Sherco 290

[civillizard68]

Hi I'm looking at rechromeing my barrel and a new piston in my 2004 sherco 290!

Totally new to trials just looking for some advise to help me along the way

As I'm looking at doing this myself bar the rechromeing

Is it something I could do myself?

[nelly1]

top end is pretty easy to do mate i always stuff tissue in the bottom end when the barrel is off so no crap or flying circlip drops in there

[dombush]

Definitely possible to be done by the home mechanic...

However, a well intended piece of advice is that if you don't have the necessary tools or know what you need to do, its probably a sign that you could do with a hand from an experienced pal or get it done somewhere.

It takes me about an hour to strip the bike to get access and then take the barrel off.

Apart from circlip pliers or hose-clip pliers there are few specialist tools needed, however if you want to measure the barrel and piston properly you'll need a bore gauge and a micrometer of the correct size.

If you're confident that the barrel is worn out and are sure that you want to replate, I suggest the following:-

• Buy a piston prior to the replate, ensure it is of an A or B size so that you can go larger if you need to do so later.
  
• Send the piston along with the barrel (and the desired piston/bore clearance) to the replating company. This way you don't need to measure the barrel as the plating company will simply diamond hone the barrel to suit your specific piston.
  

To save you getting any blank looks, a minor point is that the barrel is unlikely to be "chromed". Modern barrel plating is a patented elecro fusion process that has a numerous trade names, the most common of which is "Nikasil"

Good Luck

Dom

[joeninety]

Easiest way to get barrel replated is to send it to Splat Shop, they then measure it up and send it off to Langcourts with the size required after Nicosil plating. It is then returned to Splat Shop and they select the correct size piston, rings etc. It's then sent back to you. I think on their website there's a price for this service which includes piston (gudgeon pin if i remember correctly), rings & plating. While you're at it you might as well do the small end bearing.

The cost of this is not that cheap but no more expensive than going to Langcourts direct and then getting the piston etc from somewhere else. With Splat Shop doing it complete you know its all going to have the correct clearances. The only down side to this is you do lose your barrel for 2-3 weeks but I used used the time to split the cases and put in new crank bearings, seals and also replaced other seals like output drive shaft, kickstart & gear lever.

To just do the barrel as mentioned before no special tools needed although you will need a small torque wrench.

To split the crank cases to replace main bearings and seals you will need to remove the fly wheel that requires puller and to make things easier I also made a pin bar that locates in the two holes in the flywheel to undo the the flywheel nut. This can be loosened by putting the bike in gear with the rear brake on but as my engine was out of the frame I couldn't do this. I'd recommend removing the engine as this makes working on it so much easier and its fairly easy to get the motor out. You then need to get the clutch basket nut off and the primary gear nut off, these will be tight. After trying various methods to stop the crank and gear train rotating I ended up borrowing a electric rattle gun that removed the two nuts easily. The casings can now be split. Once split tie the gear train together to stop items falling out when you start to clean the sealing faces for new gaskets.

Putting it back together is just the reverse. Just take your time and if things aren't going right call it a day and try again the next day refreshed. If you are a member of a club there will be a few people who have done this and if you're not confident get their help, most folks are friendly and love to help out...

Hope this helps??