jockster Posted January 5, 2020 Report Share Posted January 5, 2020 Hi all, just recently got a 250 pro 2011 and the power delivery is very sudden, the bikes not done much from new, original chain sprockets ,tyres etc. Gearing is 10/41 map is set in rain mode,slow action throttle fitted. I have a 2013 300 sherco which is a lot smoother to ride and I’m really surprised how bad the gasser is! Any thoughts? Maybe jetting or needle position? cheers john. Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 5, 2020 Report Share Posted January 5, 2020 Either the carburetor is off or you need to learn better clutch control. The 250 pro is a wonderful bike. Quote Link to comment Share on other sites More sharing options...
gasserguy Posted January 5, 2020 Report Share Posted January 5, 2020 Flywheel weight & low comp head..... Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 5, 2020 Report Share Posted January 5, 2020 Gasserguy is probably right. Most Uk riders do not realize that the UK bikes are detuned compared to the rest of the world. Quote Link to comment Share on other sites More sharing options...
jockster Posted January 5, 2020 Author Report Share Posted January 5, 2020 38 minutes ago, lineaway said: Either the carburetor is off or you need to learn better clutch control. The 250 pro is a wonderful bike. Two other people have tried it and they couldn’t believe how sharp the delivery is, one said it was sharper than his 300 pro, maybe wrong jetting?cannot find carb settings to check it out Quote Link to comment Share on other sites More sharing options...
jockster Posted January 5, 2020 Author Report Share Posted January 5, 2020 18 minutes ago, gasserguy said: Flywheel weight & low comp head..... It doesn’t have a head insert to change, according to the manual/ year. I did wonder if it had a high comp head but the weren’t fitted that year. Quote Link to comment Share on other sites More sharing options...
gasserguy Posted January 5, 2020 Report Share Posted January 5, 2020 (edited) i had one from new in 2011 UK bike and kept it 3 or 4 years. S3 low compression head insert, slow action throttle and flywheel weight. It was perfect once they got fitted. Don't waste your time with carbs and jets........ https://www.splatshop.co.uk/s3-stars-cylinder-head-inserts-for-gasgas.html Edited January 5, 2020 by gasserguy Quote Link to comment Share on other sites More sharing options...
huski Posted January 5, 2020 Report Share Posted January 5, 2020 I had a 2011 250,certainly wasn't too snappy,was just right,was nowhere near as spiteful as 300 Sherco or 300 Gas gas.Are you sure you've not bought a250 with a 300 top end on it? Quote Link to comment Share on other sites More sharing options...
huski Posted January 6, 2020 Report Share Posted January 6, 2020 Ignition timing isn't adjustable on these,which is a shame,it would be an easy way of calming it down.An extra cylinder base gasket would take the edge off it. Quote Link to comment Share on other sites More sharing options...
collyolly Posted January 6, 2020 Report Share Posted January 6, 2020 Has it already been played with ? It's an old bike so may have some history I tried a top youths bike a few years ago and it was tuned for max splat it was useless for my old rider technique ! Quote Link to comment Share on other sites More sharing options...
5again Posted January 10, 2020 Report Share Posted January 10, 2020 Some years ago I inadvertently bought a used 250 Pro that was a grey import with weird extremely lean jetting, pilot, clip and main that gave it awful slow to mid transition. Apparently this was for emissions in wherever it came from. Repalced the jets to uk standard and it ran great. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted January 12, 2020 Report Share Posted January 12, 2020 On 1/5/2020 at 7:10 PM, jockster said: Two other people have tried it and they couldn’t believe how sharp the delivery is, one said it was sharper than his 300 pro, maybe wrong jetting?cannot find carb settings to check it out My mate had exactly the same problem and he was an accomplished rider. I will ask him if it was a 2011, if so it was the ignition being kokusan or not cant remember, give me a day. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted January 12, 2020 Report Share Posted January 12, 2020 On 1/5/2020 at 8:54 PM, huski said: I had a 2011 250,certainly wasn't too snappy,was just right,was nowhere near as spiteful as 300 Sherco or 300 Gas gas.Are you sure you've not bought a250 with a 300 top end on it? wouldnt make it snappy. Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted January 12, 2020 Report Share Posted January 12, 2020 On 1/5/2020 at 7:10 PM, jockster said: Two other people have tried it and they couldn’t believe how sharp the delivery is, one said it was sharper than his 300 pro, maybe wrong jetting?cannot find carb settings to check it out jetting wont make it snappy. Quote Link to comment Share on other sites More sharing options...
nzpeterb Posted January 13, 2020 Report Share Posted January 13, 2020 You note your bike is on standard gearing of 10/41. In New Zealand our Gas Gas was supplied with 11/42. The taller gearing may smooth the response. Also make sure you have a slow throttle fitted. If a Domino throttle is fitted this would be a black tube under the grip. A slow throttle has full travel over around one third of a turn, while the fast throttle movement is the same throttle opening over a quarter of a turn. Hope this helps. Regards, Peter. Quote Link to comment Share on other sites More sharing options...
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