I have a 2003 VTX 1300 (candy apple red if it matters ). I have been fouling plugs quickly. Even with new plugs, I can feel the rough running on acceleration and it backfires on deceleration. When I throttle it up I can feel the vibration of a rough running engine. Are there any diagnostic tools on that old a bike? Three is a huge shortage of independent shops near Wake County NC. The two I know of are not taking any new customers because they can't hire anyone. I don't mind working on it myself but not without any direction.

 

Might be as simple as adjusting the fuel ratio but someone might have adjusted it that way to where it is now to make it run despite other sleeping issues like loose hoses. Tool wise it’s the same tools as working on a car.. multiple screw drivers so you use the right sizes at the right spots and hopefully don’t strip any screws, sockets, needle nose pliers, etc. It isn’t a high tech engine with onboard diagnostic error codes.

 

Thank you. I ordered a fuel mixture tool that should arrive in a couple days. I don't like not having a tach to set the idle and it is the only way I know to set the mixture. It,looks like if I want to connect a tach I may need to pull the gas tank to get to the coil wires. WHen the misture tool arrives I will try to play with that. I pulled the air filter off and it is spraying fuel evenly. Ther eis no curd in the carbuetor that I can see.

 

If your fouling spark plugs quickly, the engine is probably getting excessive fuel.
Trash could be keeping the float needle valve open.
Several cases of defective Air Cutoff Valve (ACO) diaphragm allowing fuel to cause flooding.
Any signs of fuel in the air box??? You may see more if the X is vertical.
2003 has an electric fuel pump. They have had problems, usually no gas being pumped.
A link to the MR VTX Carb 101 teardown. Carb Cleaning 101

 

I love this site; great advice, good tips, and a really nice dash of sarcasm (I call it Irish wit). That being said I cannot see where the mixture screw is on my vtx1300 and I akso wonder if someone knows a good source for parts (eg, carburetor parts, LED tail light assembly). I love my bike, but it aggravates me it does not run right. I was using ehtanol free gas on the advice of my last mechanic but stopped because of the octane rating (90). I read that this bike does not like anything above 87 and higher octane can actually cause the fouling (It did not seem to matter; new plugs turned black again). Do others use ethanol free and does anyone use a fuel cleaner or boost of any sort?

 

Many of us advocate running a can of Seafoam through a couple tanks of fuel, esp. if it's been sitting unused for long, or will be, like over winter. Techron is another good one. Startron Blue is an enzyme-based compound that dissolves build-ups, but it may actually make things worse while it's working and until it burns the old crud off. The diff. between 87 and 90 is minimal. The makeup of the ethanol and the UNethanol is whats different. Granted a carb is different too from FI 1800's. My personal info is based on FI. GL

 

Make sure your fuel enrichment (aka choke) is pushed all the way in and stays there. If not, the large black plastic nut can be GENTLY tightened as its very easy to strip or break.

 

As already suggested, first thing to check is your fuel enrichment knob (choke) to make sure it is closed and not fouling your plugs. A common cause of backfiring is air being sucked in through loose header pipes. Make sure the bolts are tight to the torque spec. These are the easy things to check.

Partzilla is a decent web site for ordering OEM parts: https://www.partzilla.com/catalog/honda/motorcycle/2003/vtx1300s-a/carburetor

Use the carb cleaning link already provided and let us know how its going.

Good luck.

 

[QUOTE="The VTX has always been rated at 87 octane.
[/QUOTE]
I thought so too like you but someone posted their VIN sticker off the frame of a 02 or 03 and it said 91 octane . Dunno!

 

[QUOTE="The VTX has always been rated at 87 octane.

I thought so too like you but someone posted their VIN sticker off the frame of a 02 or 03 and it said 91 octane . Dunno!
[/QUOTE]
Don't believe everything you read. Like the owners manual that says run 33 psi in the tires.

 

Found this. explains 91 vs 87.
Something that they are the same.
RON 91 is 87 or so how I read this.

87 or 91 octane in 2002 VTX1800C?

Alright guys. I KNOW this topic has been beat to death, but I'm not fully confident in what I have read. Seems that every thread I can find recommends using 87 octane in the 1800 as "Honda built the engines for that." "It's the recommended fuel." etc. HOWEVER - my confusion sets in when I read...

www.vtxcafe.com

 

Hey y'all, again thanks for all the great information. I wacthed a video of removing the carb and since the choke knob is definielty all the way in it could be clogged internally. I also cannot seem to see the mixture screw. Somewhere I saw that there is an adjusting gadget that can be installed to replace the actual screw. It looks like I will be removing the tank and rebulding the carburetor. I plan to do a video on the process and maybe I can share it. ILl use my go pro to get it on video.

 

The choke knob should not touch the rubber grommet.
There should be a slight gap of about 1/8"
Probably off at the carb 90 degree rubber hose.
https://www.vtxoa.com/attachments/mr-vtx-carb-101-a-f-screw-aftermarket-jpg.208598/

I have not heard back from Mortsyn in Raleigh area.
He was wanting his VTX checked out after a spill.
"Need Help Finding a Repair Person/Shop" is his thread topic.
Some MC repair place in Cary set up a schedule with him.

 

Change your oil after you fix the carbon fouling. I am guessing your oil is fouled black as can be from it. It’s still oil but I’m sure it doesn’t help it’s lubrication properties when it gets pitch black like that.

 

Yeah there was a recall on those CANDY APPLE RED bikes . Looked great, but just couldn't help but foul them there SPARKIES!!!
On a serious note check all the vacuum hose for cracking or splits. What I will do is remove air cleaner and mist water from a sprayer around all the hose connections. If the bike suddenly stumbles it sucked in the water . Some people will spray some type of flammable aerosol , which you can......BE VERY CAREFULL!!!!! What have you changed , has this just happened and the bike was running great before?

 

Hey all, I cannot believe I have been MIA for 2 months. I just moved 4 weeks ago while working full time and I am now finally able to breathe again. I still have to get this plug fouling/rough acceleration/ mixture problem solved but I cant even see where the adjusment screw is. Can someone tell me how much of a tear down I need to do to install an extended mixture adjustment kit (Glenns VTX garage has one). I am tempted to just remove the carb and rebuild it but hate to do unnecessary work. On the flip side I am thinkng the choke enrichment assembly may be part of the problem. I am still riding the bike but it runs like sh*t. Someone recently posted there is a bike shop in Cary NC who works on the Honda VTX but they are so short staffed that the shop is not taking on any new clients.

 

If I were you I would tear the carb down so I could inspect everything; air circuit, piston valve, jet numbers, needle, enrichment/choke, ...

 

Yes, I agree and thank you Brett. I am now commited to tearing this down. I have ordered new jets and a mixture screw kit (to make it easier to adjust). I now need to decide if there is anything else I should look to do while it is torn down. I will likely add a tach (at least wire connectors to addd it later). This biike deserves some attention.
Appreciate all the feedback, If there are any 1300 owners who have suggestions for more performance tuning that won't break the bank let me know. Here's a photo of my baby.

 

A video of a carb tear down.

 

Another carb repair.
Remember 2003 1300 has an electric fuel pump. Many have died.
But you have carbon fouling, so excessive fuel...

 

Beautiful bike, looks garage kept. I have a 1300, also, and took the pump out. It is now gravity fed. I did replace the petcock and fuel screen at the same time. I turn the petcock to OFF after every ride. I tried putting an inline filter on the fuel line to the carb but I had a problem with the gas stopping at the filter and not going all the way to the carb. PITA. BUT, as long as the screen does it's job I won't be stuck on the side of the road with a dead pump.

 

Thank you. It was always garaged until I bought it. I don't have a garage. I will store it in a storage unit for the winter but for now it gets a cover. My project list this year, once it is running well, includes getting a nice fairing, sound system, new LED taillight assembly, and maybe some new storage. For the lover of a vintage bike; we all here know what that's like.

 

Tahnk you. So, what do people use to clean the carburetor? I dont have access to a blaster and won't use any type of acid so what works best? I don't think seafoam is strong enough. Any suggestions?

 

I spray The inside of the carburetor bowl and all fuel passages with carb cleaner. I also wear nitrile gloves and a eye protection. I also keep canned air for computer keyboards in the garage for times I just need a quick blast of something without having to fire up the compressor. I think it's strong enough to get out junk from pilot jets and main jets. If it's really gummed up take a bristle from a wire brush and shove it through there and "floss" stuff out. And do a bench test for your float valve -- after the Jets are in and the bowl is put back on the carburetor put a piece of fuel hose on the carburetor inlet and bottle feed that fuel line all the way to the top. The fuel line must be taller than the top of the carburetor. If you feel that fuel line all the way to the top and The fuel stays at the top of the line without continuing to sink, the valve is working. If you have to keep adding fuel into that line eventually the fuel will spill out of the overflow line and you'll know your float valve is not quite right.

Question: If you are fouling plugs you have a lot of fuel going to the combustion chamber, not too little. You need to make sure you have the right jetting.