dev1975 Posted April 10, 2012 Report Share Posted April 10, 2012 (edited) firstly this is my 1st tials bike its a 280 TXT 02 Edition,(pre pro) main issue is revs not dropping off fully after bike has been started and choke shut down, still seems quite high even after fully warmed up you blip it and it does not drop off like i would like only way to solve it is to wind tick over screw out tilll it drops but if left there it dies, other than that motor is sweet as a nut with no untoward noises, to try and combat it i did the following cleaned carb out which was slightly dirty, airscrew is 1 1/2 out, fuel is approx 60:1, plug is bcpr5es, not sure what the c stands for as std seems to be bpr5es, i have ordered a seal kit for the dellorto carb along with new mixture screw and choke spring, had the same sort of issue with a dtr125 which turned out to be l/h crank oil seal??, plug is not overly white though, sort of light brown around porcelin shroud and onto electrode with only the very flat tip part of electrode being a dusty white, any pointers would be appreciated as ive already found this site very usefull when i couldnt bleed front brake up, sorted it though due to thread off here so im expecting some sound advice, although its my 1st trials i have quite a few bikes and like to rectify things myself but we all need a hand now and again thanks in advance, ps are the iridium plugs worth the extra money?? Edited April 10, 2012 by DEV1975 Quote Link to comment Share on other sites More sharing options...
lineaway Posted April 10, 2012 Report Share Posted April 10, 2012 When cleaning the carb did you remove the pilot jet and make sure pilot circuit was clear? Quote Link to comment Share on other sites More sharing options...
jse Posted April 10, 2012 Report Share Posted April 10, 2012 firstly this is my 1st tials bike its a 280 TXT 02 Edition,(pre pro) main issue is revs not dropping off fully after bike has been started and choke shut down, still seems quite high even after fully warmed up you blip it and it does not drop off like i would like only way to solve it is to wind tick over screw out tilll it drops but if left there it dies, other than that motor is sweet as a nut with no untoward noises, to try and combat it i did the following cleaned carb out which was slightly dirty, airscrew is 1 1/2 out, fuel is approx 60:1, plug is bcpr5es, not sure what the c stands for as std seems to be bpr5es, i have ordered a seal kit for the dellorto carb along with new mixture screw and choke spring, had the same sort of issue with a dtr125 which turned out to be l/h crank oil seal??, plug is not overly white though, sort of light brown around porcelin shroud and onto electrode with only the very flat tip part of electrode being a dusty white, any pointers would be appreciated as ive already found this site very usefull when i couldnt bleed front brake up, sorted it though due to thread off here so im expecting some sound advice, although its my 1st trials i have quite a few bikes and like to rectify things myself but we all need a hand now and again thanks in advance, ps are the iridium plugs worth the extra money?? firstly this is my 1st tials bike its a 280 TXT 02 Edition,(pre pro) main issue is revs not dropping off fully after bike has been started and choke shut down, still seems quite high even after fully warmed up you blip it and it does not drop off like i would like only way to solve it is to wind tick over screw out tilll it drops but if left there it dies, other than that motor is sweet as a nut with no untoward noises, to try and combat it i did the following cleaned carb out which was slightly dirty, airscrew is 1 1/2 out, fuel is approx 60:1, plug is bcpr5es, not sure what the c stands for as std seems to be bpr5es, i have ordered a seal kit for the dellorto carb along with new mixture screw and choke spring, had the same sort of issue with a dtr125 which turned out to be l/h crank oil seal??, plug is not overly white though, sort of light brown around porcelin shroud and onto electrode with only the very flat tip part of electrode being a dusty white, any pointers would be appreciated as ive already found this site very usefull when i couldnt bleed front brake up, sorted it though due to thread off here so im expecting some sound advice, although its my 1st trials i have quite a few bikes and like to rectify things myself but we all need a hand now and again thanks in advance, ps are the iridium plugs worth the extra money?? The seal kit for the carb may help, especially the o-ring at the top of the slide tower. I'd check the cable to make sure there are no kinks and there is a little slack in the adjustment. Look in the throttle housing to make sure the cable is not frayed at the end. You may want to pull the flywheel to see if you have oil weeping from the seal. If it was a trans side seal, you would notice a drop in tranny fluid and lots of smoke out the exhaust. It's not unusual to have a manifold leak as they are easily overtightened and this causes "bowing" of the manifold between the bolt holes. What is your jetting, especially the pilot jet and slide #? Jon ps. In my experience, the Iridium BPR5EIX plug is worth the extra money-they require less voltage to fire, have a slightly extended heat range and resist fouling to an amazing degree. The last one I had in my Pro for 2+ years and I only changed it out of guilt, not because it showed any wear. I run them in my TY350s with equally good results. 1 Quote Link to comment Share on other sites More sharing options...
thats_a_five Posted April 10, 2012 Report Share Posted April 10, 2012 (edited) It sounds to me like a mechanical issue of the slide not able to return to the idle screw position correctly. I suggest remove the cable, the throttle housing from the bars and give them a thorough cleaning and lubrication. If the cable does not move freely after lube, replace it. Also check the spring and needle inside the top of the carb for any roughness or bending. When I got my bike, it had a problme with pulling the throttle on a little when I turned far right. I had to reroute the cable to eliminate this. Just shows how sensitive the carb can be to a little cable binding. Fro your descrition, the plug sounds like it has some "MMT" fouling beginning. MMT is a fuel additive and as that brownish ceramic looking material builds up on the plug it will eventually cause a misfire or even no spark. It acts like an oil fouled plug but when you check the plug looks clean, not oily. Change your plug once a year and you should never have a problem with it. Good plugs are a cheap investment that can help you avoid a DNF. I carry a spare plug stuffed into a piece of rubber hose zip tied to my frame just in case! Edited April 10, 2012 by Thats_a_Five Quote Link to comment Share on other sites More sharing options...
dev1975 Posted April 10, 2012 Author Report Share Posted April 10, 2012 hi thanks for all that my throttle was a little tight before and someone had overstretched the return spring so getting it back in was a little tricky but another is on its way, black carb top doesnt seem to seat fully on carb so again i ordered one as well, after i rebuild carb will see if it still happens, as a rule what is a good starting point for pilot airscrew turns out on these?, was getting petrol seeping from this screw so again ordfered all seals i will need plus new screw washer and spring, carb inlet manifold screws seem to be very tight and slightly sunk into intakemanifold , will dis assemble all this at time of carb work, can the l/h crank seal be done by removing mag and stator then driving a screw into seal then pulling it out with pliers?/ this is how i did my last one one another bike and im assuming it will be just as simple, just to clarify the plug has no brown buildup its just that colour mixture wise, really fancy one of those ultrasonioc cleaning baths for carbs etc they look to be well worth hundred quid anyway, thanks for all your constructive comments ive been on forums before for various vehicles and they seem to be a haven for arseholes that just want to take the Pi$@ but not here thanks Quote Link to comment Share on other sites More sharing options...
jse Posted April 10, 2012 Report Share Posted April 10, 2012 " black carb top doesnt seem to seat fully on carb" The carb top only goes on one way, there is a tab that fits into a slot at the top of the slide tower. The cable enters the carb top to one side so if you put it on 180 degrees off, it would pull the cable slightly longer and if combined with a tight cable, would cause the slide to hang slightly open. You might want to check that just to be sure. Jon Quote Link to comment Share on other sites More sharing options...
tltel Posted April 10, 2012 Report Share Posted April 10, 2012 Hi, Just a comment, If you have the same dellorto carb as the earlier models then the mixture adjustment screw is a fuel adjuster and not an air screw. TLTEL Quote Link to comment Share on other sites More sharing options...
60north Posted April 10, 2012 Report Share Posted April 10, 2012 hi DEV1975, as TLTEL commented the dellorto phbl carb has a fuel screw not an air screw and should be 3 - 4 turns out. i had idle problems like yours and found the reed valves not closing properly due to a small piece of rubber between the reed block and reeds. fitting the black carb cover can be tricky, i find it easier if you 'stick' the o ring to the cover with a little silicon grease to hold it in place as you line up the tab & slot. hope this helps Quote Link to comment Share on other sites More sharing options...
dev1975 Posted April 12, 2012 Author Report Share Posted April 12, 2012 (edited) right thanks, the air screw that may be a fuel screw? does this still look like an airscrew setup once removed i.e, screw, spring, washer, and rubber seal? as never come across a fuel screw before just assumed it to be mixture as it has the same make up of components, just being sure thanks Edited April 12, 2012 by DEV1975 Quote Link to comment Share on other sites More sharing options...
dev1975 Posted April 12, 2012 Author Report Share Posted April 12, 2012 (edited) to John the cap is on correctly with the tab and cutout aligned its as if the plastic has warped, assuming the fuel adjuster is actually an airscrew which im pretty sure it is what would the turns out be from closed Edited April 12, 2012 by DEV1975 Quote Link to comment Share on other sites More sharing options...
tltel Posted April 12, 2012 Report Share Posted April 12, 2012 yes! Screw,spring, washer, the more you unscrew it the more fuel you get to the primary circuit. if you strip the carb down you can see what it does. Start at about three turns out and go from there. Not saying that this will cure your problem but when you are adjusting, it helps to know what is actually happening when you turn the screw. I would still do the stator side crank seal, as long as you have a flywheel puller this is a very simple cheap job to do.(as you said earlier) TLTEL Quote Link to comment Share on other sites More sharing options...
dev1975 Posted April 12, 2012 Author Report Share Posted April 12, 2012 well carb parts came today so will fit them and also check the reeds are snapping shut, iridium plug should be here shortly and yes i have a set of pullers so will probably do the seal as well, then maybe i will be able to have a proper go on it, went out briefly other day and within 500yds or so as i got onto fields the front brake locked on just as i accelarated off in 2nd causing me to be dragged down the tarmac part of the footpath and ended up landing in a pile of dog **** and facing 180 degrees other way and a raw elbow and buttock, last owner had drilled out 2 of the 4 piston cups and not washed calipers out as i found fragments of aluminium in caliper, i can only assume this debris stopped the fluid from returning and locked front end up!!! Quote Link to comment Share on other sites More sharing options...
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