GS650 won't run without choke.

[houldsworth1]

I picked up a 1982 GS650L a few weeks back and I am going through the motions of figuring out what needs to be done. The bike has been sitting for a long time and has 75k miles on it.

I finally got around to testing it out today. After charging the battery the bike would start and run without much difficulty. The brakes work, the gears work and it sounds remarkably healthy for such a high mileage bike. So far, so good.

However it will only run and accept throttle if the choke is on (a lot). If I turn the choke off (or even mostly off) then any throttle will actually cause the revs to drop and can kill the engine. Once the revs build up (with the choke on) the bike will pull cleanly and accelerate pretty decently.

I was running with it on Prime but I think that it will work without that so that is probably a red herring.

Any thoughts?

I am planning on taking the carbs off, getting rebuild kits and just cleaning them and putting them all back together again - do you think this will solve the problem?

TIA.

Barry

[duaneage]

I think that is a good start. In addition you must look at the intake boots on the head and see if they are cracked. Take them off (you' enjoy doing that - not) and replace the o rings ( they are about 7 dollars for 4) since they are most certainly bad.

The carbs may be saved with some cleaning without a complete teardown. If your not comfortable with a complete teardown (and need gaskets, orings, and carb dipping solution) you might be able to clean the passages out with spray cleaner and get it running. After you have gotten it running again you can determine if the bike is worth putting more money and time into it.

Bikes can be fast wallet drainers, mine is in pristine condition and I still spent some dinero on her getting the bike in top shape.

[SqDancerLynn1]

ANy type of air leak or trying to run without the air filter will make it run very lean & do as you described

[houldsworth1]

Thanks. I haven't checked the air filter etc. yet. Heck...maybe all it needs is a good clean/replacement of that (wouldn't that be nice!)

Assuming it is not that easy I will probably get carb kits. I know I can get them from here... http://www.siriusconinc.com/carb/parts.asp
or

https://www.partsnmore.com/motorcycle-carb-rebuild-kits.php?make=suzuki&category=carb_kits

The latter one is $12 per carb whereas the first is $17. Anyone have any experience with dealing with these outlets?

Thanks again!

Barry
(off to check out the airbox...)

[houldsworth1]

OK...the bad news is that the air filter looks good - was still in good shape, oily and had even been oiled with proper air filter stuff. So, no simple fix there and it looks like the carbs will have to come off.

Any thoughts on the chances of this sorting itself out if I just get it running and go for a nice long run at high(ish) rpm? Probably not I assume.

The boots (or whatever they are called) that go from the carbs to the engine - are they supposed to be soft? Mine are rock hard. Are these the things that I should be looking at and replacing some sort of o-ring thing?

TIA

Barry

[Billy_Oliver880]

OK...the bad news is that the air filter looks good - was still in good shape, oily and had even been oiled with proper air filter stuff. So, no simple fix there and it looks like the carbs will have to come off.

Any thoughts on the chances of this sorting itself out if I just get it running and go for a nice long run at high(ish) rpm? Probably not I assume.

The boots (or whatever they are called) that go from the carbs to the engine - are they supposed to be soft? Mine are rock hard. Are these the things that I should be looking at and replacing some sort of o-ring thing?

TIA

Barry

Nope....It won't sort itself out. Pull the carbs and dip them. Clean every little hole in the carbs. Replace the orings and gaskets. That is what you have to do. I can't remember but one guy on here sells o-rings and you can get gaskets from www.bikebandit.com.

Carb boots are supposed to be soft and flexible. I think you should clean the carbs and replace the boots.

[LW_Icarus]

Intake boots from head to carbs have to be leak free. alot of older bikes need new ones, I think Ive had to do em on almost all the old bikes Ive bought.

The carbs are most likely plugged up. the pilot (idle) circuit is generally the culprit, and is the smallest passage so is first to plug. get new pilot jets if you have a bike shop nearby. simply spraying carb cleaner through em wont cut it.

don't ride it when it runs lean like that, you will quickly do engine damage. air cooled engines dont like to get overheated at all, and a lean cylinder will run way hot.

Synchronization is critical as well, make sure you do a very good job of bench synching them before putting them back on, and get em vacuum synched as soon as ya can.

when ya get it sorted, you wont be waiting "for the revs to come up"... that bike should run plenty strong.

[Macmatic]

I can't remember but one guy on here sells o-rings and you can get gaskets from www.bikebandit.com.

Carb boots are supposed to be soft and flexible. I think you should clean the carbs and replace the boots.[/quote]

FYI its Robert Barr who sells o-ring kits for the carb internals for both VM and CV carbs.

I sell intake boot o-rings for most of our bikes for $5 a set to GSResources member or $5.95 via ebay. None listed right at the moment but I'll have full listings again later this week.

/\/\ac

[Road_Clam]

Re: GS650 won't run without choke.

I picked up a 1982 GS650L a few weeks back and I am going through the motions of figuring out what needs to be done. The bike has been sitting for a long time and has 75k miles on it.

I finally got around to testing it out today. After charging the battery the bike would start and run without much difficulty. The brakes work, the gears work and it sounds remarkably healthy for such a high mileage bike. So far, so good.

However it will only run and accept throttle if the choke is on (a lot). If I turn the choke off (or even mostly off) then any throttle will actually cause the revs to drop and can kill the engine. Once the revs build up (with the choke on) the bike will pull cleanly and accelerate pretty decently.

I was running with it on Prime but I think that it will work without that so that is probably a red herring.

Any thoughts?

I am planning on taking the carbs off, getting rebuild kits and just cleaning them and putting them all back together again - do you think this will solve the problem?

TIA.

Barry

This is an all to familiar tell tale sign that your pilot jet(s) are plugged. The function of the pilot jets is to allow raw fuel to be passed into the carb venturi for starting and ideling, and drivability up to 1/4 throttle. If your pilots are plugged, no fuel is getting to the engine. Your choke is a manuall means of also adding raw fuel into the carb venturis. So basically your choke is supplying fuel that should be supplied by the pilot jets. Your carbs need to be dissasembled and serviced. Very common issue when older bikes sit. Rust in the fuel tank is the main culprit, as is moisture in the fuel system.

[houldsworth1]

Re: GS650 won't run without choke.

This is an all to familiar tell tale sign that your pilot jet(s) are plugged. The function of the pilot jets is to allow raw fuel to be passed into the carb venturi for starting and ideling, and drivability up to 1/4 throttle. If your pilots are plugged, no fuel is getting to the engine. Your choke is a manuall means of also adding raw fuel into the carb venturis. So basically your choke is supplying fuel that should be supplied by the pilot jets. Your carbs need to be dissasembled and serviced. Very common issue when older bikes sit. Rust in the fuel tank is the main culprit, as is moisture in the fuel system.

Thanks Road Clam.

Sounds like a perfect diagnosis as the bike will run once RPMs have built up and the throttle is open.

One last thought. Before I go pulling the carbs off (which I have done before and usually found to be a major PIA both off and on) is there any way that the pilot jets (and even main jets) can be replaced while on the bike - e.g. pop off the bowls underneath to get to them? I am assuming not since the space is very limited but, who knows, maybe this is my oppotunity to see if could have been a Gynecologist :-)

Barry

[DimitriT]

I agree with Road Clam and I think you need to take the rack off the bike and get the job done properly. You probably do not need the rebuild kits. Save the $50-$60 and just get the o-rings. If you open up the carbs and you find problems (like maybe a gouged out jet of needle valve) then you can get the kit to repair (they ship right away from CRC2) that unit. Having gone through this myself, the key point is to be organized and take your time. If you get stuck don't panic, come back here and ask questions. For instance, you may find that the screws which hold the carbs onto the rack are frozen or stripped. There's a alot of material on this web site on how to deal with that problem and alot more. On my 550L I found that disconnecting the clutch cable and removing the airbox fasteners (two on the top, one on the side) (in addition to the choke and throttle cables) made the job of removing and reinstalling the carbs alot easier. Just take it one step at a time and plan it out.

Here's the list of items I would invest in: the Barr o-ring set, an external "IV" style fuel tank (perhaps borrow one), a can of dip, 2 cans of carb cleaner, a pair of heavy rubber gloves, safety goggles, some ziplock bags (large size and small size), a vacuum synch tool (borrow one if you can), a combination locknut wrench and long neck screwdriver for the vacuum synch adjustment (borrow one if you can, not absolutely needed but makes the job easier), and a depth gauge or a 6" machinist's ruler for measuring the floats. You may also need bowl gaskets and an impact screw driver but wait and see on those.

[houldsworth1]

Thanks. I know you are right but I'm getting lazy in my old age.

One thing - I am assuming that I can keep them all as a block, there should be no reason to seperate them - right?

As for synching - I already have a 4-carb balancer tool and the funky long screwdriver / nut thing as I used to do this on my old GS550 and GS650 from years ago - as I said, I am just getting lazy. Getting the fuel to the bike while doing this was always the hardest part (maybe that is the tank you referred to). I have gotten around this in the past by using some long tubes and locating the tank up high nearby.

I am also guessing that if rust is what usually causes this then I should be adding a fuel filter in line.

TIA

Barry

[Macmatic]

1. One thing - I am assuming that I can keep them all as a block, there should be no reason to seperate them - right?

2. Getting the fuel to the bike while doing this was always the hardest part (maybe that is the tank you referred to). I have gotten around this in the past by using some long tubes and locating the tank up high nearby.

3. I am also guessing that if rust is what usually causes this then I should be adding a fuel filter in line.


Barry

1. If you're planing to "dip" the carbs they will need to come apart, off the racks or gang rails. You also need to remove the throttle plate from each carb and pull out the shaft because they have a rubber or viton seal on each side of the carb body that will get trashed by the dip. I was able to reuse mine and they are not included in the Robert Barr kit.

To get out the throttle plates you'll need a perfectly fitting phillips head screwdriver, take a carb to Sears if you have to. If its isn't just right you'll end up drilling screws and if it is right you'll probably still chew up one or two. I'm sure you can buy them from several carb parts sources.

Replace your intake boot o-rings while you've gone this far! Get them from me or someplace else but as long as you've got the carbs off the bike and are going to the trouble to rebuild the carbs there is no sense in not fixing this common problem at the same time. (4 Viton o-rings, stainless allenhead cap screws, split and flat washers $7.5 mailed in the US)


2. I put a board across the frame above the battery and set the tank there and use a longer vacuum hose, the fuel line reaches.

3. Fuel filters seem to be frowned on as being more trouble than they are worth. I don't know this first hand but I've read it here a few times from people who's advice I've grown to respect. If I was going to run a filter I'd try and get one with high flow and a cleanable screen and then make it a point to clean often during the season. Cleaning it more often than you need to in the garage is still more fun that losing power on the highway and cleaning it there.


/\/\ac

[duaneage]

Not to pile on too much more info but..

Be careful removing the float pins, the two towers that support the float can break off if you hit them. Use sharp, small diagonal cutters to pull the pins out. You can also use a piece of wood to support the tower, and then lightly tap them out. I broke a tower and went through hell repairing it.

I would replace some of the phillips head screws with allen heads because it looks better, easier to work with in the future, they are cheap from hardware stores, and your probably going to damage a few anyway.

the throttle plates might be best left on since the cleaning fluid can get around them. There is a danger of damaging the scews or not getting them quite right on the shafts. Dirt around the plates comes off easy enough.

The real goal is to get the passages inside the carb cleaned.

[Macmatic]

the throttle plates might be best left on since the cleaning fluid can get around them. There is a danger of damaging the scews or not getting them quite right on the shafts. Dirt around the plates comes off easy enough.

The real goal is to get the passages inside the carb cleaned.

The reason I suggested removing the plate was so the shaft could come out. On my CVs at least there were rubber seals on each end of the shaft down inside the shaft/bushing bore in each carb body. AFAIK those will get ruined by the carb dip if left in place.

These seals are kind of C shaped in cross section with the open side facing out.

In my case I reused my old seals but they were kind of perished so I packed around the outside with high temp, high tack silicone grease which should stay in place and stop any future leaks for a fe years at least.


/\/\ac