Backfire/hard start

[reddog]

First question! Now I get to see how great you guys really are, haha! J/k...
I have a 2007 Nomad, bought brand new early summer this year. Got 1600 miles on it. Fuel injection, mmmmm :)
So here's the scenario- my nomad starts harder than I think it should. My dads Vulcan 900 starts in 1/2 the cranks my 1600 does (maybe just the nature of a smaller engine?). Thought maybe it would get better with use, but after 1600 miles, still starts the same. Also, occasionally it will backfire on starting. Scared the spit out of me the first time, haha! Blows out right on your leg! Thought with fuel injection I would avoid backfire and hard starts more than the old carburated bike.
This might just be the nature of the beast (and it is a beast ;) ), and if so, just say so to alleviate my worries.
Thanks in advance!

[macmac]

No you are correct, something isn't right. Is this bike still all stock? No mods at all to the engine?

[reddog]

100% stock. As is from dealer.

[trosco]

Reddog, I am not trying to be smart here, this is just a question. Are you using the "Choke" that is on left front of engine by where the chrome horn is?

Well it really isn't a choke but it functions in cold starts as an assist just like chokes used to. I have a 07 nad like yours and my idle speed was low when I first got it. It was temper mental to start and would crank for a while before it did especially when cold. If I didn't get the choke pulled all the way out or give it some throttle when starting it would stall and pop off some times.
Having set on a showroom floor for 2 years probably didn't help that condition either?

[reddog]

I thought of age also, however, it was crated until ~May of this year.
As it has been 80-90 degrees here, I didn't think using the cold start would be necessary :)
Idle speed also seems to be ok, but I don't have a tach on it. Never stalled (except by my own mistake on the clutch!).

[macmac]

Which knee did you feel this on? That seems odd with an all stock intake.

Anyway since you could feel it and the bike is all stock, I would suggest as seated, you pull the right side dog bowl off...

In there you will find 2 metal objects with hoses going to them. These are Idle Solenoid Controlls (ISC's) Each one has a hose to it and leading away from it. Check that these hoses are not blown off the fittings.

If not, you will need to go deeper. The next step is to remove the backing plate.

Behind the backing plate these same hoses that turned to metal in the backing plate turn to rubber hoses again and both ends of these need to be looked at to see if they blew off back there...

There is another hose tubing back there and above to the right side of the throttle body that also could be blown off it's brass mounting port.

The othjer end of that is on the vacuum pod that runs the air to the reed valves, and is located under the tank and frame central, and the far end of that hose might be blown off too..

To see that the tank will need to be raised up some.


trosco knows the injection in part gets fuel from how much the throttle plate is open. Opening that tells the computer that there is a demand for fuel by just how much the throttle plate is open.

So the so called choke knob is locking the throttle plate at what ever point the cable has been pulled to. This does 2 things at the same time. It opens the T plate (short for throttle plate) to allow more air by and it also tells the (ecu) computer how much fuel has been demanded.

The back fire was stout indeed if you could feel it and that can lead to blowing hoses off their mountings, and will cause a big vac leak.

The term vac leak is a misnomer, but is the industry std. What a vac leak really is, is un-metered air getting to the combustion chambers, not passing thru any device it should pass thru to get there like the ISC's and or the throttle plate.

The one line to the vac pod turns on and off the pod by engine vacuum, and the pod runs air to the reed valves and then into the exhaust. The only line there that can effect intake air is the contoll hose from the throttle body to the vac pod.

[macmac]

Oh, why we need to know is many other mods remove a lot of these these items..

Don't listen to trosco either he is a wicked wise acher!

trosco someone step on yer toes er what? You always have great info to offer..

[reddog]

Thanks Mac! I'll take a look at all that when I get home tonight.
And to make things easier on all of us, instead of feeling our way around 'til you get to know me-
I'm pretty mechanically minded, do all my own engine and other work, so I understand where you're coming from when you ask questions, and can typically give decent answers if led the right direction. And I also have a pretty open and twisted sense of humor, so no worries offending or confusing me :)
If I remember correctly (which happens once in awhile), I felt the backfire from the left side, sitting on the bike.
I'll post an update soon as I check everything. Thanks!

[macmac]

Are we related?

Something must be up with trosco.... Got no idea what that might be. No one here is very delicate, but there are occasions i guess..

While each one of these bikes is an individual unto itself, most would benifit from either a TFI or Cobra fuel modual, and if nothing else was done ever... Most of these bike run way too lean in my opinion.. I had a 01 1500 that was stolen and replaced it with a 06 1600, that I have now. Both bikes got V&H baggers a cadman kit one way or another and the TFI.

Cj here aka Scott convinced me the Cobra unit is as good as the TFI, and perhaps is a smidgen easier to get set up.

There are more guys here with good info on these bikes than any other place I know. If I start naming them I will miss a bunch of them when I wouldn't want too.

trosco is one of them, and I will leave the name calling to 2.. That way everyone else can be pissed at me... Won't that be Nice?

[reddog]

I'd say we might be, but
1) Most of my relatives is from the backwoods of Kentucky and
2) I think your skill sets far outstrip mine!
For instance, if I need to heat treat something, whether it be annealing or blueing or w/e- I'll just bring it to work, haha! Sometimes there are great advantages in working for a tool manufacturing company...

[macmac]

Being cash poor does it fer me.. I can't pay and refuse to go with out..

[reddog]

Ok- pulled off my covers (both, since I hadn't checked the air filter yet) and this is what I see-
Both solenoids have one hose to them. The top fitting on both is open. Is that correct? I looked up a parts diagram online, but they're- uh- less than ideal? Yeah... The bottom ports go to two metal fittings that pass through the middle of the backing plate and go underneath the throttle body. Without completely removing it, as I'm not sure if the solenoids are the problem yet, it appears that everything else is connected. If the solenoids are correct as they are, I will remove the plate completely and check further.
I suppose I should pick up a shop manual for this bugger, eh? I tell ya, buying newer vehicles does nothing for alleviating personal shop time. I'm just going back to old vehicles when these die!

[macmac]

Yes that is correct and i was wrong.. My bike isn't stock anymore and one of the first things I did was take the ISC's off they have a hose each going to the center of the backing plate.

Right there they change to steel tubing, but for just a short distance.

If you want leave that side open, and test with WD-40. Start the engine and mist lightly right into the intake.

Listen to what ever happens. Then mist behind the backing plate aiming at the throttle body, and try to mist some past it a little and again a little up under the tank.

Between mistings wait a moment and see if any rpm change happens like it will misting into the bore directly. That first mist is to hear what to expect if you hit on a vac leak.

Try to be stingy with the WD-40, and controll how mmuch you mist, aiming for repeating the same amounts each time.

When nothing happens, after you wait aim some where else at any tubings related to the throttle body and their far ends as well.

[macmac]

A shop manual is nice, but these are not that great either.. Still it is a wise idea to have one.

I am finding errors in both mine, one for 2000 and one for 06. These are either littered with errors or showing parts there but not labling them... Lots of o rings and needle bearing show up and are not number and or counted, in the very unit they live in.. Not very impressed but it's all we got when the bike is new.

[reddog]

Hm- wd-40 idea is fairly brilliant. Used it plenty of times in the throttle body, but never as a means to find a 'vacuum' leak. I like it :)
Probably be a project for next evening.
I like the shop manuals mostly for diagrams, especially when it comes to wiring. Most of the stuff I've tore apart mechanically is fairly easy to decipher and put back together. I managed to assemble an old yamaha 400 bike that someone had took apart for no good reason without a manual. Brought in home in several cardboard boxes and an empty frame. Sold it too :) Wiring- well- I've seen curly 80's rock band hair that looked neater than some of the jobs I've seen.
Anyway- Thanks for the help!