Craig taylor Posted September 10, 2019 Report Share Posted September 10, 2019 Hi guys I’ve swapped my 2005 290 to a 2010 st300 canastany rep and the 290 was so smooth and smooth bottom end , the 300 is horrible at idle / very low end , I’ve lowered the compression , retarded the ign and slow action throttle which has helped a lot but I feel it could be much better . Has anyone swapped the 28mm flat side dellorto carb for earlier type 26mm ? , strangely it will idle with idle mixture fully in or fully out with very little difference ?? , anyone had any success with this model , ??? Quote Link to comment Share on other sites More sharing options...
lineaway Posted September 10, 2019 Report Share Posted September 10, 2019 The carb is plugged up, Keihin? The jet tower needs to be cleaned out. (But first make sure the pilot circuit is clear and working) The jet tower is the one with the security torx screws. Quote Link to comment Share on other sites More sharing options...
mcman56 Posted September 11, 2019 Report Share Posted September 11, 2019 Personally, I have found the Keihin carb particularly insensitive when trying to adjust by the "fastest idle" method. In fact, one day I was riding with a rider on a new 250 Evo and when he went to adjust the idle mixture screw found that it had fallen out. The bike still ran OK. I try and use the "adjust and try" method. Not that I would recommend it but a 26 mm OKO would be a simple swap as it is the same size and uses the same cable. Quote Link to comment Share on other sites More sharing options...
lineaway Posted September 11, 2019 Report Share Posted September 11, 2019 Why would anybody buy a copy of the real thing that is new? It is called jetting 101. By the way, move your boot to the outside of your peg. Problem solved. 1 Quote Link to comment Share on other sites More sharing options...
faussy Posted September 11, 2019 Report Share Posted September 11, 2019 (edited) Keihins are extremely sensitive to the air screw! A quarter turn is sometimes enough to turn a bike from burbling at idle to running on. If your keihin isn't responding to idle mixture adjustments, it needs a good clean Putting a 26 PHBL dellorto is basically turning it into the standard non cabestany model, so it will run fine, and ultimately less fussy. Will a smaller dellorto sort your problems at the low end, possibly.... Edited September 11, 2019 by faussy Quote Link to comment Share on other sites More sharing options...
Craig taylor Posted September 11, 2019 Author Report Share Posted September 11, 2019 (edited) Hi guys it’s a flat slide 28mm dellorto carb not Keihin, 2010 model Edited September 11, 2019 by Craig taylor Quote Link to comment Share on other sites More sharing options...
faussy Posted September 11, 2019 Report Share Posted September 11, 2019 (edited) 1 hour ago, Craig taylor said: Hi guys it’s a flat slide 28mm dellorto carb not Keihin, 2010 model oops, my bad. No experience with this carb im afraid, but the 26 mm dellorto round slide was the standard model carb back then as far as i know Edited September 11, 2019 by faussy Quote Link to comment Share on other sites More sharing options...
lineaway Posted September 11, 2019 Report Share Posted September 11, 2019 No matter the carb, you have a pilot circuit problem. That first needs to be cleaned. I would try a couple larger pilot jets to make sure before changing to a new carb. The carbs were notoriously lean on the pilot jets from the factory. Quote Link to comment Share on other sites More sharing options...
mcman56 Posted September 11, 2019 Report Share Posted September 11, 2019 Keihin PWK does not come in 26mm Quote Link to comment Share on other sites More sharing options...
copemech Posted September 11, 2019 Report Share Posted September 11, 2019 put a 26 dellorto on it and dump the flat slide! Quote Link to comment Share on other sites More sharing options...
Craig taylor Posted September 11, 2019 Author Report Share Posted September 11, 2019 1 minute ago, copemech said: put a 26 dellorto on it and dump the flat slide! If jetting does not help I will try swapping the carb to 26mm round slide , my older 290 was soo smooth ? Quote Link to comment Share on other sites More sharing options...
huski Posted September 11, 2019 Report Share Posted September 11, 2019 The Cabestany is a very different weapon to your old bike.They are much more fiery with a lot of bottom end power,it won't ever be as smooth as your old one.A dellorto would help calm it down if you can't get it how you want with the flat slide carb Quote Link to comment Share on other sites More sharing options...
pauls320 Posted September 11, 2019 Report Share Posted September 11, 2019 (edited) The 28mm carb that Craig has is most likely the Dellorto VHST 28. It was the carb Sherco was using as its performance option during those years...Some years of those rear fuel tank models had intake manifold leakage/warp problems. The carbs were on quite an angle too, so the float levels need to be set accordingly to minimize flooding and rich fueling conditions...especially on down hills. Hope you get it sorted soon☺️ Edited September 11, 2019 by pauls320 Quote Link to comment Share on other sites More sharing options...
Craig taylor Posted September 12, 2019 Author Report Share Posted September 12, 2019 14 hours ago, pauls320 said: The 28mm carb that Craig has is most likely the Dellorto VHST 28. It was the carb Sherco was using as its performance option during those years...Some years of those rear fuel tank models had intake manifold leakage/warp problems. The carbs were on quite an angle too, so the float levels need to be set accordingly to minimize flooding and rich fueling conditions...especially on down hills. Hope you get it sorted soon☺️ It is that carb , I’m going to play with jetting etc and try a 26mm normal carb just doing crank seals, reefs etc as well to make sure it’s as good as can be Quote Link to comment Share on other sites More sharing options...
pauls320 Posted September 12, 2019 Report Share Posted September 12, 2019 Not trying to add more non-problems to your ''check out ''list, but make sure your fuel delivery hoses/ routing/pump is not causing your issues. Sherco did do some updates on later models because of fueling issues on that generation sherco..Splatshop had some relevant info on wsite. good luck Quote Link to comment Share on other sites More sharing options...
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