Starting up carb’d monster after 5 years

[SpikeC]

 You know, carburetor is Latin for "don't make the beast with two backs with this!"

[joshuajcrouch]

In case anyone is following along...

Tried firing it up again Sunday evening.  Same results as before.  Motor won't idle unless I drip fuel into the intake.  Bike runs fine if I give it throttle.  Occasional backfire through the right side intake.  The backfiring only happens if the bike stalls while trying to rev the engine with throttle.

Tried again this afternoon.  Results slightly different.  Motor idles with fuel manually dripped through the intake.  Now it doesn't want to rev evenly when throttle is applied.  Motor revs up and down with consistent throttle and then eventually stalls.  Weird!  Wondering if the other jets are starting to clog or if something else is going on.

I am slowly coming to the conclusion that I will need to pull the carbs to clean them

[joshuajcrouch]

Maybe another dumb question... after further inspection of the airbox (thinking about the removal process) I noticed one of the coils on top of the airbox had a plug that was unplugged.  Looked like an electrical wire.

It will be a few days before I can try starting up the bike again, so I was wondering if that could have contributed to the lack of idle consistency?

[ducpainter]

Maybe another dumb question... after further inspection of the airbox (thinking about the removal process) I noticed one of the coils on top of the airbox had a plug that was unplugged.  Looked like an electrical wire.

It will be a few days before I can try starting up the bike again, so I was wondering if that could have contributed to the lack of idle consistency?

It was probably running on one cylinder.

[joshuajcrouch]

It was probably running on one cylinder.

I thought one cylinder felt warmer than the other.  Would that contribute to any of the symptoms I was experiencing?

[ducpainter]

I thought one cylinder felt warmer than the other.  Would that contribute to any of the symptoms I was experiencing?

Ya think? 

[joshuajcrouch]

Ya think?  

Ok so maybe that was a dumb question.  Just grasping at straws here...

Another update since I couldn't wait any longer.  I plugged the coil back in and decided to increase the idle speed to see if that would help improve things.  Sadly I am still running on one cylinder.  The horizontal was pretty warm/hot to the touch, the vertical was dead cold.  I pulled the spark plug from the vertical cylinder and it was dry.  I am wondering if the vertical cylinder is even getting fuel at all.  Maybe that is why it only runs if manually drip fuel into the intake.

Could this be due to a plugged pilot jet?  What else should I trouble shoot to figure out why the vertical cylinder isn't firing?

Thanks everyone for your patience with me

[joshuajcrouch]

After some further thought, I think the vertical cylinder was firing when I first starting trying to fire up the bike a few days ago.  The only reason that I think that is because it seems like the vertical cylinder was a lot warmer to the touch last time.  Maybe this is why the bike won't let me rev into the higher RPMs anymore.

Could one of my floats be stuck open?  Would one of the bowls be empty if I tried removing one of the drain screws?

[Ddan]

You could open the drain and see what comes out, but if nothing does, you won't know whether there's no fuel or it's just the drain is blocked from 5 years of accumulated crud. The chances of the carbs not being all crapped up  is really pretty slim, you might as well bite the bullet, take them off and clean them.  Then you'll know they're OK and can move on to the next problem.

[ducpainter]

Ok so maybe that was a dumb question.  Just grasping at straws here...

Another update since I couldn't wait any longer.  I plugged the coil back in and decided to increase the idle speed to see if that would help improve things.  Sadly I am still running on one cylinder.  The horizontal was pretty warm/hot to the touch, the vertical was dead cold.  I pulled the spark plug from the vertical cylinder and it was dry.  I am wondering if the vertical cylinder is even getting fuel at all.  Maybe that is why it only runs if manually drip fuel into the intake.

Could this be due to a plugged pilot jet?  What else should I trouble shoot to figure out why the vertical cylinder isn't firing?

Thanks everyone for your patience with me

Sorry for being a wiseass...sometimes I just can't help myself.

If the cylinder was getting fuel and it wasn't firing the plug it would be soaking wet.

I'm going to agree with Ddan that it's time to clean the carbs.

[dlearl476]

Sorry for being a wiseass...sometimes I just can't help myself.

If the cylinder was getting fuel and it wasn't firing the plug it would be soaking wet.

I'm going to agree with Ddan that it's time to clean the carbs.

+1

From personal experience you'll just be chasing your tail until you have a professional do it right (if you can't do it yourself). $150 and a new pair of spark plugs and a new idle jet later, the M900 is running like a champ again.

(I put it up last fall when I went on a three month tour and when I got back it was getting 31mpg vs it's usual 42-44)

[joshuajcrouch]

+1

From personal experience you'll just be chasing your tail until you have a professional do it right (if you can't do it yourself). $150 and a new pair of spark plugs and a new idle jet later, the M900 is running like a champ again.

(I put it up last fall when I went on a three month tour and when I got back it was getting 31mpg vs it's usual 42-44)

Thanks for the feedback.  I am going to work on removing the carbs next.  I will atleast crack them open myself to see what I am getting into.  I do have a manual so I think I can get through it myself.  Worst case scenario I can always call on you guys if I get stuck

Out of curiosity, did you pay $150 to have someone else service your carbs?  If so, who did that work for you?

Joshua

[dlearl476]

Out of curiosity, did you pay $150 to have someone else service your carbs?  If so, who did that work for you?

Joshua

Among other things yes. Last year I moved from 4500 ft to sea level and the FCRs developed some idle mixture/jet  issues. At the time I was uncertain if I was going keep the bike here so I just adjusted the idle mixture. After leaving it in storage most of the fall, and deciding to keep it here, I took it in for a little more extensive work which involved cleaning the carbs, changing idle jets, (? ) changing the spark plugs and re-dynoing to set CO levels because my mpg had dropped do radically.

On my way home from the shop I got 39 mpg, which is good considering the crap gas they make us run in the winter.

The bill for all the work was $150. ECS in Middletown did the (great,as usual) work.

[J5]

carbs are easy 

strip them down

best bet would be take them to a carb guy that can stick them in the ultrasonic cleaner

which wont cost a lot and you will know they will be clean in and out

[garryc]

i pulled the carbs apart in my M600 put in new needle jet holders, stage 2 jet kit, reset float height and replaced the bits inside with a kit. Also replaced vacuum tap with manual tap and replaced fuel pump at the same time
never done this before, so armed with a haynes manual and
http://www.ducatisuite.com/jetkit.html.

Biggest pain is what you have to remove to get to the carbs but all steps are straight forward and well explained in the above.
Decided to road test my carb rebuild by going on a 600 k trip as it felt great around town.
As soon as I got out of town I would try to open throttle at about 5500 rpm and nothing.
On return checked plugs they looked nicely tan.
thought I must have done something wrong.
Took the little horn things off the airbox and it is completely cured.
Sure it is only a 600 but roll throttle on from 5500 rpm and it just revs away.
I say give it a go