Question about 1980 Yamaha XS 400 Special

1 Answer

I had a hard time starting the 1980 xs 400, one piston is not firing, just dumping out gas smoke into the muffler. Muffler is cold on that one side.

Posted by on

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 1,978 Answers

It sounds like you have a carburetor float that is stuck in the down position flooding the cylinder with gas. Start by removing the carburetors and giving them a thorough cleaning . Closely inspect the sides and tips of the float needles.If they show wear or damage replace them. If you have black plastic floats , test that they float in a cup of gas and do not sink . If the float sinks replace it. Ethanol fuel will saturate black plastic floats over time causing them to sink. Change your plug , it is probably wet fouled from the gas and check the new plug for spark. Also check that your crankcase has not filled with gas during the flooding. That is why you should always turn your gas off when not riding so if a float sticks you do not ruin your oil. If gas has fouled your oil, change your oil.

Posted on Sep 12, 2010

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,
a 6ya expert can help you resolve that 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.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

I have a craftsman model # 316.791020 will not start have replaced with new carburetor new module new spark plug cleaned muffler plenty of fire through plug fresh gas tried small amount of gas in cyl


Remove the muffler and make sure your ring isn't seized to the piston. You should be able to move it feely. If you can't isn't not likely you're going to get it to start. Check compression too. Sometimes there simply isn't enough compression to fire the plug no matter how much spark and how much fuel.

Sep 23, 2014 | Garden

1 Answer

Why does my stihl chainsaw spray gas out muffler and carburator


I had something similar a long time ago with my Stihl chainsaw. I removed the small carbeurator and found that the gas/ carb float was at times sticking in the open position allowing too much gas to flow into the piston cylinder. The spark and compression can theoretically burn so much fuel on each compression stroke of the piston and the residual ie; overflow of gas/oil mixture is forced out the muffler on the exhaust stroke. Keep in mind the engine is a two cycle stroke engine meaning it fires each time the piston compresses and therefore if it is the float sticking open it will seem like a great deal of raw fuel being forced out the muffler. I hope this will give you a starting point to look at. Good luck and hope you don't get discouraged because the Stihl product, especially the chainsaw is one of the finest produced and on the market today.

Aug 02, 2014 | Stihl Garden

1 Answer

Can't get it started after new spark plug (gets spark), new gas, good compression tried starting fluid. Whats the problem?


Quick way to check condition of the engine is to remove the muffler. Also make sure that the spark arrest screen is clean. With muffler off, examine the condition of the piston and cylinder. If the piston looks burned and cylinder is scratched, saw will be hard to start. The cylinder and piston should look very smooth. Secondary test to verify condition of engine is to spray plenty of wd40 in cylinder and around piston, then pull the starter slowly. If you see lots of bubbles as you pull, indicates compression is leaking and will be hard to start. If cylinder/piston are in good condition, use new spark plug and retest.

Oct 18, 2011 | Poulan Wild Thing 2375 18" Gas Chain Saw...

1 Answer

Just wondering if this I need to replace the oil filter on my 1982 yamaha xs 400 with YICS or can i just lean it with kerosene?


Change the filter. Oil under pressure flows through it. This weakens the filter material. Cleaning with kerosene just abuses it more. If the filter tears or bursts after an oil change, you will soon be seing a light smoke coming from the muffler caused by unfiltered oil abraiding the pistons, rings and cylinder walls. Soon it will be heavy smoke and oil fouled spark plugs. Really, filters don't cost THAT much. They are really cheap compaired to a top end job.

Jul 23, 2010 | 1982 Yamaha XS 400 Special

1 Answer

Dual exhaust, one blowing hot one cold


IT SOUNDS LIKE THE CLUTCH SIDE PISTON HAS BLOWN OPEN UP THE HEAD AND CHECK FOR ANY DAMEGE.

Nov 09, 2009 | 1980 Yamaha XS 400 Special

2 Answers

Blue/white smoke from muffler, but when muffler is removed smoke disappears


Obviously it has had oil or similar inside it at one time or another. Have you given it enough running time to burn all that out? How old is lawnmower & was any work done recently to it?

Aug 03, 2009 | Briggs & Stratton Garden

1 Answer

Will not start


Pull muffler and check for carbon in cylinder port and muffler screen. Check piston and cylinder for scratches.

Mar 18, 2009 | Poulan Garden

Not finding what you are looking for?
1980 Yamaha XS 400 Special Logo

305 people viewed this question

Ask a Question

Usually answered in minutes!

Top Yamaha Experts

dhnguyen

Level 2 Expert

281 Answers

Steve Sweetleaf
Steve Sweetleaf

Level 3 Expert

1144 Answers

Tony

Level 3 Expert

2600 Answers

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

Answer questions

Manuals & User Guides

Loading...