EthanKing Posted May 5, 2016 Share Posted May 5, 2016 Hi guys, last night I pulled the restrictor washers from the carbs on my 02 cb500s and when then she would just about tick over and wouldn't take any revs without dying. I put the washers back in and it struggled to fire up but ran perfectly for a half a mile before loosing all power and cutting out. As it is now, it's ticking over with half choke. Any more or less and it stalls. I have checked for kinks in the fuel lines.Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 5, 2016 Share Posted May 5, 2016 Was anything else done to restrict it? Quote Link to comment Share on other sites More sharing options...
eastanglianbiker Posted May 5, 2016 Share Posted May 5, 2016 when it runs and then cuts out open the fuel cap and see if you hear a hiss of air as the breather in the cap could be blocked Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 Pretty sure it's only the washers but I put them back in so it should be back to the way it was. It's now ticking over and revving without choke but when I put on the choke fully it instantly dies. Can't take it for a spin as I'm at work but I'm confident it will die. EAB, I just noticed on the bottom of the tank there are 2 ports that don't connect to the fuel tap, a thin one and a thick one. The thick one has no pipe on it and the thin one goes to the top of the carbs but it's split so I pulled it off the tank and left it connected to the carbs. I'm guessing it's a vaccum?Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 5, 2016 Share Posted May 5, 2016 The vacuum connection is what opens the fuel tap diaphragm. It needs to connect to a connection on the cylinder head inlet stub or the carb rubber. No connection, no fuel and sucking in air. Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 There is a fuel line on the tap, and a vaccum from the tap to the cylinder head. Over on the other side of the tank there are 2 ports, the thicker one has no pipe on it at all and the thin one going to the top of the carbs which is split and I removed from tank. Sorry I can't take any pics right now I can imagine it's really hard to picture without seeing what I'm talking about.Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 Hhhmmm it seems I made a mistake last night. The pipe that split ( looks like a vaccum coming from top of carbs ) is now removed from the port on the tank and the bike is ticking over and taking revs perfect. I will take it for a spin on my lunch break and see how it rides.Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 The bike is running but now has less power than the 125 :/ I will strip it down and take some picsSent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 http://uploads.tapatalk-cdn.com/20160505/ed2f6ba07b91a1a9e1e58ce00b6970d0.jpgThey are the two ports on the tank that I don't have connected to anything. The fuel tap then has a fuel line and vaccum.Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 5, 2016 Share Posted May 5, 2016 You will run out of fuel if you ride without a vacuum connection to the tank. Why do you ask for advice and then ignore it??? Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 You will run out of fuel if you ride without a vacuum connection to the tank. Why do you ask for advice and then ignore it???Woah sorry dude I thought you were talking about the vaccum coming from the fuel tap? (Which I have connected)The only place for the small port to connect in that picture is the top of the carbs beside my throttle cable. Would that be right?The bigger port in that picture doesn't seem to have been connected to anything.Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
Tango Posted May 5, 2016 Share Posted May 5, 2016 You will run out of fuel if you ride without a vacuum connection to the tank. Why do you ask for advice and then ignore it???Whoa Alan......He wasn't ignoring advice as far as I can see. Those ports on the bottom of the tank should be overflow drain and vent. Ordinarily they should have pipes on them that go to the bottom of the bike.With your problem it sounds like fuel starvation or a blocked air filter......check your fuel line doesn't have any kinks in it and check your air filter.....and see where you go from there..... Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 Thanks Tango, so I don't need any pipes on those two ports for it to run right? I'll check both of those after work. I got a length of hose to replace any perished ones. I'm pretty sure the carbs are seated fully into both the diaphragms and airbox. The thing that I'm leaning towards now is the thin tube coming out the top of the carbs which I have leading nowhere now, I'll get pics as soon as I can but it's coming out from the rail between the two carbs and my fuel line is going into the bottom rail between the carbs.Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 5, 2016 Share Posted May 5, 2016 Sorry if I misunderstood your meaning. Are you saying that there is now a vacuum connection between the engine/carbs and your fuel tap? The other tube from your carbs could be a breather and doesn't need connecting to anything. Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 Yes correct it does look like either a breather or vaccum.Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 5, 2016 Share Posted May 5, 2016 Vacuum is normally very small bore pipe to fuel tap. Breather tends to be bigger, maybe 6mm bore. Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 The vaccum from the fuel tap is around 2-3mm ID and the one in question on the carbs is 5mm ID so must be a breather then. Cheers. Next update will be when I check the air filter and fuel line.Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 5, 2016 Share Posted May 5, 2016 Good luck and keep asking for help. Sorry about my misunderstanding. Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 Will do thanks. No problem mate worst thing is that this is my daily driver I have no other means of transport :/ should have left well enough alone lolSent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 5, 2016 Share Posted May 5, 2016 I can only think you disturbed or disconnected something when you took the washers out. Quote Link to comment Share on other sites More sharing options...
eastanglianbiker Posted May 5, 2016 Share Posted May 5, 2016 have you got the air intakes fitted back onto the carbs correctly and not folded one into the mouth of the carb or something daft as thats easily done Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 I double and triple checked everything after work and it's still really low on power, won't go past 80km/h and takes ages to get there. Ashamed to say I have given up and a lad from the club is going to have a look at it Sunday. He said he will balance the carbs for me. Could that solve the problem?Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
megawatt Posted May 5, 2016 Share Posted May 5, 2016 I doubt it, but he may see something you've missed. Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 5, 2016 Author Share Posted May 5, 2016 Yeah hopefully. He's taking it tomorrow and I'll get it back Sunday. Thanks for the help guys much appreciated!Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
EthanKing Posted May 7, 2016 Author Share Posted May 7, 2016 That guy couldn't take my bike until next week. I was riding home from work today full throttle to keep it at 80km/h and after a few splutters I suddenly had full power the smile on my face could have cracked my visor lol. Took it out the bypass then and I have 100% full power until I hit 120km/h where it starts stuttering and won't go any faster. It used to do 140km/h with no stuttering at all.I'm guessing I had a clogged jet or something and it's still a bit clogged?Sent from my G7-L01 using Tapatalk Quote Link to comment Share on other sites More sharing options...
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