Pete88

Hi All, Just hoping you guys will be able to guide me in the right direction, I want to test the primary & secondary resistance of the coil on my bike (Sherco 250 2004 with Leonelli coil) I have referred to the splat shop guide: https://www.splatshop.co.uk/coil_testing But this guide doesnt indicate which wires need to be tested in which order. Can anyone let me know what COLOUR wires I need to test to check the primary & secondary resistance of the coil? Thanks in advance & apologies if the answer I am looking for is obvious!

Is it worth cleaning the inside of the cylinder with a scotch pad too?

Thanks again Feetupfun, I can only just feel a very light score line above one of the ports, but I really have to use a fingernail to detect it (by no means the worst I have ever seen) Would acetone be any good for cleaning the piston rings & groves? On another note how much movement/rotational play should there be between the primary gear? When I hold the clutch basket still and rotate the flywheel there is a bit of movement, enough to make a small noise, is this normal of square gears?

Hi Feetupfun, So with the top end off and all apart: I cant feel any play at all at the flywheel. There is some rocking play in the big end but none up and down (certainly none that I can feel with my hands/finger tips) The little end has quite a lot of rocking play and a small amount of up/down play. The gudgeon pin has slight wear on it, I think I will replace the bearing, gudgeon pin and clips whilst I have this apart. The piston rings both seem free in their slots, I cant see any scoring on the rings, there is very light scoring on the cylinder wall, is this something to be concerned about? From what I can work out it has had a newer piston fitted as the width of the little end bearing is the same as splat shops description of the past 06 virtex piston I also discovered the transmission oil looking quite milky so I am going the do the water pump seals & check the shaft.

Thanks Miss Crabstick (great name btw) The noise tends to be most noticeable once I let off the accelerator, on the run out as the engine comes back to idle. I am guna check piston and play at the flywheel before ordering the parts but guna do a bit on an overhaul whilst I have the time! Any other hints or tips would be great, Thanks

Thanks Feetupfun, This is awesome advice, exactly what I need. I am a confident hobby engineer but i need the specific details for this type of bike, being relatively new to trials still, getting used to these machines after years of working on boat engines is interesting. I will start by checking for play at the flywheel & then get the head/cylinder off to look at the piston & rings this afternoon. I assume I can get the cylinder off with the engine still in the frame?

Thanks Kurtas, What is normal/acceptable play wen checking the crankshaft bearings by push/pull on the flywheel? Are there any specific indicators I am looking for when checking for gummed or worn piston rings? What is normal/acceptable play in the big & little end bearings? Thanks again for your help

Hi All, Just after some advice & top tips. I have a 2004 Sherco 250, it is a great bike & rides well but it has developed a bit of a tapping engine noise, I dont think it is piston slap but I could be wrong! I think it is crankshaft bearing play. Having read up on this I have learnt they are quite susceptible to wearing out. I am going order the parts I need and have a go at replacing them whilst I have all this time at home during lockdown! Do I need a clutch basket tool? Any top tips or useful knowledge would be greatly appreciated, Thanks in advance

Hi All, I am coming back to Trials after a few years break (getting through the first years of fatherhood!) I reckon I can make enough excuses now to spend more time in the garage & out on the bike so ready to get the bike out, give it a overhaul and get riding again. Guna need some advice on getting the main bearings done & few other bits. I have a 2004 Sherco 250 & the last time I run it it had a bit on an engine tap, I am assuming crankshaft bearings! Thanks for having me on the forum,