750 to 900 conversion. Fuel injection to carb

[smalone50k]

Over the winter I swapped my 2000 monster 750 motor with a 2000 monster 900 motor. Before I get started on what issue I am having I would like to know has anyone else done this before? I'm having some trouble post crash. The crash was not such a bad one. Minor dents and scratches....some broken pegs etc.

After the crash I have been having some vertical cylinder issue. The carb is coughing and backfires and then the bike stalls. The flywheel is from a 750 with a brand new pickup. Would anyone have any idea where to start?

[koko64]

What type of carbs you running?

I would check the ignition wires of the coils, ignitors, plug leads and pick up. Check the carb's float bowls as a crash can shake 'em up.
Check that no inlet manifolds have come loose and are leaking.
Check your fuel pump, tap and hoses too.
That's a place to start.

[Duck-Stew]

Ensure that your timing belts are correctly lined up.  Did the bike sit for a long time w/fuel in the carbs and on its sidestand?  If so, the line between the carbs will cause the fuel from the horizontal carb to drain into the vertical carb.  The increased fuel volume (as the fuel degrades) will cause the idle jet in the vertical carb to become gummed up.  You may need to rebuild both carbs and ensure that the idle jets are indeed as clean as possible.

I'd start there.  Also, do you know for certain that the 900 was a good runner prior to installation?

[smalone50k]

Ensure that your timing belts are correctly lined up.  Did the bike sit for a long time w/fuel in the carbs and on its sidestand?  If so, the line between the carbs will cause the fuel from the horizontal carb to drain into the vertical carb.  The increased fuel volume (as the fuel degrades) will cause the idle jet in the vertical carb to become gummed up.  You may need to rebuild both carbs and ensure that the idle jets are indeed as clean as possible.

I'd start there.  Also, do you know for certain that the 900 was a good runner prior to installation?

After the conversion the bike ran mint. After the crash the bike would run on 1 cylinder. Vertical cylinder coughs after the bike chokes. Carbs rebuilt....even replaced...they are the stock carbs off a monster 750

[Howie]

You sure you have good spark on both cylinders?

[smalone50k]

Amazing spark on both cylinders..the bike will idle fine with the choke but once the choke is off the vertical cylinder starts running wonky. Really blowing my mind. Had the bike at two separate Ducati tech's and after hundred of dollars the problem still exists.

[Howie]

Do the slides move equally when you rev the engine? 

[koko64]

^^^. Howie is asking this because if the slide doesnt rise correctly than the needle will not rise to release fuel from 1/4-3/4 throttle. The choke is an enrichening circuit that is giving some extra fuel via an alternative route.

[koko64]

Sometimes a crash can dislodge the crust that builds inside some fuel tanks. I had similar symptons and went through three fuel filters in a few months until it cleared. It affected both carbs however. Howies theory is more likely with only one carb affected. Maybe the crash dislodged a slide diaphragm.

[Howie]

You should disassemble the vertical  carb, confirm the diaphragm is good and confirm every fuel and air paasge is clear.  Check float height too.  If the diaphragm  needs replacement  change them in both carbs.  Float height must be the same in both carbs.

[smalone50k]

Do the slides move equally when you rev the engine? 

Just checked...yes both slides are moving freely. I have two set of carbs and have checked all the parts and swapped them out several times.


Really racking my brain here....taking a look at the igniton next

[Speeddog]

Are you saying that the bike has the same symptoms with either set of carbs fitted?

[smalone50k]

Are you saying that the bike has the same symptoms with either set of carbs fitted?

Yes. Tried both banks....swapped between several diaphrams....have about 100 jets...just checked the ignition timing and still the same symptoms.

Going to swap coils between heads and plug wires as well.

[koko64]

Yep, best check your ignition components for sure.

[smalone50k]

Yep, best check your ignition components for sure.

Checked all off the ignition components. Swapped the coils to the opposite sides...wires as well. Pick up coil is brand new. Belts are all lined up. This is a good one. Two Ducati tech's and right now I'm in my shop with about 7 other dudes who know their shit about bikes and none of us can come up with a solution