Vulcan Nomad 1600 FI red hot exhaust manifold

[vulcanray]

Hi everyone! I'm new to the forum so I thought I would introduce myself. I'm Ray from Calgary Alberta, Canada.

I recently bought a 2002 Vulcan Nomad 1500 FI. Beautiful bike and beautiful condition but needed a few things done. Lots of help found on this forum and others! Thanks to all for their posts!

While I sorted out some minor issues, I now have one bigger one. I hated the kuryakin hypercharger in the way of my leg. The bike had all the original air intake stuff in a box from when the hypercharger was installed. It was a bit of a task but I removed the hypercharger system and put the original parts back in. The bike starts and runs fine and actually idles better than it did before. The problem I have is that at least the rear cylinder is running too hot. Red hot exhaust manifold pipe after running just a few minutes. Also backfires on deceleration.

I know this means it's running too rich, causing unburned fuel to be burnt in the pipe but I don't know why. I should mention that it has a cobra exhaust system, not factory.

I changed the plugs and checked all the old ones as I took them out. They all looked like they were burning fine. Put the new plugs in and same thing happens.

Reed valves had been removed and the plate mod done. Air intake has had the solenoids removed and all holes blocked (unused small vacuum lines And large hole for the unused tube from the baffle system for the reed valves). Vacuum ports on air intake manifold plugged.

I've seen some posts that say something else has to be done when removing the hypercharger system. I don't think this has been chipped or has had the ignition modified.

I've watched some videos about how simple the open loop fuel injection system is. Doesn't seem like there's any adjustment there.

I'll mention again that this condition did not happen before I swapped the air intake system.

Any advice would be appreciated!

[redjay]

Are you sure the rear exhaust header pipe is not cracked ? Some bikes had issues like you described. In their case the rear header pipe was cracked near the head but if I remember correctly this was with Vance and Hines header pipes, not the Cobra header pipes. Have you checked under the seat to see if it has an aftermarket fuel processor. It could be that the unit has malfunctioned. Disconnect it at the battery and see if it still overheats.

[vulcanray]

No aftermarket control module present. No cracks. As I mentioned, this only started after I removed the kuryakin hypercharger and reinstalled the factory intake system. I have triple-checked all of the vacuum lines etc to make sure nothing got unhooked during the process but obviously something has changed.

[redjay]

Have you been on Youtube and checked videos of a hypercharger install or tried to find install instructions online for your bike ?


Is there anything in this link that can help with regard to what to plug etc ? Take a look at other articles on Gadgets page. There might be something there that can help you.

https://gadgetsfixitpage.com/article...ann-intake-kit

Maybe something in this link ?

[redjay]

Originally Posted by vulcanray

No aftermarket control module present. No cracks. As I mentioned, this only started after I removed the kuryakin hypercharger and reinstalled the factory intake system. I have triple-checked all of the vacuum lines etc to make sure nothing got unhooked during the process but obviously something has changed.

Did you find the problem ?

[andyvh1959]

If its not spitting fuel backwards into the intake it is not backfiring. What you perceive as backfiring is only exhaust popping on decel with the clutch out. Next time it happens, pull in the clutch and the popping should stop immediately. The popping is casued by a lean condition on closed throttle when the momentum of the bike (clutch out) is trying to turn the engine over and demanding more air/fuel.

Does your bike have modified or aftermarket exhaust? ANY change to the exhaust to make it breathe more free also leans out the fuel/air mix, which leads to more popping. Also, modded or aftermarket exhaust don't have enough exhaust noise damping to queit down the popping. Some ways to decreses the exhaust popping on clutch out decel:
1. Pull in the clutch, though many times this is not the best choice for riding
2. Put the stock/unmodified exhaust back on the bike, same for the intake
3. Install a fuel management system to richen up the fuel/air mix on idle

That 3rd option works for sure. I modded the exhaust on some bikes, on one I built my own muffler. All were more free breathing and all created popping on decel. I added a Power Commander or Techlusion EFI system and I "dialed" out the decel popping. But also know that closed throttle exhaust popping can not and will never damage the engine, its just noise, no harm at all.

[DragonLady58]

Pretty much what they said....but I will say this, for the rear pipe to run that hot, you definitely got a problem.
If I were you, if you don't have a tuner, I'd get one....at least you can tune the bike some.

The 1500/1600 platform is a great bike, durable, long lasting, dependable....and it won't let you down down unless you just ride the crap outta it and neglect it.
Also, you might wanna check your intake for leaks & check your injectors are spraying as they should.
Are you sure the rear plugs are the right plugs....for it to get that hot that fast, the rear pipe glowing red after just a minute of runtime is usually air leak, injector clogged, wrong plugs installed, I've even seen wrong coils installed causing this condition....