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.

 

 Either the carburetor is off or you need to learn better clutch control. The 250 pro is a wonderful bike.

Flywheel weight & low comp head.....  

 

 Gasserguy is probably right. Most Uk riders do not realize that the UK bikes are detuned compared to the rest of the world.

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 

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.

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, 20206 yr by gasserguy

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?

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.

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 !

 

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.

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.

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.

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.

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.