Well I've been quiet for a while due to a broken wire in the wiring loom on the car, took 3 days to find!!! Due to this we have decided to change it so that means the bike will have to wait untill next year now as the ducati fund is now the car deposit fund. I will pull the carbs off soon and check the float height and hope to get it ready this year for next, that ride out will have to wait till next year Al!!
Al I know how you feel but try this HOW TO PICK UP YOUR MOTORCYCLE - FALLEN OR DROPPED BIKE - YouTube
Well just popped the carbs off and all my problems are becoming clear. The E tubes are worn i think, and the main jet size is 128, but if i am right you don't get that size in a dynojet kit? I think that they should be 150, if so can i get them from DJ or will i need to buy a full kit? As for the tubes where's is the best place to get them from?
Lets start with the easy bit as best as I know it. The Emulsion tubes can be got from Allens Performance in the UK or from Factory Pro in the USA. I think you may find they are also a Yamaha TDM carb part. Allens have the OEM tubes which wear (even more so with Dynojet needles in them)..........but Factory Pro make theirs so they don't wear so easily. Right....jets.....The OEM main jet should be 140. The Dynojet main jets should be a 144 or a 148 for a Stage 2 DJ kit..................Stage 1 would be 124 or 128. Therefore it seems you have a DJ Stage 1 kit fitted...........Don't confuse OEM jet sizes with DJ jets........a 140 is not a 140 as such......... You can tell if it is a Mikuni jet because it will have a little square-ish logo stamped on it..........DJ just have the number. If you are running with a cut about airbox lid and 'race' pipes etc, then you should have a Stage 2 kit fitted..............I assume there are no numbers on the needles (Stage 1 & 2 are '729' and usually aren't marked).........If you post a pic of the needle, I can tell you if it is DJ or not. If you speak to Technical at DJ they will probably help you out with new jets, but there is no point in that unless you are aiming for Stage 2.........which looking at the DJ specifications I have here, all you need to do is change the jets (assuming you have a cut airbox and open zorsts). Also, if you think your needles are worn, then send them to DJ.............they will replace them FOC. And.......if you find your carb spares bill is getting high, let me know what you need............I might have what you want.....except emulsion tubes! AL
Thanks Al, def DJ needles and springs. Just looked at the book and it is a stage one kit, when I bought it I was told it was a stage two kit. This was fitted at 30,000 miles with free flow zorst and air box mod with K&N in box. Will get some new jets from DJ and send them the needles to look at. New tubes well over due if those ones had done nearly 50,000 miles??
Its easy to tell if the emulsion tubes are worn...............Just look at the top of them, and judge if the hole is round or not......
Well I went into Made In Italy Motorbikes at lunch time and had a chat with one of the machanics. He had a look at the tubes and after I told him of the running problems he said he would be surprised if it was down to them. He said that float height might be worth looking at and changing the jet to the stage 2 size. Might be worth changing the tubes but I think I will give it a go without first so I can pin point the problem. if it still so won't run then I'll change them. Here's fir hoping, will ring DJ tomorrow and get the jets underway.
Did he give you a clue as to what the float height should be? And which side of the float to measure? AL
Apparently there is no OEM setting for the fuel level / float height measurement. And, the information I have been given by people that we believe are experts is confusing to say the least. Anyway.......The float height when set roughly in the correct position only affects the pilot / idle circuit........It has to be seriously 'out' to affect the main jets. The general setting from what I can establish from the experts is a float measurement of 14mm (float height above the carb gasket face with the carb, sort of upside down)........15mm reduces the fuel level and weakens the pilot circuit and 13mm increases the fuel level and richens the pilot circuit. When I took mine apart one was 9mm and the other was 12mm.........setting them both at 14mm wasn't right, so I tried 13mm and now it is 12.5mm........Sev's has been altered to 12mm I believe. However.........I checked with Factory Pro what measurement they use.......Yep......14mm as a starting point.........and on their website they say they measure to the rectangular float, not the diamond shaped float (about 4mm difference)........But, the guy from Factory Pro emailed me to say he uses the diamond float! Looking at it, IMO measuring to the diamond float isn't really correct as it means the fuel level is too low.....but I could be wrong about that......But if you think about it, 14mm on the diamond float means the rectangular float is at 18mm. Best guess, I reckon is set yours at 12mm (but check what yours are before you alter anything)..... ....what you do is take the float bowl and reverse it so that it holds the float assembly in place while you are setting them, then tip the carbs upside down and sort of at a 45 degree angle so you can see the float tag just touching the sprung loaded needle.........don't let it compress the needle spring. Measure at right angles to the gasket face to the highest part of the float when upside down. Apologies if the setting doesn't suit your carbs, but it is a bit of trial and error it seems. AL PS........Why not pop up to Made In Italy again and ask the mechanic what measurement he sets them at and which float he measures? It might prove useful.
Thanks for that Al, 14mm was the number I had in my head and the machanic at made on Italy agrees, didn't ask which float he uses. Still haven't managed to ring DJ yet, been realy bussy at work, hope to tomorrow to get the new jets sorted. Are they quick at delivery? Got my new car bowl so I can get my oil heater back on while I wait. Will have a mesure up tomorrow and let you know.
DJ turned round new needles in three days max..........With regard to the jets, talk to technical guys and perhaps tell them what you found out and that you need to upgrade the jets because of what a previous owner did to the airbox and zorsts..........See if you can blag both sizes as well. I have a spare pair of non-heater bowls!
Tried DJ yesterday but their lads were a BSB, so will try again next week might drop an email first, give them a heads up. I got a new bowl last week Al, thanks for the offer any way, it was only £10. Will measure up float height today if I get chance. I take it i adjust the height (if needed) by bending the metal tag above the valve?
Yep........correct........you don't need to bend it much at all to make a difference......I use a Biro top sticky out bit to do it. Bend it towards the valve to decrease fuel level (or increase the height of the float above the gasket face) or vice versa. Make a note of your current float height before you alter anything, just in case it isn't fuel level that is giving you grief........I suspect one of your problems will be solved when you get the right jets in there........ ......if you get stuck with getting jets, I may have some that will do for the time being......I will have a look today......had a look............got 150s and 155s. PS........Have a really good look at the float needle tips and make sure they aren't worn. PPS.....Scroll to the bottom Factory Pro Float Height Tool PPPS......Also go to www.factorypro.com then click on Online Sales/continue to Online Sales/Ducati/750SS carburated.......then scroll to about halfway down.
Just measured and ones at 11mm and ones at 12mm. Acorrding to factorypro must be less than half mm between them. Think I'll start at 13mm with new jets and go from there.
As the fuel level affects the pilot circuit / slow running, even if you are a bit out with the measurements, you can generally adjust it with the pilot screws.......so if your fuel level is too low (ie you have the floats at say, 15mm) you might find the pilot screws have to be turned out more than OEM and DJ settings (DJ for Stage 2 is 3.5 turns out)...........
Got my new jets from DJ yesterday but they sent the wrong ones even after I told them what I wanted. The have sent DJ jets but these are treaded, dose anyone now which type of jet I need so I can get the right ones on the way??
Yes, you need main jets for BDST 38 Mikuni carbs......they aren't threaded....So they will need to send you the right ones........If I were you, send them an email with a photo of the ones you have and say, "like this but with a bigger hole...." AL
Told them on the phone exactly what I needed and what it was for, but still got the wrong ones. I'll ring them on Monday and try to get the right ones.
