Hi all. Back in the sport after a break of almost 50 years. Loving it. I've built a Magician, with a 25 LA, a Flite Streak, with a 20 FP, and an Orcrist combat wing, with a Taipan 15. All fly well, the pilot is slowly re-learning old skills. I certainly appreciate how much easier the newer OS engines are to start, compared to the various units I had back in the day.

I've recently bought an OS 25 FSR. Looks new, it will get to Australia (where I am) in about 3 weeks. I'll build a Riley Wooten Demon for it, the extra power (compared to my 25 LA and 20 FP) should move it around nicely.

Only problem. The engine appears to be lacking a needle valve (the spray bar is in place). I was aware of this when I made the purchase, I'll need to find a replacement. In particular, I can source locally an Enya 25S Needle Valve Assembly with the following dimensions:

Spray Bar Diameter   3.98   mm
Spray Bar Length   12.5   mm
Thread length   12.5   mm
Nipple Length   6.0   mm
Overall Length   33.6   mm
Fuel Hole Offset   8.5   mm
Fuel Hole Size   1.0   mm

Does anyone know if this will fit the OS 25 FSR? In particular, if the spray bar diameter is the same, then I should be able to get everything else to line up.

If you're going to fly it on a Demon as you said, I would use a remote needle with just a fuel fitting going into the venturi. You can use the std. spray bar; just plug up the needle valve side.

With the clone Magnum , which is cinch bar , I threw in a 7.5 mm bore Fox BB 25 intake , Filed to smaller spigot .
Used a old rattly Taipan N V A  , Goes thru outside the case . Gave a marvelous run . I figure it works like a Weber
emulsification tube - as it ran sh*t if I seaed the needle with fuel tube .

Finger Tip on Needle to shift on one side  only ratchety lock , it'd rock & run clean . Click - click , sensitive Adjustment .
Back to Marvelous burbble Finger OFF .

Tank was angle cut straight vent . Outside of tank level with NVA ( fore & aft ) .

Worn to 9 1/2 flexi Tornado 10 x 6 , or a Black 9 x 6 , or a black 9 x 4 if your having trouble in the wind .
Gives a Good Load Response to gusts , Also , Rich / Full 4 stroke in level flight . Max Lean running across the top of the circle -
As LEVEL all the fuels inside of ( the circle ) it . Overhead , its all Under It . So Progressive power up with altitude and a 4-2 break .
Brake ? Downhill .

In a 48 ounce Nobler size thing . on 55 foot of .018 in gales , to 70 foot of .012 , tho has dragged itself thru the schedule on slack . 016 at 70 foot .
Keeps on keeping on . Pulled all the FSR's down ( Was given a TT clone & a OS for $ 10 ) ALL had grtty bearings . BOTHER . Tho the 250.000 mile
Magnums are just loose & not really gritty , thyre a bit past it . So maybe pull the backplate & get a flashlite in there to see if its all brown &  gloopy .

IF its ' fresh ' it may well be fine . But seems the r c blokes mostly throw them aside unflush'n'oiled . So they rot from the nitro & need a clean up
Three out of three , in this case . If the Oxide comes away running , there goes your cylinder fit - So eyeball the inside of it before , justin Case .

Hi all. Thanks for the pointers. I should be able to figure out a way forward.

Upon returning to the sport I've been struck how helpful and friendly folk are, both here and at my local club.. No surprise really, but pleasant nonetheless.