Continuing Saga of my 2000 M750...

[krista]

imho:
read this:
http://www.factorypro.com/prod_pages/prodd08.html

Buy this (links are to my business, but can be bought anywhere):
http://ca-cycleworks.com/carburetor-wire-cleaner
... and maybe this too:
http://ca-cycleworks.com/ha013290

You don't need to take too many parts off... airbox, then loosen carbs from the manifolds. Put lots of rags down, then you can take float bowls off right there (leaving hoses and cables attached) then get out the jet that looks like this:


Make sure the intake ports are blocked off with rags/towels. Also maybe get a cardbard box that a case of soda or water comes in then rest the carbs on top of that. The purpose of rags and cardboard box is to help prevent tiny metal parts from inside carburetors falling onto or into the engine.

Look through the jet at a light. You need to see a circular dot through it from end to end. If it only is a dim glow, it is clogged. If you can't see through it, it's clogged. This is the single hardest thing to get right in a carb clean or rebuild and unless the jets come out and a wire goes through, will not unclog via other methods.

Then you poke the skinniest wire from the wire cleaner kit through it a few time to ensure that you can see light through it. You'll probably also see a small column of dirt on the tip of the wire.

Here's a good image I found on Google Images (not perfectly the same as Ducati Mikunis, but close):


The pilot jet is up in that well.

[koko64]

Very interesting.

I just used the that wire cleaner on my slow fuel jets a few days ago and I didn't realise how clogged they were. The varnish was slowly 'jetting down" the slow fuel jets. The ID was shrinking over time and leaning out the mixture to 1/4 throttle. After using the wire cleaners I had richer plug colors. I was able to go back a size with clean jets. I really underestimated the effect of the varnish. I use local premium fuels that are quite waxy with extra detergents designed for high pressure injectors, not carbs at 3 psi that many of us run. Should be an item for periodic maintenance. A fuels engineer warned me about this a few years ago. He said the very detergents that clean injectors at 40-50 psi clag jets at 3 psi. He wasn't wrong.

Something to think about.

[Javamoose]

imho:
read this:
http://www.factorypro.com/prod_pages/prodd08.html

Buy this (links are to my business, but can be bought anywhere):
http://ca-cycleworks.com/carburetor-wire-cleaner
... and maybe this too:
http://ca-cycleworks.com/ha013290

You don't need to take too many parts off... airbox, then loosen carbs from the manifolds. Put lots of rags down, then you can take float bowls off right there (leaving hoses and cables attached) then get out the jet that looks like this:


Make sure the intake ports are blocked off with rags/towels. Also maybe get a cardbard box that a case of soda or water comes in then rest the carbs on top of that. The purpose of rags and cardboard box is to help prevent tiny metal parts from inside carburetors falling onto or into the engine.

Look through the jet at a light. You need to see a circular dot through it from end to end. If it only is a dim glow, it is clogged. If you can't see through it, it's clogged. This is the single hardest thing to get right in a carb clean or rebuild and unless the jets come out and a wire goes through, will not unclog via other methods.

Then you poke the skinniest wire from the wire cleaner kit through it a few time to ensure that you can see light through it. You'll probably also see a small column of dirt on the tip of the wire.

Here's a good image I found on Google Images (not perfectly the same as Ducati Mikunis, but close):
http://www.fzrarchives.com/gallery/albums/userpics/normal_bowlrevised.JPG

The pilot jet is up in that well.

Thanks for taking the time to write that out, seems pretty straight forward.  Another question, the owner/tech at the Ducati shop out here said that the factory needles/emulsion tubes/things don't wear (only aftermarket ones) and that even with 19K miles on my bike, they are fine (said they checked them).

I'm still torn between doing this myself, or taking back to the Duc shop that charged me $500 to do it (and resisting the urge to throw it through their window) - and insisting they make it right for no extra money.

[krista]

The brass needle jet / emulsion tubes do wear with all stock parts; should be lots of talk about it on here. I would agree with it is probable they have wear at 19k miles, but do not have a feeling for how much. People that actually work on a lot of Ducks will have a better idea here. And the needle jet / emulsion tubes wear faster when a jet kit is installed.

The "Factory Pro" brand nickel plated needle jet / emulsion tubes do not wear.

[Howie]

Yes, needle jets do wear.  Pilot jets generally don't.  Inspect the needle jets with a magnifying glass.  If they look oval, replace.  If they have mileage on them since you are in there anyway, replace.  Presently I have Factory Pro needle jets with Dynojet needles in mine.  Longevity?  Don't know yet.

[Javamoose]

So, gunk in the carbs, one slow jet clogged and the other partially clogged.  Shop is saying that grit/sediment is getting past the filter, they suspect bit of the tank liner are flaking off.  Which totally sucks, since I relined the tank with the KBS Coatings kit back in 2010.  Now I'm worried to ride it because it'll likely just gunk up the carbs again.

[krista]

Get a tiny inline filter and put it right there up against the carbs. We do similar for new FCR kits we sell and attach a fuel filter right there to the carbs for exactly this reason.

Do that, go ride, be happy.

[Javamoose]

Get a tiny inline filter and put it right there up against the carbs. We do similar for new FCR kits we sell and attach a fuel filter right there to the carbs for exactly this reason.

Recommendation on a filter?  It has the normal inline fuel filter just after the tank...

Do that, go ride, be happy.

That's all I want to do! 

[krista]

Any kind at the auto store with 5/16" inlet and outlet. Here's one. They'll be on the wall by oil filters somewhere.

The smaller the better. Also buy 3 hose clamps and a little bit of 5/16" hose to go between filter and carbs.

[Javamoose]

Any kind at the auto store with 5/16" inlet and outlet. Here's one. They'll be on the wall by oil filters somewhere.

The smaller the better. Also buy 3 hose clamps and a little bit of 5/16" hose to go between filter and carbs.

So, since that looks pretty close to the other inline filter after the tank, which I'm assuming are all similar pore size...would it actually catch the stuff that is getting past the first filter?

What size are the orifices in the slow jets (I'm guessing they have the smallest, easiest to clog), because most fuel filters are around 10 micron (0.0004") pore size.  I can't imagine slow jets have that small of an orifice?

Edit:  Sorry, realize it might seem like I'm doubting your advice, and I'm not...just trying to figure things out...

[jjjrules]

That one is a paper filter. There are motorcycle specific filters you can get that will trap very fine particles - I use them on my VMX bikes

http://www.ebay.com.au/itm/2-X-GENUINE-VISU-FILTERS-1-4-6MM-MOTORCYCLE-FUEL-FILTERS-INLINE-HONDA-HARLEY-/251376583614?_trksid=p2054897.l4275

This one I have used with much success

http://www.ebay.com.au/itm/Visu-Inline-Carburetor-Fuel-Filter-for-Kawasaki-Dirt-Bikes-Motorcycle-/161139070987?_trksid=p2054897.l4276

[koko64]

I use Visu filters (the first example above "flat type"). Made in the USA. Local Yamaha/Husky dirt bike shop has them.
I like being able to see into the filter to see how full it gets and what kind of crap accumulates.

[the_Journeyman]

When you twist the throttle from idle, what is the response like?  Snappy or does it lag or hesitate before it actually throttles up?

JM

[Javamoose]

So, runs great after having the jets cleaned.  Also, I found a permanent fix for it:



Sorry guys, I'll be back in the Ducati fold some day...but for now, it's Honda love. 

[Speeddog]

Your moto soul will slowly wither away from lack of nourishment.
We pray you will realize that the appliance you are now riding is the culprit.