Posted May 27, 201113 yr just brought home a xs250 as a project for my son however has no spark whats the best way to establish if power is getting to the points regards Jez
May 27, 201113 yr Moderator just brought home a xs250 as a project for my son however has no spark whats the best way to establish if power is getting to the points regards Jez get a battery! check fuses by removing and cleaning the glass fuses. no power as such across the points its a ground for the coils.
May 28, 201113 yr Author get a battery! check fuses by removing and cleaning the glass fuses. no power as such across the points its a ground for the coils. fuses seems all good every thing else works ? Thanks for reply i have a few questions i am very good in all mechs but tend to get lost with ignition timing and have learnt since electronic stuff so points are a mystery to me any help would be great do the points draw there power from the battery or the alternator/generator how do i test that power is getting to the points and does it need to be turning over to test this? should i be able to see the points generate/release a spark? (atm cant see anything) Jez
May 29, 201113 yr Moderator fuses seems all good every thing else works ? Thanks for reply i have a few questions i am very good in all mechs but tend to get lost with ignition timing and have learnt since electronic stuff so points are a mystery to me any help would be great do the points draw there power from the battery or the alternator/generator how do i test that power is getting to the points and does it need to be turning over to test this? should i be able to see the points generate/release a spark? (atm cant see anything) Jez If you look at the wiring diagram, the pints earth the coils which have a red/white positive feed via the ignition switch. ther is also a condesor to prevent sparks across the points, preventing arcing (sparks) which will erode the contact surface. the time the contacts are closed it powers up the coils in primary coil and when the contacts separate, the built up power in the coils has no where to go so passes to the secondary coils and jumps the spark plug gap (the easiest earth path). thats why HT leads are well insulated, stopping any earth leakage. hope that sinmplified explanation helps.
May 30, 201113 yr Author Hi yeah thanks all under stood the wiring around the points coils and power were all wrong and (fiddled with) i have put that all right and she starts but runs very poorly and will not rev am now researching how to set the points in relation to tdc gonna order a condeser and clean carbs I have one question I presume there will be some tdc marks on generator flywheel is flywheel wet or dry do i need to drop the oil?
May 30, 201113 yr Moderator Hi yeah thanks all under stood the wiring around the points coils and power were all wrong and (fiddled with) i have put that all right and she starts but runs very poorly and will not rev am now researching how to set the points in relation to tdc gonna order a condeser and clean carbs I have one question I presume there will be some tdc marks on generator flywheel is flywheel wet or dry do i need to drop the oil? Rf (right fire) Lf (guess) no flywheels on the xs, you just remove the left cover (4 allen bolts) on the centre stand and the oil won't come out! tip; if you over fill the oil, you can get rid of excess via the side stand method!
May 30, 201113 yr Author Hi set points they were out but it has made no differeance checked carb all looks spotless almost as if been cleaned before diaphrams look good good blue spark at plug so bike starts with time and effort but not without a petrol prime down cylinders once started struggles to keep going and will not rev i am a bit lost now .... not sure what to try next has anyone any ideas ... Jez
May 30, 201113 yr Moderator Hi set points they were out but it has made no differeance checked carb all looks spotless almost as if been cleaned before diaphrams look good good blue spark at plug so bike starts with time and effort but not without a petrol prime down cylinders once started struggles to keep going and will not rev i am a bit lost now .... not sure what to try next has anyone any ideas ... Jez now i'm confused, you said there was no spark in your first post. so you now got a spark now and there is another problem? is there anything thing else we should know?
May 30, 201113 yr Author Sorry yes no spark to begin with ... but got that sorted the wiring was all bodged ... but it struggled to start since then ... we have retimed the points which were out sligtly but engine still runs poorly and will not rev it will not start without priming the cylinders with petrol i have checked the carbs they look very clean and the diaphrams look good I am a bit lost now i suspect lack of fuel but logicaly it should get there as the carbs look good will strip cabs next I suppose regards Jez
May 31, 201113 yr Moderator Sorry yes no spark to begin with ... but got that sorted the wiring was all bodged ... but it struggled to start since then ... we have retimed the points which were out sligtly but engine still runs poorly and will not rev it will not start without priming the cylinders with petrol i have checked the carbs they look very clean and the diaphrams look good I am a bit lost now i suspect lack of fuel but logicaly it should get there as the carbs look good will strip cabs next I suppose regards Jez Carbs are very picky on the xs's. they may LOOk clean, but in honesty, they need ultra sonic clesaning. "Mervin the mod" on this forum can do them. there are lots of small orificies, i cleaned mine but still ended up sending them away to be ultrasonically cleaned. You can get Keyster carb kits from NRP in Manchester if you want to overhall your carbs and replace the jets etc.
June 2, 201113 yr Author Carbs are very picky on the xs's. they may LOOk clean, but in honesty, they need ultra sonic clesaning. "Mervin the mod" on this forum can do them. there are lots of small orificies, i cleaned mine but still ended up sending them away to be ultrasonically cleaned. You can get Keyster carb kits from NRP in Manchester if you want to overhall your carbs and replace the jets etc. what about single carb conversions is that done I have a few various old style VM mikunis lying around ? and a host of jets
June 2, 201113 yr Moderator what about single carb conversions is that done I have a few various old style VM mikunis lying around ? and a host of jets can be done and has been done. strangly the original jets are ok as the engine is a 180' crank so only one piston needs a charge of fuel in any given time.
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