Hi DG

The bike I rode had been ridden for around 3 Months by its owner I believe. Also, the bike hadn't been fettled with from its stock setup.

I really wanted to like the bike as I'm a fan of 4 stroke engines but I was very dissapointed.. but you may absolutely love yours so good luck

p.s .. it still sounds naff

3 months old? sounds like a pre production model.

3 months old? sounds like a pre production model.

I guessed at 3 months but thinking now about its condition, It may be a lot newer. The guy riding it was 'trying it out' from his mate who couldn't get on with it but I got the impression he had had it for a while.

Mr Ant man

I'd say definetely pre-production model by the riding characteristics, and the sound 'cos the new ones have larger exhaust openings at the final muffler (needed less back pressure apparently - some stalling on engine braking on pre prod models) The sound is now way better!

You can tell current model because exhaust openings are asymetrical - round opening on left side, oval on right side (Pre prod model both sides were the same)

Heaps of other changes on current model also to carby intake, jetting, port intake, fuel pump etc. The bike runs pretty sweetly now.

Must concur about running a bike in properly before fiddling with anything. And always keep copious notes so you can return to a base line or previous setup.

We have had one on a dyno and ended up back with the stock 07 jets and 2.5 turns on the mixture for Max power - too easy.

My sy250F runs sweet , im a club / c grade rider and for me comming from 270 beta's and sherco's etc its very rider friendly lots of power , great suspension easy to start sounds like a 4 stroke should sound. Ive ridden a Repsol 4RT a fair bit for the last year and the comparison is quite differant when it was on stock settings the 4RT 1st gear is much higher than the sy250 and tries to get away from you abit when balancing on the clutch.

I also think when it comes to build quallity the 4rt has alot of aluminium where the sy250 uses plastics and tubular alloys and a tonn of billet parts including the centers of the wheels where its machined billet with anodiesed gold edges.. and the foot pegs are a work of art and much larger than the 4RT pegs.

Reviving this thread, I bought an 07 a couple of years ago for a play bike ( my main bike is a 4rt)  This 07 has a lot of clutch drag, have done the plate restacking shuffle and the washer addition, have had a slight improvement with these mods, have not done the drilling the basket mod yet. Has anyone replaced the steel plates with the Tusk dimpled plates for a yzf and if so, any improvement? The dimpled plates were a huge improvement on my 4rt. Is ahamayFrank still on here?

Thanks, Ken

Edited March 19, 20188 yr by trials930

Update, I drilled the clutch basket, doubling the number of factory drilled holes, and installed the Tusk dimpled steel plates, the clutch now feels perfect, no drag, can find neutral very easily. Next is installing the Athena 290 kit.