OS91 or YS91?

[helihead]

i have os 91szh in both my synergys and had loads of problems with mixtures till i got 2 clines which made a hole load of differance cosistant power and good till the end of the tank ,
however i have now used the ys 91 sr i have to conciede its' a very nice motor indeed also had the recomended todd bennet muffler very nice and quiet too.so ys it has to be.
but well worth spending the £125,00 for the muffler..and it is the recomended pipe..

[Steve]

YS91SR and Hatori Todd Bennet muffler here too in my Vibe

[Arwel]

Weel I've bought a YS 91 SR and the Hatori pipe for it! Will let you all know how it goes in the 700!\ Thanks for all your help!

[dogg5306]

The YS91SR has the edge at the moment, especially if you think about the fact that that version is already very successfull, but you've got the YS91SR-RR which provides you even more torque... and I'm waiting for James O'Neal dual glow carb... that one will be a real "chef d'oeuvre"

[colin n]

Dual glow carb

that i would like to see

[ChrisB]

I decided to buy a YS 91 SR to try as on reflection,i was in the position where i had say one third of my flights running rich,then one third on song and occasional lean points on the last part of the tank.

I have put 7 tanks thru the YS today and in my opinion the difference is night and day,the YS on default needle settings just runs like a dream,i have come in 4 clicks on the main needle and will leave that there,i may lean the midrange out a bit as its still slightly rich but the power is there and most importantly its totally consistent thru the flight.

I see the new Align engine is over £200 as is the new OS all exhaust pressure regulated,this is a no brainer considering Probuild,the YS importer sells the SR for £209.

I would also like to give Probuild a massive thumbs up,Phil was great to talk to and it was a pleasure doing business with them,the first purchase of many probably.

I would also like to openly say a big thankyou to Matt Lodge for his help and hands on advice getting the 700 setup and recommending the YS in the first place.

I have just had a fantastic day at the field and i am still shaking.

7 flights on the 700 then one on the 450 which was interesting to say the least

So to summarise i think the OS is fine if you want to modify it or accept inconsistencies,if not get a YS

[mattie-lodge]

The YS 91 SR is a good motor Chris and have been impressed with the way it has performed with me. Its a ronseal engine. 'Does exactly what it says on the can'

Glad you had a good day dude

[ChrisB]

I am still trying to calm down

I am like a kid with a new toy right now