Bike stalls after starting up and flat spot off idle

[mendonjo]

Hello Everyone,

I'm pretty new to EH ownership (s/n 1315) but am having a few issues I was hoping to get some guidance on.

Firstly the bike has 12.9k miles on it, I bought it with the updated air filter support and a super wide air filter.  It has slash cut mufflers and the gas is fresh.  After I got the bike I sent the ECM to Atlantic for the Super X tune but the problems I will describe still remain.

Problem:  When I start the bike it fires right up - for about one second and then it dies.  Sometimes I have to do this 3 or 4 times before it will stay running.

Problem 2:  It has a definite weak spot off idle.  It gets much better when the bike is hot but when its cold/warm I have to keep blipping the throttle to keep from dying right off idle.

The IAC does indeed move, the plugs are newish.  Any ideas would be much appreciated.

Joe

[Donkey Hotey]

My first guess and probably correct one is going to be bad o rings on the fuel regulator and where the regulator mates to the pump. I’ve had two bikes with the exact same symptoms and it was a lack of fuel pressure getting to the injectors. If those o rings are bad the pump can work as hard as it wants and the o rings just dump it all back into the tank.

The rough and erratic idle may also be partly due to a bad vacuum plug on the throttle body. Make sure that thing is sealed.

The slightly less possible problem would be leaking intake seals on the manifild at the heads. Basically if air is leaking into the intake the idle air controller works overtime trying to open and close to maintain a constant idle.

Oh, and welcome aboard. These bikes are really a treasure to have.

[mendonjo]

Thanks Greg!  I bet that's it.  I noticed too when restarting the bike jus after it died the fuel pump was going full blast.  In retrospect that seemed kinda odd, it only ran for half a second why does the fuel pump need to be working so hard ?

Are the O rings something I have to get from Atlantic or does someone know where to get Viton rings ?  (Harbor freight, Autozone, etc)

I sure am glad to have a path to follow - thanks again Greg.

Joe

[Donkey Hotey]

There are a couple of different sizes between all of them. You have to carefully pull back the fingers holding the regulator in place to get it apart. There are two different diameters there and a third between the pump outlet and the regulator housing. You could carefully measure them all and get them from McMaster but then you’re buying packages of them for 1 or 2 rings. I’d just order them from Atlantic.

They also have the newer, better sock type filter to put on the inlet. The inlet screen that the factory used is usually toast from the alcohol in the gas. Again: available elsewhere but it’ll take you time to research and find it. Or just buy theirs. 

You also need to use a zip tie or two to make sure the flexible plastic fuel hose is held in position properly or it leaks too. There are photos around here of what that looks like when it’s right.

It helps to make a puller to get the pump out. You can probably make your own with a big black ABS sewer pipe cap with a hole drilled in the center. Get one larger than the tank flange and then a screw that fits the center of the fuel pump.

[mendonjo]

Shoot .  I will post a pic on the facebook page because i cant seem to here but the pump came out fine.  One oring between the regulator housing and the brass pump nipple.  Everthing seemed ok

[Donkey Hotey]

There are also two o rings sealing the regulator to the plastic regulator body. That’s the thing with the metal fingers in the upper left corner of your photo. Those also need to be checked / replaced. 

[mendonjo]

Yep I took the regulator apart too.  The O rings were a little gooey.  Only four O rings in total?  The big one at the base, the transfer nipple from the pump to the regulator, and the two in the regulator?

Thank you!

[mendonjo]

On second inspection the regulator O rings looked pretty bad.  Ordered everything from Atlantic li

[Donkey Hotey]

Those o rings were shot on two of my bikes when I bought them. There’s a fair chance that’s all that was wrong with yours. Post how it turns out. It’ll help others in the future.

[wytfut]

glad you guys got that figured out... cool...
apparently I was enjoying thanksgiving too much... missed all of this until now...

note on those O rings between regulator and pump.... I had one fit so poorly I had to take stailess steel wire (kept breaking off zippys) to hold the reg snug to pump....   for what ever reason that regulator metal housing really isn't machine fit tight, or too tight...
Pulled that pum 3 times by the time I got it snug enuff...

Bruce

[Donkey Hotey]

Bruce, how did you discover that was where it was leaking? Man, that would be frustrating to have to find. I think most people find the o-rings on the pump snout but, don't realize there are two more hiding there on that regulator.

1989 took a tow truck ride home after much erratic running before I discovered those extra two o-rings in there.

[wytfut]

Greg....
It just wasn't fitting correctly... By touch... Kept trying to pop off... Were my only clues...
Sorry for SLO replies... Holiday and my wife is getting hip replaced today...  Haven't had much X time lately..
Bruce

[mendonjo]

Hello Wytfut,

when you say "note on those O rings between regulator and pump.... I had one fit so poorly "  do you mean the regulator to the plastic housing it fits into which is held in place by a stainless clamp or the regulator housing to the pump (brass nipple)?

Joe

[wytfut]

Been a while since I've been in there..
And there isnt an exploded ... To remind me. I also was talking to Marty today about 3D building that plastic part for her.
I'm pretty sure yes......     
I definitely remember which X it was...  Fuel system was a mess

[Donkey Hotey]

Joe? Any news? Did your bike start or has snow done you in for the season?