lewis cosgrove

Its a 2007 Sherco.

Dellorto PHBL 26 First off its a FUEL screw not an air screw on the Dellorto. Pilot Jet : 33-36 Main Jet : 118-120 On a 33/34 pilot the fuel should be 3.5 turns out. If you are on the richer 35/36 the fuel screw its best to lean it out to around 2.5 to 3 turns out. Wouldn't think the s3 exhaust would effect it really... not sure... Check your spark plug colour, should be a nice chocolate brown colour.

Copemech, are these the reeds you use? http://boyesen.com/power-reeds-360.html

On the Sherco website it says the 2012 250's come with a 33 pilot, i would turn the fuel screw to 3.5 on 33. Just take the carb off and check, plus give it a clean while your at it.

Have the idle step up so that you can creep the bike forward slipping the clutch without throttle. Whats jets are in at the moment?

Upload a video of the bike running so we can hear it.

http://www.trialscentral.com/forums/topic/17883-the-great-how-much-oil-question/ 80:1 is most popular for a reason .

I think if the clutch discs have swollen that can cause drag, you can measure the width of the full clutch pack when removed (no need for the clutch holding tool thats for removing the clutch basket). Also make sure the clutch lever is adjusted correctly and bled right first (no air bubbles). Do all the gears run smooth when selected?. I would also check your selector spring which can break on Shercos. Its located behind the clutch basket(holding tool needed) so no need to spit the crankcase. Though i am not sure that's the problem, you can kind of see the selector spring without taking off the clutch basket if you get a torch, check that its not snapped.

I think that most people mix it at 80:1, which is 62.5 ml to every 5 litres of petrol. It does say in the manual for my Sherco to run it at 50:1 which is OK but when using a trials bike as its meant to be 80:1 is more suited as it wont oil up the plug as much. However if you are planning on using it more like a trail bike more oil can never be a bad thing.

Any ideas? Thanks

If the bike had no air filter the air fuel mixture would have been lean. This could have caused overheating in the cylinder head, wearing down quicker because for the lack of oil/fuel. Be sure to clean the carb as there was nothing stopping dirt from entering and blocking jets etc. Also the dirt could have ended up in the cylinder head scoring the piston, you can do a quick check by removing the exhaust then look through the hole with a torch to inspect the piston.

Some symptoms can be loss of power, low compression, smoking exhaust and fouled spark plugs. If your not sure you could check the piston for "Blow back", this is when carbon deposits build up below the rings. If so the rings are worn and should be changed.

So what is the correct amount then Cope? http://www.sherco.com/tl_files/core/pdf/manuels/2009MaintenanceManual_ST2T.pdf "330cc 150mm air vol" When i done it i just made sure there was an air gap around 150mm on each leg. Seems to have worked fine...

http://www.shercousa.com/pdfs/sherco_fork_seal_replacement-1.pdf I changed the fork oil on my Sherco 2009 not long ago, 330 ml is the amount to use.

The "squish" can be altered by using less or more base gaskets. This simply increases and decreases the clearance between the piston and head of the cylinder. I have a Sherco 290, with the squish set to 1.2mm which is stock. For a Gas Gas i not sure what the exact "squish" should be, check the web and other forums on TC for an answer from someone that has a Gasser. 0.8mm could be to low but this knock most likely was the worn bearing. Also with the correct "squish" set be sure to tighten the cylinder base/head nuts to factory torque settings.

If the small end bearing fell to pieces in your hand it would have most defiantly have been causing a knock. (Not sure if the bearings the same, probably will be though) If the rings are worn change them while your in there. You said you changed the piston to s3, when re-installing did you set the squish correctly? Also check the con rod has no up and down movement, its alright if it can move slightly sideways.

The more tired i get, the more fast it becomes. Until it becomes just a wheelie. The Slow-mo one is more like it, just need to try and do some in a row. Ill upload a video in future if i get better.

I think the the rear wheel left the ground once, which i am pleased about Probably should try and learn an easier technique first though..........................

After i posted this i realized the shim was on top because there was only 1 standard gasket at 1mm... so it has to be (Blonde Moment). There must not be the white silicon ring improving the seal at the top then. I have some hylomar which ill use as suggested with the shim in the middle. Thanks

I am going to set the squish to 1.20mm (Splatshop recommended) So I have 2 standard 0.5mm gaskets and 1 Shim 0.2 mm. Not sure if there is a certain way they go on, as the standard ones have white rings around the bits where the coolant flows to seal against the metal? But the shim doesn't. So would it go standard, shim , then a standard again, so the shim in the middle? But when I was taking off the old gaskets it looked like the shim was on top of the 1 standard (1mm) gasket from the factory....

One of my favorite trials bike videos The hopping bit is great too!