insultaco Posted January 17, 2011 Report Share Posted January 17, 2011 Hello all. My sons TY80 (normally starts 1st/2nd kick) has refused to start for the past few days. If I strip the carb, blow everything out, blow clean the plug, put it all back together again and kick it over, it will try for approx 5-10 secs to start (splutters and kind of fires, but sounds laboured), then dies and won't go again unless you repeat the above and even then it may not fire... It has a VERY clean carb with new Main, Needle and Pilot Jets, new float needle assembly and new Return Spring and I've confirmed the needle height is correct and that the float is set correctly as per Haynes manual setting instructions. The jet needle has no visible wear. The slide goes up and down easily and the throttle cable has been lubricated and gives a smooth action. The pilot screw is out 1.5 turns from seated. I've stripped the choke assy., pilot screw and tickover screw and blown everything out. I've had the reeds off and given them a clean, but they appeared pretty clean anyway. I've stripped the fuel tap filter, which was full of swarf and other c**p. The flow rate appears to have been OK even before the strip-down. Its a brand new plug (see previous post) and the spark appears good. It has good clean points and .35mm points gap at TDC. I've disconnected the kill switch to exclude this as an issue, but that is new and the problem is the same even if its connected or not. It has new crank seals etc fitted by TYTrials.co.uk and new piston and rings fitted by the previous owners Dad, compression appears fine. The fuel is new and mixed at 50:1 Please help, I've had to exclude my son from tha garage because he's getting the back-lash of my frustration with his bike!!! Cheers Mick Quote Link to comment Share on other sites More sharing options...
jse Posted January 17, 2011 Report Share Posted January 17, 2011 Hello all. My sons TY80 (normally starts 1st/2nd kick) has refused to start for the past few days. If I strip the carb, blow everything out, blow clean the plug, put it all back together again and kick it over, it will try for approx 5-10 secs to start (splutters and kind of fires, but sounds laboured), then dies and won't go again unless you repeat the above and even then it may not fire... It has a VERY clean carb with new Main, Needle and Pilot Jets, new float needle assembly and new Return Spring and I've confirmed the needle height is correct and that the float is set correctly as per Haynes manual setting instructions. The jet needle has no visible wear. The slide goes up and down easily and the throttle cable has been lubricated and gives a smooth action. The pilot screw is out 1.5 turns from seated. I've stripped the choke assy., pilot screw and tickover screw and blown everything out. I've had the reeds off and given them a clean, but they appeared pretty clean anyway. I've stripped the fuel tap filter, which was full of swarf and other c**p. The flow rate appears to have been OK even before the strip-down. Its a brand new plug (see previous post) and the spark appears good. It has good clean points and .35mm points gap at TDC. I've disconnected the kill switch to exclude this as an issue, but that is new and the problem is the same even if its connected or not. It has new crank seals etc fitted by TYTrials.co.uk and new piston and rings fitted by the previous owners Dad, compression appears fine. The fuel is new and mixed at 50:1 Please help, I've had to exclude my son from tha garage because he's getting the back-lash of my frustration with his bike!!! Cheers Mick Generally, you need three things for a two-stroke to fire off and at least run for a period of time: 1- Fuel/air mix in a ratio close to 15/1 2- compression 3- spark at a reasonably accurate time in the crank cycle It sounds like the first two are covered, so I'd look for an electrical problem such as poor plug cap, bad grounding of system, wiring shorting out (especially down around the stator area where you can't see it) etc. You can check for spark but this is not always a positive indicator of performance as a plug will emit a spark when the plug is taken out but not under compression when installed. Jon Quote Link to comment Share on other sites More sharing options...
neil king Posted January 18, 2011 Report Share Posted January 18, 2011 Try a little wider gap on the points. Quote Link to comment Share on other sites More sharing options...
alan_nc Posted January 18, 2011 Report Share Posted January 18, 2011 (edited) Jon has pretty well covered it. Always: What happened between the time it "started 1st, 2nd kick", and "won't start". You said compression "seems" fine - what is it actually? The wrong piston or ring put in by the P.O. could be leaving to much clearance. Take the carb off, squirt some gas directly into the cylinder - the bike should start and run for a few seconds. If it does you have a carb problem....If it doesn't you probably have a compression or timing problem. HTH Alan Edited January 18, 2011 by Alan_nc Quote Link to comment Share on other sites More sharing options...
neil king Posted January 18, 2011 Report Share Posted January 18, 2011 Try a little wider gap on the points. .45 mm Quote Link to comment Share on other sites More sharing options...
neil king Posted January 18, 2011 Report Share Posted January 18, 2011 .45 mm If that changes anything, then you can narrow the gap a little. Quote Link to comment Share on other sites More sharing options...
insultaco Posted January 19, 2011 Author Report Share Posted January 19, 2011 I've just changed the Points/Coil/Plug/Cap/Condensor Ignition Tune Up Kit - http://www.tytrials.co.uk/trailandtrialsuk/prod_147762--61014-Ignition-Tune-Up-Kit-TY80.html Coil/Cap - http://www.tytrials.co.uk/trailandtrialsuk/prod_153950-HT-Coil-amp-Cap-TY80.html all of which came to around Quote Link to comment Share on other sites More sharing options...
turps Posted January 19, 2011 Report Share Posted January 19, 2011 Had the same problem at the weekend with my sons, it had recently had a tune up kit for the ignition and the plug had only about 4 hours use. After stripping the carb to no avail I put a new plug in and it ran pefect. I was thinking of changing the grade of plug from a B6 to maybe a B5 to see if it lasts a bit longer and not hole the piston hopefully Quote Link to comment Share on other sites More sharing options...
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