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XS400, Bad Idle


akamor
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Gothca. Thanks for all of your help. When I get home today I will try it out. Will keep you updated.

Adam

nice one, well after you have that sorted we can go through if the mixture is set right but 1 thing at a time m8 B) catch u l8r have fun

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nice one, well after you have that sorted we can go through if the mixture is set right but 1 thing at a time m8 B) catch u l8r have fun

I got the motorcycle idling properly which is awesome. Now I am having another (more serious?) problem. When I keep the bike under 2000 rpm the throttle response is great. When I bring it over 2000 rpm the engine will rev up uncontrollably to 3000+ rpm then SLOWLY come back to an idle. I have no idea what could be causing this. Where should I start looking? I had a pretty serious backfire last night and a friend suggested that my butterfly valves in the carburetor are getting stuck? Is this possible? I was going to check it tomorrow morning. Another friend suggested it could be a vacuum leak. To me that sounds more probable.

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sounds like the mixture is rich take your spark plugs out and have a look to see what colour they are, if there realy dark or close to black then you need to change the carb needle setting, (same if there light or close to white)

take the needles out and put the pointy bit facing down you should then see a black bit on the top of the needle (like a thick washer) (pointy end = bottom) check the manual to see what setting it should be (its normaly half way) set them to what the manual sais for now then pop them back in and see what happens. then once thats done we can fine tune it. :D

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iv just read the other post and ppl are saying do the pilot/air screw at 2.5 turns out, to get the mixture right try that 1st and see what happens then but probs best check the needles to see if there set right. once thats done get back to me and we can go through fine tuning it.

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iv just read the other post and ppl are saying do the pilot/air screw at 2.5 turns out, to get the mixture right try that 1st and see what happens then but probs best check the needles to see if there set right. once thats done get back to me and we can go through fine tuning it.

I will do all of this, but first I have another question. The 'H' shaped hose that connects the two airboxes to the carburetors seems to be far too short to work well. I can connect it securely around the mouth of the carburetor but then it is not securely fastened around the airbox or vice versa. Are there any tricks for making it all connect well. I can almost definitely feel air flowing around the hose-airbox connection. Could this have an affect?

Adam

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I will do all of this, but first I have another question. The 'H' shaped hose that connects the two airboxes to the carburetors seems to be far too short to work well. I can connect it securely around the mouth of the carburetor but then it is not securely fastened around the airbox or vice versa. Are there any tricks for making it all connect well. I can almost definitely feel air flowing around the hose-airbox connection. Could this have an affect?

Adam

tie wrap it and see if that helps, and anything leaking is never good lol

edit:- sorry didnt read it properly. think it should be ok for now as the air gets sucked into it from the airbox but if your concerned about it try wrapping some black electrical tape round where it links into the airbox (if you stretch the tape when you wrap it then it will act like shrink wrap and make it air tight) if you do that for now till you can find a perminant fix.

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think il need a pic for that one m8 as its a little tricky to explain lol

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think il need a pic for that one m8 as its a little tricky to explain lol

It is okay. I understand you. I will adjust the pilot screw to 2.5 turns then possibly adjust the need when I get home from work today. You will probably be asleep by then so we can discuss more over the weekend or on Monday. Thanks!

Adam

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ok m8 im always checking the forum so if you wanted pm me a time to b on and we can go through it all in one go catch u l8r m8 good luck

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When the engine hangs at a higher RPM and will not come down immediately, the mixture is too LEAN, NOT too rich. 2.5 turns out is not enough. Go to 3.5 and adjust slightly up or down from there based on the plugs or a Colortune.

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