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Discussion Starter · #1 ·
First thing first:
1995 900ss cr
15,000
Had it for 3 years only put 200 miles on it and has been mostly sitting. I know I know but I'm coming around to finally ride it.
It's always started poorly and bumpy (rpm)

I'll try to make this sweet and simple. Firstly I'm a noob and I'm not familiar with carbs or motorcycles but I think I can hold my own.
I'll be doing the work myself.

I've also read about 8 threads on this but they off track.

It's been a year or so since I turned my bike on. The last time was when I filled her up of gas and it was leaking gas from the overflow tube.
I didnt end up riding cause I didnt want some of that gas burning up on the exhaust and perhaps catching the bike on fire.

So I put her away the worst way possible... just left it on it's own for a just over a year.
Eventually the tank was emptied out on it's own. I thought it leaked out...

Actually fuel was in the crankcase and I just emptied the thing.

https://youtu.be/hxN-awS_sc0

My floats are most likely stuck open so now i have to take the bike apart and fix that.
There is a video on youtube to help me with the removal process.

Now... I know the stock carbs arent exactly reliable and peices go bad.
I know there are rebuilt kits.
I've done research now for 2 days and I cant find what I need.
All I need is a link so I can buy a reliable kit to fix the stock carbs.
I'm not sure which kit I need or brand.
I cant afford new $1500 keihens carbs or used $800 ones.

If you can take it easy on me that would also be appreciated.
Thanks in advanced to whoever can help an idiot in need.
 

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Discussion Starter · #2 ·
Also... since my whole motor got full of fuel... what else do I need to do?
Do I have to take apart the motor as well? Or would running the motor with new oil and after the carbs are done be good to go?
I was told the pistons might be full of fuel as well.

I just dumped all the oil and took the filter off, nothing else is coming out.
 

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First thing first:

I know there are rebuilt kits.
I've done research now for 2 days and I cant find what I need.
All I need is a link so I can buy a reliable kit to fix the stock carbs.
I'm not sure which kit I need or brand.

Thanks in advanced to whoever can help an idiot in need.
I am assuming that you have the stock BDST 38mm Mikuni carbs.

It is highly likely that a rebuild is required. Your idle jets will likely be badly clogged. You will need to physically clear them with a length of guitar string. Other things might work, but a guitar string is of a known diameter so you don't accidentally ream out the idle jet to a larger size.

I got my kit from a company in Thailand called LiteTek.
https://litetek.co/Carb_Kit_Ducati.html

Good quality product at very reasonable prices.

As I don't know what kind of maintenance history you have on the carbs, you'll want to replace the emulsion tubes which have a nasty habit of "ovaling" where the needle slide moves within them.

I got Factory Pro titanium needles and then new emulsion tubes from Bike Bandit or Partsfish or other online parts house. I got emulsion tubes (needle jets) for a Yamaha TDM850. The TDM uses the same 38mm Mikunis.

Hope that helps. If you can swing it, I can highly recommend https://customcarbservices.com/

Based on personal experience, as a satisfied customer. Hope this is all of some help......sean
 

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Discussion Starter · #4 ·
I am assuming that you have the stock BDST 38mm Mikuni carbs.

It is highly likely that a rebuild is required. Your idle jets will likely be badly clogged. You will need to physically clear them with a length of guitar string. Other things might work, but a guitar string is of a known diameter so you don't accidentally ream out the idle jet to a larger size.

I got my kit from a company in Thailand called LiteTek.
https://litetek.co/Carb_Kit_Ducati.html

Good quality product at very reasonable prices.

As I don't know what kind of maintenance history you have on the carbs, you'll want to replace the emulsion tubes which have a nasty habit of "ovaling" where the needle slide moves within them.

I got Factory Pro titanium needles and then new emulsion tubes from Bike Bandit or Partsfish or other online parts house. I got emulsion tubes (needle jets) for a Yamaha TDM850. The TDM uses the same 38mm Mikunis.

Hope that helps. If you can swing it, I can highly recommend https://customcarbservices.com/

Based on personal experience, as a satisfied customer. Hope this is all of some help......sean
Stock yes... service i've never done any to it nor do I know if the previous owner did or not.

I'll look for the rebuilt kit you mentioned on that site.
Good thing I own 8 guitars.

I'll look for Factory Pro titanium needles for my application and emulsion tubes for a Yamaha TDM850 on ebay or wherever.

Also "customcarbservices.com" can just do the work on the carbs themselves if I ship it to them? They're in New York I'm in California.
I'll see if I contact them and ask for what I need.

Thanks for the help.
 

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See my post for the basics
https://www.ducati.ms/forums/241-tech-forum/719105-mikuni-bdst38-carburetors.html

Re the engine full of fuel - you've already drained the engine's crankcase. Put the bike on a rear wheel stand, remove the spark plugs, and put the bike in 4th or 5th gear and slowly turn the engine over to clear any fuel out of the combustion chambers. You may want bungie rags over but not near the plug holes to prevent the gas from getting everywhere. Note that there still may be gas in the front cylinder's exhaust pipe, but should not be that much if any. Let the bike sit so that any remining gas evaps out of the cyls but keep the rags over the plug holes to prevent anything from entering. Turn the bike over again with the rear wheel. If no gas is now spraying out of the plug holes, you are done - button it up, replace the oil filter and fill with Mob 1 15-50.

Once you do the carbs, you'll be ready to restart the engine, but you will have to balance the carbs when the bike is up to temperature. Don't let it idle to do this - get it close, ride it and then balance them
 

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Jaime - I would not bother trying to clean the starter (idle) jets. These are right on the jet block and are easy to remove - one for each carb. Buy new ones - most of the rebuild kits will come with them. Then, when you feel like it, screw around with the dirty starter jets later. Check them but the rest of the jets are much larger in ID so they are probably OK, but I would clean them nonetheless. And blow air or carb cleaner through the rest of the passages in the carbs. The BDST38's that you probably have are easy to work with - just go slow and methodically. There are also youtube vids out there for rebuilding them, plus a how to on the link I sent above.
 

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I guess the first question is how much of a gambling man are you?

Two separate issues... well maybe three if we count the tank.

Lets start with the tank first as it is easiest.

1. rusted?
2. green gas eating hoses?
3. varnished?

fix those.

Carburetor

If possible I would get them ultrasonically cleaned, it is not a guarantee but it does help a lot. Change your jets and keep them the same brand as you had unless you are changing jetting. Ie: if you have a factory jet kit do not replace with dynojet , EBC or jets made in soome third world counter that are not labeled. If you do simply know that a jet will meter different fuel even though it has the same number printed on it. I have dyno proof of this, make your life easier insist on staying with one brand jets are marked with a makers mark for a reason usually.

All parts should be available from Ducati as well as the TDM850 so you should be able to get what you need though you never specified what you do need.

The carbs are reliable as far as carbs go no better or worse than others from a reliability standpoint but you can not leave fuel in a carb long without causing harm, you know that now. It is all fixable and if you farm out what you cannot do and do the rest yourself you should be able to have them running fine in no time. Resist the urge to take too much apart as I see many more issues caused by well meaning people than problems solved. Focus on the problems and do not fix things that are not broke. I have bikes with FCR's and still run thee same carbs on my 750ss track bike, they work just fine.

The engine has gas because a float stuck which may have been caused from debris in the tank sticking the float. Either way if you left the cases filled with gasoline you may have no issues or need a rebuild. This is where we get to see if you like to gamble.

1. scenario you put in fresh oil and run it for a short period of time and then change it kind of like a flush. If the bike does not smoke excessively or it does but stops doing so the cylinders are fine. If on oil changes you do not see a large amount of metal suddenly appear on the magnet (chips not slivers) and do not feel a vibration in the bars then your main bearings are likely fine. If you do not hear a rapping noise in the motor and find copper flakes inside your oil filter then your rod bearings are likely fine.

So if going with scenario #1 be sure to check that it
Does stop smoking.
Has no change in metal on the drain plug magnet
Has no copper in the oil filter you dissect or oil you drain at future changes.
no new strange noises or vibrations in the motor such as the pistons hitting the heads.

If it passes these you should be fine I have seen it done more than a few times with little to no harm noticed. You do need to be vigilant at least for a while to make sure no greater harm is done if something starts to go bad.

2. scenario you tear the engine down and rebuild , Gas/oil can glaze cylinder walls. rod bearings can soften the babbit and fail. main/all bearings can Fret from contamination and simply chip away. Seals obviously can weep after a solvent (gasoline) has been soaking them.

If it were mine I would start with scenario #1 and just be hyper vigilant for bad signs. If you get away with it great if not well you need to do scenario #2 but do not ignore any of the signs of a future failure as it will get expensive if you do. My biggest concern is not the gas in the oil nearly as much as the length of time it was sitting in there.

So do you feel lucky..........
 

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I've just removed the carbs from my 1997 900SS for the first time and it turned out to be easier then I tought it would be.

Most important tool you'll need are your eyes. Look at everything, look again, determine how to unbold/remove it, look one more time, make notes or photos and go ahead.
Second most important tool you'll need are your brains. If it will not come loose, don't go crazy and use brute force. Think again, look again, read again and only then try again.
Third most important tool is Google. Search on Mikuni BDST 38 and you'll find lots of photo's, drawings, videos,... Check these, learn what each part in the carb does and how it works.

If you carbs are taken apart (keep the parts separate in little bags with V (vertical cylinder) and H (horizontal cylinder) on them) start cleaning the body (internal and external) with everything you can find and does the job without scratching or deforming anything.
I used a toothbrush, tooth picks, cotton swabs, pieces of microfiber towels, copper braids,...
I found an easy and good way to clean the jets, I described the process here.

Usually the jets are all cleanable and most of the time you can re-use them. Look for wear, oval holes, cracks,... If you find any, replace.
If the gaskets are in good shape you probably can re-use them too but I would advice to renew them.
There's a company called Keyster. They supply kits with only the gaskets, O-rings and float valve or kits with all that plus all the jets. Click here for Ducati 900SS rebuild kits.

I'm European and there is a Dutch shop (Dellorto & Weber Carburateurs, sproeiers, venturi's & revisiesets) with lots of Mikuni parts. I don't know how about shipping but maybe this guy can help you out with a dealer closer to you?
Ebay is helpful as well. Search for "carburator rebuild kit Ducati SS" or "carburator rebuild kit Yamaha TDM 850".

In the end, I liked this job. It's not rocket science and you'll learn things about you're bike and you will see why she doing what she's doing.

Google searches that were very helpful to me: "Mikuni BDST 38" "Mikuni BDST float height" "Mikuni BDST rebuild" "How to clean a carburator"

Good luck!!
 

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Also "customcarbservices.com" can just do the work on the carbs themselves if I ship it to them? They're in New York I'm in California.
I'll see if I contact them and ask for what I need.

Thanks for the help.
Yes, all the work you need done on the carbs can be done by custom carb services.

I'm in California too, and shipped to NY. Not an issue. The results you see on the website are not fake. I sent my carbs looking like they were ready for the scrap bin and they came back looking new. Not an exaggeration.....sean
 

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Discussion Starter · #10 ·
Tomorrow morning I will begin to take the bike apart... I will also be sending my carbs to "The Ducati man" at CustomCarbService.com. I will continue to post here.

While I am at it I am also considering buying Dynacoils set from CACycleWorks as I heard nothing but good stuff from that kit.
 

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Discussion Starter · #11 ·
Once you do the carbs, you'll be ready to restart the engine, but you will have to balance the carbs when the bike is up to temperature. Don't let it idle to do this - get it close, ride it and then balance them
http://www.ducatisuite.com/carbsynch.html

I will be using this method to sync my carbs once all said and done. I will keep doing research so I know what in doing.

And when you say "get it close", do you mean I should do a rough carb sync before I ride the bike to warm it up... then after do the actual good sync?
 

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Tomorrow morning I will begin to take the bike apart... I will also be sending my carbs to "The Ducati man" at CustomCarbService.com. I will continue to post here.

While I am at it I am also considering buying Dynacoils set from CACycleWorks as I heard nothing but good stuff from that kit.
I can vouch for the ca cycleworks coil kit. Includes new coils, plugs, wires/caps, and is 100% plug and play easy install.

Cheers
 

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Same problems

I just went through the carbs on my 95. I purchased a used set on ebay. I feared messing with the existing carbs and tearing the old diaphragms. I ordered my parts from Europe -new kits and diaphragms for less than $200. Tried it out when weather permitted. Seems fine in the cold temps. The old carbs had super high floats and pretty large mains as well as worn emulsion tubes. I can't believe that the bike ran okay with the old carbs. My engine is a little low on compression. I am not a master tech, but I suspect that the excess fuel is hard on the rings as well as the rest of the engine. If you would like a contact, let me know. I'll have to wait till spring to fine tune.
 

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Ducati Suite- Carburetor Synchronization

I will be using this method to sync my carbs once all said and done. I will keep doing research so I know what in doing.

And when you say "get it close", do you mean I should do a rough carb sync before I ride the bike to warm it up... then after do the actual good sync?
Jaime - yes, just get it close to ride it - do this by ear, get it warm and come back. They may be good enough when you get them back from the carb guys - start it up and see. Make sure that, after you install the carbs, you take the play out of the cables so that there is virtually none at the screw adjusters on the carb.

You need some sort of manometer to balance the carbs - either the mercury "carb stix", the "Twinmax" or the gauge that you see on the site you noted. My preference is the twin max and you will need to get (2) air take offs to screw into the intake runners between the carb and engine. The balance hoses go to these take offs. I simply made up a couple of Allen screws with a hole drilled all the way through on center.
https://www.twinmax.eu/
I also recommend setting up a fan - preferably two - in front of the engine while you balance the carbs

The BDST38 carb is a "CV" or constant velocity carb which means that the throttle cable is connected to a butterfly, not to the slide and main jet as in a "flat slide" carb or similar. It works by the butterfly movement changing the pressure on one side of the diaphragm on the top of the carb, thus raising or lowering the slide that lets the fuel/air into the engine. Thus, it is critical to make sure the diaphragm has no holes otherwise you will never get it to run right. The carb guys you will use will check that. I am mentioning this because you cannot do a test balance on the CV carbs the way you would on a flat slide carb - with the flat sliders, you can see and feel if the sliders are working together. Have to use the meter on a CV carb.

BTW, the "sky is not falling" on your engine. The bottom ends on your engine are reliable even with a bit of abuse so my bet is that it will be fine once you get it running properly. But I would get the bike running and tuned, ride it a few miles and then change the oil/filter again. This is cheap insurance
 

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Discussion Starter · #16 · (Edited)
Just got the carbs out and it looks like someone already worked on them before... its missing 2 bolts on one side. I just opened them up to pour the fuel out.

I circled what I think is the carb synchronize screw.

I also got two torn lines... I'm not sure what they are for but I pulled them out and I'm going to replace them. They are the 2 lines that come out of the brass (copper) fittings from each carb. One of them has a springed sleeve. What kinds of lines are these? They go into a plastic cover and dont seem to have anything to do with actual fuel.
 

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I believe that the lines in question are breathers going into a one way valve
 

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The missing screws are the ones you took out to get the cable bracket off, you are not the first to do this.

The screw circled IS your sync screw

The hoses that are broken feed the upper chamber of the diaphragms, the hoses run to a triangular plastic box mounted on the frame. If you remove them and blow air over them your slides will open, so running with the lines in a place that wind effects them will be bad for tuning. This is why the factory ran them to a box . The springs were there to keep the thin hoses from collapsing as a pinched line will prevent the slide from opening.
 
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