bondy Posted March 28, 2012 Report Share Posted March 28, 2012 hi all ive just put my 199A motor back in i tryed a bing carb i have but was havin none so i tryed a mukuni i have started up troubel is am havin problems tryin to set the carb up it ticks over but dosent sound has it should its got an electrice igntion from bult uk it was running ok last time i had it running witch was last year it has a new air filter witch isnt dirty but i sprayed pj air filter oil on it ive never cleaned it since last year but the bike hasnt been used would this have anything to do with the air flow? Quote Link to comment Share on other sites More sharing options...
pschrauber Posted March 28, 2012 Report Share Posted March 28, 2012 (edited) If I have understood you right your engine is running hot after you have mounted the Mikuni carb, beside this the engine sound have changed. If so your engine might run too lean, there can be different reasons for this, first you have a too small main jet installed, the ignition might not be adjusted right, you might have air leaks, ... I would first try again with the original carb you might have from another bike, (when I understood right you have some Bultacos). If the engine runs fine with the original carb the ignition is not the problem if not adjust first the ignition until the engine runs very well. Then mount the Mikuni carb again, there might be a difference in diameter between the inlet-rubber-tube and your carb and the connection is not air tight so the engine sucks additional air which leads to a too lean air gas mixture. You can check out the connections between carb and engine with brake cleaner. Let the engine run (idle) the spray a little bit of air cleaner to the connection carb to inlet-rubber, if the engine starts to pick up rpm then you have an air leak and might need an extra bushing. I would also check the inlet rubber for cracks. If the ignition is set properly and you have checked that there are no air leaks then I would take a bigger main jet, around 10% bigger then what you have installed now, this might work but if the bike still runs to lean you should post it and we will look further. Anyway it is very essential that all other components like ignition work very well before you can re-jet your carb to the engine. Edited March 28, 2012 by PSchrauber Quote Link to comment Share on other sites More sharing options...
bondy Posted March 28, 2012 Author Report Share Posted March 28, 2012 hi the igntion is eletrice and ajust its self but you can ajust it. the rubber from the carb to the manifold is to big how can i over come this? allso the air box has a crack in it at the back its been fixed once but the crack is still there going back to the igntion would it need reajusting? the intructions that came with the igntion dont mention that you can ajust it. Quote Link to comment Share on other sites More sharing options...
penno350 Posted March 28, 2012 Report Share Posted March 28, 2012 So where does the hot bit come in? Quote Link to comment Share on other sites More sharing options...
bondy Posted March 28, 2012 Author Report Share Posted March 28, 2012 may be me i dont know but the clutch case was hot so was the magneto may be because its not been run for quit abit? i just dont recall it getting so hot before ill have to go over evrrything i had a new air box on last time witch is on my other bult allso it could just be because it was ticking over high that it got hot? Quote Link to comment Share on other sites More sharing options...
pschrauber Posted March 28, 2012 Report Share Posted March 28, 2012 (edited) Mmmh never heard about an self adjusting ignition? Even the electronical ignition must get an impulse to produce the electricty for the spark. I would recommed to go through the manual that came with the ignition and follow the there recorded instruction very well. (I don't have an electronical ignition on my Sherpa but electronical ignition system on my KTM and the groundplate has to be adjust to some mm befor tdc otherwise the ignition will not work properly.) To the crack you have in the airbox, that's a pitty but doesn't affect the gas air mixture, the same with any air leaks you have in the tubes or the airbox befor the air goes in the carb. It is good to close these air leaks but they will not affect the air gas mixture. Anyway if you have an air leak there the air that comes in is unfiltered which is not so good. Any air leaks you have in the maifold or rubber tube between carburator and engine are a real problem as they will affect the air gas mixture (as already mentioned). So the inner diameter of your rubber inlet is toO big for the connector of the carb, then you have to make you a bushing that will fit to the outer diameter of the connector of the carb and the inner diameter of the inlet rubber. The differences between the connectors of the bing carb to a Dell'Orto you can see here, the differences to the Mikuni should be likewise: So I had the same problem with the Dell'Orto carb which has too a much smaller connector, so I have made a bushing out of nylon as you can see here: I had to make bushings on both sides as they where both smaller. If you don't have any possibilities to turn you your own bushings you might talk to wayne weedon at billetparts, he makes tail adapters for carburators, mabe he will manufacture you a custom made for your Mikuni: http://www.billetpar..._48.html?page=2 Without this issue fixed you can't use the carb for your Bultaco, running the engine too lean can lead to piston seize! The heat of the engine is the result of a too lean gas-air mix where the main reason lies in your airleak or gap between manifold and carburator connector/tail. Edited March 28, 2012 by PSchrauber Quote Link to comment Share on other sites More sharing options...
bondy Posted March 29, 2012 Author Report Share Posted March 29, 2012 hello again ive sorted it the inlet rubber wasnt on tight enough where did you get that carb from with the clear bottom? Quote Link to comment Share on other sites More sharing options...
pschrauber Posted March 29, 2012 Report Share Posted March 29, 2012 (edited) The carb is from Dell'Orto i have a dealer here nearby, Stein-Dinse, he sells them, likewise jets, nozzels, ... http://www.stein-din...php?language=en The bowl is special and is made by Malossi in Italy, they came out in 1981 with these, they where fancy to have and where mounted to the bike in the beginning 80's, a couple of years later this fashion was over again. Anyway, if you will get one, be aware, don't use to much force when fastening the screw they can crack easy, also the surface can be dull when using abrasive rags, ... it's still plastic, you can get them here: http://www.malossist...2.aspx?FG=D.ORT Did you get your ignition sorted? Edited March 29, 2012 by PSchrauber Quote Link to comment Share on other sites More sharing options...
bondy Posted March 30, 2012 Author Report Share Posted March 30, 2012 hello again yes the bike is sorted know silly me i didnt have the inlet hose on tight enough come to think about it the nose i could hear was air being sucked so i to the carb off and made sure it was on tight put it back on and all good. anougther question for you i cant remeber witch side of the bracket dose the chain tenstioner go? had a look in my maual it shows it gose on the inside of the bracket nearest to the wheel but the spring dosnt sit right on the swing arm? Quote Link to comment Share on other sites More sharing options...
pschrauber Posted March 30, 2012 Report Share Posted March 30, 2012 hello again yes the bike is sorted know silly me i didnt have the inlet hose on tight enough come to think about it the nose i could hear was air being sucked so i to the carb off and made sure it was on tight put it back on and all good. anougther question for you i cant remeber witch side of the bracket dose the chain tenstioner go? had a look in my maual it shows it gose on the inside of the bracket nearest to the wheel but the spring dosnt sit right on the swing arm? Maybe this pic will help you: Patrik Quote Link to comment Share on other sites More sharing options...
bondy Posted March 30, 2012 Author Report Share Posted March 30, 2012 yes that helps thank you. Quote Link to comment Share on other sites More sharing options...
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