I recently became the owner of this webra that I know little about. It does have a dynamix carb, and I have a pretty good instruction sheet on how to set the mixture.

Does anyone here own one of these engines? I see the engine is rated for speeds up to 17.5K? Is this engine really timed to run at these speeds? Or should I run this in the rpm range of a sport .61 with a sport muffler?

These specs are copied off the webra site.




volum ccm / cu in 11.50 / 0.70

power PS / KW 2.50 / 1.85

rpm 1/min 2500 - 17500

bore mm 24.70

stroke mm 24.00

weight g 470

system of control front intake

porting Schnürle

ballbearing 2

liner piston set ABC

crankshaft mm 9,5

crankshaft 1/4" 28UNF

carburettor 1024/316

The Webra "Speed" series are fine, powerful engines. They like to rev and like small props. If the specs say 17.5k, I don't doubt it at all. I have a Speed .32 that turns a 10-4 APC at 15.3k. The Dynamix carb can by picky to adjust, but it's what helps give the engine its power. The C (chrome) part of the ABC is extremely hard and the engine definitely needs break in time. Don't run it slobbering rich during this, but in a only SLIGHTLY lean two cycle. These engines are carefully built with tight tolerances and will last you a long time if properly taken care of. Use a castor/synthetic oil blend fuel like Morgan's Omega. The Speed engines like nitro, too, so even up to 25% is ok although they run just fine on 10%-15%.

This webra is not a Typical "ABC". The cylinder is chromed brass and the piston has a dykes ring on it.

I don't know much about the Speed 70, but my 32 speed is also ABCD( ABC with Dykes ring) and Dynamix carb. It is an awesome engine.

turbo

That's right. All the more reason it needs some break-in. I have a .32 Speed GT that is true ABC with a standard carb - not Dynamix.

The Speed 70 is a rare and desirable engine. It is mechanically stronger and better balanced than the speed 80, which is just a bored 61LS. Prop it the same as a 60 (13000 rpm) and enjoy better power and fuel draw. An ABC-ring setup lets the engine handle a lot of heat while being able to eat dirt with minimal damage. It can use the same muffler/header as OS61fsr and Enya 60X.

Thanks all for the advice, I bought the speed 70 because I already have a speed 50 and 91, they are great running engines. I had never seen or heard of the 70, but bought it based on the speed engines reputation of being great running engines.

This is the only 70 I have come accross, why are they not more common?

Webras were getting very expensive at that point in time while cheaper alternatives became available.