Whats Changed

[Scooterlam]

I recently rebuilt a TS1 engine, new seals through out new crank and piston.
its a TS1 200 and it had suffered with piston failure on two occasions with the original asso pistons with the very square windows. I've been waiting a while and last year AFs released the woosner piston this was drilled and the skirt arched by AFs.
Built the bike up with the carb that had been on the bike for the last 25 years with the jetting as it was before. It starts first dab every time ( has a lowish comp ratio for saftey and runs happily on 95 ron).
The problem is the bottom end performance has disappeared. its just goes backwards when i try and cruise, get it up onto the needle and a few revs and it flies.
Its real hard work, good fun for a bit but you wouldn't want to do Euro on it.

It machine guns on the pilot jet and the plug is black but dry when chopped at those revs. I've gone down one on the pilot and need to do some more chops, but a little fiddle with the mixture screw and its got some of its old pep back.

Question is, Can the size and shape of the windows have an effect on the jetting.

[carlos fandango]

Is the crown height (profile) the same on the wossner as the old piston , Asso i assume ?

[Scooterlam]

Yes Russ well i hope so.
It wasn't the jap profile, fliat top.
but now you've got me worried.
I'll check with AFs website.
i plug chopped it today and its better with the smaller jet.
still on/off when I roll thru the 1/4 throttle position.
not totally happy with the HT cap.
I think part of the problem is ive been riding my avanti for so long and its such a different power delivery Its going to take a while to change my riding style.

[MickYork]

I know you haven't adjusted it but what is your timing ? is it static or auto retard ?

The problems are similar to my Avanti when I had static 17 degree, which was sorted by fitting an M-Tech.

[Scooterlam]

I,m going to re strobe it as i have changed the crank and for the life of me i cant 100% remember doing it. I'm sure check the basics first I have But best practice would be to do it again.
The thing is it feels like fueling as its throttle position rather than revs or load. But if I was giving advice i would say check the basics first and i am now mindful tht I,m running the risk of having down jetted to mask a problem, that if i then fix that problem i could be left running weak.
dropping the pilot means i can get into fourth at 60 instead of 70 now

[Donnie]

Haven't you gone through the whole carb yet? Ie rejetted it completely?

[Scooterlam]

The engine had been together for 25 years prior to this rebuild and dynoed.
The components have been like for like replacements. With the exception of the piston. Window size and shape.
I've done a couple of hundred miles since rebuild and mid range and top end are as far as I remember unchanged.

[Mr G in NYC]

Sounds like fuel flow ? Fast flow tap fitted ? G
Tank cleaned out , no sediment .

[Scooterlam]

I'll check but it seems to be more a case of too much at 1/8th -1/4 throttle.
I will check the float needle is holding but I,m pretty sure it is as i often forget to turn the fuel off for long periods, last time 3 years
And yes i have changed fuel.

[Dazts1]

Reed petals ok , are they open when they should be closed ?(lost there snappiness ) Have the edges feathered ? A lot of running troubles can come from reeds

[Scooterlam]

Reeds were New in at rebuild checked for fit and edges.