I Give Up...This Honda TRX450 Is a NIGHTMARE 

The problem is in the mid body of the carb...almost certainly. As I said before, there are o rings in there that deteriorate over time and clog fuel passages. You have to crack that mid body open.

I’m with all the other comments on inconsistent spark from faulty stater. Keep us posted Joe. Love learning new troubleshooting strategies 🤘🏼

Hey man my buddy and I both have tax 450rs. His is the Same year as that one, thing ran fine for years then one day he was having the same exact issue. We checked all the stuff you did, went as far as replacing the cdi and stator…. With same thing still happening. Definitely a fuel issue. One simple thing we totally over looked the gas tank, upon inspection we noticed that the internal filter at the petcock inside the tank had disintegrated and there as a bunch of debris in the tank. The plastic pieces were so had to see because they were practically clear. We took of the petcock removed the rest of the filter, did not get another filter for the petcock. We just ordered some clear blue fuel line and a tusk in-line filter and installed those after flushing the gas tank. We took apart the carb again and cleaned every nook and cranny again. We put the carb back to factory settings and crossed our fingers… the thing ran like a scalded dog! It had never run that good ever! So what we found out is that the debris was getting into the float bowl needle valve shut off and holding it open dumping way too much fuel into the carb and flooding out the circuit. I hope this works for you we used an air compressor to clean out everything on that carb. Then little plastic pieces were so hard to see. We hav not had that same issue since.

Honestly Joe, @ about 3:35, where you were looking for a consistent spark, I only saw one and no more spark while the starter was spinning the engine until you let up on the starter button. There was one last spark at the end. I watched several times to be sure. Now, I don't know if the spark, after the initial one, wasn't picked up by the sensor in your camera, but I felt that it was important to tell you. About to resume the video and watch 'till the end.

Hey Joe, In the video @3.25 I did not see consistent spark. It sparked at first, then it looks like it quits sparking until right at the end. Maybe I just couldn't see it on video. But I think it might be an electrical problem. Coil, Stator, CDI ??? IDK.

Take a timing light and test it under load. If the light keeps flashing when the engine slows down, it's a gas problem. When it stops flashing, it's a ignition problem. Just an idea:) Keep up the good work, man.

Try a different coil , almost any will work , I had same problem on my old yz400f at a race years ago and swap coil from my vintage bike at that time a 75 tm400 Suzuki and bingo finished my race weekend, just a a easy suggestion to try , never give up !! My moto coach from years ago always told me " winners never quit and quitters never win " I have lived my life from these simple words ❤ great job joe 👏

Do not give up you have came to far I really want to see you fix this one!

My son's raptor 350 was acting like that. It turned out to be the CDI. Before ordering new parts, take a look at the stator and pick up coil. May be a loose connection in there.

I had a studdering issue on a 08 crf 450r and after much trying to solve i finally fixed it by bonding the 2 piece slide together with a silicone . i found it hard to believe this could have caused it but it was the reason. There is a rubber seal there stock. I found this by others having same problem with this solution. The system is to keep the slide from getting sucked against the body. No problem since i did that. I appreciate your vids and I feel this will work

Don’t give up! You can’t let that thing beat you

In the beginning of the video, when you were checking spark, it was cutting In and out, not constant at all.(3:36 sparks a few times, but doesn’t spark again until 3:43)

You can't give up on this. You're going to fix it, and the information you gather will be extremely useful in the future.

It's definitely the mid body gaskets in the carb its runs exactly how mine did Joe during the warmup started and idled perfectly but when the engine has some heat it started to act up like the TRX does under load too. So then I split the carb and noticed the o-ring gaskets have flattened they also use a little glue to hold them in place during assembly at the factory it started to break down because of the fuel and partially covered one of the passages around the seal. Mine was original from 2006 CRF 450x had the white paint on the bolts from factory first and only bike I ever bought brand new. They had to of been replaced before on the TRX by now might have been installed with too much or wrong glue and has deteriorated from the fuel also. I ordered a mid body gasket kit and it runs perfect just like before I replaced them 4 yrs ago though and still good after resetting the adjustments I was messing around with too before. I don't like these carbs either they are finicky so much going on in there it took me a few tries to figure it out... Awesome work Joe good videos!

Replace stator, CDI and coil. Ride after each switch to identify which was the culprit. Great channel, great content. Cheers bro

Joe, the problem seems to be electrical at this point. The way it bogs and shuts down looks like some kind of electrical failure (ground, stator, coil, etc). Don't give up, keep us posted.

Wonder if it could be the coil, I’ve seen them act like that before,sure seems to be something intermittent with spark, because of the way the spark plugs looked. Good luck, appreciate your tanacity, don’t give up.

I had something like this happen. It ended up being the coil. I would look for electrical problems

Hello there young man. There was a 1998 yamaha vk540 that was given to me freely around this month last year, and I had the same problems as your Honda trx450 and it gave up on me on a trail. It kept on dying on me and start… I didn’t know why and what was happening, but I finally figured it out to the problem. Each time I went for a ride on it, it would act up the same way your quad is doing. So I still have to replace the stator, so try out replacing the stator. My snowmobile acted up for three weeks until it wouldn’t start up again. Have yourself a good day young man and I can’t wait for your upcoming videos. You’re doing a good job. Two thumbs up for teaching us and showing us how to work on our machines (quads, trikes)

what i love about your video's is your humility,and you are very intelligent.

at 23:50 you will notice a spark down by the radiator fan unit when you accelerate the throttle, possible short. Turn off the lights to check, it might just be the background lighting though.

I APPLAUD your PERSISTENCE !

Never give up Joe ,ull crack it brother!🤔😬👍👊👊🙏👍👊

It’s acting like an intermittent spark issue. Bad stator or coil. It’s also “hunting” at idol which shows an air/fuel mixture problem and that’s usually a sign of a bad seal or a gasket. It could also be a bad boot from the carb to the intake. Mustie1’s videos could help you too. He does these vids all the time.

Test stator cdi coil pick up coil parking brake make sure it’s getting good flow for fuel gas cap run it on reserve petcock could be clogged

Hey Joe, I'm liking your electrical troubleshooting savvy. That for sure one ups me.👊🏼

I think that carb gasket is called the mid body gasket if you haven’t already looked into it

Check the leak jet on your accelerator pump. Should be 50 or less. Also try tuning your ap timing with the screw on the accelerator pump arm.

Love your videos bro. You have a good eye for sweet quads. You’re a hell of a mechanic. Or are in the making of one. You have a good mind for it. I have to say you still aren’t the best rider/racer rather. Always a critic right lol. I love how these guys commenting like they know exactly what it is and it’s so simple. I have a problem with my 07 450R. Cranks runs fine then dies. Dude I’ve Brennan all up her skirt and I’m baffled.

I just rebuild an old atc, and had a similar problem. When it warmed up if I tilted it to the right or turned left or was on a slight right off-camber trail it would do this. I tried everything finally, I took off the stator and it looked and tested fine but right before I put it back in I noticed the smallest wear spot in the stator wire. Apparently, the wire had worn thru and when it warmed up and it moved to the right by gravity or centrifugal force it would ground out. Try warming it up and then tilting it to one side and holding it there while idling, if it turns off immediately this could be your problem, Remember to do both sides.

To keep moisture out of your fuel tanks in any of your four-wheelers.&etc. Throughout the winter every full up spray two/2 squirts of yes I'm saying WD-40 into the fuel tanks.

Keep me posted. My quad is doing the same thing. I have a 2006 trx 450r. I'm almost about to give up myself!! I'm going to completely take this carb apart and sonic clean it, replace the orings in between body's and then go from there. I basically did everything you did and have the same results it's driving me nuts about to sell it

Their also known as A carburetor divider split block gaskets center.& Lower & upper intake gaskets. That's why I recommend getting A new carburetor complete gasket replacement kit for that carburetor.& intake& O-ring seals.& New jets.& Venture tube.& Blow pump jet.

3 things to try. 1. Run a ground from the batt. to the head. Bad ground from eng. to frame are any place in between 2. When riding blow into the tank to add press. to the tank. I once had a dirt bike that had a small piece of the inside of the fuel line acting like a valve. 3. Bypass the kill switch/ignition switch as they could be shorting out intermittently. Like John Beach said your spark is not consistent.

Check messures of stator and CDI , even try new CDI . Check messures of the coil . Check the magnet wheeldrive .

Change the carby gasket then check the exuast system sounds like the back pressure almost like under load something blocking it so doesn't want to open up but at idle revs out some sort of blockage or it is electrical but you checked most of that out and was gd try exhaust and carb gasket and stater is a bit of mystery could be air leak do the easier stuff first then the other your a wizard and magic this stuff all the time you'll crack it keep up the great work love your work and have learnt so much from watching your builds here down under love it champion 🤘🏻🤘🏻😎😎😎😎😎😎😎❤️

Accelerate pump tuning is critical for no big. Basically tune it to where it just hits the slide and turn it back a hair. Test it and repeat. You want the accelerator pump squirt to be immediate and the o-ring mod helps which attaches the top of the pushrod together allowing a faster response. JD jetting really helps in this situation especially with the needle. Also replace ALL gaskets in carb including mid-body which is prone to issues

I gotta say, my honest opinion, for what ever that is worth is that you might be chasing Two issues at once. I am thinking these guys yelling it's carb might be correct because of the gas problems you are having, ie acting like it is out of gas etc. And I am thinking the guys yelling it's electrical are right as well. Probably coil but possibly stator. But it sure seems like you are chasing Two gremlins not just one. Looking at it like that makes way more sense for all the fun you been having with it. Cause if you was seeing sparks bouncing around that certainly isn't a carb issue, but then again your sparks bouncing aren't going to cause the wierd fuel issues you are having so just look at it as two separate problems causing one problem. That is the bike runs like crap. Lol good luck like everyone else here I am sure you are gonna win this battle

As a few others mentioned, the video only shows the plug firing when you first tried cranking and at the very end right before you let up. Thought it was worth mentioning.

My initial comment is right on, bogging down at WOT (wide open throttle for the noobs in the room) means a lack of sufficient fuel flow and the A/F mixture is still off.

Cmon you gotta let Vinny out to run with you when you ride, he obviously wants to and I like watching him chase you 😂

You can do the zip tie mod or oring mod for the accelerator pump timing,the linkage on the pump gets play in it and the zip tie mod will help it stay tight, the slide will wear the carb body down and they will be sloppy,and yes the mid body gasket gets mushy from the ethanol in the gas

It's A petroleum distillates inside of WD-40 spray that helps remove water.& Moisture out. it works in vehicles to also. 2 to 4 sprays into the fuel tank treats A full tank.,or under full to.

Just order a rebuild kit for the carb. It comes with a different needle (with clips for changing height). Make sure you get the correct spark plug too. Carb rebuild and plug.

Gasket problems tend to be more consistent I wouldn’t imagine it’s the mid body gasket.

Intermittent problems are the worst to diagnose and fix. it sounds like it maybe a regulator/rectifier issue. I hope you find the problem and get over the frustration. Best of luck Joe. I am betting on you.

Yes it can do that if it's sucking in air slightly from around the out of the carburetor joe.

Jets are clear and accelerator pump is working you know that which means you have fuel. Timing is perfect compression is also good. I’d lean towards spark

Had a very similar problem that about made me insane. After hours of troubleshooting with no success I added several shims to the jet needle and solved the problem. For some reason, it took a number of shims (improved with each one). I was able to go back to the original/stock jet and it worked perfectly.

I thought I seen some sparks coming out of the plug on the fan for the radiator

Ive never seen a carb with a tps but that surging is exactly how a bad tps acts on a fuel injected bike. People are saying bad stator but ive never heard of a stator fail intermittently like that. If youre sure every electrical connection is good (ignition switch, kill switch etc) id maybe throw a tps in it and if that doesnt fix it then a cdi. Just buy from a seller who accepts returns lol

Check the gas cap vent....if it has any restriction it will slow the fuel down leaving the tank and starve the carburetor of fuel

I have a 52 (48 now) pilot with a 165 main I believe. Way larger than stock.. Runs great. open airbox w/ UNI filter, slip on and stage 2 HC

Reminds me of figuring out the fueling issues on my ltr 450. Bought it and found out it was getting fuel in the oil and turned out the cherry bomb burnt out and was flooding the system, fixed it with a power commander. After a while it developed a big in the middle of the rpms and turned out the rev extend plug burned up and was messing up the air fuel mix on the mid range and making it run lean. I leaned don't plug anything into the diagnostic port on the ltr 450

Make sure the coil has a good ground, and that all grounds are good!

When idling go tap the CDI box and see if the engine cuts out. I had the same problem it was a bad solder joint in CDI box. Also check for up and down movement of the flywheel it could be hitting the stator.

I have one of those trx450, and I had a similar problem, when I was cruising it ran fine but when I gave it full throttle the engine turned off and the problem was the gas cap was clogged and it didn't let the gas go down well the gravity was bad, but that trx sounds more like an electrical problem, when you put the one way bearing, that has some marks that are time and I did not see in the first video that you put everything in time, cut a piece of the spark plug wire and screw the spark plug boot back on, run the trx without the airbox cover

Yeah agree with you joe defo electrical got to be stator at higher power which it seems to be intermittent you’ve basically done everything to this quad would be good if you had a donor stator to try to see if that’s what it is but I think you’ve nailed it mate what else could it be I think it would fly too so frustrating mate hope you get it sorted take care and all the best 👍👍🔧🔧🔧🔧👌

I had a 2007 TRX450r back in the day and I’d have to say it was my favorite stock quad I have ever owned. Reliable and had great power delivery just very smooth. I wish Honda would release a new 450 sport quads

All the mid section o rings and ultrasonic clean it . Make sure float is adjusted and put new float needle. Also adjust valves

Someone in here said the coil. I had a jet ski that ran great and would fall on its face when it warmed up. Tested the coil and I could not get a straight reading. It was all over the place. Changed the coil and was back in business. At least give it a test first. Also make sure the coil is grounded properly to the frame.

Just go fuel injected. I installed the fuel injection kit and thing works. Got tired of the jetting crap. 👍🏾

Try replacing stator and make sure float bowl isn't sticking I had same issue on one of my quads and it fixed it

It's called the center split block carburetor gasket could be leaking.& Bad yes.

Buy strobe light. Hook it up and tape the thing (and its trigger) to the handlebars to see if the strobe light cuts out when the engine cutout happens...then it would be electrical. If it is not electrical, I would "TRY" to temporarily substitute the existing carb - if you got one sitting around that fits the intake boot. Might not run "right" but if the cutout stops, then I would replace(?) the existing carb.

Had same problem on my kids cobra race chassis with a kx85 motor. Started fine, when the bike warms up (gets hot running a lap or 2 on track) then it cuts out and dies. You can take the stator cover off and spray brake cleaner on it and if it dies that’s your problem . Anyway. I replaced the ststor and boom. Fixed. Chased this electrical problem for 3 months thinking it was the tune/fuel/carb.

I had a similar problem a while ago with our trx400. Carb on carb off could not find a problem at all everything seemed fine and could not find out what the hell. Only difference I had ours cut out after a while of riding. I replaced the hole carb and it seemed to have fixed the problem. Not saying it’s what you need to do but it worked for me.

I had a trx 450r. It was a great bike and the only issues i had with it was the starter clutch, starter reduction gear, and the jets clogged one time after sitting. My year was an 07 and I don't remember their being a accelerator pump on the float bowl. The issue with the bike was it only like it to be hot. In other words it would not run when it was cold. I remember going on a ride and we rode about 20 minutes and when I came to a stop the bike would stall. After a very long ride the bike would finally run great. It had similar starting issues. I am no expert, but it sounds electrical. I worked on a race car one time in where the spark plug wires would break up under a load. Only way we found that out was a chassis dyno. Man, I wish I could help could offer more advice. electrical gremlins suck. Oh, if you invest in jet kits, look into Dyno Jet. They are base out of Las Vegas. The needle has many adjustments, and the kit comes with lots of jets. I use them in all my bike. Lastly, thanks for the channel I enjoy your videos a lot. Best of luck with this one, I know you will figure this one out.

Sometimes potensiometers, which I guess is what the throttle position sensor is, can get noisy when the carbon track gets dirty. You might not be able to measure the fault as it sits on the bench, but put some current through it on a vibrating motor might have an effect. Potensiometers cost next to nothing and should be easy to substitute for elimination purposes.

I didn’t see consistent spark

Yeah thinking out of nowhere it needs a bigger jet is the wrong way for sure . Setting the air mixer right from the get go is key . You idle circuit should be adjusted at the sir corrector with throttle closed then the idle set after . Forcing more fuel is a no go . And pretty sure you have a electric issue .

That troubleshooting was pretty nice. Big change from parts cannon tries and my usual technique. I had a trx 250 cdi that would start, give spark but die after 5 min. They can fail in the running but idle fine, I've seen it. Maybe get a spark tester and see if it's losing spark when it surges.

If you did not check the O Ring on the seat above the needle pull it out and take a look bro.

Check throttle contacts in thumb throttle switch on handle bar. Look for spacing or any loose contact points.

If you saw sparks on the tailpipe, take it to a very dark place and start it up and while it’s idling look at the CDI box and watch the light show.

Joe have a look at the video 17.40 can see white sparkling ✨️ next to the fan when you used the throttle

Problems like this if it isn't the carb its often the stator plate not working properly. Check each coil is putting out the correct voltage. Some coils run the HT side and others the lights etc. The lighting coils put out about 14V and the HT coils put out much more. Forgot how much. Something like 80V...if my memory is working correctly...easy test with multimeter. These faults can be really annoying as sometimes the bike runs then it won't. On off intermittently... Heat and vibration effect damaged coils..you'l find it runs spot on then it stops dead when it's a dodgy stator plate..

Good to see when you cant figure it out you ask for thoughts but need to do follow up and let us know what fixed it or if you never got fixed up!

I have an old ATC 200 that does almost the exact same thing. I'm convinced its a spark issue. Cuts out so cleanly and erratically that i don't think the carb is the issue

Check the charging system. Should be 13-14 volts seen the rectifier go bad and put out 30 -40 volts. 12 volt ignition systems don’t like that kinda voltage. The cdi unit. Check it at idle and half and full throttle. Good luck keep the videos coming.

Also replace the diaphragm for the accelerator pump. It might look good but I could have pin holes in it.

Did you check if it is not clogged up in the gas cap vent and tube. If I was starting the motor of 250cc and it blows a lot of gases of my gasoline tank that vent in either two direction. You have the accelerator lever instead of switch the throttle handle for rough terrain and turn riding. Usually, the lever for throttle cannot come back to idle with the spring that pull the lever back. I am that way as a professional rider in the lowest profile seat height for either street and motocross dirt circuit track. I did jump bike as high and as far as I could at same time going 40 MPH. The twist-free throttle handle helps two hands into better grip in rough terrain. The dwell of the motor cycle can be adjust for better fuel mileage as I hope that would clear the rich in Hydrocarbon exhaust gases for one cylinder motor in 230cc up to TRX450cc. The motor is with the coolant temperature and it reads way too cold until the motor is hot around 900 degree Fahrenheit at ambient temperature near the cylinder and header is the nominal. The radiator made the cylinder into around 275 degree Fahrenheit. That is the main reason why the gases is high in Hydrocarbon with special hydrocarbon reading scale from under $100.00 dollars analyzer online EBAY order. The ECM is not program but reprogram the ECM into the EPROM chip of the Motorcycle adjusting the rich fuel and air mixture switch and medium nominal stoichiometric 26.5 air to 1 part of gas for 29 PSI outside barometric reading. During the 2007 when the TRX450 was build their barometric was reading about 18 PSI near high elevation cases the rich exhaust of hydrocarbon so more steam comes out but too high Hydrocarbon means the steam doesn't come out of the tail pipe. Very clean invincible exhaust is the TRX450cc. Wait till the outside early morning making the steam of water that must make smoke out of the exhaust engine gases. It is require for newest engine to make smoke or steam at 1,800 RPM. Thank you.

Float bowl vent is plugged

He is right its the rubber gaskets in the mid body of the carb.

Try buying a stator shift angle sensor i am pretty sure thats is the problème hope you fix it just don’t give up your almost there

Similar problem on my raptor 350 ended up being the cdi. Put your ear to the cdi when ignition is on mine made a screeching sound. I bought a cheap £14 Chinese cdi to see if that was the problem and it worked.

I think your right about the stator, I bought another ltz400 for cheap, and it ran and had spark but when you hit the gas it would die,it sounded horrible, I pulled the stator cover off and a Allen bolt broke off and chewed up the stator

It definitely sounds like an electrical problem, probably the stator or magneto wires. I've had problems like this on my dirtbike. Love the content hope you figure it out!

MY DAUGHTER IS VERY YOUNG SHE'S ONLY 49 AND SHE WAS CAUGHT IN THE MIDDLE OF THE CROSSFIRE AND UPSET ABOUT THAT!

Flush fuel tank New petcock lean it down little more . Ignition coil replacement. Few ideas.

Possibly the stator. It's gonna test fine since the bike starts but possible at high speed it's starts to loose signal. The only way is to hook a scope to the pick up and record wave signals while riding it.

Not consistent spark. Watch your video from 3:38 to 3:46. It spark 3-4 turn overs then stops. At 3:45 it starts sparking again. Hope you see what I’ve seen. Good luck and don’t give up!

A little late but I would say CDI. I bought a carb clean special three wheeler in great shape other than it wouldn’t start. Well I got it to start and the real reason someone let it sit was because it would bog randomly just as you described. I replaced the CDI with a spare I had and it ran perfectly. So I would say CDI. Another tip is you can heat up the CDI in the oven to drive out moisture. Maybe that will work. I know CDIs are expensive. Good video!

Don't give up, if anyone can fix it you can Joe

Ok ive been reading the comments not one person has said anything about the air/fuel screw the stock ones are junk and the o rings tend to wear out. When you hit the gas it sounds like my bike when my fuel screw is to in as i adjust she comes to life change fuel screw bro its cheap and worth a shot

I had a raptor 350 a while back and it was having similar issues. Bogging like crazy, I thought it was electrical. I bought a aftermarket carb, and the issue was solved

I have had a similar problem with a motorcycle. The spark plugs were the same at yours like the sintoms. Spark plugs too cold or too hot. Pay attention. If the spark plugs is too hot(reach too hight temperature) it burns the carbon deposit on the top and cause random self sparkink.

I had the same issue. Luckily I had a friends bike that I was able to swapped CDI, coil, and carb, made no difference. Bought $30 stator off amazon and has been running great for 2 years now

I think electrical. I am not familiar with the carb gaskets getting mentioned, but the inconsistency despite all the carb work makes me believe its electrical. A ground issue, stater, or a broken wire that fails under load maybe? Very puzzling.

Adjust the valves!!! Cold❄️