What is this?

[spwalker09]

I need some info, please...'83 GS450L, symptoms are poor cold starting (but will run eventually after some cranking), non functional choke, fuel dripping from airbox vent after long run

On the RH (#2) carb, theres a line coming off of it. I remember someone mentioning about a vacuum line on one of the carbs that should go to the petcock...is this it?

Looks like it was capped off by a PO. From what people have told me, no fuel will flow from the petcock if theres no vacuum on the line, however, fuel flows from the petcock now and the bike runs (just not well when cold, and fuel drips out of the bottom airbox vent after a while). Theres an empty nipple on the petcock, is this where that line is supposed to go?

Next step this afternoon is to do a valve check to see if they are within spec, and the carbs are out, to be cleaned in the next couple of days when its supposed to rain. But since I don't know these bikes that well I want to chase down any more potential problems before putting it back together thinking its fixed when its not

Thanks!

Steve

 

[Dave8338]

Not positive on the 450 but yes, that looks to be the vacuum line for the petcock. A PO may have blocked that off and run it on the PRI position. The fuel from the air box suggests two problems. Stuck or dirty float valves and a petcock that deserves its; place on a shelf in the garrage, as a momento.

Have you cleaned the carbs correctly, yet?
(edit) make sure you soak those carbs and not just blast some spray carb cleaner through them.

You mention the valves are next on the list. This will help greatly with a poor cold starter.

 

[spwalker09]

Nope, I pulled them today because its nice out (the bike sits outside under a cover) but its likely to rain tomorrow, so I'm thinking about cleaning them when its not-so-nice out.

The valve clearance check will be later this afternoon. How will I be able to tell what shims are in it now (i.e. are they labeled or am I going to have to borrow a set of calipers?)

 

[spwalker09]

Not positive on the 450 but yes, that looks to be the vacuum line for the petcock. A PO may have blocked that off and run it on the PRI position.

Which makes me wonder. This is my first bike, so I assumed running it in the "PRI" or "RES" position was how to run it. If the petcock is down in the "OFF" position, and the vaccum line is hooked up, fuel will be pulled through?

Sorry if this sounds ignorant...

 

[BassCliff]

Hi,

What is the other end of that hose connected to?

Click below for more information:

Where Do These Hoses Go?


Thank you for your indulgence,

BassCliff

 

[Dave8338]

PRI position= Prime. Used for priming the bowls after storage or rebuild.
RES position= Reserve. Try not running on that as a 'usual means of practice', you may run out!
RUN position is where you want to be. The vacuum pulls the petcock open and allows fuel to flow.

OFF??? If you have a vacuum petcock, off is in the run position with the bike not running.

Have a look: http://www.bikebandit.com/1983-suzuki-motorcycle-gs450ld-fuel-cock/o/m6035sch238731

 

[Richsuz]

Hikacking a little. Is this the same hose one would suck seafoam with?

 

[Dave8338]

Hikacking a little. Is this the same hose one would suck seafoam with?

Yes BUT...If you're running Seafoam through a bike and you use THAT hose, you're only going to effect 1 carb (and very little at that as it is a straight vaccuum and does nothing for the jets, needle, float valve, ect).
Better to run it in the fuel, that is really where it should go.

 

[Larry D]

Hikacking a little. Is this the same hose one would suck seafoam with?

Huh ??

Just put a splash into the tank........

 

[Richsuz]

Thanks guys. I used the Seafoam in the Gas tank, and it did wonders. Then I put it in the Crank case and I could also tell a difference in the smoothness and clutch engagement. The vaccum port (as sugested by Seafoam was the only place I hadn't used it in, as per can instructions. So I will use the last third on subsequent gas tanks...And yes I ran the SF in the crank for less than 50 miles, empty the oil overnight and replanished with fresh stuff.

 

[Steve]

Huh ??

Just put a splash into the tank........

Depending on what you are trying to accomplish with the Seafoam, "a splash" might actually be half the can.

.

 

[Dave8338]

Depending on what you are trying to accomplish with the Seafoam, "a splash" might actually be half the can.

.

Yep...what he said! :-\\\

 

[Larry D]

I never heard of sucking it up through the vacuum tube.....is that on the can ??

I've never read the can either.......

 

[Richsuz]

I dont have the can nearby, but I either read it on the can, on the website or saw it on a Youtube video. Pretty sure its on the can, on the section to clean oxygen sensors and other bits on that line.

 

[Richsuz]

From the seafoam web page, Gasoline Engine FAQ's

Using Sea Foam through a vacuum line is easy and safe if you remember one thing. Liquids don’t compress and can cause an engine to hydro lock if too much liquid is applied. Always regulate the rate at which Sea Foam goes into the engine. Never insert the vacuum line into the bottle of Sea Foam, always pour Sea Foam slowly into the vacuum line.
It is important to make sure the engine is at operating temperature. Then find a vacuum line that feeds all cylinders, usually the PCV hose or the vacuum brake booster line may feed all cylinders. If you are in doubt as to which vacuum line to use, YOU MUST check with a certified auto technician.
After the correct vacuum line has been located, start engine and disconnect vacuum line. With engine at idle and at operating temperature slowly pour Sea Foam into vacuum line. It is important to control the rate at which Sea Foam goes into the vacuum line. The engine will labor while applying Sea Foam. Pour enough Sea Foam into the vacuum line to make the engine labor at idle, but not enough to stall engine.
After 1/3 to ? can of Sea Foam has been induced into the engine, shut engine off and let sit (hot soak) for about 5 minutes and reconnect vacuum line. After the 5 minute hot soak period, restart engine in a well ventilated area as exhaust may be extreme for a short time. Road test the vehicle immediately after start up, driving aggressively until exhaust looks normal. This usually takes up to 5 miles. It is always better and safer to road test car to clean the gum, varnish and carbon out of the engine.
By doing this you have done an intense carbon cleaning procedure to your engine. This operation is recommended once a year or every 15,000 miles.

 

[spwalker09]

People use Seafoam thru vacuum lines to clean carbon deposits off valves and the combustion chamber. I guess its a more intense way than just adding it to the gas.

But re-hijacking my thread back, I checked my valve clearances this afternoon, and found my exhaust valves to be less than .03mm (the smallest feeler I had) which is below spec - intakes were between .06mm and .07mm.

My next question is: can you remove the shim without the tool? I read Steve's "zip-tie" method, and it looks like it doesn't apply to twins because you can't see the exhaust valve open through the spark plug hole. Is there any other way to get at the shims w/o using the tool?

Thanks!

EDIT: Nevermind, I ordered the tool (couldn't hurt to have one....)

 

[spwalker09]

PRI position= Prime. Used for priming the bowls after storage or rebuild.
RES position= Reserve. Try not running on that as a 'usual means of practice', you may run out!
RUN position is where you want to be. The vacuum pulls the petcock open and allows fuel to flow.

OFF??? If you have a vacuum petcock, off is in the run position with the bike not running.

Have a look: http://www.bikebandit.com/1983-suzuki-motorcycle-gs450ld-fuel-cock/o/m6035sch238731

Yeah I had another look at the bike, and it says ON, not OFF. Oh well, damn kids these days don't listen to anyone (or read, in my case ). I guess that solves the petcock issue...still have to look into the carbs as to why the choke isn't working (or does it require the vacuum line to run properly? )

 

[Steve]

My next question is: can you remove the shim without the tool? I read Steve's "zip-tie" method, and it looks like it doesn't apply to twins because you can't see the exhaust valve open through the spark plug hole. Is there any other way to get at the shims w/o using the tool?

I have never tried it on a twin, but I don't see why it woudn't work. Just point the folded end of the zip-tie toward where the valve would be, then turn the crank to see if the valve captures it. :-k

By the way, it's not my method. I believe credit is given to Mr. Matchless on that one.

.

 

[spwalker09]

I have never tried it on a twin, but I don't see why it woudn't work. Just point the folded end of the zip-tie toward where the valve would be, then turn the crank to see if the valve captures it. :-k

By the way, it's not my method. I believe credit is given to Mr. Matchless on that one.

.

Much appreciated, Steve, but I felt it best due to my inexperience to learn how to do it the right way. I ordered the tool from RevZilla, and should only take a couple days to get here (its supposed to be nasty here tomorrow anyway), once I know what shims I have, I'll go .05mm over, and run down the street to the local shop that has the shims I need. A few other projects (cleaning the carbs, finding a way to get the god-blessed intake boots off) and she should be ready for the road (again...)

 

[Dave8338]

No need for the vacuum line to have the choke work. My guess is that there are plugged passages in the choke circuit, that are giving you the problem. A good soak in the carb tub, will fix that.