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Carb porblems. Upgrade/rebuild options?

Started by E_xz550, July 15, 2014, 10:07:38 PM

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E_xz550

Hey, I'm a new guy here. Thanks for letting me on, I recently purchased an 82 vision for dirt cheap. It seems as though I'm having some carb problems. I can start the bike and it fires right up, but it seems like its intermittently firing on only one cylinder. Most of the time it idles on both. When I go to ride the bike, if I just open up the throttle, the bike only runs on one cylinder and only sometimes does the second cylinder kick in; but if I ease on the throttle and keep it light (instead of just gunning it) the bike runs beautifully, and fires on both cylinders.

I'm attributing this to the carbs. So my question is: would a simple rebuild or re-jet and cleaning of the carbs fix this? Or what carbs can replace the stock ones and provide better performance/stability?

I've done my best to research and understand this, but I personally have had no luck. If anyone could show me in the right direction or give any advice, that would be wonderful.

QBS

We haven't seen much progress on the alternative carb fitment front.  If you haven't given your carbs a thorough cleaning, that would be a good place to start.  Install a fuel filter asap.  Check the YICS for leakage.  Welcome to the group.  Where are you?  Another Vnary may be close by.

E_xz550

Fuel filter has already been installed, and I was planning on doing a clean and sync this weekend with a friend. As far as YICS goes, I've seen picture of the system and what it looks like on the bikes, and I can say for sure that mine doesn't have it haha. One of the previous owners must have taken it off. I'm located in Lincolnton, NC but the bike is in my friends garage right now in Denver, NC.

This is my first bike, so I'm new to the maintenance. What all does cleaning the carbs entail? Just dipping them after removing all the brass fixtures?

E_xz550

So I took apart and cleaned my carbs, the inside was surprisingly clean!! Looked liek a previous owner did a very good job of cleaning. I removed all the brass fixtures I could get, then proceeded to dip the carbs. After they soaked for a while, I sprayed through all the holes and nooks with carb cleaner. I then reassembled the carbs and took a look at the rubber flange pieces that go to the intake opening on the head.

They had cracks in them, so I took a bit of rtv and covered all of them (temporary fix). I put everything back together, then let the carbs fill with fuel and prime, with about 1/3 choke the bike fired up; but like I explained in previous posts, it only runs on one cylinder most of the time. This still occurs, but it's not as bad. There is significantly more throttle response while riding the bike when I dont just completely dump the throttle. I still have yet to synch the carbs (what vacuum ports do I use for that??) and how do I adjust them to sync???

Sorry guys, I'm new and still pretty clueless when it comes to carbs and motorcycles. Any and all advice is welcome!

drtaco

now you know why you got it at good deal :laugh:, just kiddin. I don't know much except what I picked up off here. from what I've read was when one cyl dies out (believe it is the front) check out the rev- limiter (you can search the board for more info on the yellow/black wire). on the rubber flanges do the same , I ordered some from Germany and they were brand new (don't know how old but were never used and felt like just made).
if you didn't want to search just wait these guys are good, they'll post and tell ya where to look or what to do.

fret not

RTV silicone is not fuel resistant, so beware of any future vacuum leaks in your intake boots.  One of the boots is still available from Yamaha for a small fortune, but IS available.  It can be used for the other cylinder too, just cap off the big vacuum fitting.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Rikugun

Quote from: drtaco on July 24, 2014, 10:01:24 PM
if you didn't want to search just wait these guys are good, they'll post and tell ya where to look or what to do.
Although we do appreciate those who make an attempt to educate themselves. Having some mechanical aptitude, tools, and a manual really goes a long way too.  ;)
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

The Prophet of Doom

Quote from: Rikugun on July 25, 2014, 08:40:14 AM
Quote from: drtaco on July 24, 2014, 10:01:24 PM
if you didn't want to search just wait these guys are good, they'll post and tell ya where to look or what to do.
Although we do appreciate those who make an attempt to educate themselves. Having some mechanical aptitude, tools, and a manual really goes a long way too.  ;)
Mechanical aptitude is overrated.  Determination and deep pockets are far more important.  For every dollar less than list price you pay for your bike you will end up paying three for tools and spares :-)

Every question you could possibly ask about this bike is already in the archives, so learn to use search.  That will find you service manuals as well for syncing procedures and a design for a $4 manometer.

There are no replacement carbs for clueless people.  Some have put Weber and other carbs on, but it really is an expert undertaking.  the stock carbs work fine if they are set up correctly.

Kiwi

When i first got my vision it was running on 1 cylinder most of the time.
Search for how to disable the revlimiter.
Basically the rev limiter was kicking in and killing a cylinder, even at idle.
US 82 XZ550 with the flapper Airbox

b_racuda

I am also repairing my carbs and wondering if I am missing a part.  In the picture attached is on the right side a hole where is nothing attached but on the left side there is a screw (behind the idle adjustment). Is this allright or am I missing a part?

Re-Vision

Set screw for a carb sleeve.      BDC

b_racuda

I have now cleaned both carbs,  renewed jets with the Keyster components and tried to adjust them.  I got it started and to idle but when giving more gas it says "booo". So definetely running lean. Started to find any leaks and realized that I don't have seal in the air filter box.

Before the repairing I went to local work shop and asked rhem to adjust the carbs. They phoned me and told that they can't adjust them because they are leaking gas to the bowls and the bike is running rich. The adjustment was done with the dynamometer and the maximium power from the rear wheel was only 43hp. The rear wheel reading gives about 10% less than straight from the engine. Nevertheless I am missing about 15hp at the moment. The dynamometer result are attached. There is curve for hp,  Nm and air/gas ratio.

b_racuda

Just opened my fuel filter when trying to locate the problem. I don't know what that stuff is but no wonder that there wasn't enough gas available in the carbs. 

pullshocks

Look in the fuel pump too.  Varnish can also form there.

Rikugun

#14
I'm not sure I'd characterize that gunk as varnish but a good idea to check the pump. Is the gunk soft or crystalline?

Getting back to your "missing carb part" question, I'm not sure which casting feature you are talking about. I notice the unused idle speed adjusting screw mount on the right carb but I don't think that's what you're talking about.

There should be 2 set screws per carb body for the primary and secondary venturi and one protrudes more than the other. There are several variations on these carbs and the screws are located differently on them. I see the secondary venturi set screw on both carbs. Do both carbs also have somewhere on them a screw securing the primary venturi?
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

b_racuda

#15
The gunk is soft. Have to open the pump later, now my Vision is running again and it is time to drive for a while. I looked at the parts fiche and noticed that I am missing the 11H-14455-00 band which is keeping the air cleaner box top part from the middle. Have to figure out some solution for that. Anyone know where to get diapragm set 5 11H-1490H-00? It was not included in the Keyster set for the fuel pump. Also the accelerator spray tube was attached so tightly that I didn´t get it apart (the one with the ball). Maybe at the winter I try to take the carbs loose again and dip them.

Now after carb works the bike is totally different. Only when the revs are under 4000rpm there is slight hesitation before the bike starts to accelerate. Not sure why, any suggestions?

The missing part is marked with the red arrow in the attachment. This is not the secondary venturi screw, did find them and they are attached. I tried to look from Haynes but it didn´t have that part in it. Maybe it is primary venturi.

Rikugun

Yes, it appears (as Re-Vision stated) you are missing the primary venturi set screw.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

pullshocks

How about "gummy residue " "congealed fuel" or "gremlin snot (mucous)"

b_racuda

Did some studying yesterday from the topic "FREE XZ550 and XZ400 resources" and especially from the document "XZ550RJ Performance Troubleshooting (2)". Somewhere else I did also read that when putting Keyster components in this procedure should be done. So today I adjusted accelerator pump rod, now it is much shorter than before and it did help! Now the Vision starts from low rpm's and there is not any bogging. The bike is so smooth and fun to ride!

All the hard work has now paid off. After changing the stator, regulator, fuse box, some wiring, cams, fittings under carbs, sealing the air box, repairing the YICS, putting new battery and installing Keyster components to carbs now the Vision finally works! I have to also mention that for every new problem which has occurred I have been able to find solution from these websites. Now it is just enjoying the ride 8)

Guerrero

lucky you!I did the same except install keyster,and i guess my YICS was fine,still runs bad.and starts really hard..
Quote from: b_racuda on July 28, 2014, 12:56:16 PM
Did some studying yesterday from the topic "FREE XZ550 and XZ400 resources" and especially from the document "XZ550RJ Performance Troubleshooting (2)". Somewhere else I did also read that when putting Keyster components in this procedure should be done. So today I adjusted accelerator pump rod, now it is much shorter than before and it did help! Now the Vision starts from low rpm's and there is not any bogging. The bike is so smooth and fun to ride!

All the hard work has now paid off. After changing the stator, regulator, fuse box, some wiring, cams, fittings under carbs, sealing the air box, repairing the YICS, putting new battery and installing Keyster components to carbs now the Vision finally works! I have to also mention that for every new problem which has occurred I have been able to find solution from these websites. Now it is just enjoying the ride 8)