With the wife out it was carburettor strip down time on the kitchen side, better light there. 1992 900ss - BDST 38 B67. I am mid bike strip down and cleaning everything up. Wanted to totally strip carby for cleaning possible soda blasting but I am wondering about the how wise it is to take the butterfly disc out. The 2 cross head screws were a bit tight than I remembered in a previous life they looked like they were punched over on the end. I turned carby round and they did look to be punched / dimpled. I would like to take them out to clean but not sure of future implications ie screws not secure when put back and end up in the cylinder. Also can you pull off the plated cap that covers shaft end, would like to get new one or replate. Any thoughts or experience with this would be appreciated. Gaz.
My advice? Don't attempt removal of the butterfly.......... 1) Firstly you will ruin the shaft and the butterfly itself when you try filing off the punched screw ends......(you try using a file in there, holding against the spring, at your risk) 2) Try sourcing replacement screws 3) Try getting the butterfly back into its original position 4) How do you intend punching the end of the screws again?......Hammer and punch = Bent shaft Yes you can get the cover off, but you will make a mess of it......Unlikely you will find a new replacement. PS.....Don't remove the little alloy round plug you can see from underneath (immediately below the three holes in the throat at the edge of the butterfly) when the float bowl has been removed. If you need to know what's available for these carbs (and cost) just ask......see the saga of 'B*****d Bike' in the Supersport section.........I now know a lot about these carbs....mine are BDST 38 B70 carbs so they won't be much different if at all. AL.
Thanks, I kind of suspected this, that's why I asked. Thanks for the good advice, if you have been there - done that, it's good enough for me. It took me a while to realise which bit was the plug, I am sure if I had noticed it I would have taken it out thanks again. Will check out the jetting to see if standard. This is the info I have: Main jet 140 Main air jet 70 (Hynes) 60 (Ducati workshop manual) Needle valve jet Y-2 pilot jet/Idling jet 42.5 Jet needle 5C19 Position from top 4th Needle valve jet Y-2 Pilot air jet 60/1.4 Throttle valve 130 Float height 14mm Seen this somewhere: idle mixture screw setting specified is 3 turns for the horizontal cylinder and 3-1/4th turn for the vertical cylinder and also 2.5 - 3.5 turns out for setting up. Got Allens performance Ltd at the back of my mind for any parts I might need, not too far unless anyone knows anyone else in Sheffield / Doncaster area. Cheers again Gaz
Allens Performance.....CORRECT.....Steve or Dave for sales.......They are out of stock for float assemblies (includes floats, float needle, seat and O ring). I have a 750SS with the carbs off waiting for a bl**dy float, but I also have a pair of 900SS carbs, stripped, so I can check all the sizes, even though it had a Dynojet kit fitted because the only things that change are the diaphragm spring and the main needle, and sometimes the main jets......I also have the owners handbook which has nearly all the sizes for 600/750/900 ess-esses. The main things that appear to differ between the 750 and the 900 are the emulsion tube size, pilot jet and needle position. The chart below is what is available for these carbs from Allens (and I guess elsewhere).....you will find the same carbs on the Yamaha 850TDM (and one of the TRX variants).... [TABLE="class: MsoNormalTable"] [TR] [TD] Bracket/starter plunger[/TD] [TD] MRT-H/175[/TD] [/TR] [TR] [TD] Clip/jet needle[/TD] [TD="width: 188"] TM32/90[/TD] [/TR] [TR] [TD="width: 306"] Cover/air cut valve[/TD] [TD="width: 188"] MRT-H/250[/TD] [/TR] [TR] [TD="width: 306"] Diaphragm/air cut valve[/TD] [TD="width: 188"] MRT-H/005[/TD] [/TR] [TR] [TD="width: 306"] Diaphragm/throttle valve[/TD] [TD="width: 188"] MRT-H/072[/TD] [/TR] [TR] [TD="width: 306"] Drain screw/float bowl[/TD] [TD="width: 188"] MRT-H/190[/TD] [/TR] [TR] [TD="width: 306"] Float bowl[/TD] [TD="width: 188"] MRT-H/090[/TD] [/TR] [TR] [TD="width: 306"] Float including needle valve assy[/TD] [TD="width: 188"] N213010-17[/TD] [/TR] [TR] [TD="width: 306"] Fuel inlet [/TD] [TD="width: 188"] MRT-H/185[/TD] [/TR] [TR] [TD="width: 306"] Jet block[/TD] [TD="width: 188"] MRT-H/160[/TD] [/TR] [TR] [TD="width: 306"] Jet needle[/TD] [TD="width: 188"] J8-5C19[/TD] [/TR] [TR] [TD="width: 306"] Main jet[/TD] [TD="width: 188"] N208099-size[/TD] [/TR] [TR] [TD="width: 306"] Needle jet - 611 (750)[/TD] [TD="width: 188"] 750-Y-6[/TD] [/TR] [TR] [TD="width: 306"] Needle jet - 611 (900)[/TD] [TD="width: 188"] 900-Y-2[/TD] [/TR] [TR] [TD="width: 306"] O-ring/main jet[/TD] [TD="width: 188"] 616-12001[/TD] [/TR] [TR] [TD="width: 306"] O-ring/needle valve assy[/TD] [TD="width: 188"] 616-23003[/TD] [/TR] [TR] [TD="width: 306"] O-ring/pilot mixture screw[/TD] [TD="width: 188"] N133037[/TD] [/TR] [TR] [TD="width: 306"] O-ring/throttle valve guide[/TD] [TD="width: 188"] N138198[/TD] [/TR] [TR] [TD="width: 306"] O-ring/top cover[/TD] [TD="width: 188"] MRT-H/106[/TD] [/TR] [TR] [TD="width: 306"] Pilot jet[/TD] [TD="width: 188"] N151067-size[/TD] [/TR] [TR] [TD="width: 306"] Pilot mixture screw[/TD] [TD="width: 188"] MRT-H/172[/TD] [/TR] [TR] [TD="width: 306"] Plastic washer/jet needle[/TD] [TD="width: 188"] MRT-H/118[/TD] [/TR] [TR] [TD="width: 306"] Retaining plate/main jet[/TD] [TD="width: 188"] MRT-H/123[/TD] [/TR] [TR] [TD="width: 306"] Rubber seal/starter plunger[/TD] [TD="width: 188"] MRT-H/163[/TD] [/TR] [TR] [TD="width: 306"] Screw/jet block[/TD] [TD="width: 188"] MRT-H/119[/TD] [/TR] [TR] [TD="width: 306"] Seal/float bowl[/TD] [TD="width: 188"] MRT-H/161[/TD] [/TR] [TR] [TD="width: 306"] Seal/fuel inlet[/TD] [TD="width: 188"] MRT-H/046[/TD] [/TR] [TR] [TD="width: 306"] Seal/jet block [/TD] [TD="width: 188"] MRT-H/162[/TD] [/TR] [TR] [TD="width: 306"] Sealing plate/starter plunger[/TD] [TD="width: 188"] MRT-H/177[/TD] [/TR] [TR] [TD="width: 306"] Spring/pilot mixture screw [/TD] [TD="width: 188"] N133206[/TD] [/TR] [TR] [TD="width: 306"] Spring/throttle valve[/TD] [TD="width: 188"] MRT-H/157[/TD] [/TR] [TR] [TD="width: 306"] Starter jet[/TD] [TD="width: 188"] N100604-size[/TD] [/TR] [TR] [TD="width: 306"] Starter plunger[/TD] [TD="width: 188"] MRT-H/176[/TD] [/TR] [TR] [TD="width: 306"] Throttle valve guide[/TD] [TD="width: 188"] MRT-H/126[/TD] [/TR] [TR] [TD="width: 306"] Throttle valve including diaphragm [/TD] [TD="width: 188"] MRT-H/151[/TD] [/TR] [TR] [TD="width: 306"] Top cover/throttle valve[/TD] [TD="width: 188"] MRT-H/134[/TD] [/TR] [TR] [TD="width: 306"] Washer/pilot mixture screw [/TD] [TD="width: 188"] VM12/33[/TD] [/TR] [/TABLE] How's that for service?:wink: AL.
Yes I like the service – as long as it was with a smile. I quoted the Jet stuff and settings from the Ducati service manual (at the time I thought I should really find out where these all are and do a diagram) Starting with the first question first. Yes I also have starting jet & main air jet as same thing. Looking in the bell mouth of the carby there are 2 holes at the bottom the left is the Main air jet and the right is the Pilot air jet 1 (from the Ducati service manual & Haynes 3.9) There seems to be 2 pilot air jets, Jet 1 mentioned above and Pilot air jet 2 (1.4 dia). This is in the top of the carby under the rubber diaphragm in a passage that goes to the air cut off valve. It does seem to have a slot in it so presume it will come out (might leave that alone for a bit) Throttle valve 130. Yes this is the butterfly, just looked and it has 130 stamped on it. Many thanks again AL, Cheers Gaz
Those jets you mention almost certainly would be correct as I belive there is no reason for anyone to have changed them.....but I'll confirm the sizes later today when I have finished battling my way through the undergrowth here. AL Jet below the diaphragm is indeed 1.4; pilot air jet (right side hole of the carb mouth) is 60...these are in a 900SS carb. The left side hole has a jet in it, but so far I haven't removed it....basically because I have nothing with which to remove it. For the covers on the ends of the butterfly shafts, you could always find a suitable plastic cup....but they want to be a tight fit to keep crap and water out. If you have split the carbs (have good fun getting them back together!!) check the air cutoff diaphragm and the choke needles. Cut-off is under the white plastic cover, choke needles are held on by two plastic tag clips.....(You can check both diaphragm and choke needles when the carbs are together but you need to be a bit ingenious to get the screws and clips out) AL.
Not sure my statement of: "starting jet & main air jet are same thing" is correct. In the Ducati manual it did not mention Starting jet in the table of settings but it was shown in the diagrams, so might of made an assumption because numbers were similar. Anyway I have the following jets on a 1992 900ss: Main jet 140 Starter jet 70 pilot jet/Idling jet 42.5 (above jets are in the jet carrier) Jet needle 5C19 Position from top 4th So think Iam good to go. I am going to leave the others alone they don't look like they have been touched, no marks on them. Got one carb cleaned up ok - petrol and a ultrasonic cleaner I picked up of ebay about £35 (it's not a bad size 2.5L have not had it long - others at this size were selling at about £60-£70 and I am sure they are the same spec.) so might even leave the soda blasting. I will leave the caps alone they have a bit of corrosion on them, same with the return spring and cam, don't think its worth messing with them. Yes split the carbs - noticed a little arm I needed to get back in between a spring and adjuster that looked fun. Air cut odd diaphragm looked ok. The choke needles - unless they are supposed to look eroded and worn out - are eroded and worm out, so think need new ones. Thanks for help on this. Cheers Gaz.
The choke needles have a light surface texture from new.....when they wear, they tend to get thinner where the 'pin' changes to the 'tapered' bit... AL
Yes, noticed the slight surface text but they have definitely necked down on the taper, will need a couple of these. Just remembered ultrasonic cleaner was off amazon distributed by "Bogue" but can't seem to find any at the minute. Will try and get a camera sort soon (the Mrs lost the other one) and get some pics on. Also found a little fuel filter in the swivel fuel supply "T" and also found a small washer and 'o' ring in the idle mixture screw orifice. Cheers, Gaz.
At least the little inline filter lets you know how much cr*p is getting past the main filter........and a washer and O-ring on the pilot screws is correct....I replaced my O-rings. AL.
