Hi all,

Got my first trials bike a 2007 Sherco 290 (altered timing and an S3 low comp head to tame it a bit ha ha ha)

I know a lot of people will tell me it's the wrong bike for a starter but hey ho that's life....

Couple of questions,

1. Tyre pressure, I'm reading 4psi rear 6psi front as a recommendation, would any of you change that for a 15st rider ???

2. Oil ratio ? Never had a premix 2t before, what would you recommend ????

Cheers all

Jody

Those pressures suit most peoples weight except juniors, if you're really concerned with bending rims etc then try maybe 1 or 2psi more

Use a synthetic oil mixed at 80:1, any lower ratio than that will just clog the packing in the exhaust over time

personally id go 6 rear and 8/10 in front ,,you need to mix 5 litres ( not a full plastic red/green can ) petrol to 90ml synthetic 2t oil = 55to1 but you could go 70to1 =71ml i prefer to have a little more so use 90ml to 5 litres

Cheers boys

5 will be fine maybe 5.5 if its rocky, I run 4.5 and weigh more. Front 6 is good, 8 or 10 waaayyy too much.

4/5 for rear is good, except if it's an IRC, in which case 6psi as they have a very soft carcass. IME

They are a right obscure 'Vee Rubber' 'Trial Benissimo' ha ha ha

Think I'll be buying some others soon........

Vee rubber are not disastrous. Had a couple of seasons of them on my Rev3 whwn I got back to the sport. However, they have hard sidewalls so don't work well at low pressures because the tread becomes concave. 4Psi is fine for everything though.

Graham

80:1 is fine with good oil. Would noy use more for putting about.

Cheers for all the info boys, spent the day cleaning and checking

Previous owner copper greased everything........but put that much on it was everywhere......like a bit sticky dirt magnet ha ha ha

Noticed some play in the swingarm bearings I didn't notice when I bought it........

20 notes for bearings quite good I thought

While that's out being done ill drop the engine and put the S3 head on

Roll on spanner time next weekend

yep 4psi rear usually good if muddy may drop to 3psi about 6psi front is good, if front tire pushes out too much when turning maybe drop to 5psi. it takes some expirementation to get what ya like.

Pre mix for modern bikes standard seems to be 80:1

and a 2.9 is not a bad bike for a beginning trials rider that has experience on other bikes. Just take your time to get used to it and you will enjoy it.

Some play in the swingarm bearings is normal. I would estimate somewhere about 3-5 mm when lifting the wheel with bike on stand even off new. Might just want to clean and inspect, re-grease heavily and see whot you got. Those bearing tolerances add up.

The swingarm moves up/down/left/right about 6mm at the bearings, more on the RH than LH

Noticed a light knocking when hopping the rear to turn it round

I agree with 80:1 using a good quality synthetic. There really is no point in using more oil. The trouble is that 5L of fuel at 80:1 is an awkward 62.5ml of oil. I buy my fuel 4L at a time which is a much more convienient 50ml of oil.

I'm running my Sherco 250 at 95ml to 5 litres of fuel. As I've just done main bearings after one of the cages disintergrated I'm a bit weary about going any weaker on the mix. The new main bearings are fully sealed wheras the ones that came out were open so atleast the new ones dont need the fuel / oil mix for lube.

After putting it all back together with new mains, piston, barrel replated it started on the 7th kick and sounded lovely with a nice 2T pop exhaust note. After the first trial something started to sound rattley. Not had chance to investigate yet but beleive this sound (top end rattle sound???) can be normal for even new Sherco's? Its really pronounced when you let off the throttle or pull the clutch in. With this in mind I do wonder if the mix is strong enough as the Sherco handbook (sheet of paper) says 50:1