Wessie34 Posted June 11, 2016 Share Posted June 11, 2016 Hi folks, I need a bit of help understanding carb set up . Barrel porting standard, k & n filter in airbox, 35/1 pre mix so using 135 (instead of 130 ) main jet. Bike ran quite well from tick over, ( but surged on over run) . Once fully warmed the engine started pinking so I've raised the needle a notch, pinking gone, less surging, bike pulls better apart from virtually closed to 1/8 ish throttle ! So I've opened air screw to three full turns and it's a lot better but not perfect. Question is do I need a smaller pilot jet ? Hi everyone, it's great to be back, Dave. Link to comment Share on other sites More sharing options...
blackhat250 Posted June 11, 2016 Share Posted June 11, 2016 That the pilot area of throttle dave,. if you screw air screw fully home. and the motor dosnt stall, then pilot is too small, my book says 25. standard for CT3, [175] . WHAT IN YOURS, Link to comment Share on other sites More sharing options...
Wessie34 Posted June 12, 2016 Author Share Posted June 12, 2016 Phew, not sure John, I think it's a 30 ? All my data is at home, I'm motor homing in Wales ( it's pissing down ) and the bike is our runaround ( bit cramped for two ! ) I'll try it later with the screwing in thing as it's quite loud ! Off now it's breakfast time. Dave 1 Link to comment Share on other sites More sharing options...
blackhat250 Posted June 12, 2016 Share Posted June 12, 2016 Screw in the air screw a tad dave it usually cures the surging, unless u"v an Airleak , Link to comment Share on other sites More sharing options...
Wessie34 Posted June 14, 2016 Author Share Posted June 14, 2016 Air leak ! That sends the shivers through me ! Ok , so screwed the air screw in while on tickover and engine will cut out ( had to slightly touch the throttle to prevent it stalling ) , so maybe pilot correct? I have another throttle valve with different cutout / angle which came with this carb but I swopped it, I'll change back when I get home. Meanwhile, been out to Aberystwyth today ( got drenched) and now pilot circuit virtually non existent, but, got spanner out and four bolt manifold worked slack, ooh ! now waiting for rain to stop and I'll take it for a run, the joys of a two stroke classic ! 1 Link to comment Share on other sites More sharing options...
Wessie34 Posted June 15, 2016 Author Share Posted June 15, 2016 It's like a damn blog this ! Might be talking to myself but that's fine. So, started bike this morning still no small throttle response, so out for a run to Aberdyfi ( nice pub lunch ) and piss wet on way home. Removed pilot jet and all looked good, quick road rest and no change so will put up with having to use either no throttle or accelerate ! Quite loud in built up areas with a DEP can, it deafens the missus on the back, sorry locals. Ok, that's me for a bit, any ideas anyone ? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 15, 2016 Moderator Share Posted June 15, 2016 Mine ran a bit shitty once because the reed petals weren't seating well, they were aftermarket ones at the time. I swapped them for a good set of original ones and noticed a great improvement because more fuel was staying in the engine at low revs... as for the very loud DEP, well it shouldn't be that loud...again I had an aftermarket can that I had re-packed using the loose fibres they sell, trouble is it packs so solid that it loses much of it's ability to actually silence and affects performance badly...now I always use the matting, its much more airy if you like, sounds better and performs better too. Link to comment Share on other sites More sharing options...
Wessie34 Posted June 16, 2016 Author Share Posted June 16, 2016 Hmm, thanks for that, a couple of things to think about. Especially the reed valves, didn't think of that, I think there's some on the spare engine, I'll do that as soon as I get home next week. Cheers, Dave PS. Can the reed petals be inspected visually or is it suck it and see ? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 16, 2016 Moderator Share Posted June 16, 2016 according to the manual the reed valve bending limit is 0.3mm Link to comment Share on other sites More sharing options...
Wessie34 Posted June 16, 2016 Author Share Posted June 16, 2016 Brilliant, thanks. I'll have a play when I get home. Link to comment Share on other sites More sharing options...
blackhat250 Posted June 16, 2016 Share Posted June 16, 2016 Whats happening dave, ? can you not open throttle without bogging?, is it spluttering thru midrange, ? what colour is plug, sounds ritch , Link to comment Share on other sites More sharing options...
Wessie34 Posted June 19, 2016 Author Share Posted June 19, 2016 Definitely not rich, ( well I don't think so ) bike was pinking when fully warm, I lifted the needle and much better response and pinking only noticeable on foll throttle ! ( maybe, possibly, the low end got worse but I'll check). Then maybe a bigger main once I've sorted the low response. The engine is fine on a tiny throttle but try a little more and it goes " der der der "! If I open the throttle to accelerate as normal it pulls fine, so the only problem is cruising at slowish speeds, 20-30 mph through towns etc is hellish. I'll pull the reeds this week and maybe fit some spares I have, cheers, Dave Link to comment Share on other sites More sharing options...
Wessie34 Posted June 26, 2016 Author Share Posted June 26, 2016 So, today I've changed the carb back to the original, 2H500 ( but cleaned with air gun and fitted correct jets) fitted new float valve so set the float to 21mm which I think I set to 23ish last time, warmed it up and gave it a run, the same ! So, changed the reeds for some old ( slightly stiffer ) pair and , the same ! I noticed the emulsion tube is different on the two carbs so I thought it would cure it. Also ran the bike and sprayed wd40 type stuff and then carb cleaner in the region of the alternator seal and engine note didn't change ! So, before I strip and check the carb again is there an alternative jet needle I could try? Just a thought. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 26, 2016 Moderator Share Posted June 26, 2016 The correct jet needle for 2H500 is Needle, 4j13 Clip position 3 from top Link to comment Share on other sites More sharing options...
Wessie34 Posted June 27, 2016 Author Share Posted June 27, 2016 That's what's in so I think you've confirmed my next step, pull the motor and split cases ! Must be an air leak in there. Is there an easy way to do a leak test? I'm guessing you have to remove barrel and piston to do that anyway ? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 27, 2016 Moderator Share Posted June 27, 2016 where are you wessie,? I made a gadget for leak testing once Link to comment Share on other sites More sharing options...
blackhat250 Posted June 27, 2016 Share Posted June 27, 2016 Iwas experimenting yest, [ on dt400], when it got hot, [ 400f on tour tech ] it started to surge & pink, stopped, screwed air screw in 1/2 a turn, . it ran 10degree cooler.[ 387 the hottest, all day, ] and was smooth on over-run, another experiment, on a steep downhill, [ twistys,] I shoved on the choke, / it was like an engine brake , smooth, and the temp dropped 50degree in 2 minutes , so air is the killer of 2strokes , Link to comment Share on other sites More sharing options...
Wessie34 Posted June 28, 2016 Author Share Posted June 28, 2016 I'm in Mirfield, West Yorkshire, I looked at the link, great idea, if you're not local ( I don't mean will you do it !) I could make one myself. Just a thought, wouldn't the gearbox oil froth up (and burn) if the right hand seal was leaking ? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 28, 2016 Moderator Share Posted June 28, 2016 3 hours ago, Wessie34 said: I'm in Mirfield, West Yorkshire, I looked at the link, great idea, if you're not local ( I don't mean will you do it !) I could make one myself. Just a thought, wouldn't the gearbox oil froth up (and burn) if the right hand seal was leaking ? yes and it would smoke white, smell bad...and possibly you'd smell petrol in the oil Link to comment Share on other sites More sharing options...
Wessie34 Posted June 29, 2016 Author Share Posted June 29, 2016 I'll check the left hand seal again this weekend more thoroughly and then maybe strip it, or sell it ! Link to comment Share on other sites More sharing options...
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