Question about 1985 Yamaha XJ 600

1 Answer

Throttle is stuck. Will not open carburetors.

Posted by on

Ad

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 3,567 Answers

I am guessing the bike has been sitting for awhile. If so, chances are the slides are stuck in the throat of the carbs. The "glue" is gas that has evaporated, ( while sitting ), leaving varnish behind. Remove the air filter and then put a screwdriver into the filter side of each carb then gently pry the slide upward. If the slides do not easily lift upward you will need to spray some carb cleaner into the slide area and work the slides until they are free.

The bike has CV carbs. This means atmospheric pressure (or the lack of it really ), is what lifts the slides. You said the throttle is stuck. That is why I started with checking to see that the slides are actually stuck or actually free to move up and down. If the throttle grip opens and closes as any other bike does and the slides are free to move, the problem is that either no vacuum is getting to the rubber diaphragm or the diaphragm is cracked or punctured and thus is loosing the vacuum. Before I loose you in CV carb theory, let me ask you to rate my answer.

The throttle cable is not hooked up to the slides. It is hooked up to the butterfly. Without the engine running , the slides CAN NOT lift upward. When the butterfly valve is closed, very little air is moving in the carb bore. (The engine is getting some air and fuel through the pilot circuit, which we'll describe later.) With very little air flowing, the air in the carb bore and the air in the closed chamber above the diaphragm are at close to the atmospheric pressure of the outside air.

Open the butterfly and several things happen.
1. Air now speeds through and venturi effect (low air pressure) at the point of the slide (variable venturi) is created.

2. The low air pressure at the venturi is transmitted up through the holes in the slide to the closed chamber above the diaphragm. This lowers the air pressure in that chamber.

3. The open air below the diaphragm now wants to rush into that chamber to equalize the pressure, but it can't because there is no passage.

4. So it does the next best thing and tries to PUSH its way in through the underside of the soft diaphragm.

5. The diaphragm can't let the air in, but it is flexible so it gives way and is pushed upward by the outside air pressure.

6. As the diaphragm goes up, it pulls the slide with it, and with the slide, pulls the tapered jet needle upward in the needle jet to provide more fuel.

7. As more air flows, even more fuel is pushed into the air stream, and the engine rpm increases.

Posted on Sep 07, 2010

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Snapper string trimmer throttle starts but will not idle down runs like throttle is open can not get engine to idle or run at low rpms


Perhaps something is stuck in the throttle actuator, or perhaps the carburetor is loose. Check the bolts or screws that hold it on the motor block, but if they are very loose, you probably should replace the gasket(s)!

Apr 19, 2017 | Snapper Garden

1 Answer

Model pp4218 throttle stuck open


I assume you are referring to a pullen pro chain saw. If so, the cable that links from the trigger to the carburetor is stuck. This can happen due to trash and dirt stuck in the trigger area, or the carburetor needs cleaning. Or the cable or wire to the carburetor is bent. See if the connection between the trigger and carb moves freely when not running.

May 02, 2016 | Poulan Pro 42CC 2 Cycle Chainsaw, 18"

1 Answer

Why does homelite chainsaw runs wide open?


if your saying your saw runs full speed as soon as it starts , one of two things is happening :
(1) your low speed carb jet is too far open
(2) your throttle trigger has disconnected or become stuck from your carburetor and now the throttle blade inside carb is full open

Jun 15, 2014 | Homelite Garden

3 Answers

Tiller runs at full throddle and tines continue to turn. Unable to lower throddle. What do I do?


Sounds like the throttle cable is sticking or the carburetor butterfly is sticking.
Squirt some WD-40 into the cable that attaches to the throttle handle and onto the mechanism the cable hooks to at the carburetor. Carefully actuate the throttle and see if the mechanism is moving smoothly. It may need several squirts and some actuation before it become free.

Jun 08, 2014 | Mantis 2-Cycle Tiller

1 Answer

I think the accelerator for vento scooter is stuck and when it shuts off makes a weird noise


You should know it if the accelerator (throttle) is stuck. If the throttle moves freely and the engine responds, it's not stuck. If the engine doesn't respond to input from the throttle it needs to be thoroughly checked from the throttle assembly on the handlebars to the carburetor. A corroded, kinked, or frayed cable can cause the throttle to stick. DO NOT RIDE WITH A STUCK THROTTLE! If it does hang wide open, hit the kill switch immediately and sort the issue out before trying to start the scooter again.

Jan 06, 2014 | Motorcycles

1 Answer

1987 Kawasaki GPX 750 R stalls with the throttle


Hi, Anonymous and the usual suspects are:
1. Idle port, transfer ports, slow air jet clogged.
2. Idle adjusting screw set too low.
3. Air fuel mixture adjustment too lean.
4. Pilot/slow fuel jet clogged.
5. Faulty accelerator pump.
6. Float level too low.
7. Float bowl contaminated old fuel, water, dirt, rust, etc.
8. Carburetor bowl vent line clogged/blocked/pinched.
9. Fuel line to carburetor kinked or pinched.
10. Fuel filter clogged.
11. Intake manifold leak.
12. The gas cap is not venting properly or fuel tank venting system blocked.
13. Vacuum line from intake manifold to petcock broken, cracked, or not attached, carburetor vent line plugged.
14. Needle and seat stuck closed in the float bowl.
15. Multi carburetors not in sync.
16. Faulty fuel pump or internal fuel line has pinholes.
17. Fuel injectors clogged or faulty.
18. Faulty throttle position sensor.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
Ninja starts but dies when open the throttle
Kawasaki dies when choke comes off or throttle increase
Kawasaki Zx600 Gpz Gpx750 Fours Service Repair Manual Download Manuals... $15
OEM Parts for Kawasaki
1989 Kawasaki Ninja 750R Owner Manual

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e


Sep 15, 2013 | 1987 kawasaki GPX 750 R

1 Answer

Rs50 alitalia throttle stuck on full revs


Hi, Anonymous you either have a throttle cable that needs lubrication or it is so contaminated with dirt/rust it needs replacing or your carburetor slide is stuck and needs attention and I am sorry you can't find the first and best tool you ever bought for your Aprilia but despair not for a mere $10 you can download another one. For more information about your issue, please visit the websites below. Good luck and have a nice day.
How to lube your motorcycle throttle and clutch cable the cheap way No...
How to install throttle cable into the old slider carbs
how to clean and rebuild motorcycle carburetor for maximum performance
https://www.tradebit.com/filesharing.php/search/0/2011+aprilia+rs+50+replica

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/gregg_c0ec1df182c7330e




Feb 17, 2013 | 2011 Aprilia RS 50 Replica Alitalia

2 Answers

Throttle stuck wide open


what make model year????? That would help everytime

Jan 08, 2013 | Chevrolet S 10 Cars & Trucks

2 Answers

Model P3314 throttle is stuck


Remove the air cleaner assembly to see the carburetor throttle mechanism and open the handle so that you can access the throttle trigger. There should be either a cable or wire connecting the trigger to the throttle arm on the carburetor. Try moving the trigger and see if it responds at the carburetor. Is the carburetor arm against the idle stop screw, wide open, or some where in between? There should be a spring at the throttle arm that returns the arm to the idle stop if the cable/wire is disconnected. The trigger mechanism may be jammed with sawdust to prevent movement. Hope this helps!

Mar 19, 2010 | Poulan Garden

2 Answers

I have a 1982 Pontiac Trans Am, everything is basically stock on the car besides my K&N filter, magnaflow exhaust, and edelbrock valve covers. It is equipped with a 4 barrel carb. My problem is that...


That carburator most likely has vacuum secondaries, meaning that the secondaries won't open until there is enough vacuum for them to operate, usually mid or full throttle. You can try to operate them by hand to confirm that the shaft isn't stuck.

Mar 17, 2010 | 1998 Pontiac Trans

Not finding what you are looking for?
1985 Yamaha XJ 600 Logo

241 people viewed this question

Ask a Question

Usually answered in minutes!

Top Yamaha Experts

Tom

Level 2 Expert

314 Answers

vince

Level 3 Expert

1216 Answers

Steve Sweetleaf
Steve Sweetleaf

Level 3 Expert

1165 Answers

Are you a Yamaha Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...