Vance Blosser Posted May 18, 2019 Report Share Posted May 18, 2019 I believe it's gas vapor and not really air. I've managed to get mine full by unhooking the bottom and tilting it up, and after running and getting things warm, the 'air' is back in the filter. Works fine so I stopped caring. Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 18, 2019 Author Report Share Posted May 18, 2019 Hi, Ok I check my tank and in outlet. The pipe is about sticking out inside the tank just above the bottom. The inside diameter of the petcock pipe looks for me about 3 mm. Rather small in my opinion, but ok, it has been working before. There is no filter in the tank, but it looks like there are no(t much) particles in the petrol. I changed out the inline filter and no dirt got in them when opening the petcock valve. I tried to tune the carbs at IDLE with the carbtune. Strange things are happening and I hope you guys can help me.1) I checked how many turns from now position to completely screwed in clockwise. This was 5 complete turns.2) the carbtune pro is connected to the "calibration ports" see attachements. - the Carbtune pro rods are doing almost nothing, I have to change the screws rather much before the move a little bit.3) remove the airhoses to the carbs. Here comes now and then a sound like an air compressor which blows of a little bit.4) I tune (as good as I can with these almost not moving carbtune rods) and get a rather nice IDLE, but as I do not have a tachometer I guess it is a rather high RPM. -reducing the IDLE ends up in a unstable speed, it goes from high IDLE to low IDLE and even stops (there is petrol in the filters although it seems to be almost nothing). -the unstable speed comes when giving gas and release the gas handle. Goes fine back to IDLE but after a short time the speed drops for some reason. -when stopped I need to give gas to get the machine running again, so I can turn the idle screw clockwise again to get the engine running IDLE.3) The engine makes som popping sounds. My questions to those who have tuned these bike many times before:1) which tools do you use? Carbtune og Twinmax or ??2) can the calibration port really be used for calibration equipment?3) Is 5 turn from seatposition (seatposition = completely in clockwise), not rather high? Remember the former owner had it running fine me says.4) What could be the reason that the IDLE is moving?5) What could be the reason that it stops?6) Is the a better carburetor which is from this time AND which can be mounted to the Dnepr MT16? Quote Link to comment Share on other sites More sharing options...
racepres Posted May 18, 2019 Report Share Posted May 18, 2019 Huh???? I been tuning by Ear [by guess and by god] all my life, on Everything..... The old Dnepr starts in one kick...always and runs out good.. I will go look for my old write-up on my Carbs...Or... search for Walboro needles or something like that!!! Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 19, 2019 Author Report Share Posted May 19, 2019 Hello again, No one here who can tell me if the "calibration ports" no.27 on drawing really can be used for balancing equipment?The carbtune I use is hardly moving. I tried the methode I found in the articles and try to find idle for each side. Hard to say if they have similair speed, but on my (halv deaf) ears I am pretty close.Looking forward to hear some experience from you guys/ladies. Quote Link to comment Share on other sites More sharing options...
Vance Blosser Posted May 19, 2019 Report Share Posted May 19, 2019 I'm not familiar with these carbs, but if that port is on the side next to the engine it looks like it should be usable for balancing. If it's on the intake side I don't know what it does. Does it have a good vacuum when you take the cap off? Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 19, 2019 Author Report Share Posted May 19, 2019 I'm not familiar with these carbs, but if that port is on the side next to the engine it looks like it should be usable for balancing. If it's on the intake side I don't know what it does. Does it have a good vacuum when you take the cap off?Funny enough it there is no cap on these. It looks for me as the bore goes right down to the fuel chamber....... which carb do you use? Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 19, 2019 Author Report Share Posted May 19, 2019 Hello again, No one here who can tell me if the "calibration ports" no.27 on drawing really can be used for balancing equipment?The carbtune I use is hardly moving. I tried the methode I found in the articles and try to find idle for each side. Hard to say if they have similair speed, but on my (halv deaf) ears I am pretty close.Looking forward to hear some experience from you guys/ladies. ok been riding a tour and filling up the tank. When starting the engine again I could not get it started without using the throttle. Used about 10 kicks to get it running:-( Does this mean the idle is to low? Or what is the reason it starts when cold (without choke), but not when warm? I ask a lot as all my former bike where japanse and I never had any starting problems there. Quote Link to comment Share on other sites More sharing options...
racepres Posted May 19, 2019 Report Share Posted May 19, 2019 Hello again, No one here who can tell me if the "calibration ports" no.27 on drawing really can be used for balancing equipment?The carbtune I use is hardly moving. I tried the methode I found in the articles and try to find idle for each side. Hard to say if they have similair speed, but on my (halv deaf) ears I am pretty close.Looking forward to hear some experience from you guys/ladies. ok been riding a tour and filling up the tank. When starting the engine again I could not get it started without using the throttle. Used about 10 kicks to get it running:-( Does this mean the idle is to low? Or what is the reason it starts when cold (without choke), but not when warm? I ask a lot as all my former bike where japanse and I never had any starting problems there. If the "tuning port" is uncapped... it ain't nuthin... but, if there is vacume at this "port" it Must be Plugged to run properly...an intake leake will ruin an engine in short order...You really need to find an old British Bike Indy!!!!Or plug any potential intake leak, and tune by RPM or even MPH [best to do this on the Stand]... Balance is the Last thing I do... simply using my finger in the Intake for a preliminary... It will run even if quite badly out of Balance... Quote Link to comment Share on other sites More sharing options...
HJKO Posted May 20, 2019 Author Report Share Posted May 20, 2019 @Russian Bike Nut What do you mean by "old british bike indy"? Quote Link to comment Share on other sites More sharing options...
racepres Posted May 20, 2019 Report Share Posted May 20, 2019 @Russian Bike Nut What do you mean by "old british bike indy"?A mechanic who specializes in Brit Bikes knows as much about dual carb setups as anybody is likely to. Independent Bike Shop Quote Link to comment Share on other sites More sharing options...
Scott E Posted June 30, 2020 Report Share Posted June 30, 2020 Never use those paper element type fuel filters in a gravity flow fuel system. They restrict fuel flow too much even when new. They are designed for use with fuel pumps in pressurized fuel systems. You can buy screen type in-line fuel filters in small engine shops that will work perfectly on Ural and Dnepr motorcycles. Briggs & Stratton Model #5018H is a good choice. It has a 150 micron screen inside and will not restrict fuel flow as long as it's not full of trash. Quote Link to comment Share on other sites More sharing options...
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