2.65mm 2.65mm 2.70mm

As you can see 2 intake clearances are too small for me to measure. So assuming the clearances would be .03 or .02 mm I dont think there exists a shim to get me in the middle of the range like .05mm. Should I just order one step down, so 2.60 for number 2intake and move the 2.65 to number 4intake?
Are clearances near the top of the range ok? Sorry if this is confusing, its the first bike Ive had with shims.

My shim holders...

 

[Steve]

Going to the top of the clearance range is actually preferred by many of us.
Some will actually go just a bit over, to .09 mm.

You now have a copy of the spreadsheet, just enter the info and do what it suggests.

.

 

[SqDancerLynn1]

Take a careful look at the charging system. Even if it is currently working I would install a Honda regulator. The 79GS850 has a 12 pole stator which can be hard to find.
YOU should NOT be turning the motor with the shims removed
I see that you removed the cams

 

[Lunchbox88]

Im looking to replace the seat or find a kit to re-foam and recover it. Does anyone know what models of bikes I could pull a seat from, or have anything laying around. I like the flatter style with a small ridge instead of the bucket style.

Also an update:
-New break pads just came in, so hopefully in a day or two I will find time to go over all of the calipers.
-Checking dealer tomorrow for shims

 

[DanTheMan]

Im looking to replace the seat or find a kit to re-foam and recover it. Does anyone know what models of bikes I could pull a seat from, or have anything laying around. I like the flatter style with a small ridge instead of the bucket style.

Also an update:
-New break pads just came in, so hopefully in a day or two I will find time to go over all of the calipers.
-Checking dealer tomorrow for shims

So, you have a Saddlemen bucket style replacement seat? Your bike is a '79 GS850G? I didn't notice on your frame pictures how the seat mounting was set up. Does it have a side latch/key and hinges or a rear key and hooks at the front? The standard seats are available through e-bay, they show up there and several people will post them in parts section here. You could also post in the Parts Wanted. Looking good so far.

On edit: I see you've got the standard "G" latching and hinge system. Shouldn't be too hard to locate one of those seats.

 

[850 Combat]

1979 -1981 GS850G and GS1000G seats fit your bike.

I'm not sure about your O rings, I have the other type. Per David Barr, it would be the 32mm. I'm sure he knows.