Getting a GS850 up to speed

[Mr. Brown]

This is going to be an ongoing project, so I figured I'd start one thread for the entire adventure.

As I posted in the "New Guy" forum, I just purchased a '81 Gs850L off of Craigslist. My understanding is that it had not run in 3 weeks. The rectifier needed to be replaced, and I should be off and running.

I got it home, ordered the rectifier, and logged into the GS Resources for the first time. I learned that I should expect the carbs to be funky after a 3 week rest, and that I should definitely do something with the airbox. The boots were next to the carbs, not attached. The bike was dripping oil, and the kickstand is stripped, causing the bike to lean at an extreme angle.

I installed the rectifier, and learned to use the centerstand. I figured she could use an oil change, because I couldn't see the oil level through the window. Turns out she had about 2 quarts too much oil! I drained her out, replaced the filter, and filled her up with 10w40 Motorcycle oil.

After a few hours with a hairdryer, I got the airbox back on the carbs. I've ordered new boots, as the old ones are warped, but I think I've got a decent vacuum into the box. I also swapped out the spark plugs, so I'm starting with a blank slate.

I have a friend with some experience coming over tonight to help me clean the carbs, and examine everything else. In anticipation of his visit, I bought a manual and went through the regular maintanence section. I unscrewed the "oil level" screw and there was about 1 pint too much oil there as well... no wonder she's dripping. And this is after sitting for a month!

After I get my evaluation this afternoon, I'll post more. Any comments or suggestions would be great!

Again, nice to meet all of you, and thanks for your help!

As a Side note... as I was browsing the forums today, I came across someone with a very similar bike to mine... Wait, That IS my bike! Cool, now I can look at all his posts and see what I'm in for...

 

[SqDancerLynn1]

A good possibility some of the excess oil was GAS. Check the petcock operation. It would also be advisable to replace the carb Needle seat O rings

 

[Mr. Brown]

Petcock's fine. I checked that today, as well as tearing down the carbs to check them out. The jets, screens, o-rings and needles look squeaky clean.

Two issues I'm focusing on at the moment.
-The boots from the carbs to the airbox are old, hard, and deformed. They gotta be leaking.
-The cable from the coil to spark plug #2 is bad, causing #2 to miss.

I'll resolve these issues this week, and let you know how it goes.

A good possibility some of the excess oil was GAS. Check the petcock operation. It would also be advisable to replace the carb Needle seat O rings

 

[koolaid_kid]

Sounds like you are on the right track. The rubber needs to be soft and pliable. These bikes are very sensitive to jetting, so everything in the intake path needs to seal very well or it will not run correctly.
Keep up the good work, it will be worth it in the end.

 

[bwringer]

Another rite of passage for 850 owners is to remove the covers at the left and right ends of the airbox and seal them with weatherstripping. You wouldn't think so, but these will leak enough air to make an 850 run way too lean.

After that, the next challenge is to get the correct amount of oil on the foam air filter element. Use only the very lightest spritz of actual air filter oil. Do NOT soak it in engine oil or it will be too restrictive and cause the bike to run rich. If it's already been soaked, wait until no one's looking and wash the foam thoroughly with hot water and dish detergent (don't use solvent on the foam). The faint film of oil left after a good detergent washing is all you need -- dry thoroughly and reinstall.

If the foam crumbles, then you'll want a new air filter -- most people use the blue/green Uni filters, but there are also K&N filters that work well if not over-oiled.

 

[Steve]

As mentioned, you are on the right track, but if you want to start with a really clean slate, check the valves, too. 8-[

Normal clearance is very small, and normal operation makes it decrease, so you don't have a lot of leeway in this issue.


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[Mr. Brown]

Which valves? I feel like I looked at several yesterday....
Sorry, still improving my vocab

Def. have to seal the airbox, and apparently the filter is oversoaked... she's almost dripping ...

Thanks everyone!

As mentioned, you are on the right track, but if you want to start with a really clean slate, check the valves, too. 8-[

Normal clearance is very small, and normal operation makes it decrease, so you don't have a lot of leeway in this issue.


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[bwringer]

Fouling and misfiring on #2 is the classic sign of a bad petcock -- the vacuum diaphragm gets the tiniest invisible pinhole after 20 years or so, then when the bike is running, juuuuuuuuust enough gas makes its way into the vacuum port on #2 to make that cylinder run rich and foul. It will also, over time, allow gas to leak into the engine.

When the problem starts, the amount of gas is so small that there's not really good way to "check" the petcock and verify that this isn't happening. If the petcock appears original or close to it, you'd be best off to simply replace it so you can forget about petcock problems for another 20 years.

The overfilling you described really does sound like there was gas in the oil, too.

 

[bwringer]

As mentioned, you are on the right track, but if you want to start with a really clean slate, check the valves, too. 8-[

Normal clearance is very small, and normal operation makes it decrease, so you don't have a lot of leeway in this issue.


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Yes, definitely check the intake and exhaust valve clearances. The procedure is simple and clearly outlined in any of the three available manuals (Suzuki, Clymer, Haynes). It's also quite common to find that valve clearances have been neglected by previous owners who couldn't figure out why the bike wasn't running well. Most bike shops charge a fortune for this simple service, so a lot of owners simply skipped it instead of learning how to do it themselves.

Manuals:
http://repairmanual.com

Silicone lifetime valve cover and breather cover gaskets:
http://realgaskets.com

Valve shim tool and shims:
http://z1enterprises.com
http://crc2onlinecatalog.com

 

[Mr. Brown]

#2's main problem was that I ripped the cable out of the boot trying to reattach the fuel tank.:shock: What is the best way to solve that issue? Should I replace the whole cable, or can I get a secure connection with the old boot? I have the original coil, so replacing the cable could be difficult.

Are you saying that the fuel will leak out of the petcock and into the vaccum hose? That hose has been replaced, and is currently nowhere near the petcock.

I cleaned out the filter, and I'm awaiting new airbox boots. WalMart was out of weather stripping, so I'll hit Home Depot tomorrow.

At the bottom of my airbox, there's a hole 1in x 4in. A friend told me there's supposed to be a rubber snorkel-looking thing attached there. Obviously, a hole that large is gonna cause a problem. Can I seal it? Should I leave a slit? I can't seem to find "airbox snorkel thing" on any parts lists...

Fouling and misfiring on #2 is the classic sign of a bad petcock -- the vacuum diaphragm gets the tiniest invisible pinhole after 20 years or so, then when the bike is running, juuuuuuuuust enough gas makes its way into the vacuum port on #2 to make that cylinder run rich and foul. It will also, over time, allow gas to leak into the engine.

When the problem starts, the amount of gas is so small that there's not really good way to "check" the petcock and verify that this isn't happening. If the petcock appears original or close to it, you'd be best off to simply replace it so you can forget about petcock problems for another 20 years.

The overfilling you described really does sound like there was gas in the oil, too.

 

[Mr. Brown]

So... an update.
-Weather stripped the box.
-Got some new airbox boots... They are amazing! Who knew rubber could be THAT flexible! Can't wait to pop them in!
-In the meantime, I ran it tonight to see what improvement the airbox sealing made, and pipe #2 was cool. I pulled the plug, and it is the cleanest of the lot! Like it hasn't been running at all... hmmmm.... So I cranked her back up, and wiggled the wires to get a better connection... you can see where this is going...
ZAP!!!:shock:
Yow... Well, I guess that's the issue. I guess that means the boot is cracked? So, I'll head for the Dealership tomorrow, grab a new wire, toss in the new boots, and cross my fingers. [-o<

I'm moving to Orlando at the end of the week, and I would love to get her running before then. I drive across the Bay Bridge twice a day, and would love to take that trip at least once. (It is a 5 mile bridge across the Mobile Delta... a gorgeous view...)

I'd still like to know where I can get a new airbox snorkel. I have some duct tape holding the gap nearly shut, but how shut is too shut?

I figured out what valves ya'll were talkin' about, and plan to get on that after the move.
-=T=-

 

[Nessism]

When you say "air box boot" are you refering to the boots between the carb and the head or on the other side? The head side boots seal to the engine with a large O-ring that very commonly leak. Even if the boots are soft you should pull them off and replace the O-ring.

Regarding the coil, NGK makes spark plug caps that fit our bikes and don't cost a whole lot of money. Z1 Enterprises sells them among other places.

 

[Mr. Brown]

I referring to the boots from the carb to the box. I will order new o-rings and swap those too.

I went to my local Suzuki shop and got some NGK boots. The #2 pipe is still noticeably colder, but the whole bike runs a LOT better due to the sealed airbox/new boots. I was even able to get it to idle with no choke, something that's never happened before. I started to adjust the idle screw, to get it down from 2200rpm to about 1500, when I noticed it start to get really hot, and smoke more than usual.

I haven't tried switching the plugs, to see if I have a wiring issue.

There is a lot of oil build up on the bottom of the engine and the muffler. It smokes when the bike is running, but it's never been that bad until today.

So, either I'm running it too lean (I'm missing the airbox snorkel and guessing as to the size the gap should be. Maybe it's too small?) or I have a leak or blown gasket somewhere.

Still, it's good to have the airbox taken care of. The exhaust doesn't look factory. Most factory ends look like showerheads... a center pipe with 5 or 6 round pipes around it. Mine has a center pipe, and that's it. It's still a 4-2 design. The pipes themselves are pretty clean, but the muffler (the h-shaped thing referred to as the 'body pre-muffler' on bikebandit) is very grimy, and possibly corroded. The front of the engine, above and below the pipes, is pretty oily too. Maybe I have a head gasket problem? Oh god, please....

Any input?

When you say "air box boot" are you refering to the boots between the carb and the head or on the other side? The head side boots seal to the engine with a large O-ring that very commonly leak. Even if the boots are soft you should pull them off and replace the O-ring.

Regarding the coil, NGK makes spark plug caps that fit our bikes and don't cost a whole lot of money. Z1 Enterprises sells them among other places.

 

[Mr. Brown]

I just learned that the O-Rings that were suggested to me earlier can cause this uneven engine performance issue... they are on the way.

As for the dirty engine and muffler, I guess I will clean up the grime and see if it reappears. That should make it easier to trace.

 

[Mr. Brown]

Stuck...

Stuck...

I took a few weeks off the project to move to Central Florida. After two weeks, I figured I should run her for a minute to keep things from clogging up.

I did manage to get in and change the o-rings between the airbox boots and the engine. The old ones looked fine, but I swapped 'em out while I was there.

It looks like the trip in the Uhaul jarred my headlamp, and it won't light up. Other than that, she runs like she usually does. Cranks right up, idles at about 3k with the choke on, dies when I try to wean off the choke.

She'll run for about 5 mins, and then really starts to heat up. Smoke starts to stream from the underside where oil build up is. It'll start to run rough, and finally die.

I can't figure out why it won't run without the choke. I've sealed the airbox ends, replaced the boots from the box to the carbs, cleaned the filter, and swapped the o-rings. I can't believe there's a problem on the air intake side of things. I did notice a small exhaust leak from a cracked weld, but that can't hurt things too badly, can it?

The pipes seemed to be consistently hot, none of the problems I had with #2 before replacing the spark plug boot.

I'd appreciate some suggestions on where to go next. I don't want to have to break down and take her to a shop, but I feel like I'm at a dead end.

Thanks!

 

[frasermanx]

BLOWN Head gasket?

BLOWN Head gasket?

I have similar problem with a 1980 GS850. Starts and runs ok but will not accelerate past 3k rpm under load. I have riden around the block in all gears but it dies when I turn up the throttle. I don't have the airbox on because the tubes are so stiff so I have suspected that it might run lean. I have cleaned the carbs twice quite thoroughly with small wires in the jets etc. Timing is not a problem, all 4 cylinders run well although #2 is only 90 lbs. compression with the others 100 or better.

#2 cylinder does spit back occasionally with flame. Because the front of the engine is oily I was told that these engines are notorious for blowing the head gasket .. but I found that hard to believe ... now I am not sure...

The previous owner GAVE me this bike he was so frustrated so I happy although I am beginning to understand his frustration !!

Any truth to this tale about BLOWN HEAD GASKET with this year engine model ? Later years don't have this problem ....

 

[Killer2600]

I have similar problem with a 1980 GS850. Starts and runs ok but will not accelerate past 3k rpm under load. I have riden around the block in all gears but it dies when I turn up the throttle. I don't have the airbox on because the tubes are so stiff so I have suspected that it might run lean. I have cleaned the carbs twice quite thoroughly with small wires in the jets etc. Timing is not a problem, all 4 cylinders run well although #2 is only 90 lbs. compression with the others 100 or better.

#2 cylinder does spit back occasionally with flame. Because the front of the engine is oily I was told that these engines are notorious for blowing the head gasket .. but I found that hard to believe ... now I am not sure...

The previous owner GAVE me this bike he was so frustrated so I happy although I am beginning to understand his frustration !!

Any truth to this tale about BLOWN HEAD GASKET with this year engine model ? Later years don't have this problem ....

With bikes these old and the fact that they are air cooled and often times left to sit for a long while a blown head gasket is quite possible and although I haven't tried it for myself I've been told by numerous wise men that these bikes won't run well without the airbox and that you need the airbox if you wanna run it above 3k rpm.

Really don't understand your logic regarding the airbox, it may leak and make the engine run lean so you take it off and make the engine run much leaner anyway. The carbs were designed to work in conjunction with the airbox so without it they will run like crap.

 

[49er]

I referring to the boots from the carb to the box. I will order new o-rings and swap those too.

I went to my local Suzuki shop and got some NGK boots. The #2 pipe is still noticeably colder, but the whole bike runs a LOT better due to the sealed airbox/new boots. I was even able to get it to idle with no choke, something that's never happened before. I started to adjust the idle screw, to get it down from 2200rpm to about 1500, when I noticed it start to get really hot, and smoke more than usual.

I haven't tried switching the plugs, to see if I have a wiring issue.

There is a lot of oil build up on the bottom of the engine and the muffler. It smokes when the bike is running, but it's never been that bad until today.

So, either I'm running it too lean (I'm missing the airbox snorkel and guessing as to the size the gap should be. Maybe it's too small?) or I have a leak or blown gasket somewhere.

Still, it's good to have the airbox taken care of. The exhaust doesn't look factory. Most factory ends look like showerheads... a center pipe with 5 or 6 round pipes around it. Mine has a center pipe, and that's it. It's still a 4-2 design. The pipes themselves are pretty clean, but the muffler (the h-shaped thing referred to as the 'body pre-muffler' on bikebandit) is very grimy, and possibly corroded. The front of the engine, above and below the pipes, is pretty oily too. Maybe I have a head gasket problem? Oh god, please....

Any input?

I had a similar problem with my '79 850 before the engine rebuild. I would arrive back from a ride and it would fume around the back of the engine and oil would leak from the cam chain tensioner, and drip from the botom of the airbox. The answer was found to be a completly blocked engine breather track inside the top of the airbox. Rust builds up and closes the breather tract and causes the crankcase and cam cover areas to pressurise. This pressure started oil leaks in all manner of places around the engine.
You can check for a suspected head gasket by doing a compression check on each cylinder.
Check out your airbox breather first.

 

[frasermanx]

tips

tips

Yes thanks for tips. I clean carbs often for other riders... yes I know about the airbox being needed for bike to run properly. Unfortunately I can't get the airbox to stay on since the rubbers are very old and stiff -- kinda like me !!

So I am looking for 2" hose of some kind to use instead to at least get the engine running at past 3k rpm

Great tip about breather on top of cam box !!! I would not be surprised to find I have the same problem....

Actually my BMW is worth more $$$ .. and I might sell it and keep the GS850 since I really need the $$$ ...unless someone in Toronto area wants the bike

call me at 416 994 7oneonezero cell phone

 

[Steve]

runs ok but will not accelerate past 3k rpm under load. ... I don't have the airbox on because the tubes are so stiff so I have suspected that it might run lean. ....

Believe it or not, these bike just flat-out will NOT run without the airbox or pods on the front of the carbs. :shock:

For testing purposes ONLY, you can fold a shop rag in half and drape it over the carb intakes. Use tape or zip-ties to hold it to the two outer carbs. This give is just enough restriction to run decently, but do not do this for jetting checks.


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