Mech

I think those computers are pretty simple software and will probably only set that code if the sensor is actually not getting it's signal to the ecu. On modern things they do calculate and deduce bad out of range readings, and things like a key or cam being out of time, but as far as I know it's not done on those. Have a read up and you may find they do deduce things like that though. Things are improving all the time. It started and ran with the temporary ecu, so the crank key presumably is ok. There's no reason the crank sensor should short because of the dunking, and a new aftermarket gave the same code.. Have you checked/cleaned, or disconnected the kill switch and ign switch ? The manual should have a list of conditions that cause the code, and what the ecu does in response.. such as switch to base figures to limp home or shut right down.. If you read those really carefully you may get some ideas.. You sound pretty onto it.. you'll get it .. But I'll have a read up later and have a think about it and get back to you..

In some philosophies they say there are three types of men, the enlightened ones, the ignorant, and those that are willfully ignorant. Of the three, only the willfully ignorant can't be helped.

You need to pull the head off again obviously, then you'll need a spring compressor, or a friend that has one you can borrow to get the valves out, then you need one or possibly two new valves and they need to be "lapped in", which you do using something called grinding paste. You can buy grinding paste in small tubs from an engineering supply shop, and they will also be able to sell you something called a valve sucker.. that's what we call them here in N.Z. anyway.. It's to hold and work the valve when you are doing the lapping in. It would be a good idea to get the manual or have a read up on valve lapping.. it's simple but needs pictures really to show what you are trying to achieve, which is an air tight seal of the valve. When you've done the lapping in, it's really important to clean and oil the valve seats before you put it back together, they need a hard rub with a damp cloth to get the abrasive compound dust out of the metal seat, and, you need to drop the lapped in valves into place, flip the head upside down and fill the combustion chamber with petrol and make sure that the valves are sealing totally.. If you get the result shown in books they should be right. Then you need to fit new valve guide seals, lube everything and put the valve springs, with the metal washers that go between the springs and the head(very important, look for them when you are taking the valves out or they can get lost), back on. The valve springs are held by little tapered wedges which can get lost easily, especially as you let the spring compressor off as you are assembling, so make sure they are properly seated, and keep your hand over them as you let the compressor off. Once the head is reassembled you are back at where you were when you did the head gasket.. Take care to get the cam timing right, get everything absolutely clean, especially all the sealing surfaces, and you should be right. Get a manual, they are free to download off here, and have a read about the valve lapping, or google it and have a read up with pictures.

I'm an old dude too.. it keeps me from my shovel to be here.. You're welcome.

If you go to the top of this page and hover on "more", then click on "repair manuals", it will open into a new page, then on the right you will see a list of makes, choose suzuki and it will take you to workshop manuals you can download. To get the carby out of the bike, undo the two clamps on the inlet and engine side of the carby, then it's best to undo two bolts at the back of the air box behind the carby and lever/push the airbox down and back. Remove the hoses from the carby and pull the carby up at the back and out of the engine. Then you undo the choke cable at the fitting on the carby, and undo a plate where the throttle cable goes to the carby, and unclip the cable.

The carby should still be fine unless you were trying to get it running by adjusting the carby. If the cam timing was off by very much at all, the valve can be being held open when the piston comes up, then the piston hits the valve and it bends the head of the valve sideways.. Bent valve. It happens ! Take the sparkplug out and put your finger in/over the hole, kick the engine over and it should blow your finger out with force. If you can hold your finger in there.. you have not got enough compression.

You might have bent a valve.. Has it got compression now? Is it firing at all, trying to start, or nothing happening at all ? You could try starting it, then take the spark plug out and check whether there is fuel getting on it.. Then attach it to the lead, rest the plug on the engine, and watch for spark while you crank it over.

Try it, do your own experiments, swap the emulsion tube on your bike, see what effect it has.. Remove a tube with a stack of small holes, and replace it with a tube with one big hole further up the tube.. see if they both perform the same.

That tube is in a drilling that fills with fuel when the throttle is closed, it fills via the main jet and those small holes. It fills to the level of the fuel in the float bowl. When the throttle is opened, that fuel level in the drilling drops as fuel is drawn back through the small holes. To start with there is some air being drawn through the top small holes and fuel through the lower small holes. The fuel level in the drilling drops until no more fuel is being drawn from the drilling, but only through the main jet, and it's mixed with air from more and more of those small holes as they get uncovered. That drilling is sometimes referred to as the "acceleration well". You are lucky that I'm a patient man Randy... but I do have my limits. Just saying....

Yeah well you can believe whatever you want Randy, and you are welcome to your opinions.

The bikes are all the same from 2008 to 2016(I think 16, might be later). The LT-A500XP or the KQ500 manuals are both right for you. As long as the spark plug gap is right it will be ok. The exhaust.. you will have to expand the muffler out to get it to fit over the sealing sleeve. The stub is so the sleeve can't get pushed too far along the pipe as you fit the muffler on. Some just have a ring welded on instead. If the clamp is welded to the muffler,you should cut the weld and take it off, then use a succession of bigger sockets as anvils to tap against from the outside of the mufflers tube. Put a big socket on an extension (for a handle), and drive it in tight, then beat the distorted sections of pipe down against it, gently, then use a slightly bigger socket driven in a bit tight and repeat the process. The new sealing sleeve is thick and soft and has to slip onto the pipe, and into the muffler nicely, or it will get chewed up. That box with hoses is I think going to be a canister to catch fumes from the fuel tank, so follow breather hoses from the tank and you may find it. It is probably only on certain models(californian and some european markets most likely). If you read right through the manual it will no doubt explain it. If you work your way through those steps I list above I'm sure you will find the problem.. without buying a lot of parts that aren't needed.. Get a manual, the one with the most pages will be best. Have a read. If you find anything that doesn't seem right ask and I'll check t out again.

And looking through the manual I see the muffler doesn't have a drain bung, but it does have a spark arrestor at the back, with three bolts holding it..Those definitely block up.. I'd clean that and fix the exhaust leak. Then I'd check the spark plug and gap, look for air leaks, then anything that would cause it to not get enough fuel.. Low injector voltage, fuel filter, bad connection to injector.. Then electrical, air temp sensor, water temp sensor.. If those are out of range, but still connected, they won't cause a trouble code but can still make the mixture wrong. If the temp sensors(or anything) are causing a slightly lean mixture, it will probably run ok with hard acceleration when the ecu tells it to give it more gas, but falter and possibly backfire out the inlet when you throttle back or run it at light loads.. If you can confirm whether it has that canister with hoses and wires it will be helpful.

The injector is meant to run at battery voltage.. I'd check that. And wriggle it's wire while it's idling. Anything that makes the mixture lean could cause your symptoms.

I think your basic model is probably a LTA500XP/Z. That should cover the running gear. The other differences should just be decorative as far as I can see. I think too that your particular bike will be a 2012.. they had lower handlebars. And, I think a good place to start with your problem would be to check there are no air leaks between the injector and the engine.. Including any hoses that could let air in. Engine start sprayed around the throttle body while it's running may show something.

Do any of these look like your manual ? Scroll right down.. https://www.manualslib.com/brand/suzuki/offroad-vehicle.html

If you go to https://www.mickhone.com.au/partFinder/fiche/suzuki#content and look in the years 2009 and 2011, you will see there are several models of LTA500. Have a look in every model and check their wiring sections. In the 2009 models, down the bottom of the section listings there is a unclassified section, and in there there are wiring listings as well, check those and then have a look on your bike whether it has that box with hoses and wires coming off it..

The join there is meant to have a thick walled sleeve of somethng like asbestos. https://www.mickhone.com.au/partFinder/fiche/suzuki/2011/lt-a500x/muffler#next There will be too many tiny differences for anyone to explain to you. You need to get the manual, (which can be downloaded for free), and look in parts listings(That site I've posted shows two LTA500X and LTA500XP), and figure the differences out. In the back of the service manual it will have a section called the supplement quite likely, and there they mention any differences. What's not in the supplement section, is the same as the main part of the manual If you confirm what model you have, I'll download the correct manual and have a read and see if I can help..

Yeah Randy.. they are all very critical and carefully chosen.. And.. carbies are not junk.. Just the wrong one for the job. Read the tests we do to check mixtures and settings.. See if anyone(any one qualified) suggests snapping the throttle open as a test.. on the type of carby you have.. If you want to snap the carby open, which is not a good driving technique, then get a pumped carby.. And you see those small holes stacked up on one tube.. that indicates it needs/gets a lot of enrichment as it comes onto the needle, which means it's running lean somewhere else.. slide probably. Not all acceleration compensation is richening, sometimes they run things rich, and then lean them temporarily or after attaining speed.

I saw that "super tuning" manual, but there are better, more appropriate ones for you. Mikuni ones. I did a search putting the jap brands in front of technical training manuals and there were a few for sale, all hard copy though.. And yeah, you know the emulsion tube, and how some of them have small holes half way up them, well those are important, they mix air in, but they also serve as enricheners as the needle takes over.. they are part of the acceleration compensation.. Not all two-stroke engines have those holes. You should read the tuning process, the order of operation, and the tests.. Then you might have more luck.

A blocked fuel filter or low fuel pressure could cause a lean mixture. Only at set speeds is probably significant.. I thought we'd sorted the model and got the right manual.. So what have you noticed about the bike that isn't as the manual says ?

Here's some examples.. not very relevant but.. http://www.autoshop101.com/autoshop15.html

That's all very interesting and fine Randy, but no carby is junk by default.. Just wrong for the bike or badly tuned/setup. Perhaps your mates, and all those people that could never get jetting right, didn't know how things worked, or what they were doing. Perhaps they were fitting carbies that were inappropriate for the bike. If you work at a dealer, they often send people away for training, training provided by the manufacturer. At those courses they provide things called "technical training manuals", which explain in great detail how every component/system works, then how the components/systems work on any machine in combination with the other components you may find on various models in their lineup, then often an explanation of them all working together on some specific model as an example. If you want to know how things work Randy, or anyone else, get hold of some "technical training manuals". They are out there... They have them for things like electrical systems, electronics, fuel injection, carbys, transmissions, a specific engine design or engine design in general, chassis, body repair.. anything about automotive machinery. It doesn't matter if the training manual you get is for some other make,(even a car one), the principles are all the same, they are just combined in different ways that the various manufacturers prefer to use. If we know how the components work, and interact, we can figure any makes running gear out. If we know what all the systems in a carby are, and how they interact, and then follow the recommended procedure/order of operations, we can tune any carb to a vehicle as long as it's an appropriate size for the engine and requirements. Carbies, even the most complicated ones, are really very simple bits of technology, using very simple principles. All the circuits in them overlap in operation and there is always more than one way to overcome any particular problem.. But we need to choose the correct change or we make things worse. hence following the correct process/procedure.

Some more thoughts, for those that are having problems... One thing that does get put together wrong is.. the slide needle has nearly always got a washer/spacer above and below the clip, and sometimes those spacers, especially plastic ones, can be different thickness, by up to about one mill. The manuals hardly ever explain which is which. One mill can be adjusted with the c clip on the needle, but it's always better to check/try which way the spacers are if the needle seem to be set wrong. Needles do get bent, and that can cause rough running at certain speeds. I've replaced needles for that reason. Slides wear, but I've got plenty of bikes running fine with really worn slides. Slide needles wear slightly after a long time, but I've got bikes running fine, with wear on the needle that could be seen with the naked eye. Jets, they say they wear, but we can buy jet measuring tools, which I've used, and the wear is minute even after a lot of use. To all intents and purposes, jets don't wear. Hope that's useful..

Often, a model of bike comes out with the same carby model, but with different specs, (and part number), which have different jets, slide, needle etc.. The details are found in the supplement section of the manual. Almost any of the variations will run pretty well on any of the year/version of bike they were made for, as long as everything in the carby is a matched set, as designed by the manufacturer and spelled out in the supplement section. Start thinking you can improve on their design work, and mixing and changing things, is not a good idea.

Ha.. In all my years I've never needed to modify a slide, or needle.. But, we are all at low altitude and a small market, so we don't have many variables. I have tuned bikes for competition though, and made up carbies and tuned them, worn parts and all. I'd recommend getting the manual for your bike, checking you have the correct carb, that all of it's jets and settings are right for that carb for that market, and then tune it as the manufacturer recommend.. which is the way I've been recommending. If it's not the correct carby for your bike, get a manual that has the specs for that carby, exactly that carby, for the market the carby was intended for, with the slide and needle it has, and then check/change jets from there till it's running right.