piggywiggywoo Posted March 31, 2017 Report Share Posted March 31, 2017 I have a Fantic 200 in excellent condition. But it is very hard to start when hot. Having read posts about bikes running for 20 minutes then being difficult to start, I concluded it must be an electrical problem. so I have replaced the source coil, fitted a new Blue Ducati coil on the frame having checked for good earths Re wired all connections, replaced the trigger pulse coil, new plug , cap and lead. It still won't start when hot. i have checked the various coil resistances and they are correct. Out of frustration I borrowed a complete ignition assembly from a known good bike and it still plays up from when hot The bike starts easily from cold, maybe runs a little rich, but when running is very good. It will run again normally as soon as it cools down. Now thinking it could be the crank seals , but it's not using oil and doesn't smoke oh and it's got a new carb. Any ideas I'm at a loss! Quote Link to comment Share on other sites More sharing options...
timdog Posted March 31, 2017 Report Share Posted March 31, 2017 Had that once on a car, turned out to be ht lead, carbon breaking down when hot, car conked out. Soon as cool again off it went. Not sure if theres anything you havent replaced that could cause that Quote Link to comment Share on other sites More sharing options...
totalshell Posted March 31, 2017 Report Share Posted March 31, 2017 put another 'good' carb on. then check timing if it persists. Quote Link to comment Share on other sites More sharing options...
shyted Posted March 31, 2017 Report Share Posted March 31, 2017 (edited) Has the motor been rebuilt before you owned it ? Is the insulator and inlet rubber between the cylinder and carb in good condition. Are you getting "pinking" when it gets hot or any other sounds from the top end or barrel ? Is it only starting problems or does it show other signs of breaking down. What's the plug like when you get the break down, or have you not looked? Take a spare plug next time your out. Check the spark colour when cold ,then when it won't start and if you have in fact got a spark .Then all your doing is reaching into a pocket for the plug, removing the HT cap, putting the plug in it , earthing it out and booting it over, see if you have a good spark. Process of elimination. If you have a spark and it was running fine, then start to look at fuel. See if the carbs getting hot, Don't stab into the dark, or it will end up costing you plenty you don't need to part with Let us all know chief. May be easier to give a diagnosis by internet. Hope those suggestions help. Regards Ted Edited March 31, 2017 by shyted Quote Link to comment Share on other sites More sharing options...
piggywiggywoo Posted March 31, 2017 Author Report Share Posted March 31, 2017 Hi yes the motor has been rebuilt it always runs fine ,hot or cold, with no noises just after walking a section after a lap or so it will refuse to start initially Then after 10 mins start and run normally Plug looks a little rich inlet and carb rubbers are new Already cost me plenty, I am now thinking could it be a fuel blockage, but it runs fine until I stop it and would tick over forever. As I say all new electrics including wiring Crank seals ? Quote Link to comment Share on other sites More sharing options...
feetupfun Posted April 1, 2017 Report Share Posted April 1, 2017 Test for it being a "too-lean" issue by next time it won't restart when hot, engage the starting circuit (the "choke" lever). This will help it to hot-start better if it is a little bit lean on the pilot jet. Similarly kick it with throttle fully open and "choke" off to test if it is flooding the engine somehow when stopped. Another thing to do is to fit a clear fuel line or a clear in-line fuel filter so you can see if there is a problem happening with fuel supply to the carby bowl when it is hot and stopped. Beware that sometimes a float valve will work fine while the motor is running but stick open or shut when there is no vibration. Another thing is that a leak at the ignition side crank seal will not reveal itself as smoky exhaust Quote Link to comment Share on other sites More sharing options...
eddie1 Posted April 1, 2017 Report Share Posted April 1, 2017 I have just had a similar problem Long story short I disconnected the kill switch from the coil and it solved the problem. I have yet to replace the kill switch but will do before the next trial. Quote Link to comment Share on other sites More sharing options...
piggywiggywoo Posted April 1, 2017 Author Report Share Posted April 1, 2017 Interesting your comments eddie1 about the kill switch. I have been testing a lot over many hours and at times thought I'd cured the problem Usually I would change an ignition component and then test. Often without the kill switch wired Its comming off again today to rule it out, maybe I have overlooked the obvious. Feetupfun thanks for your suggestions about weak and rich running tests. I have had a lot of input from knowledgable friends at trials and we have tried all methods of starting Full throttle no throttle choke on etc. 5 mins to cool down and as good as new Like I said FRUSTRATING Will keep you all posted Thanks for all suggestions 1 Quote Link to comment Share on other sites More sharing options...
turbo Posted April 1, 2017 Report Share Posted April 1, 2017 Hi mate , i listen to what you say but this has all the hallmarks of the stator failing (usually when hot ) . Have you checked the readings when hot ? better still change the stator if only to start eliminating (again) sorry ! 1 Quote Link to comment Share on other sites More sharing options...
piggywiggywoo Posted April 1, 2017 Author Report Share Posted April 1, 2017 (edited) Removed the kill switch but still no joy Have now tried two known working stator sand still the same problem Its weird when hot I can leave the bike ticking over happliy and it will run all day. Stop it , but then can not get it started. Not great when walking sections Removing the plug it's a good coffee colour but dry. Would indicate a fuelling issue , but how comes it will tick over. Could it be drawing fuel thru when running , but not creating enough suck from the kickstart procedure The new dellorto carb floats are plastic as is the arm I don't think it's possible to adjust the float level The tank tap appears ok, the needle valve is new and the carb filter clean? Very Frustrated Edited April 1, 2017 by piggywiggywoo Quote Link to comment Share on other sites More sharing options...
gbmoto Posted April 2, 2017 Report Share Posted April 2, 2017 I had a new 200 back in the day and the general issues were finding neutral and starting when hot. Was waiting at a section next to Brian Fowler one day and having a bit of a grumble. He suggested Rock Oil .... which instantly made neutral available......and if it doesn't start, kick over a couple of times with full throttle.....then no throttle...generally it started fine. Prior to that it was once a long walk back to the car park (where it then started fine) or making sure I parked at the top of a hill to bump it! But this was when they were new.....loads of different wear issues may be in the equation now...although it looks like you have excluded most. Quote Link to comment Share on other sites More sharing options...
scorpa250 Posted April 2, 2017 Report Share Posted April 2, 2017 14 hours ago, piggywiggywoo said: Is the fuel cap breather ok ? i had a bike that did similar symptoms and that was the cause . Quote Link to comment Share on other sites More sharing options...
piggywiggywoo Posted April 2, 2017 Author Report Share Posted April 2, 2017 (edited) Been doing a lot of testing today, and the bikes now starting when hot ,Hooray Out of desperation , I rechecked the float heights , spot on 23.5 mm Then I removed the needle jet from the carb and replaced it with one I had tried in the old carb. Both where marked 200 But were massively different in size. One needle fitted and the other was like a cock in a sock. So I went for the larger one and starting is now improved if not perfect. Thanks for all the help and suggestions Edited April 2, 2017 by piggywiggywoo 4 Quote Link to comment Share on other sites More sharing options...
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