pete12341987 Posted July 9, 2013 Share Posted July 9, 2013 Hi every body, I have a dragstar 125, I recently had the spark plug re threaded on the rear cylinder so I had to take the head off, I have now put it all back together and it seems to struggle starting, but when I eventually get it going after about a minute and a half it fires up and now ticks over after I messed with the idle screw, but if I turn it off and try and start it again I get the same problem, sometimes takes a little longer to fire. It seems to only want to start if I have the throttle wide open, but even then it struggles and if I close the throttle it just spins the starter with not a great deal else. Iv cleaned the plugs, carbs, air filter and petrol pumps, im pretty sure the timing is correct other wise it would start at all? please can some one help Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 9, 2013 Moderator Share Posted July 9, 2013 Did you set up your timing chain properly as per the manual Pete? Link to comment Share on other sites More sharing options...
Ttaskmaster Posted July 10, 2013 Share Posted July 10, 2013 Cleaned the fuel line as well? Balanced the carbs? Decent plugs, clean with appropriate gaps? Put oil in? Check and re-check everything, especially if you can do it for free. Replace the cheapest parts first. Link to comment Share on other sites More sharing options...
pete12341987 Posted July 10, 2013 Author Share Posted July 10, 2013 thank you task master, yes iv done all the things you say it was running perfectly fine before I took the head off thank you airhead, im going to look into it further when I finish work today thank you both for the advise, ill let you know Link to comment Share on other sites More sharing options...
KirriePete Posted July 10, 2013 Share Posted July 10, 2013 I'm with Airhead on this one - if the bike was running fine before you lifted the head and that's the only thing you've done, then that's where the problem must lie. One tooth out on cam timing will give you the symptoms you have described - it'll run, but not very well and starting will be hit and miss at best - it's even possible to get the cams 180 degrees out of phase, so it's trying to suck through the exhaust and blow through the inlet. As it's a twin the other pot will be doing most of the work and the bad cylinder will be fighting it, hence the need for WOT to get it running at all - you've got a 62.5cc single driving a 62.5cc compressor essentially. HTH Link to comment Share on other sites More sharing options...
dt502001 Posted July 10, 2013 Share Posted July 10, 2013 +1 your cam timming is out Link to comment Share on other sites More sharing options...
pete12341987 Posted July 11, 2013 Author Share Posted July 11, 2013 thank you everybody for your advise I found out that the bike was sucking in air from the bottom of the head so iv replaced the gasket and solved the sucking problem but the bike still appears to struggle starting, iv checked the timing and the carb, and it all appears to be ok, im very stuck now and cant figure it out, can someone please help Link to comment Share on other sites More sharing options...
Ttaskmaster Posted July 11, 2013 Share Posted July 11, 2013 After balancing, did you put the vacuum covers back on? Got the needles in right and everything? Have the carb boots splut open, perhaps? Have you got the carb screws out far enough? Turn them all the way in then bring each one out by EXACTLY 3½ turns... and I really do mean EXACTLY 3½ turns. If that makes starting easier, adjust them in/out to suit, but do all the screws the EXACT same. Link to comment Share on other sites More sharing options...
dt502001 Posted July 11, 2013 Share Posted July 11, 2013 As task said and spray some wd 40 around the intake rubbers and vac line when running and see if the bike reacts then you have found another air leak. Link to comment Share on other sites More sharing options...
pete12341987 Posted July 12, 2013 Author Share Posted July 12, 2013 thank you task master and dt502001, everything with the carb is good and iv done the spray test and doesn't seem to react, I noticed today when I tried to fire it up that as it was trying there was a little black smoke from the exhaust, but when running theres no smoke, im absolutely stumped Link to comment Share on other sites More sharing options...
Ttaskmaster Posted July 12, 2013 Share Posted July 12, 2013 Have you got too much oil in the sump? Also, re-check the timing exactly as per the manual. Link to comment Share on other sites More sharing options...
dt502001 Posted July 12, 2013 Share Posted July 12, 2013 Try a commpression test and get back with the outcome and as task said make sure the cams are perfect 1 tooth out is all it needs to be . Also you said you cleaned the spark plugs have you tried new plugs? And when the bike fires up do both exhaust pipe get equaly hot? Link to comment Share on other sites More sharing options...
pete12341987 Posted July 14, 2013 Author Share Posted July 14, 2013 thank you everyone for the feed back, theres not to much oil in the sump, the timing is also spot on, i am unable to do a compression test but the exhausts get equaly hot. it may sound very silly but the bike is easier to start when its cold and it appears to struggle as it gets hotter, it will tick over for a couple of minutes then just slowly shut off, then it struggles starting again. Link to comment Share on other sites More sharing options...
neversaydie Posted July 14, 2013 Share Posted July 14, 2013 thank you everyone for the feed back, theres not to much oil in the sump, the timing is also spot on, i am unable to do a compression test but the exhausts get equaly hot. it may sound very silly but the bike is easier to start when its cold and it appears to struggle as it gets hotter, it will tick over for a couple of minutes then just slowly shut off, then it struggles starting again. Cant remeber clearly now,as ive not had the dragstar now for a while, but is there a PRI position on the fuel cock? If there is, switch it to that and try starting/running Link to comment Share on other sites More sharing options...
pete12341987 Posted July 15, 2013 Author Share Posted July 15, 2013 hi neversaydie, yes there is a PRI on the fuel cock, i will try that when i finish work later, thank you Link to comment Share on other sites More sharing options...
pete12341987 Posted July 15, 2013 Author Share Posted July 15, 2013 i have left in on PRI and it seems to be the same, when cold it will fire up first time and run, but then when warm if switched off it will struggle to start, im going to change the oil for new stuff although i dont think that will make a difference? Link to comment Share on other sites More sharing options...
Ttaskmaster Posted July 15, 2013 Share Posted July 15, 2013 No, don't leave it in Prime... Switch to Prime, start it and let it idle for a short bit, then turn to On and continue like that. Prime is just to push a bit more fuel through and usually used if you've run dry or close to it, as in ran a fair bit on Reserve. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 15, 2013 Moderator Share Posted July 15, 2013 another easy check is try it without the airfilter in to eliminate a dirty clogged filter Link to comment Share on other sites More sharing options...
pete12341987 Posted July 15, 2013 Author Share Posted July 15, 2013 thank you for the comments iv put a new air filter in so that's eliminated, the fuel tap is set to on, but once again when cold it will fire up first time then after its ran a little bit it doesn't want to tick over and it struggles to start when turned off, im very confused Link to comment Share on other sites More sharing options...
Ttaskmaster Posted July 15, 2013 Share Posted July 15, 2013 Are you starting/running it with choke on? Link to comment Share on other sites More sharing options...
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