Brand new to motorbikes and trials bike, bought myself a 2004 sherco 290 the other day to mess around on and have a bit of fun.

The bike rides absolutely fine however there is a strange tapping nose coming from the engine that doesn't sound quite right, anyone have any idea what it could be ? 

heres a link to a video of the noise...

cheers. 

Does it disappear when you pull the cluth in ?

 That is an 03 by the way and you need new mains. That year was known for the mains to spin in the case.

pulling the clutch in doesn't make any difference to the tapping noise,

new mains? is this a big job to do? 

 

 Complete engine teardown.

Sloppy piston, con rod bearings I am thinking....rebuild time. Hope you did not pay too much for your new bike.

As above,won't be cheap,might work out better to sell it as spares/repairs and get something better and take a mate who knows about bikes

Thanks for the guidence

I bought it pretty cheap (£900) i knew it sounded rough and would some maintaining , i was looking for a project to get stuck into over the winter time so it will be a good challange 

I would guess that RYP USA website will hsve all the info you need to strip a Sherco motor.

Hi, I had an 07' 125/200 that sounded like that, I did all of the above suggestions and still lived with that noise for two years. Someone at a trial commented that it sounded like a sewing machine, so I sold it still running terrific.

cheers Taff

 The Sherco  is actually very easy to work on. The trouble can be the mains spin in the cases. The short cure instead of new cases was to dimple up the cases where the bearings sit. That was actually a service memo from Sherco.

Look in the posted links above for the manual on doing the main bearings, hardest part is getting the engine out. Make sure you replace the crank seals with viton versions

Describing how to check the big end for wear is a bit hard but basically hold the crank steady & push & pull on the rod to feel whether there is play up & down rather than side to side. Piston wear really needs proper measuring equipment but if it has gouges or large amount of discoloration below the rings replacement is definitely needed. Piston kits aren't cheap, find out what Beta charges for a 270 piston kit as they are the exact same part made by vertex & may be cheaper

How far from splatshop are you? Chris etc are a wealth of knowledge & should be able to supply everything you need, I've done my bearings before with parts from them & I live on the other side of the world 

Thanks for all the replies lads its all helpful to me, hopefully i will have time to dive into this project over the weekend.

 so to change the piston do i need to take the engine out or can i just take the head/barrel off? 

 

 

On 12/11/2017 at 1:07 AM, tony27 said:

Look in the posted links above for the manual on doing the main bearings, hardest part is getting the engine out. Make sure you replace the crank seals with viton versions

Describing how to check the big end for wear is a bit hard but basically hold the crank steady & push & pull on the rod to feel whether there is play up & down rather than side to side. Piston wear really needs proper measuring equipment but if it has gouges or large amount of discoloration below the rings replacement is definitely needed. Piston kits aren't cheap, find out what Beta charges for a 270 piston kit as they are the exact same part made by vertex & may be cheaper

How far from splatshop are you? Chris etc are a wealth of knowledge & should be able to supply everything you need, I've done my bearings before with parts from them & I live on the other side of the world 

I live quite far from splatshop but i have already been in contact with Chris and he is super helpful! he seems to know whats going on so i will find out what damage has been done when i take it apart. 

 

If you're unsure of the condition of the big end etc it's best to give it to someone who knows what they're looking for, ideally a trials dealer if possible. A engine reconditioner will be able to accurately measure the bore for you

I find splatshop's site great for ordering parts with how suggestions of other parts needed come up at the bottom. I would suggest replace the waterpump seals & bearings while the engine is apart, check the shaft for grooves as well

Do not remove the head from the cylinder if you haven't already, it's not necessary for doing the piston & will save you needing to buy new o-rings which are 1 use only

Edited November 15, 20178 yr by tony27