viciousvinny Posted April 18, 2010 Report Share Posted April 18, 2010 hello, i have just bought an 05 sherco 320, it has apparently had all the necessary mods, i think the carb is a 28mm, i made the fatal error of turning the mixture screw thinking it was tickover !! now i don't know where i am and when i do manage to start it, as soon as i blip the throttle, it bogs and stalls, i have tried it in and out and just get the same result, are they very sensitive, and is there a 'base' setting? thanks Quote Link to comment Share on other sites More sharing options...
copemech Posted April 18, 2010 Report Share Posted April 18, 2010 If the bike has a 28 Kiehin installed, seems they were coming in at between 1/2 and 3/4 turn out if properly jetted. Quote Link to comment Share on other sites More sharing options...
viciousvinny Posted April 18, 2010 Author Report Share Posted April 18, 2010 Thanks, i'm a little confused, as the screw i adjusted WAS the big one with the spring behind it, which is the idle screw?? i gave the bike 2 big revs before this, and it seemed to splutter a bit afterwoods? is felt like it was going to stall, so i tightened the idle screw, strangely this is hardly making any difference, it was then very hard to start and bogged and stalled when blipping the throttle, this was like it for half an hour or so and i have given up and put it back in the shed, could it have flooded the carb somehow when i revved it hard a couple of times? Quote Link to comment Share on other sites More sharing options...
viciousvinny Posted April 18, 2010 Author Report Share Posted April 18, 2010 just checked carb and its a dellorto vhst28, the small left screw is out 2 and half turns, the bigger right screw with the spring is the idle screw i hope, when i managed to get it running earlier after i had hard revved it, it smelt very rich, almost stinging my eyes? Quote Link to comment Share on other sites More sharing options...
copemech Posted April 19, 2010 Report Share Posted April 19, 2010 Mmmm, well I believe the VHST is similar to the PHBL on the 2T's in that the one with the spring visable is indeed the idle speed control and if the other is to your left and on the engine side it will be a fuel mix screr for low speeds(note not an airscrew) as the more you open it the richer it gets. I think I would try a new sparkie first. May have fouled on cold start choke. Misfire after that. Next would be giving the carb a good clean and blow. My initial thoughts anyway. Quote Link to comment Share on other sites More sharing options...
autostream Posted April 19, 2010 Report Share Posted April 19, 2010 just checked carb and its a dellorto vhst28, the small left screw is out 2 and half turns, the bigger right screw with the spring is the idle screw i hope, when i managed to get it running earlier after i had hard revved it, it smelt very rich, almost stinging my eyes? Harsh exhaust stinging eyes and nose is usually an indication of lean, not rich. Excess fuel is smelly and black but not agressive to the senses. Quote Link to comment Share on other sites More sharing options...
viciousvinny Posted April 19, 2010 Author Report Share Posted April 19, 2010 thanks , could still do with some idea of number of turns for mixture screw?/ Quote Link to comment Share on other sites More sharing options...
viciousvinny Posted April 19, 2010 Author Report Share Posted April 19, 2010 I pulled the plug today, it was sooted as someone suggested earlier, but I checked gap and it had been left at.8 I changed it to .6 and it starts lovely, but is now struggling a bit just as you start to open the throttle pulling away, it holds back a touch, then goes, I think i'm going to remove the carb and give it a good clean as the carb overflowed earlier. which would suggest the floats are sticking. Quote Link to comment Share on other sites More sharing options...
copemech Posted April 20, 2010 Report Share Posted April 20, 2010 I pulled the plug today, it was sooted as someone suggested earlier, but I checked gap and it had been left at.8I changed it to .6 and it starts lovely, but is now struggling a bit just as you start to open the throttle pulling away, it holds back a touch, then goes, I think i'm going to remove the carb and give it a good clean as the carb overflowed earlier. which would suggest the floats are sticking. Well, maybe you made some progress. I would still get a fresh plug in her. Be sure to remove the jets screws and blow through all passages in the carb, including the two small ones in the bore using carb or brake cleaner and air. A fine wire able to pass through the low speed jet is always helpful yey you may need to find one that small. The 2.5 turn setting on the dellorto fuel screw is not neccessarily bad, as it depends upon the pilot jet size and such, will vary on the day as well, but at least sounds as though it is in range. Be sure to remove the round banjo cover on the fuel inlet to the carb and clean that screen inside as well. Note angle if inlet prior to removing bolt.. Quote Link to comment Share on other sites More sharing options...
viciousvinny Posted April 20, 2010 Author Report Share Posted April 20, 2010 thanks, just dropped it off at REPS motorcycles, he's going to strip the carb, clean and rejet it if it needs it, can't wait...... Quote Link to comment Share on other sites More sharing options...
bobtlr Posted April 20, 2010 Report Share Posted April 20, 2010 hey, on my bike when i have trouble starting its 9 times out of 10 the spark plug it still seems to work fine ( nice spark if you check it) but the bike will not run i cant help on the carb side mine has an oko 24 mm and it works great. best regards bob Quote Link to comment Share on other sites More sharing options...
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