starr870 Posted January 15, 2014 Report Share Posted January 15, 2014 I have been trying to set the carb up on my techno as the bike will not rev out cleanly when accelerating. So far I have changed the air box to carb rubber connector to eliminate air leaks, checked the inlet manifold and the reeds and these seam fine with no broken petals. I have put the needle clip into the middle groove and it is still the same! Does anyone know what the standard jet sizes should be so I can check the ones fitted to my carb, this has been very frustrating as the bike starts and idles and unless its revved flat out it performs faultlessly. Andy. Quote Link to comment Share on other sites More sharing options...
starr870 Posted January 18, 2014 Author Report Share Posted January 18, 2014 Do the jets have sizes stamped on them? Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 18, 2014 Report Share Posted January 18, 2014 Yes, the jets are each marked. Main should be 150, the pilot 27.5 or 30. Quote Link to comment Share on other sites More sharing options...
starr870 Posted January 22, 2014 Author Report Share Posted January 22, 2014 Where is the pilot jet marked as I can't see any marking on it, I have also found that the fuel pipe has a big kink in it that was behind the carb that I couldn't see before stripping the carb out, could this be causing fuel starvation at full throttle? Quote Link to comment Share on other sites More sharing options...
dadof2 Posted January 22, 2014 Report Share Posted January 22, 2014 what actually happens when you try to rev it? Does it just start cutting out or does it misfire with a fair bit of smoke? Quote Link to comment Share on other sites More sharing options...
starr870 Posted January 22, 2014 Author Report Share Posted January 22, 2014 It does smoke a bit and it does sort of misfire, but doesn't misfire. I have cleaned the carb out twice in the last couple of months and it is totally clean and my oil pre mix has been fairly rich which I have now changed to 70% and I also put new silencer packing in as the last lot had disintegrated. when the bike is on idle it almost sounds as if it is "four stroking" not like any other 2 stroke that I have had and I don't know how to change the carb settings to improve this. Quote Link to comment Share on other sites More sharing options...
dan williams Posted January 23, 2014 Report Share Posted January 23, 2014 Check out the Mikuni thread sticky'd to the top of the forum. Float level and travel should be adjusted and a 27.5 pilot jet is used around here for operation at sea level. Check to make sure your choke circuit is closing all the way. Quote Link to comment Share on other sites More sharing options...
starr870 Posted January 23, 2014 Author Report Share Posted January 23, 2014 I have taken the choke mechanism out and it moves up and down ok, when starting from cold it increases the idle speed and decreases when pushed in. How will I know that it is fully closing? Quote Link to comment Share on other sites More sharing options...
worldtrialchamp Posted January 24, 2014 Report Share Posted January 24, 2014 has the entire exhaust system/combustion chamber been removed of ALL carbon? if not, you're embarking on a wild goose chase Quote Link to comment Share on other sites More sharing options...
starr870 Posted January 24, 2014 Author Report Share Posted January 24, 2014 how Would i remove all the carbon from the middle box and front pipe, I have had the entire exhaust apart before and the deposits are rock hard. How would I go about cleaning the combustion chamber? Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 24, 2014 Report Share Posted January 24, 2014 It does smoke a bit and it does sort of misfire, but doesn't misfire. I have cleaned the carb out twice in the last couple of months and it is totally clean and my oil pre mix has been fairly rich which I have now changed to 70% and I also put new silencer packing in as the last lot had disintegrated. when the bike is on idle it almost sounds as if it is "four stroking" not like any other 2 stroke that I have had and I don't know how to change the carb settings to improve this. It is possible to pack the silencer too tight to make it choke itself. Also change to another new plug, just to rule it out. Quote Link to comment Share on other sites More sharing options...
dan williams Posted January 25, 2014 Report Share Posted January 25, 2014 Usually if the choke isn't setting all the way you can tell by pushing on it with it closed. If nothing changes you're probably OK. Quote Link to comment Share on other sites More sharing options...
starr870 Posted January 25, 2014 Author Report Share Posted January 25, 2014 When I re pack my silencer I us the sheet type material which I cut to the length of the silencer then wrap around the baffle tube , I think it was made by Apico. I will get a new plug today and reassemble the bike and try pushing on the choke plunger to see if this makes a difference. Very frustrating!! But thanks for the replies Andy. Quote Link to comment Share on other sites More sharing options...
worldtrialchamp Posted January 25, 2014 Report Share Posted January 25, 2014 starr870 The encrusted carbon in the exhaust is an often overlooked matter. Its critical on a two stroke engine that the exhaust is kept in new condition and/or regularly restored to new condition.......on a bike the age of a Techno, if it hasn't been performed before, I can imagine the deposits are extremely thick. To answer your question, the best way for me to do it is to burn it out with oxy acetylene. Often, tuning issues will be resolved simply by removing the carbon in the exhaust and the combustion chamber and ensuring the compression is 100% (fresh set of piston rings) If you're not concerned about the exhaust finish, just have it burnt out or go to an engine reconditioning shop and have it hot tubbed to remove ALL carbon deposits. There are other ways that you could try to clean it at home, but in my experience (I don't want to spend hours and hours doing this as its something I do annually) I prefer a quick effective solution. Others on here may offer other alternatives, but they do not suit me...the point is that it must be done, regardless of method Quote Link to comment Share on other sites More sharing options...
starr870 Posted January 26, 2014 Author Report Share Posted January 26, 2014 (edited) Thanks Worldtrialschamp, Is it possible to use caustic soda if I block up one end of the front pipe and the middle box and fill them with a solution. I do have access to oxy acetylene at work how would i go about burning it off without melting the middle box as its made of aluminium? Where on the pilot jet can I see the size marked? What does the pilot jet do exactly? Andy. Edited January 26, 2014 by starr870 Quote Link to comment Share on other sites More sharing options...
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