Yamaha XS 650H Special II Exhaust Problems?

[IamTheMarcus]

Hello, I recently started my motorcycle was checking to see if the bike was getting warmed up. I touch my Right side pipe, and it's hot enough to burn you pretty bad, but then I touch my Left side pipe and it's cool enough to keep your hand on it. (Keep in mind this was after about 15 minutes of running) The Right side muffler has about a 1/2 inch x 1/2 inch hole in it so I'm not sure if that's allowing more air to flow through it and heat it up faster than the left?

Feel free to help..

 

[retiredgentleman]

The left cylinder is not firing..................could be lack of spark or lack of fuel. Do some detective work.

 

[IamTheMarcus]

The left cylinder is not firing..................could be lack of spark or lack of fuel. Do some detective work.

I just checked the spark from the spark plugs and they seem to be sparking fine, although I have about 1/6 of a tank of my 3.9 gal tank. I will be filling up my tank tomorrow, due to me winterizing my bike since up in Wisconsin it's pretty cold

 

[IamTheMarcus]

Anymore help would be much appreciated, also I have stock exhaust.

 

[peanut]

retiredgentleman has given you the answer albeit rather rudely.

Your left cylinder is not firing . You need fuel, and air in the right mixture ,compression and a spark at the correct time its that simple. One or more of those things is not occurring in your left cylinder. You need to check everything .

If you have a spark at the correct time and the cylinder is not firing then check your plug for fuel. it should be wet with unburnt gas. If it isn't then you have a fuel delivery problem .If it is wet with gas then check the compression

 

[IamTheMarcus]

retiredgentleman has given you the answer albeit rather rudely.

Your left cylinder is not firing . You need fuel, and air in the right mixture ,compression and a spark at the correct time its that simple. One or more of those things is not occurring in your left cylinder. You need to check everything .

If you have a spark at the correct time and the cylinder is not firing then check your plug for fuel. it should be wet with unburnt gas. If it isn't then you have a fuel delivery problem .If it is wet with gas then check the compression

Hm, I'll check into that, and is it bad to run a motorcycle on one cylinder?

 

[nj1639]

Fifty percent of your motor isn't firing. Imagine fifty percent of a V-8 not firing.......
Swap the spark plug leads and see if it swaps firing. Easy to do, takes less than a minute and it's a start to finding the cure.

 

[IamTheMarcus]

Swap the spark plug leads and see if it swaps firing. Easy to do, takes less than a minute and it's a start to finding the cure.

Alright so I swapped wires, putting the left side spark plug connector on to the right side, started up, and still the right side warmed up, and not the left. I'm guessing both leads are intact and working. So I'm not sure what to do next... :/

 

[gggGary]

Have you ridden it? is it making power? Sometimes an idle circuit in one carb will be plugged but the mid and high speed jets are open and flowing gas. There are some simple things you might try to unplug an idle circuit if that's the issue but honestly from what you are saying in your posts, you messing with your carbs might not be a good thing.

 

[650Skull]

These bike will run on 1 cylinder, not very fast but will do it.

This problem should be addressed in the trouble shooting part of your manual. Because you have an electronic ignition the spark plug has to be grounded at all times, when testing for spark.

Tech menu is your friend and the top left search. Do some research and read your manual.

I typed in "one cylinder is not firing" into the top left search and This is what come up

Lots of help on the site but like RG says you have to help yourself as well.

Read, learn, confused, ask

 

[IamTheMarcus]

Have you ridden it? is it making power? Sometimes an idle circuit in one carb will be plugged but the mid and high speed jets are open and flowing gas. There are some simple things you might try to unplug an idle circuit if that's the issue but honestly from what you are saying in your posts, you messing with your carbs might not be a good thing.

It did generate power, until tonight when I tried attempting to ride it out of the driveway, but wouldn't rev over 1800 RPM then killing itself. (Even in neutral) It is pretty low on gas, although refilling it tomorrow.

On the Carbs side of things, I removed them, cleaned them, and put them back on the bike. (They were gummed up so bad the floats wouldn't move an inch.) They are shiny clean at the moment.

I'm not sure where the idle circuit is, and don't know what it looks like, sorry..

 

[retiredgentleman]

It did generate power, until tonight when I tried attempting to ride it out of the driveway, but wouldn't rev over 1800 RPM then killing itself. (Even in neutral) It is pretty low on gas, although refilling it tomorrow.

On the Carbs side of things, I removed them, cleaned them, and put them back on the bike. (They were gummed up so bad the floats wouldn't move an inch.) They are shiny clean at the moment.

I'm not sure where the idle circuit is, and don't know what it looks like, sorry..

You're not going to have success unless you spend time reading up on CV carbs. The "Tech" section has lots of good information on CV carbs. If your bike is stock then you likely have BS34 carbs. Find the "Carb Guide" and read it all.

No need to be sorry just because you are new to these bikes. If you don't know what the idle circuit is, then you have not done a proper inspection and clean of the carbs.
You should not have put the carbs back on the bike so quickly.

I suspect you didn't remove and inspect the pilot jets. Take the carbs off again and set them upside down on the bench. Take the float bowls off, and you should find a rubber plug. Remove the rubber plug and you will see the head of the pilot jet. Find a screw driver that will fit the slot in the pilot jet. You want a screwdriver that is a tight fit in the slot or you may damage the brass slot. Remove the pilot jets and take a close look at the very tiny orifice. On your right carb the orifice is likely clear, but it could be plugged up on the left one. Use some carb cleaner and maybe a very fine wire to probe the orifice. Don't force any wire that is to large as that could enlarge the jet, which is bad.

Read the numbers on the jets so you know what size they are. When you put them back in, only use a small amount of torque.

You also want to locate the mixture screw/pilot screw and find out how many turns they are set at.

Since the carbs are on the bench, this is the time to set the float levels according to the table you read about in the "Carb Guide".

 

[IamTheMarcus]

Thanks for the info, but would doing this fix the left cylinder not firing? Sorry I'm still a bit clueless.

 

[retiredgentleman]

Thanks for the info, but would doing this fix the left cylinder not firing? Sorry I'm still a bit clueless.

There's no guarantees when working on old motorcycles. However, the pilot circuit/idle circuit/low speed circuit is known to cause a lot of problems.

When was the last time your engine ran well, or did you just buy it? What is the history of the engine?

 

[5twins]

As you've discovered, there's more to cleaning carbs than just cleaning the outsides and any areas and parts you can see in the float bowls. You have to clean the internal passageways and jets, the paths the fuel uses to get from the bowl into the main bore of the carb. From your description of how gummed up you found things in your float bowls, I would say a full strip and cleaning is required. That means removing the main and pilot jets, the mix screw and it's associated parts, and last but not least, the needle jet. Many overlook the needle jet and that's a big mistake. It can and does get terribly gummed up. OK, first up is a look at where your main and pilot jets are located .....

Once you remove the main and the washer under it, this is what you'll see. This is the bottom of the needle jet. Tap it up and into the main carb bore to remove it .....

Once removed, this is what they look like. Notice the rows of small holes up and down the sides in the necked down area between the top and bottom bosses. This area is what gets all gummed up .....

When you pull the mix screws, make sure you get all the parts out with them. There's a little spring, flat washer, and an o-ring that goes along with the screw .....

 

[xjwmx]

Regarding the pilot jet, it's not always easy to get it out without making it worse than it was. It's kind of cheating, but after you strip all the rest down and clean it good you might want to just hit the pilot jet in place thoroughly with a carb cleaner straw. It's not the best way to clean that "pilot circuit" but it might be good enough to get that side running. I don't want your first time to involve buying new pilot jets after you've had to figure out some way to hack out the old ones, unnecessarily.

 

[peanut]

I guess you guys have already forgotten that you are talking to a 14 year old Kid

http://www.xs650.com/forum/showthread.php?t=30679&page=2

Marcus doesn't even know how to check that the spark plug has got fuel on it !

or if its getting a correctly timed spark !

He's told you he is clueless and yet without a shred of diagnostic evidence you've got him him stripping his 35 year old twin carbs into little pieces !

I'm beginning to wonder just who is the novice here

 

[xjwmx]

He's too young to get a license. Might as well work on it for a couple of years.

 

[retiredgentleman]

His age does not matter. If he plans to drive one of these old bikes he has to learn how to maintain them. He's on the right web site to learn. The sooner he increases his knowledge the better will be his biking experience.

 

[peanut]

thats all very well but its not him that I am criticising here .

What is the point in telling a complete novice to strip his carbs when neither he or you are able to to establish whether or not there is actually a fuel delivery problem or not ?

Check the basics properly first in order to be able to make a sensible diagnosis before suggesting to complete novices to strip complex components ,possibly needlessly , and maybe making the initial problem 10x worse in the process.