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Do I have a vacuum leak? It sure sounds like one but my carb holders are only 3 years old.

The bike starts fine but sounds terrible. Very rough idle. Idled very well last fall. If I spray enough starter fluid on the carb holders it will die.

I am looking for some advice on what my next step should be.

I have done a valve adjustment. I only needed to change one shim (went one size down on an intake side).

I have a stock exhaust system, plugged crossover, it has some leaks but nothing terrible, I switched to pods. Went to #37 idle jets. Needle clip 3rd position. Main jets I am not sure, I used a #62 bit (#96 jet) but after drilling a #61 bit fits (#99 jet). I have not changed the float position since I set it 3 years ago. A clear tube test shows the fuel level below the gasket.

#4 carb leaks intermittently out of the drain nipple. The o ring seat is nicked from my attempt to pick out the old gasket, and damages the o ring as soon as the drain screw is tightened. Shouldn't it leak all the time if this is the cause? I have a hose connected to this nipple routed up above the fuel level to compensate for this in the meantime.

Highest and best idle is achieved with air screws 2 turns out however I have a backfire at that position. Turn the air screws in and the backfire turns into a miss that eventually goes away. However the more the air screws are turned in the idle lowers and becomes worse.

The bike starts without choke and slightly smokes which tells me it is rich. However if I spray starting fluid on the carb holders it will bog down; you can see this in my video. If I keep spraying starting fluid it will die. If I rev the engine it returns to idle slower than normal. This tells me it is lean and the carb holders are leaking air.

I am very confused. Before I replace my 3 year old carb holders I am looking for any advice on what to do next.

Thank you.

They didn't seal properly.
Steve

Those settings would normally be very rich, even with pods.

Have you seen some of the last 4 or 5 Kz550 threads on jetting for pods etc?

By the sound, I would say you have issues other than jetting, maybe issues other than carbs.
It might help to bring up the old thread you had for this project rather than have multiple dissociated threads. There are hundreds of 550 carb threads and it's hard to remember the details from all of them.

Even though a thread may get very long, it helps to keep all of the posts in one thread so we can look back and see what you did with the engine, ignition, exhaust, carbs, which rebuild kits you used to get needles, etc.

Have you done a water test on the exhaust? The link started by Zirfan has a good video showing how to find the non-firing cylinder with the water test.

The_Proletariat wrote: ...
#4 carb leaks intermittently out of the drain nipple. The o ring seat is nicked from my attempt to pick out the old gasket, and damages the o ring as soon as the drain screw is tightened. Shouldn't it leak all the time if this is the cause? I have a hose connected to this nipple routed up above the fuel level to compensate for this in the meantime....

That is a bad idea. If it is a float level issue, that hose (acting as a stand pipe) effectively blocks any overflow escape, and will result in gas pouring into the carb throat. From there it has nowhere to go but in the cylinder or out of the filter.

I've mentioned in multiple threads, but not sure if your old one was one of them, about the dimple on the float tang. That might explain the periodic leak from the carbs.

The scratch on the o-ring surface would depend on which o-ring you are referring to. There are two on the drain screw.

loudhvx wrote: Those settings would normally be very rich, even with pods.
Have you seen some of the last 4 or 5 Kz550 threads on jetting for pods etc?

There are many threads on pods and the early KZ550 carbs. Those carbs do well with pods because they are so simple... mechanical slide, two jets and an air screw.
For a starting point, you will probably want 96 or 98 mains, and stock (32) to 37 pilot jets, but they are not available.

I think he is masking the leanness of the idle jet and needle by going overboard with the main jets.

We're talking about a 550A or 550C, correct? That uses TK-22 carbs.
I would go from 32 idle jet to 37 idle jet. Get adjustable needles and set them to 3rd or 4th clip from the top, and I'd start with 100 or 102 mains.

- Pods with open exhaust

With pods, you will probably want 34 pilots.

Recommends 34

You will likely want:
94, 96, or maybe 98 mains
34 or 37 pilots

pods, stock exhaust

1981 KZ550 LTD
TK-22 Carbs
Pods (i know i know)
dunstall style megaphone dual exhaust (slip on's)
Pilot Jet drilled to 36.8 ((#79 bit)
Main Jet drilled to 96.5 (#62 bit)
Aftermarket Needle (also known as 4D93 The Canadian adjustable needle) at Clip position 3

Lou, I have spent a lot of time going through your threads because they are so informative. Based on other's experiences I did not think I was out of the ballpark on my jetting choices. Perhaps I was wrong, or I misunderstood what I was reading.

By the sound, I would say you have issues other than jetting, maybe issues other than carbs.

What are you thinking?

It might help to bring up the old thread you had for this project rather than have multiple dissociated threads. There are hundreds of 550 carb threads and it's hard to remember the details from all of them.

Even though a thread may get very long, it helps to keep all of the posts in one thread so we can look back and see what you did with the engine, ignition, exhaust, carbs, which rebuild kits you used to get needles, etc.

I apologize. I will do this from now on.

Have you done a water test on the exhaust? The link started by Zirfan has a good video showing how to find the non-firing cylinder with the water test.

I have not. I will look for this video.

The_Proletariat wrote: ...
#4 carb leaks intermittently out of the drain nipple. The o ring seat is nicked from my attempt to pick out the old gasket, and damages the o ring as soon as the drain screw is tightened. Shouldn't it leak all the time if this is the cause? I have a hose connected to this nipple routed up above the fuel level to compensate for this in the meantime....

That is a bad idea. If it is a float level issue, that hose (acting as a stand pipe) effectively blocks any overflow escape, and will result in gas pouring into the carb throat. From there it has nowhere to go but in the cylinder or out of the filter.

I did not think of that.

I've mentioned in multiple threads, but not sure if your old one was one of them, about the dimple on the float tang. That might explain the periodic leak from the carbs.

I will check this.

The scratch on the o-ring surface would depend on which o-ring you are referring to. There are two on the drain screw.

Yes. The tapered seat deep inside the bowl, where the smaller, inner drain screw o ring seats.

There are many ways to jet for a given motor/exhaust/intake setup. The different items that can be changed have some overlap, so there are many combinations that end up working reasonably well.

So if someone wants to overjet the main to compensate for a needle that may be in a leaner setting needle (for instance, if one wants to use the stock needle without shims), they will have a higher number main than someone who wants to shim the needle. Likewise for pilot jet versus needle.

So for a given setup (in your case, pods, slightly modded exhaust), there may be a range of pilot, needle settings, and mains. Possible settings may include a 37 pilot, or needle at third clip, or 99 main, but in my experience, using all of those at the same time would be overly rich for all throttle positions.

The problem with doing jetting before verifying all other aspects of motor/ignition/carbs is that once you drill the jets, you can't go back.

Without going into extreme detail, the order you want to follow is:

Check compression.
Make sure valves are properly adjusted if they are unknown or haven't been adjusted in many miles.
Make sure air-suction-system is not leaking air into exhaust ports.
Check for spark on all four cylinders (done properly so as to not damage ignition).
Check for timing and proper advance.
Check for vac leaks, and fix as necessary.
Check choke plates and flaps.
Check for fuel flow from petcock (and have correct filter type if necessary).
Check fuel level in carbs and make sure they don't leak.
Make sure carbs are at least bench synced, but prefer actual sync.
Make sure full throttle position is set to no further than full-open.

Then as a double check make sure all four cylinders are firing with water test.
Check plugs for any that are different from others.
If these checks fail, then you need to go back through the earlier steps to find out why.

Then start analyzing how it runs, and what jetting may need to be done.

Because, as you can see, there are so many variables to check before we even get to jetting, it would be nice to see that all of those things were addressed in a single project-thread.

The video was very choppy on my old computer so it's hard to say how much was the playback, and how much was the motor stumbling, but it sounded poor enough to say there is likely other issues besides jetting.

I have dealt with so many instances where all sorts of jetting changes were being done on a bike that was only firing on half of its cylinders.

Zirfan's video is probably the best, recent example. Luckily he figured out early that he had a misfire.

Regarding the vac-leak test:
Starter fluid is very reactive, so even if a tiny bit gets into the air filters, there will be a reaction.
You might want to use something slightly less vaporizing, like carb cleaner.
I would avoid anything that leaves a residue of oil etc.
You must use one of those little red hoses that come with the can.
Then try to dribble the cleaner around the mating surfaces of the carb holders to the engine.
That's hard to do with a new can since it will want to spray out like crazy, but you must make sure the cleaner is not getting sucked into the filter area.

loudhvx wrote:
Check compression.
Make sure valves are properly adjusted if they are unknown or haven't been adjusted in many miles.
Make sure air-suction-system is not leaking air into exhaust ports.
Check for spark on all four cylinders (done properly so as to not damage ignition).
Check for timing and proper advance.
Check for vac leaks, and fix as necessary.
Check choke plates and flaps.
Check for fuel flow from petcock (and have correct filter type if necessary).
Check fuel level in carbs and make sure they don't leak.
Make sure carbs are at least bench synced, but prefer actual sync.
Make sure full throttle position is set to no further than full-open.

Then as a double check make sure all four cylinders are firing with water test.
Check plugs for any that are different from others.
If these checks fail, then you need to go back through the earlier steps to find out why.

Then start analyzing how it runs, and what jetting may need to be done.

I can answer some of these inspections.

Have not done compression test. When it is running right, it sounds fantastic and pulls hard. Oil consumption is minimal. Because of this I never felt like I needed to. Will need to acquire compression tester.
I checked the valves earlier this month. I had no symptoms of tight valves, and only checked them because it had been 5000 miles since last check. Only one valve needed adjustment, and it was still in spec. I just wanted it on the loose side of spec.
Air suction system is removed. The snouts on the valve cover are plugged.
Have not checked for spark this year. Had good spark last year. Need to check.
Timing was set with a test light when I installed the Dyna. I marked the timing plate with paint.
I have lubed the timing advancer yearly. It has never been stuck. Is currently free.
Vacuum leaks - believe my carb holders are leaking.
Choke plates are glued shut.
For this test was supplying engine from a portable fuel tank. Bypass petcock.
Fuel level has not been changed. Possible needle valves not aligned with float "dimple".
Carbs were vacuum synced last year. A visual inspection shows slide cutaways to be at very similar heights.
WOT set per your website.

Because, as you can see, there are so many variables to check before we even get to jetting, it would be nice to see that all of those things were addressed in a single project-thread.

I have been scolded on other forums for combining topics into one thread. I apologize if I was rude or caused confusion. I know I am confused constantly.

I have dealt with so many instances where all sorts of jetting changes were being done on a bike that was only firing on half of its cylinders.

It is unscientific, but the engine did respond to each individual air screw change. Leads me to believe all cylinders are firing, but need to perform water test to verify. A misfire does exist. Believe on cylinder 3 or 4, which had the greatest response to the starting fluid.

Regarding the vac-leak test:
Starter fluid is very reactive, so even if a tiny bit gets into the air filters, there will be a reaction.
You might want to use something slightly less vaporizing, like carb cleaner.
I would avoid anything that leaves a residue of oil etc.
You must use one of those little red hoses that come with the can.
Then try to dribble the cleaner around the mating surfaces of the carb holders to the engine.
That's hard to do with a new can since it will want to spray out like crazy, but you must make sure the cleaner is not getting sucked into the filter area.

I did not know these issues with starting fluid. Will recheck with carb cleaner.

Also since I used the wrong jets what size do you recommend? I would like to keep the needle clip at #3.

Yeah, the thread-police are in full force, but to be fair, it is so the title of the thread pertains to the contents of the thread. So if you title the thread "My 550 project problems", or some generic title, then that will cover everything. It's not rude or anything, but being concise just makes it easier for others to help. It will also hopefully cut down on having to answer the same questions about when you last checked tire pressure etc.

For instance, I did not remember you had a Dyna S ignition. That suddenly increases the likelihood of ignition being a problem. Not that the Dyna S is necessarily problematic, but they do seem slightly less reliable than the factory ignition. They are also more sensitive to voltage problems, so a confirmation on battery voltage and charging system would also be in order.

Another question, then would be the coils. Are they brand new 3-ohm coils? The Dyna S is not rated to use the factory coils. Dyna recommends coils that are 3-ohm or greater. The factory, electronic-ignition coils are less than 3 ohms. This can damage the Dyna S. Luckily Dyna is pretty good about giving low cost replacements to damaged ignitions.

Since we haven't mentioned it yet, you should also confirm the plug wires are going to the correct plugs. The right coil should have the skinny black wire, and fires cylinders 1 and 4. Left coil is green and 2-3.

With the choke plates sealed off, as you probably know, choke application will be very touchy until the engine warms up, so any evaluation of how it is running must be done warm enough so the choke can be removed completely. And before making jetting assessments, on an average warm day (70's), this means at least 10 to 20 minutes of riding.

The last 550 I jetted, we ended up with all stock jets, and the factory needle with about a .5 shim. The non-adjustable needle is the same as the adjustable needle on the second clip from the top. So even the stock jets with the needle on the 3rd clip would have been too rich. That bike had the Emgo type pods and a Mac exhaust (which breathes more than stock exhaust at low RPM, but maybe not as much at higher RPMs).

Another development found last year, is the flooding of bogus rebuild kits on ebay. My site has a page on how to identify these rebuild kits which have non-useable needles in them.
Kits:
gpzweb.s3-website-us-east-1.amazonaws.co...TK22rebuildKits.html

Needle problem:
gpzweb.s3-website-us-east-1.amazonaws.co...K22threeNeedles.html

So, for now, Since the jets are drilled, I would recommend just going to the 2nd clip on the needles. But if it runs better on the thord clip, as is, then leave it. You need it to at least run good enough to warm up.

The first thing, at this point, however, is to determine for sure if you are getting fire on at least 3 cylinders.

Maybe if we ask really nicely, Steve will move this to the project forum, if you'd like, and let you re-title it as "The_Proletariat 550 project" or some other working class band .

loudhvx wrote: For instance, I did not remember you had a Dyna S ignition. That suddenly increases the likelihood of ignition being a problem. Not that the Dyna S is necessarily problematic, but they do seem slightly less reliable than the factory ignition. They are also more sensitive to voltage problems, so a confirmation on battery voltage and charging system would also be in order.

3rd year running I had to buy a new battery. I have a weak charging system and was unable to successfully diagnose the problem.

kzrider.com/forum/4-electrical/597772-19...r-rr?start=40#673328

To avoid reading the thread, the only charging component not replaced was the rotor which is simply not an option due to cost. I resorted to modifying the headlight wiring so I can turn it off. Once I did this and put the battery on a maintainer every night I had no more problems last year.

Another question, then would be the coils. Are they brand new 3-ohm coils? The Dyna S is not rated to use the factory coils. Dyna recommends coils that are 3-ohm or greater. The factory, electronic-ignition coils are less than 3 ohms. This can damage the Dyna S. Luckily Dyna is pretty good about giving low cost replacements to damaged ignitions.

I use dual output green 3 ohm coils. 3 years old, installed with the Dyna pickup, have 5000 miles on them.

Since we haven't mentioned it yet, you should also confirm the plug wires are going to the correct plugs. The right coil should have the skinny black wire, and fires cylinders 1 and 4. Left coil is green and 2-3.

Because of these wire lengths in the harness I would be surprised if I messed this up but will recheck.

With the choke plates sealed off, as you probably know, choke application will be very touchy until the engine warms up, so any evaluation of how it is running must be done warm enough so the choke can be removed completely. And before making jetting assessments, on an average warm day (70's), this means at least 10 to 20 minutes of riding.

Indeed. It takes the "right touch" to start and keep my 550 running if it is cold.

Another development found last year, is the flooding of bogus rebuild kits on ebay. My site has a page on how to identify these rebuild kits which have non-useable needles in them.
Kits:
gpzweb.s3-website-us-east-1.amazonaws.co...TK22rebuildKits.html

Needle problem:
gpzweb.s3-website-us-east-1.amazonaws.co...K22threeNeedles.html

Used K&L kits.

The last 550 I jetted, we ended up with all stock jets, and the factory needle with about a .5 shim. The non-adjustable needle is the same as the adjustable needle on the second clip from the top. So even the stock jets with the needle on the 3rd clip would have been too rich. That bike had the Emgo type pods and a Mac exhaust (which breathes more than stock exhaust at low RPM, but maybe not as much at higher RPMs).

So, for now, Since the jets are drilled, I would recommend just going to the 2nd clip on the needles. But if it runs better on the thord clip, as is, then leave it. You need it to at least run good enough to warm up.

I have non drilled jets. I can put them back in and recheck.

The first thing, at this point, however, is to determine for sure if you are getting fire on at least 3 cylinders.

Looks like I need a spark test and water test.

Maybe if we ask really nicely, Steve will move this to the project forum, if you'd like, and let you re-title it as "The_Proletariat 550 project" or some other working class band .

Steve, could you please do this for me? Thank you.

loudhvx wrote:
Maybe if we ask really nicely, Steve will move this to the project forum, if you'd like, and let you re-title it as "The_Proletariat 550 project" or some other working class band

The_Proletariat 550 wrote:
Steve, could you please do this for me? Thank you.


Will pinch-hit for Steve.



And here it is for better or worse, in the Projects forum under topic, The_Proletariat 550 project.

Good Fortune!