If we are talking about the jet sizes then are those the numbers on the top of the jet? The reason why I went for sigma is because there was a 60 pound difference between one and the other. The jet kit is stage two, I also gave the buy the full description of what was changed in my bike so he should adjust the jets to suit perfectly. The thing with the carb is that it was stripped to pieces and cleaned twice since march, maybbe its the seals that cause all that hussle. I will check the valves anyway as they have to be checked every...? 2-3k ish miles? This bloody weather isn't motivating me to put my hands on the bike at all... I have to clear some space in my Mini garage before i do anything.
The numbers will be on the jet somewhere.....depends what make they are..........If they are OEM jets they will have a small square logo next to them.....if your jets have just numbers, they may already be Dynojet. If you would care to post a pic of the needle and the spring, I can tell you if it is already a Dynojet kit that is fitted (or parts of a Dynojet kit). I have had my bike for three years and haven't checked the valves yet. However, I doubt if the Sigma kit will make much difference to the problem, other than making it worse....so until you have established what is causing it, I wouldn't fit it yet......simply because you will have to start messing with the airbox if it is stage 2 and you have open pipes etc etc. AL
From what you are saying and what your picture is showing, these are the stock jets because they have this funny looking square on them with a letter "R" before. It looks like I have my main jet smaller than it should be because 128 instead of 132.5, but why would it be if it's an oem part presumably for this exact bike? I'm going to order the seals for this carb, hopefully what other people are saying; "Yamaha TDM 850 has the same carbs" is true because there is no seals for my bike on ebay and the ones for TDM cost abour 15 pounds.
Well there is a problem staight away by the sounds of it, because if you are correct, you have the wrong size main jet, it's probably running weak.....(I have the tech details for a '97 600SS here in the Owners Handbook)... .....and if you have an OEM needle in the wrong jet, then F knows what notch it should be on......come to that F knows what notch a DJ needle should be on either! As I said earlier, post a pic of the needle and the spring..... Also be warned.....a Mikuni jet that says it is a 140 isn't the same as a Dynojet that says it is a 140.......one is measured by diameter, the other is measured by flow rate........as for Sigma, I don't have a clue. Seals etc......Allens Performance Mikuni & Keihin Carbs AL.
That looks very like a Dynojet needle and Dynojet spring but I can't make out what the three jets you show are......the top one says 20 or 70 and is an OEM jet......the bottom two say 128 and are not OEM. I posted this on another thread somewhere......you decide what you are lookin at.... AL
the starter jet is ok at 70 but as AL says if the two main jets are 120 or 128 they are too small. Even the 350SS ran 127.5 main jets. More and more i'm tending to think these carbs are from another bike live an FZR or a TDM as that size main would be about right for a 250 cc cylinder. have you got 4 fixing screws holding on your float bowl or two?
Hi again, sorry for the delay on the response and everything, I was bussy with work and some family issues resulted in me having absolutely no time to get to the computer and to put my hands on the bike. I will try to get to my bike tomorrow to give you some updates. Thanks a lot for your help and sorry for the delay once more.
Here is some update as I have eventually managed to rip the carbs out from my bike. When I took the carbs out, it turned out that the jets in the carb that are (were) installed now have the correct jets (132.5, 70 and I think 37.5 or something) whereas the old carbs had the smaller ones (128) which were mistakeably thought of being the same size as the ones in the new set of carbs and because of that I have come up with a hypothesis. The hypothesis states that when the bike wasn't running in the first place (before I changed the exhaust and bought a new set of carbs) it had the same problem as it has now. After changing the carbs it was running well for a period of time. The problem came back when I changed the pipes which increased the air flow. The solution seemes straight forward and makes me wonder why I even bothered you guys as I could have just stripped the new carbs and looked myself. Basically it was originally running on lean mixture because of the smaller jets (128) before I changed the carbs. I changed the carbs so it started running reasonably well as it had a good mixture setting with correct jets (132.5) however after changing the pipes which increased the air flow, the new jets (132.5) become insufficient and made the mixture lean because of the increased air flow and therefore the bike came back to having the same problem it had before. I'm going to wait for the jets from states which from my understanding will sort the problem for 95%. By the way, all the jets on the new carb have the square logo on them plus the needles and springs look exacly like the ones on the OEM picture. I will ask to keep the topic open for replies because I maybe unlucky and the 5% will kick in and the jets maybe insufficient to sort out the problem. Thanks for your patience and all the help you gave me. Regards.
took me a while but I get what you are saying above now! You are probably right about the exhausts as depending how 'free flowing' they are compared to original then they could need larger main jets as a starting point. Other things to consider :- does it have a standard air filter and a standard (unchopped) air filter lid? Even if it has a K&N or BMC with a standard lid chances are this would also upset the jetting particularly when combined with non-std exhausts. I am guessing that you checked for air leaks then? (inlet rubbers undamaged and a nice snug fit on carb AND manifold). Would still like to know how many float bowl screws you have as this could determine why jets were non-std. As you have a spare set of main jets now you could open them up yourself if you are confident with a drill and have a delicate hand. I would try 135 for a kick-off (1.35 mm).
I know it was confusing, I was thinking of writing that in bullet points to make it clearer. Basically, Old carbs with small jets not good, new carb with new jets good, new exhaust with new jets not good. It simply needs newer jets hehe. It has a standard air filter by the looks of it, it says K&N PART on it but I think it's the typical stock as K&Ns came with Ducatis didn't they? The lid has not been touched, I didn't want to make any more damage than there was. There aren't any leaks, I've checked both the inlet and air filter rubbers. I have come up with a bit of an irresponsible idea as I've made tiny gooves on the air inlet on the carb so that the rubbers will hold on to them as they didn't in the past and after a "few" miles they would slip of causing me having to correct them. The float bowl is held on four screws and the membrane one is held on two. I was thinking of doing the drilling by myself however where will I get such small drill bits and what size of needle shim will I need? These are the grooves I was talking about. Edit: I've found a set of 150 mini drill bits however it doesn't contain .05s so just 0.1, 0.2 etc.
Oh dear.........Firstly a K&N air filter won't be standard / OEM. Secondly, if you are running open pipes and a jet kit, you will need to remove the rubber trumpets from the airbox lid at least....some people have had to cut their airbox lid about to get the performance right (there are plenty of articles and threads on various forums to show you what to do). If the airbox to carb rubbers are slipping off the carbs, then there is something wrong with the fitting or the components. However, the main rubbers to check for leaks are the carb to manifold ones...these are the ones that will cause problems. With regard to jets, I recommend you don't drill them unless you are as good an engineer as Chris who probably has much better equipment than many of us do; and can keep a drill straight.... ..instead, buy some jets from Allens Performance or somewhere like that.....maybe 135s will do it, but you can also lift the needle one notch to see if that makes a difference to say, 132.5s. NB, don't forget the fact that the OEM Mikuni jets are measured in millimetres whereas Dynojet are measured by flow rate, so a 130 OEM mikuni jet will not be the same as a Dynojet 130 (and I suspect the same will apply to Sigma). Plus if you have Dynojet springs, Dynojet needles etc, then you will have serious problems if you are trying to mix them with OEM jets. Dynojet will exchange needles free of charge if they are worn.......but you also need to check the emulsion tubes to see if they have worn, because they will wear badly long before a Dynojet needle will....if the holes in the emulsion tubes are oval, then they are worn. I don't know why you think you need needle shims at this stage......until you get your bike somewher near running right, then don't even think about introducing another element....shims are for fine tuning and are 0.5mm thick, which are used to raise the needle slightly, IE, not a full notch.....(you can get them from Dynojet but I wouldn't bother at this stage if I were you). AL
as AL says if you do have a genuine K&N* aftermarket filter (could be wrong but not aware they were ever fitted as std) then this will need a slightly larger main jet. If it were me and had access to a std (usually yellow filter paper) filter I would fit that and try for starters. * if you've nothing to compare with then it's understandable that you wouldn't know but basically it's quite heavy for a filter, looks expensive, has a fine wire mesh over the paper and filter paper is usually a kind of light purple from memory. shame you filed the grooves kozacki, sorry to say that action will make sealing worse ultimately - i wish you had told us first (you have a spare pair of bodies luckily). AL disagrees with me on some of what i'm about to say but will say it anyway :- due to the slightly 'coachbuilt' approach of our beloved Ducati manufacturer the whole airbox fitting can vary slightly from bike to bike (loom in the way, too close to frame tubes, tank clearance, battery box nesting plus IT'S screws lining up...) which can mean that the filter box doesn't sit 'in repose'* when you come to fit it and finally tighten the carb to filter box jubilee clips (and this is assuming you have already checked the carb to manifold rubbers in exactly the same way as follows (these are usually 'good as gold' in my experience)). Apart from carefully jiggling and even modifying to make filter/battery housing sit* there are 3 things you must do :- 1/ Inspect the rubbers for wear/distortion/tearing/sloppy fit plus corresponding faces of course. 2/ remove all traces of oil on mating faces - if these 'top' rubbers are allready saturated in oil even after wiping then you need new ones. 3/ Carefully tighten jubilee clips until they are 'just tight enough' - a test you can do is to try and revolve clip by pushing screw head to see how easily it swivels and as soon as it's really difficult to swivel then it is tight. Overtightening combined with over-slippery mating faces combined with filter body not sitting in repose is the reason that the rubbers will try and 'pop-off' in time (MOO)
I don't disagree with any of what you say above, Chris......I was just too lazy to type it all out.... AK
I supopose you didn't expect me to come back but oh well, here I am. I was waiting for this bloody salesman from states to do something about the jets until I had to force a refund and bought dynojets stage 2, costly buggers thou. I had two options given by bynojet, installing either 144s or 148s (equivalent to 135 and 139ish in micuni measurments). I went for 148, installed the whole kit and nothing, still the same, not even a little bit better. I will try to give dynojet technical support a call tomorrow, do you know if they are experienced with all the stuff or is it just that they are being given a number of possible reasons and they provide you with one of them when you give them the info whats going on with the bike?
OK......Let's try from scratch. 1) You have fitted a Dynojet Stage 2 Kit....(Dynojet will just sell you what kit you ask for.....in my experience, they aren't problem solvers). 2) Assuming you have fitted the kit properly (IE needle on third notch etc etc)....At this stage, it won't matter which main jet size you fit. 3) Have you checked the emulsion tubes for wear? 4) Have you checked the main diaphragms for age, wear, splits? 5) Have you checked the air cut-off diaphragms for age, wear, splits? 6) Have you checked the 'choke' needles for excess wear and that the choke mechanism on the carb works properly? 7) Have you checked the float needles and seats for wear? 8) Have you set the float heights correctly? 9) Have you checked that the pilot screws are good and the little O rings and washers are OK? Also check that the pilot screw seats in the carbs are OK. 10) Have you checked that the carb balance is roughly equal?......Use a very thin piece of wire to see if the butterflies are in roughly the same slightly open position. 11) If you have done all that and have checked the inlet manifold rubbers aren't split etc, then I reckon the following are your next moves. 12) Remove the airbox top cover and leave it off until you get near to solving the problems. 13) Change both the spark plug caps and plug leads....I would use NGK caps and decent wire core leads. 14) Switch the CDI igniter boxes over to see if the problem switches to the other cylinder. 15) Switch the coils over...ditto 16) Check the resistance of the pick-ups to see if they are within the acceptable range. 17) Whip the belt covers off and make sure all three timing marks line up properly. 18) I haven't done this yet on my Ducati, so I don't know if it will work (always used to on my Guzzis)....turn the engine over by hand with the ignition on and spark plugs out.....make sure the plugs are in their caps and earth them against the engine. As you are turning the engine over, watch the timing marks through the little window.....when they line up, can you hear / see a spark from the appropriate plug? Failing any of the above solving the problem, I can't help you any more and others may be able to take it further. FYI...in cold weather, my SS always starts, but the horiz cylinder doesn't kick in for a few seconds...and in any weather, it will chuff through the airbox occassionally untill it has warmed right up. AL.
Right, sorry for taking so long. I will have a look at it I think tomorrow, I will put it back to stock setup (old pipe and jets etc.) and I will see if its the pipes that cause all the problems cos if its the pipes then I dont think there is much point looking for the problems in the carburation. If it will be the pipes then it will srink the amount of variables and therefore I will be able to track the problem quicker but for now the pipes are the main target.
Regardless of which pipes you have fitted, you should definitely check Items 2 -11 in the list......Thereafter Items 13 - 17.........fundamental items. IMO just changing the pipes won't cure one cylinder cutting out. Your bike should run regardless of which pipes, albeit it may not run well, depending on the jetting etc; and, sorry to be harsh, but I think you are wasting a lot of time p*ssing about changing parts without doing the fundamentals first. AL
10 out of 10 for patience and determination AL - I would have to read whole thread again as have forgotten where we got to :smile:
