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Discussion Starter #1
Hello all,
I just posted a thread in the introductory section to introduce myself. I've searched the forums for my particular problem and have not been able to find the answer so I'm hoping you all can help.

Last week I did the acct to mcct conversion that a lot of you have done and until yesterday afternoon the bike was running better than ever. My wife and I went on a short ride, then went for dinner. After dinner, the bike would not start easily, and when I got it started it backfired and popped in first and second gear. When I was in 3rd and 4th gear it had more power and less popping. Every time I came to a stop or slowed down the bike would die or almost die.
There was a strong smell of gas, but I couldn't see any leakage once I got home and parked. The rear plugs are wet with gas, and the front plugs are wet with what I believe is oil and not carbon.
Any chance this is related to the mcct conversion?
 

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I doubt your installation of the mcct has anything to do with this, especially after you said the bike was running great.

My first guess is a stuck float, causing fuel to run into your intake. Check for gas in the oil. So try the back-blow method and some seafoam.
 

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Discussion Starter #3
What are your thoughts about the oil on the front plugs? I am worried it's a seal. Would that happen seemingly out of nowhere?
 

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I think once you get the motor running properly again it will go away. Piston walls are oiled and if you get too much fuel in the combustion chamber it can wash the oil off and deposit it on the plugs (and valves)
The only way for oil (and just oil) to foul a plug is if the rings are severely worn or you have a valve that's not sealing. You'd likely notice this by loss of power, or by doing a compression check.
 

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Discussion Starter #5
Ok, thanks so much. I have been afraid that I was going to be pulling out the engine. I'm going to do a compression check tomorrow. I'll do what you suggested first. I hope that's all it is. It would certainly explain oil and gas on the plugs at the same time and the strong smell of gas while riding. I also have a 98 Sportster and am not keen on resorting to riding that with my wife on the back.
 

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Discussion Starter #6
So I cleaned the plugs and did the back blow to the carbs. I was able to start it and drive it a while with seafoam in the tank but it is still having trouble in first and second gears. Sounds and acts almost normal in higher gears. Still lots of noise coming from the right tail pipe. Looks like gas coming out of the pipe also. Strangely the rpms are erratic now.
 

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Dirty pilot jet(s) maybe. Or dirty carbs all around, stuck float.
 

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Discussion Starter #8
Looks like im pulling the carbs and if i do that I might as well do the ear shave. Last time i rebuilt the carbs i did it with the surge tank in place. That was not much fun. Thanks for the advice people! I will need more.


Sent from my iPhone using Tapatalk
 

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First do a compression check. That will confirm or eliminate low compression as a problem. No sense in doing a lot of work for nothing. If the compression is ok, then I would completely disassemble and clean the carbs. If you have never worked on Vulcan 750 carbs before, they are very different than most carbs. They are basically 2 carbs designed as a single assembly, the float chamber is all one piece. I advise against doing the earshave thing, but that's up to you. I have found that reinstalling the carbs with the stock airbox is not as difficult as many say.

I see no way that replacing the cam chain tensioners could possibly have anything to do with the problems you are describing. How did you do the cam chain tensioners? Did you use the TOC tensioners, or did you convert the ACCTs to MCCTs? I highly recommend and use the TOC tensioners.
 

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Discussion Starter #10
Hey thank you for the response. I rebuilt these carbs a couple of years ago. I had a frustratingly difficult time getting them back in with the surge tank in the bike. I'm interested to know why you don't recommend the ear shave procedure. My reticence to do it is particulates. Is there an engine performance drawback?

I did my own mcct conversion based on what I read in these forums. I didn't JB weld a 10mm nut inside the housing. I was pretty uneasy about adjusting the screw to be honest. The bike was running great after I did the conversion but I can't say I could hear a difference with 2 or 3 turns in or out.

Is the TOC housing the primary reason to use their conversion?
 

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I don't recommend the earshave thing for a couple of reasons. It can lean out the air/fuel mixture and require rejetting the carbs. But the main reason is the filter most people use to do it. I have done enough research on K&N type filters that I am certain that they do not filter nearly as well as the stock filters. However there is another way to do it, and that is to use foam UNI pod type filters, and keep them oiled. With both the K&N type or the foam UNI filters, it is the oil that stops the dirt. But I don't believe the K&N type has enough surface area to filter properly even when kept oiled. You can see through an unoiled K&N, you can't see through an unoiled UNI.

I don't recommend converting the oem tensioners to manual also for two reasons. One is that they are cast aluminum, and not very strong. The chains pound on the tensioners really hard, and I'm afraid of the housings cracking. And without the nut on the inside, you are basically using very small threads only designed to hold the cap over the adjuster screw to put tension on the chains. I can't see them lasting very long. A company called TOC Manual Tensioner makes solid steel manual tensioners that are about as bulletproof as you can get. I used them on my '02 from about 25,000 miles until 108,000 miles, when the engine finally failed due to a broken cam chain. It is likely I damaged the cam chains early on, I let them rattle for a while, then replaced them with new oem tensioners which only lasted about 10,000 miles before the rattling came back. That's when I got the TOC tensioners. I'm going to use the ones from my '02 on my recently purchased 21,000 mile '97.

As for removing/installing the carbs with the stock intake system, here is a copy and paste from another thread I posted this on.


First of all, you need to remove the tank, and have a good flashlight. There are 4 rubber connectors, 2 elbows that go between the carbs and the heads, and two ducts that go between the carbs and airbox. All 4 of these are different. it is important to know where each one goes. First, remove both air filter housings. They prevent the airbox from being moved up. Then wrap something around the bottom of the airbox and around the frame to hold it up. Otherwise it will try to drop when you remove the ducts between the carbs and airbox. The ducts are a bit difficult to get out of the airbox. Squeeze them a round a bit, and spray plenty of WD-40 around where they fit into the airbox. Make sure they are not stuck. You will have to flatten them out a little with your hands to get them out of the airbox. The WD-40 helps a lot. It makes them really slippery. Do not remove the throttle cables. once you have the carb to airbox ducts removed, make sure the airbox is as high as you can get it and is held tightly inn place, This gives you room above the carbs to work. Next, remove the carburetors. Leave the rubber elbow attached to the front cylinder head, and the rear rubber elbow attached to the rear carburetor. Once everything is loose, spray some WD-40 on everything, then wiggle the carburetor assembly out from the right side, then remove the cables. It may seem like the carburetors won't fit through the opening on the right side, but they will. They just have to be oriented correctly and they come right out.



Now, take a look at the Rubber ducts that go between the carburetors and the airbox. You will notice there is some extra rubber around the top, where the ducts connect to the airbox, and it is very stiff. Notice that there is a groove in the ducts. This groove fits in the airbox, and holds the duct in place. The bottom edge has to be outside the airbox, the inside has to be inside the airbox. It fits kind of like a rubber grommet. The hardest part of putting everything back together if making the ducts fit back in the holes in the bottom of the airbox. The problem is the really stiff rubber at the top of the ducts. I took a box cutter knife, and VERY CAREFULLY trimmed off some of this rubber, to make the duct a lot more flexible. DO NOT get too close to the groove. With some of that rubber cut off, the duct will be a lot more flexible. You can usually pop them in with your fingers, but if not, use a piece of 1/4" wood dowel rod with the rough edges sanded down. DO NOT use a screwdriver. That rubber is real easy to poke a hole in. That mistake cost me $65 once. Once the ducts are snapped in all the way around, you can tell by looking at them whether they are seated properly. The bottom ridge of the groove should be even all the way around, and the duct should turn in the airbox. The fit between the airbox and the groove in the rubber ducts is what seals them. I did this mod at about 30,000 miles on my '02, and it lasted to 108,000 when a cam chain broke. You need to make sure that all the rubber ducts and elbows are in the right place and oriented properly. They have little rubber tabs on them to help align them. This is not a fast job, but it does not have to be difficult. Everything does fit. If it doesn't there is a reason. Just use plenty of WD-40, and all the rubber parts will go together easily. It's kind of like mounting a tire. To me that is an easy job, but there are those that just don't seem to get it. I have replaced a lot of rear tires on Vulcan 750s, and never had any problems. Others will tell you that you have to have a tire mounting machine.
 

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Discussion Starter #12
I appreciate the thorough response. I'm not planning to continue using the mcct tensioner as is. I have been planning to glue a nut to the inside until I have some scratch for the TOC tensioners. I don't feel great about the stock housing either.

Some great advice regarding reinstalling the carbs with the surge tank installed. It's been raining for days here in North New Jersey and I'm without a garage. It's driving me nuts not to be able to troubleshoot right now.

A 5 gallon bucket and some levers make an excellent tire mounting machine btw.
 

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A 5 gallon bucket and some levers make an excellent tire mounting machine btw.
Zipties! Lets you slip the tire on with your bare hands, and no wheel damage.
 

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Please explain.
There's many youtubes about it, most make it look harder than it should be. I just picked this one because it's short for you, and saved me typing it out.

If you're going to try it later, I can give some tips. One thing I haven't seen anyone do... I stand the wheel up, hold the spoke in one hand, and pop the tire on with the other. He would've been much quicker in the video if he'd started with some soap, but this shows the gist of how it works.

So far I've done my Vulcan, a V-Rod, and a Boulevard. Front/rear on all three. Hardest part is breaking the bead, if I keep it up I'll spend $100 on this bead breaker.

Beadbuster There are others available similar to this one.
https://beadbuster.com/

 

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Discussion Starter #16
That is fantastic. I changed mine this fall. I am sure I put a few gouges in my wheels. I used a 2 x 4 and a piece of scrap wood under the edge of my car to break the beads. It was easier than I thought it was going to be. At one point I thought I was going to break the leverage board.
 

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That is fantastic. I changed mine this fall. I am sure I put a few gouges in my wheels. I used a 2 x 4 and a piece of scrap wood under the edge of my car to break the beads. It was easier than I thought it was going to be. At one point I thought I was going to break the leverage board.

I break tractor and atv beads by driving up onto the sidewalls. That Beadbuster looks fantastic to me, and a lot smaller to keep around than conventional bead breakers.

The Vulcan has nearly perfect wheels, so I used a 2x4 block and a large c-clamp to break the bead.

On my 2nd wheel I decided to try mounting with the tire standing up. Seat the wheel in at the bottom of the tire, push the wheel spoke away from you and pull the top of tire toward you.

Have to squeeze the beads together while tightening the zipties, end with the beads touching each other all the way around. Thinnest ziptie that doesn't break is best. I connected two together to make one wrap.
 

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Discussion Starter #18
Yeah i've seen that one. I would not fight not having to drag everything out to the car. I grew up changing the tires on my dad's tubeless Kenworth tires. A couple of good blows with a bead breaking hammer and it was done. I'm kindof surprised those aluminum wheels stood up to the abuse. I wasn't that careful.
 

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Last set of atv wheels, I made about 10 passes with the truck on each wheel, turning the tire between every other pass. Also left the truck parked on the tire overnight a couple of times, and hosed the beads with 5-56 in the spot that was pressed down. When I came out the next morning bead was down. Tire shop told me to leave a little air in them next time, zipties wouldn't work on those. I trussed two of them up and immediately saw they weren't going on that way.

Semi tires seem to break easy with that bar. I think the beads are formed differently and the 90psi air keeps them on the bead. My Peterbilt tractor had 14 Alcoa wheels, had them all off/on in one day, I didn't want to do that again.

Road service would come out, peel both dual tires off and change tires leaving the wheels on.
 

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Discussion Starter #20
Last set of atv wheels, I made about 10 passes with the truck on each wheel, turning the tire between every other pass. Also left the truck parked on the tire overnight a couple of times, and hosed the beads with 5-56 in the spot that was pressed down. When I came out the next morning bead was down. Tire shop told me to leave a little air in them next time, zipties wouldn't work on those. I trussed two of them up and immediately saw they weren't going on that way.

Semi tires seem to break easy with that bar. I think the beads are formed differently and the 90psi air keeps them on the bead. My Peterbilt tractor had 14 Alcoa wheels, had them all off/on in one day, I didn't want to do that again.

Road service would come out, peel both dual tires off and change tires leaving the wheels on.

What did you haul? My dad did cross country runs until I was about 15. He bought a reefer and started doing a produce circuit run from Los Angeles, to Northern Cali, then to Santa Fe and back to LA. Now he and his youngest brother run their dad's diesel mechanic shop in New Mexico. I spent a lot of time driving around the country in a truck rather than hang with my friends in the summer time.
 
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