mark h Posted November 13, 2008 Share Posted November 13, 2008 Hiya Fellers, this is my first time so be gentle, I`ve been refurbishing an 1983 xs250, managed to get the engine to start, with no filter, Box totally U/S, Put on two new K&N filters no start, removed filters, Still no start,(usually starts without any trouble), Continued to try and start and to my amazement the carbs blew right off the the engine, now thats not good thinks i, I`d better get some help, So here i am, Also obviously the tube from the engine that go`s in the airbox is just blowing in the wind, i`d be grateful for any help, many thank, Mark. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted November 13, 2008 Moderator Share Posted November 13, 2008 Have you tried to get it to run since, if it is running a wasted spark on the ignition and the cylinders havent fired then it could fire on what should be the exhaust stroke when in theory there is nothing to burn. But as you had been trying to get it running the cyl were full. To blow back hard enough to do what it did i would say it fired with the inlets open. Could be you have disturbed something ig related when you swapped the filters? My gut feeling would be ignition TBH but you had it running beforehand.....?? Oh welcome to the funny farm....what no, not the jacket, i don't like the jacket .......nooooooooooooooo Link to comment Share on other sites More sharing options...
Moderator YamaHead Posted November 13, 2008 Moderator Share Posted November 13, 2008 to the forum Mark 1st of all.....make sure & tighten those clamps on the intake rubbers! 2ndly......alot of your starting woes could be caused by your jetting being "off" from a lack of airbox. Going up a coupla sizes on your main jets could be a step in the right direction. Link to comment Share on other sites More sharing options...
mark h Posted November 14, 2008 Author Share Posted November 14, 2008 Have you tried to get it to run since, if it is running a wasted spark on the ignition and the cylinders havent fired then it could fire on what should be the exhaust stroke when in theory there is nothing to burn. But as you had been trying to get it running the cyl were full. To blow back hard enough to do what it did i would say it fired with the inlets open. Could be you have disturbed something ig related when you swapped the filters? My gut feeling would be ignition TBH but you had it running beforehand.....?? Oh welcome to the funny farm....what no, not the jacket, i don't like the jacket .......nooooooooooooooo Hi ya, no prob beforhand, could well be the wiring, Shot ta shit basiclly, cheers, Link to comment Share on other sites More sharing options...
JimR Posted November 14, 2008 Share Posted November 14, 2008 Have you tried to get it to run since, if it is running a wasted spark on the ignition and the cylinders havent fired then it could fire on what should be the exhaust stroke when in theory there is nothing to burn. But as you had been trying to get it running the cyl were full. To blow back hard enough to do what it did i would say it fired with the inlets open. Could be you have disturbed something ig related when you swapped the filters? My gut feeling would be ignition TBH but you had it running beforehand.....?? Oh welcome to the funny farm....what no, not the jacket, i don't like the jacket .......nooooooooooooooo Hi XS250 is not a wasted spark system but where well touchy with the way the engine was set up .... The Dwell angle was well critical if not set to 22.5 degrees they would act up no end. loosing the carbs from the manifolds was also quite common when the ignition was incorrectly set, the airboxes used to keep the damm things on with those stops (airboxes) removed the carbs are free to pop off when ever the engine misfires ... so my advice is to set the ignition timming/dwell, tappits and carb balance then run the motor and plug chop it to see what jetting needs to be altered, but bear in mind those CV carbs can give 'false results'. one more check to do .. the tube from the petrol tap to the R/h manifold a small leak there will allow fuel supply but also make the r/h cylinder run weaker than it should. Regards Jim Link to comment Share on other sites More sharing options...
mark h Posted November 14, 2008 Author Share Posted November 14, 2008 Hi XS250 is not a wasted spark system but where well touchy with the way the engine was set up .... The Dwell angle was well critical if not set to 22.5 degrees they would act up no end. loosing the carbs from the manifolds was also quite common when the ignition was incorrectly set, the airboxes used to keep the damm things on with those stops (airboxes) removed the carbs are free to pop off when ever the engine misfires ... so my advice is to set the ignition timming/dwell, tappits and carb balance then run the motor and plug chop it to see what jetting needs to be altered, but bear in mind those CV carbs can give 'false results'. one more check to do .. the tube from the petrol tap to the R/h manifold a small leak there will allow fuel supply but also make the r/h cylinder run weaker than it should. Regards Jim Hi Jim, Many thank`s for your help, I think the prob`s with this bike are mostly neglect, Most of the wiring is SHOT, Today i`ve been sorting and DRYING as much as i could, Got the old girl fired up, But very erratic on idle, Still slight blow back into filters, And miner misfiring, Not to bad at all when on higher rev`s, I put this down to too much unburnt fuel, will adjusting the mixture screw help?, Also there is a split on the fuel line as it joins the R/H manifold, (good thinking), Now about this tube Blowing in the wind, from engine to airbox so some sort of vent?, What do i do with it?, YES I`ve left myself open for a pun there, Many thank`s , Mark. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted November 14, 2008 Moderator Share Posted November 14, 2008 Hi Jim, Many thank`s for your help, I think the prob`s with this bike are mostly neglect, Most of the wiring is SHOT, Today i`ve been sorting and DRYING as much as i could, Got the old girl fired up, But very erratic on idle, Still slight blow back into filters, And miner misfiring, Not to bad at all when on higher rev`s, I put this down to too much unburnt fuel, will adjusting the mixture screw help?, Also there is a split on the fuel line as it joins the R/H manifold, (good thinking), Now about this tube Blowing in the wind, from engine to airbox so some sort of vent?, What do i do with it?, YES I`ve left myself open for a pun there, Many thank`s , Mark. most use a breather filter. theres an NOS wiring loom on ebay at the mo' Item number: 370108474847 Link to comment Share on other sites More sharing options...
mark h Posted November 15, 2008 Author Share Posted November 15, 2008 most use a breather filter. theres an NOS wiring loom on ebay at the mo' Item number: 370108474847 Thanks Drewpy, I may just have a punt, Mark. Link to comment Share on other sites More sharing options...
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