YDS7Paul Posted August 6, 2015 Share Posted August 6, 2015 Hello all I am new to this forum and have a 1978 XS250. The bike is a runner but difficult to start, It spent 6 weeks in a m/c repair shop having the voltage regulator changed and the carbs sonic cleaned along with some other diagnostic work. Eventually I just collected it as they were unable to find the starting fault and suggested new carbs. The bike it seems at some point had 400 barrels and pistons fitted. The carbs are as far as I can tell still 250 original. I have stripped and cleaned them and had the sonic cleaned but still have starting issues. Since collecting the bike I have spent quite a lot of time myself stripping, cleaning and setting up the carbs, also checking and replacing the plugs and checking the compression which was very good. Is this something you may be able to help with please. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted August 6, 2015 Moderator Share Posted August 6, 2015 Wecome. Would be good if you say hi in the new members area. You will be regarded as a one of many just begging the answer to an issue then vanishing.Happens far too often and puts people of responding.That aside we have a couple of xs nutters who love em. They should be able to help. Ps. Put you in the workshop. Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 6, 2015 Author Share Posted August 6, 2015 Have posted now in new members area, with the amount of work that need doing I will be around for a long time. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted August 6, 2015 Moderator Share Posted August 6, 2015 are the carbs' choke a lever or a pull to operate?I assume it eventually starts but how?fires on 1 cyl and then 2 chimes in or does it get straight to it? I'd suggest looking at your timing first, that'sclean contacts, contacts gap, take off left cover and find LF to check ignition timing. (even better use a strobe) and check RF timingif the bike has had a 400 barrel and head on, the carbs will have had the mains and pilot jets increased so you need to check if they have the correct ones for the 120 and also check the needle position and type. that'll do for starters Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 6, 2015 Author Share Posted August 6, 2015 Hi Drewpy thanks for the response I will double check the points and timing although the m/c shop said they had checked it. I wondered if when the barrels were changed the original carbs were put back and not altered. Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 6, 2015 Author Share Posted August 6, 2015 I missed the first part of your post, the choke is a lever that you push down. To start the bike I turn the tap to prime and let the bowls fill up. Then put the choke on sometimes kick it over a couple of times then use the starter. It will turn over for ages hardly firing then it will eventually fire and try to run on the r/h cylinder. If I continue it usually will start and run on both. It does not run really smoothly but I have managed to get it to tick over at around 1000rpm. Sometimes even after running for 10 - 20 mins if I turn it off it will not restart, eventually the battery dies. Thanks again for the reply. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted August 6, 2015 Moderator Share Posted August 6, 2015 I missed the first part of your post, the choke is a lever that you push down. To start the bike I turn the tap to prime and let the bowls fill up. Then put the choke on sometimes kick it over a couple of times then use the starter. It will turn over for ages hardly firing then it will eventually fire and try to run on the r/h cylinder. If I continue it usually will start and run on both. It does not run really smoothly but I have managed to get it to tick over at around 1000rpm. Sometimes even after running for 10 - 20 mins if I turn it off it will not restart, eventually the battery dies. Thanks again for the reply.so you have the 250 carbs then. you need to confirm that they have the 250 jets in. I never trust garage mechanics tbh, its not their bike and usually give those jobs to the "Saturday boy" you shouldn't need to prime the carbs, its on a vacuum tap which lets the fuel flow. check that fuel does flow if you need to do this, could be partially blocked. make sure you have an inline fuel filter too Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 7, 2015 Author Share Posted August 7, 2015 thanks I will check out the jets at the weekend and post back the size, also will check again on the operation of the fuel tap. Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 8, 2015 Author Share Posted August 8, 2015 Hi got the carbs off and apart. They seem clean and I have taken out the jet I think you mentioned. They are both E120 and I will give them a clean and blast out. I have posted some pictures. Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 8, 2015 Author Share Posted August 8, 2015 Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 8, 2015 Author Share Posted August 8, 2015 Checked to inlet rubbers and they are both fine, the od of the carb outlet is 31.5mm. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted August 8, 2015 Moderator Share Posted August 8, 2015 on the float bowl, see the little drilling on the lip? shoot some carb cleaner down it, thats the choke route. Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 8, 2015 Author Share Posted August 8, 2015 Done that and put it back together started straight up on the button. Turned it off and would not restart then battery died. Jumped it off car started ok a couple of times. Took jump leads off and wouldn't start used the kick start and it went. The electrics were supposed to be done but do you think it may be a voltage issue after all that Link to comment Share on other sites More sharing options...
Moderator drewpy Posted August 8, 2015 Moderator Share Posted August 8, 2015 could be, batteries don't really last all that well in a motorcycle Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 8, 2015 Author Share Posted August 8, 2015 Charged the battery, put it on and the bl**dy thing started. All that time on the carbs ! at least I know they are good. I suspect a tired starter motor are they available does anyone know. The battery was replaced in May14 but the bike has hardly been used in that time so \I will replace that as well. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted August 8, 2015 Moderator Share Posted August 8, 2015 put it on a trickle charger, keeps them sweet glad you sorted it Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 8, 2015 Author Share Posted August 8, 2015 Not sure it's sorted will try to start it tomorrow and see if it starts but thanks so much for your help Link to comment Share on other sites More sharing options...
YDS7Paul Posted August 9, 2015 Author Share Posted August 9, 2015 Bike started ok so checked the voltage at the battery. It was 11.8 with the engine off and 13.4 running at 3000 is this about right Link to comment Share on other sites More sharing options...
slice Posted August 9, 2015 Share Posted August 9, 2015 Sounds about right, if it goes over 15Volts then check the regulator but yours is more or less spot on. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted August 9, 2015 Moderator Share Posted August 9, 2015 good batteries should be on 13 volts, yours is below that. 13.4 running is ok for a 11 volt base line. Its a field coil system so the battery creates the magnetism, low battery, low charging output Link to comment Share on other sites More sharing options...
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