Ignition Coils for M900

[MonsterDave]

I have a question/problem I'm hoping you guys can help with...

I have a '99 M900 that I put FCR 41's in two years ago to help solve a performance problem. The problem is when I hold the throttle open for a few seconds, it starts to cough and sputter and bog down like it's not getting enough gas. It has, on occasion, actually stalled as well. After it sits for minute, it starts fine and runs but will do it again if I get on it. It doesn't seem to be any different if the weather is warm or not. Last year I put in a new fuel pump (standard Mikuni replacement) and it seemed to help for a while but now is doing it again. I've read some articles saying that if my valves are out of adjustment, that it could cause something like this as well. Not sure if that's accurate or not in my case. I have not checked them either way yet.

Here's my question...

Will upgrading to some new 2V coils (from CA Cycleworks) solve this problem? Or is there an option of putting in a larger, more powerful fuel pump? It just seems like it's starving for gas. I know enough about motors to be somewhat dangerous but would appreciate any help anyone can provide.

Thanks,

[Nibor]

If it is starved of fuel, improving the spark with CA coils won't help that problem. That said, I would still buy them, they rock! Had them on my 97 750 for a year or so. If you had mikuni's still, I would guess it's the needles ovaled and you're actually flooding a bit. But since it's FCRs I have no clue  yet to fit my 39s.

Maybe Koko64 may have some more ideas?

[ducpainter]

It sounds like a vent issue, or possibly a fuel pump issue.

Check to see if the vent lines coming out of the rear of the tank are kinked.

Based on your post it really sounds like delivery issue.

I'd pull the fuel line from the carbs and crank the motor to be certain fuel spurts out. It won't be constant.

If it doesn't it's the pump.

If it does it could be a vent problem.

Let us know.

[ducatigirl100]

I got exacly the same symtoms  

I've got the ca cycleworks coils. And they are not the reason
my somptoms:

When it gets really hot  the bike stalls like its not getting any gas ... I stop let the bike cool down and it runs fine ....what I've ruled out so far :
Bad gas .....mmm. thats just a myth
carbs ...... spark plugs are a butiefull coffee brown
coils ......... I've put another set  of coils...same symtoms
Fuel pump...if defective the bike would not start back
vacuum hose for the fuel pump.... I've change it  ....not the problem...

From my understanding the problem seams to be electrical....... to mutch eat =no ignition

What is left  
ignition modules.... my best bet
pick up coils......got new ones 300$   not istalled wet
magneto....unlikelly but there a wire there fot the ignition

[Howie]

Direct replacement Mikuni fuel pump delivers enough volume for a V8.  Wouldn't hurt to check anyway.  Soft fuel lines can collapse, particularly the line from the pump to the carbs.  +1 on kinked lines.  If you still have the vacuum fuel shut off it could be a problem.  How is the fuel filter? 

[MonsterDave]

Thanks everyone for the response.

- I have checked the fuel lines and they appear fine. I think I'm going to replace them any way. It's a cheap fix.

- The fuel pump is new last summer.

- I will try the "pull the fuel line from the carbs" thing. It should work since the fuel pump is new but who knows?

- The bike is kept in a clean/dry garage so I don't think moisture is problem.

- I replaced the fuel filter at the same time I did the fuel pump.

- Also, fresh premium gas.

- ducatigirl100 have you ever noticed that your starter button will not work every once in a great while? Like when the bike is cold and you have to hit the starter a couple of times, does yours "miss" or not work? I just noticed that happened the last time I started it. I turned the key off and back on and it worked. Weird  (also the first time running for the year which took quite a few attempts)

This certainly sounds like a delivery problem but why? What could I be missing?

Thanks again,

[ducatigirl100]

Yes .   when I push start ..sometimes it just does the  "click" from the selenoid.... but the starter motor dosent turn...   I have a motogadget gauge ...and it tell the voltage in real time ....   the reason the starter motor dosent turn is the voltage drop when I press start. It can drop to 9v  ! So the starter motor dosent turn....

But this problem is not related it comes from ....well.... just tring to start the bike too mutch...

if you add a delevery problem the bike would not start ...period....

out of specs valves ... also not an issue...because the bike would  .. backfire and make all sorth of... "put,put,prout" noise's

A collapse vaccum  hose the goes from the fuel pump to the intake  of the vertical cylinder is a god thing to check...   if the line is to "soft" it will collapse when the full pump is functioning

The fuel pump works  like a vacuum .... it suck air in order to work...   its the same thing if you try to suck in a stray .... to mutch vacuum will collapse the stray if its to soft  and   no Pepsi will come up... as an example  

I've change that vacuum line... I've chaged that line to a really hard rubber line  ...not results

I'm looking more to the elecrical side now....

[koko64]

Do the fuel flow test and bypass the vacuum tap if you have one as was suggested.
Vacuum taps are a common failure you can search here.
CCW coils are a good upgrade you will notice over old oem coils.
You're in good hands as DP and I seek Howies advice.
Good luck and let us know how you go.

[koko64]

Gday 100.
Check the small plug to your solenoid. They come loose. Failing relay under the seat can cause that symptom. Even a sticky solenoid. Maybe corrosion at your switch, starter terminals, etc?

[ducatigirl100]

Gday 100.
Check the small plug to your solenoid. They come loose. Failing relay under the seat can cause that symptom. Even a sticky solenoid. Maybe corrosion at your switch, starter terminals, etc?

I look at the plug that goes to the selenoid ... its a old one and I add to put a ty-rap to old the plug in place ..... ahhhh  these old bikes 

[koko64]

Me too.

[MonsterDave]

OK, I've replaced the fuel lines and it still does it. Seems to be even worse than before. I'm about to remove the line from the carb to see if the fuel pump spurts or not. Should have done this before I know.

So while it did this I was trying to really pay attention to what else is going on and it seems like it's missing. It's not a total audible miss as much as something I can feel. Kind of jerky.

Thoughts?

[koko64]

Do the fuel flow tests suggested to identify or rule out a fuel supply issue. If there is plenty of fuel flowing then you can turn your attention to other issues like ignition/spark.

[ducatigirl100]

Do the fuel flow tests suggested to identify or rule out a fuel supply issue. If there is plenty of fuel flowing then you can turn your attention to other issues like ignition/spark.

this... 

[MonsterDave]

Ok, just pulled the fuel line off the carb and I have plenty of fuel coming out. Never even got the chance to hit the starter gas was coming out so much.

Next?