1982 GS850 backfires and has no power

[Michaelgratz]

Freshly cleaned the carb on my GS850, it now idles without the choke. However, when I rev it and the RPMs come back down, it backfires real bad out the exhaust. When the bike is turned off, smoke sometimes comes out the intake boot between the boot and the engine metal. Also, when it?s in gear on the center stand, the wheel does spin, but when on the ground it has lower power and won?t move as it wants to die. What could be causing this?? also, it smokes while idling and running in general. There is an exhaust leak and the spark plugs are pretty dark but not wet. Bike also did sit outside for a few years before I bought it.

 

[Redman]

Michael, Welcome to GSR.

smoke from carb boot makes me think the orings in there (up against head) are all hard and shrunk. This will also cause other problems as it sucks IN air there. The boots will probably be hard to remove if never have been replaced, so will be first time in 30 plus years to loosen those screews. Look on cycle oring site for a set of orings and a replacement set of bolts. If the boots are hard, probably should replace those also, the 50 dollar will be worth it.

When you say you cleaned the carbs, do you mean you sprayed carb cleaner into the carbs? Maybe took out jets and sprayed carb cleaner? Seems like what you did made some improvement, so was gunk in carbs (probably from sitting unused for so long). But a better cleaning is complete disassembly, breaking each carb from rack so can dip each one in carb dip for 24 hours, and replacing all orings (again, cycle orings site).

a couple other things to mention:
- be aware that the spark plug caps can go bad or partly bad, and are replaceable. Just pull and unscrew. Should measure 5k ohms.
- 1982 850g: do learn about the hub/spline in the rear wheel. ( not in the rear drive, IN the wheel)

do do post pic of this 850. We need to know if it is the maroon one or the black one before can give any more technical advice.
(joking) (but do like pictures)

 

[Guest]

Freshly cleaned the carb on my GS850, it now idles without the choke. However, when I rev it and the RPMs come back down, it backfires real bad out the exhaust. When the bike is turned off, smoke sometimes comes out the intake boot between the boot and the engine metal. Also, when it’s in gear on the center stand, the wheel does spin, but when on the ground it has lower power and won’t move as it wants to die. What could be causing this?? also, it smokes while idling and running in general. There is an exhaust leak and the spark plugs are pretty dark but not wet. Bike also did sit outside for a few years before I bought it.

Sounds like you have many issues going on. How did you clean your carbs? Did you completely disassembly them and use carb dip or an ultrasonic cleaner? If not then I recommend that it is done properly. The smoke coming out of the intake boot is because you need new orings in there. You can get what you need from cycleorings.com along with the orings for your carbs. Your exhaust back fire may be caused by multiple things from tight exhaust valves, exhaust leaks(maybe holes in the bottom of the pipes) or if the baffle has been removed it may be sucking air back in and igniting unburnt fuel, which since you say the plugs are black might be the problem. That can be caused by many things also, weak coils, too much fuel or not enough air in the fuel/air ratio, which will happen from improper jetting or cleaning. There are air jets in the venturi part of the carb that if not clear will cause it to run rich.

Do you have the stock exhaust and air box and filter? Pics would be nice and info about any mods performed on the bike in the past.

 

[Michaelgratz]

This is the machine. I sprayed carb cleaner, let all the jets and bits soak, and scrubbed it all with a metal brush and made sure everything was nice and clean. In June I am trying to go on a 5,000 mile trip from Minnesota to Colorado and I want to use this bike... is there anyway I can "bandaid" these issues to better determine if it will be able to make it that far? I don't want to invest a ton of time and money just for it to still have issues without end. Everything is stock, but due to the bike sitting out for years before I bought it the airbox was a literal mouse nest and the filter was nonexistant.

 

[Steve]

It won't matter much for this discussion, but in later questions it will be important to note that you have an '82 850GL, not an 850G as mentioned in the first post.

If you want reliable operation, you will need to fully disassemble the carbs and soak the bodies in carb cleaner overnight, then re-assemble with new o-rings. Do NOT waste your money on "rebuild kits". Also soak the brass bits inside the carbs, but NOT the 'choke' plunger or any other parts that have rubber bits. While the carbs are off, order up a set of o-rings for the carbs AND the intake boots from cycleorings.com. Treat yourself, get the stainless bolts for the boots, too. That total expenditure will be less than $25.

Yes, you will need to re-sync the carbs, but that is standard maintenance.

While you are at this, you need to check valve clearances, too.

Last thought: you must travel using the same maps that I do. :-k
From Lakeville to Cortez, CO (far southwest corner) is just under 1300 miles. A round trip would be 2600 miles. That is less than 5000 KILOMETERS, can't imagine the detours that would rack up 5000 MILES. That's OK, though, I did a trip from Los Angeles to central New Mexico, but went through Washington DC on the way. :-\\\

.

 

[Guest]

View attachment 56550 This is the machine. I sprayed carb cleaner, let all the jets and bits soak, and scrubbed it all with a metal brush and made sure everything was nice and clean. In June I am trying to go on a 5,000 mile trip from Minnesota to Colorado and I want to use this bike... is there anyway I can "bandaid" these issues to better determine if it will be able to make it that far? I don't want to invest a ton of time and money just for it to still have issues without end. Everything is stock, but due to the bike sitting out for years before I bought it the airbox was a literal mouse nest and the filter was nonexistant.

What you describe is not carb cleaning, that is making them look better, but the good news is you have 8 months to fix everything and that's plenty of time, but I wouldn't procrastinate. You want it up and running long before then so you can put some miles on it to make sure an gremlins aren't hiding somewhere and you want to get familiar riding the bike while it's not loaded down and I'd load it down with everything you intend on taking with you and make some short trips in case you do have issues. Thoroughly clean the carbs, adjust the valves, replace rubber parts like vacuum lines and brake hoses, clean all the wire connector ends and repair any suspect wires, brake pads, brake fluids and tires. It sounds like a lot and there are more things you should do, like check the charging system and battery health, but the good thin is each of these things can be handled if you read up and follow the tutorials on Bikecliffs web page. Take one at a time and each item can be done in a few hours per item some in just minutes. Set yourself a schedule. Brakes one day, electrical another and so on. It can be done if you are determined or you can fork over $50-100 an hour for a shop to do it.

 

[Redman]

Yes, you have a GL.
side panel will say 850L , but the model that you will see in n parts catalog is 850GL (850GLX if include the year designation). All of which has no relation to the running issues since the engine and carbs and most of the drive train is the same between G and GL.
other observation is your bike is still in stock configuration, including the stock handle bars.
aside from the carb and other running situations, I suggest you take some trips on that bike. Maybe start with 50 miles then 100 then 150 then 200. at some point you may find that something needs to change to be able to ride that stock L any distance. But that is an entirely different conversation. For now let’s get it running right.

dont misunderstand Steve. You can get carb orings and intake boot orings (not the boots themselves) from cycle oring web site ( cycle oring by a fine GSR member doing us all a fine service.)

 

[Michaelgratz]

We are going to be in Colorado for about 2 weeks touring up and down pikes peak, Utah, Arizona, etc. the bike is at my dads so I can only work on it every other weekend... I?ll have to move the bike to the house I live at with my mom but he?s the more mechanically inclined one. I would hate to spend a ton of time on this just for it to have a MAJOR issue wrong with it, so would something like a compression test determine that it?s not an engine failure causing the lack of power?

 

[Big T]

You are trying to short cut the needed work needed to get an old bike that has been sitting.
Many of us have made that mistake and accumulated that knowledge on this site:

http://members.dslextreme.com/users/bikecliff/

Read this first to get an idea of what I'm talking about

https://www.thegsresources.com/_for...Newbie-Mistakes&highlight=top newbie mistakes

as it is based upon people trying to do the least amount of work, leading to the most amount of work

If you bought a 30 year old bike to ride, thinking it would only take a few dollars to get it going, you're mistaken. Your situation will require $500-$1,000 in tires, rubber bits, tools and supplies and other parts. Then, you'll have a bike that will run 50,000 miles.

 

[Michaelgratz]

I read those beginner mistakes and that other link you gave me I have been on before. I bought this bike for $600 and it is in pretty rough shape. I knew it was going to need some money to get working but not that much... on top of that it is cosmetically very rough. The blinker switch housing and the ignition switch housing for example both are completely faded and impossible to read. I do want to learn and restore this bike, but being a teenager still in highschool, I just don't know if I have the money to invest on this.

 

[LAB3]

I read those beginner mistakes and that other link you gave me I have been on before. I bought this bike for $600 and it is in pretty rough shape. I knew it was going to need some money to get working but not that much... on top of that it is cosmetically very rough. The blinker switch housing and the ignition switch housing for example both are completely faded and impossible to read. I do want to learn and restore this bike, but being a teenager still in highschool, I just don't know if I have the money to invest on this.

Here's your choices:

1) Bite the bullet and do everything nessessary to make the bike right like everyone else has suggested. Manuals are downloadable plus you and Dad might be able to make some lasting memories together.

2) Part it out on Craigslist, eBay etc you just might make enough to buy something ready to ride if you carefully word your ads and play your cards right.

3) Sell it as is "Runs but needs work"

 

[Michaelgratz]

I'll really have to think about this. My dad wants me to just sell it and buy a Harley like him and I only see him every other weekend so our time to work on it is very limited.

What would I need to get it running? So far I've gathered that I would need carburator O ring set, tires, intake boot o rings and screws, exhaust, steering head bearing (we figured that one out), brakes and brake hoses, vacuum lines that are hard, sychronozation tool, whatever I need to adjust the valves, whatever goop they use where the valves are kept (its leaking oil there), and a voltage tester to test wires and spark plug wires? Did I miss anything?

 

[LAB3]

Looks like you have a basic list going, that's a good thing! Sounds like you don't have much or any experience with a road bike, an 850 is quite a bit to handle for a newbie. Ask your dad what HE started out with, my guess is it wasn't an HD!
My son who was in his late 20's at the time and had ZERO experience got ticked off when I wouldn't let him take my 920 Virago for a ride, he didn't have any knowledge of how to handle that much weight.

Maybe a smaller bike would be a better choice in your case. Either way, a $600 bike like my GS450 is still going take another $500 or more to get into "road trip" condition. The thing is, winter is coming and you don't have to lay out your cash all at once while doing a rehab on an old bike. Think of what you'll have when you're done and what you'd have if you did nothing and peed away that same amount of money 5 or 10 bucks at a time on things you'll never remember.

 

[Redman]

............
................................so would something like a compression test determine that it’s not an engine failure causing the lack of power?

Yes. CAn get a compression guage for 20some bucks. Or maybe some gear head you know has one you can borrow.

If it was some major catastrophic engine failure, I dont think it would run as much as you say it is without some obvious symptoms (constant backfire, knocking, etcetera)

.................
..........................but being a teenager still in highschool, I just don't know if I have the money to invest on this.

A teenager that got a GS, not a crotch rocket...!
We will help you with your GS.

But then again, getting an old neglected bike; have to assume is going to be some expense.

... .... sell it and buy a Harley.... .... ....

We will help you with your GS.

Even if you had, say, $3000 to spend on a bike, what Harley can you get for that?

I think the good carb cleaning, the orings (and maybe intake boots) will get you a lot of results.

Hum, you can only work on it every other weekend..... how about during the winter, does this include a good indoor heated work area?

.................
..........................but being a teenager still in highschool, I just don't know if I have the money to invest on this.

I suppose that is a point to consider.
If you thought you were gonna get a rideable safe bike for 600 plus a couple hundred.... that would be unlikley.
But could happen, maybe this bike with the carb clean and the o-rings, and then probably tires.

A better condition bike in good running order might be more like a couple thousand, and then still needs something yet also.

So, maybe something like a mo'cykl is not that high on your priority list any time in the next few years. Maybe later when you might have some income.
You do need to be thinking of the next 5 - 10 years, not just what you think would be cool now.

Again: Lots of folks here wanting to help you.
(but dont know of any active GSR members in Min'pls-StPaul area.)

.

 

[Guest]

It's going to depend on what you want to do. I don't think you'll need to spend a grand, it can be done for less than $500. If you want top of the line tires that will allow you to scrape the pegs with no fear, then your going to pay dearly, but if you just want some good all around tires that will give you good miles, they can be had for around $200 if you shop smartly. Find deals online and take that to your local Cyclegear and they will price match even if the have to order them. The orings are fairly cheap and Cycleorings has everything you'll need. Most everything else you'll need can be found on eBay, but stay away from Chinese parts, as the quality of some items are questionable. With your charging system, get a good quality stator if needed and by a used SH775 regulator/rectifier made for the Polaris Razor. You will have to do some custom wiring, but it's not hard and there are plenty of instructions on the web. Don't buy one without the SH775 written on the end, no matter how cheap it is, you can find real used ones from a Razor fro around $50 and even less. This is a part where a used one is ok as they seem to be very durable and last a long time.

Also you should get a voltmeter, they aren't very expensive or don't have to be for what you will need it for, but a compression tester can be borrowed from you local parts store. You never know, they may even have synchronizer or join a couple of other motorcycle forums and maybe there will be someone that lives near you that has some. There is a thing called bench syncing, which is basically adjusting all the carbs so they have exactly the same amount of opening at the butterfly, which in most cases is spot on if the valves have been adjusted correctly and there are no vacuum leaks. I've done many sets of carbs and bench synced them only to find out when I did hook up the gauges, they were almost perfect.

 

[Michaelgratz]

I actually do have a compression test kit, so I will try that just to see if one of the cylinders is bad. I ride a rebel 250 that my dad has and a shadow 600 that my stepdad has, and my dad started on a maxim 550. I have put over a thousand miles between both the bikes which isn't much but isn't nothing either. The O'rings are cheap, I'll just get those. Is there a somewhat cheap way I can patch up the exhaust just to see how it runs with something that isn't leaking? I would obviously get something in one piece when the time comes but I don't want to drop $200 on an exhaust if the bike is still going to run like crap regardless. I do have a heated garage at my dad's to work in, and if it came down to it I could bring it to my mom's but my stepdad is a bit more "shade tree mechanic" than my dad, so I don't really want to work on it with him

 

[Michaelgratz]

okay, I'm biting the bullet and pricing parts for this bike; I could swear this bike had rubber intake boots, yet the cycleorings.com has gaskets for metal intake "boots". do rubber intakes not need them?

 

[Steve]

Your intake boots are actually two pieces bonded together. There is a metal part that actually rests on the cylinder head, then a rubber boot that reaches back to accept the carb. There is a thin veneer of rubber over the metal part, which will give the appearance of being all-rubber. As the boots age, that veneer will tend to flake off, but that's OK, as long as the boot is still bonded to the metal.

The screws that hold the boots to the head seem to be made of aged Cheddar cheese, so be VERY careful removing them. Your best bet will be to use a hand impact driver. Most of them have a removeable head that has a 3/8" square drive. Just use some LONG extensions from your socket set, you can get the handle back, over the battery area, where you can actually hit it with a hammer. Although the heads on the screws are actually JIS, not Phillips, a #3 Phillips bit in the driver will do the job. Just be sure it is fully-seated before smacking it into submission. Just as soon as possible, toss them in the trash can, where they belong.

.