K Racing

The O.S.SPEED 21XZ-B has been supported by many top drivers worldwide due to its high performance and achieving excellent results at many major races including podium positions at the last two World Championships.

Succeeding potential of ‘masterpiece’ O.S.SPEED 21XZ-B and adding further tuning to meet the current racing trend, the “Spec.II” will be released soon.

New drop-in type outer head with special laser marking contributes to lower CG and better cooling efficiency. Each inner part has been modified for smoother acceleration up to top speed. New lighter piston and connecting rod contribute to better response to driver’s throttle operation. Lighter DLC coated, tungsten weight pressed-in and silicone potted crankshaft reduces friction loss further. Further evolved O.S.SPEED 21XZ-B Spec.II is born to win big races.

FEATURES
●New lighter piston and connecting rod
●New crankshaft features lighter weight, DLC coating, tungsten weight and silicone potting for optimum rotating mass
●New outer head features low CG and better cooling efficiency.
●Well-established 21J double-adjust carburetor is employed. 6mm, 6.5mm and 7mm restrictors are supplied as standard.

Specifications
Displacement: 3.49 cc (0.213 cu.in.)
Bore: 16.27mm (0.641 in.)
Stroke: 16.8mm (0.661 in.)
Practical RPM: 4,000-42,000 r.p.m.
Output: 2.65ps / 2.61 hp / 34,000 r.p.m.
Weight: 355g (12.52oz.)

Standard Accessories
Glow Plug p3
Carburetor Reducers: 6.5mm installed, 6mm and 7mm supplied
Exhaust Seal Ring
Dust Cap Set (3mm/16mm/18mm)

K Racing

Rsickles

iTrader: (21)

Just as I expected.

Too bad it costs $550. The old Speed dropped rather quickly in price, so here's hoping this one does too.

am

Lighter piston... I know someone who weight it...

Paulus

Got the new engine in front off me, the first thing i noticed is OS went back to the Long needle setup.
Wen i have time i will look inside the engine to see whats new.

Now lets hope we get better wetter soon so i can report back about the performance.

hookem34

iTrader: (17)

Holy smokes! That's some cheddar for a "stock" engine. I know the Speeds are good (I finally broke down and bought one), but I've got a $450 Nova that will blow its doors off.

Would love to see pics of the internals. I'm sure it looks puurrrttyyy.

banjodog

iTrader: (1)

looking to get in to a good race engine but the $sssss to much. maybe i will stick with the .21xp

ForwardBite

iTrader: (50)

I've heard that OS is going back to the short stroke like the VZ's. I hope they do!

I assume the Spec II is still long stroke. Can anyone confirm what stroke the Spec II is?

mjealey

iTrader: (7)

It is a long stroke, same as XZ-b speed.

Rsickles

iTrader: (21)

FWIW, was told Spec 2 replacement parts likely wouldn't be here until at least another month.

Anyone got pics of the engine broken down?

bigjayjay1

iTrader: (86)

Might have to go back to black again, these look pretty sick.. I'm interested in the carb needles, long or short and overall performance from bottom to top.. I'm suspecting the bottom to be a tad quicker with a softer mid to a higher top..

thecatman

iTrader: (12)

I hope they have fixed the bearing issues, I had 2 of the previous model and both lost there bearings at 2 gallons. Made me Switch after 6 years of running this engine. Most people I know were breaking them open brand new and changing bearings before break in, to avoid the problem and placing the old carbs on them also.
With the previous engine I could run them 5-6 gallons, rebuild them and get another 5-6 out of them. Then I would rebuild a 3rd time and use as back up engine.... Sure miss the smooth idle and power of this motor. Just too much money know to have it fail in 2 gallons

Frank L

iTrader: (148)

I should have them by Friday. I'll post up a few pics.

It's a J1 carb or long needle carb. I'll let you know in the performance. Won't get them on the track for another 2 weeks but break in will start in Friday

morgoth

Which parts did you change when you rebuilded them?
My vzb speed has now 7 gallons true it and it's still going with strong with more than enough compression. I love OS Speeds

thecatman

iTrader: (12)

Which parts did you change when you rebuilt them?
My vzb speed has now 7 gallons true it and it's still going with strong with more than enough compression. I love OS Speeds

I would replace P/S/R and both bearings. No crank unless the coating was worn off