boss351

My Feedback: (6)

Can anyone tell me about the OS MAX 25F SR and how it compares to the OS 25FX.

Thanks

Adam

jaka

Hi!
Not much difference really...... the old .25FSR is at least 20 years old and has a lapped iron piston running in a steel cylinder (might be that some newer FSR:s were made with ABC piston /cylinders) versus the new OS .25 that has an ABN piston/cylinder.
Carb works the same with a highspeed needle and idleneedle ...like every other carb on the market (except Webra Dynamix) and both have two ballbearings....power is about the same.

Regards!
Jan K
Sweden

boss351

My Feedback: (6)

Thanks.

Would I be able to get a mufler extension (1/2") for the older engine? Is the screw spacing etc the same for the muffler bolt-up?

RC Fan

Dear boss 351

Do you have the 25 FSR?

If so could you please confirm the bore and stroke of the engine as I am currently looking for a replacement piston+cylinder for mine (around 20 yrs old engine). 'Am exploring the possibility of installing a 25 FX or TT 25 Pro cylinder and piston.

Many Thanks

boss351

My Feedback: (6)

I have this information from someone that does have one:

Displacement: 0.248 cu. in.
Bore: 0.708 in.
Stroke: 0.630 in.

Hope it is correct and can help!

Adam

RC Fan

Thanks Adam -

Sure does help. It appears that OS has not changed the P+C spec when they discontinued the FSR series and started the FX series. Like I mentioned earlier - I am looking for a replacement P+C for my 25 FSR. You have helped me narrow down my search.

Many thanks again

marquisvns

I know it's a 13 year old post, but have you any success using FX piston/cylinder for the FSR? Port locations and sizes are the same?

wolfiberkleid

Can somebody let me know the difference in mesh from a os gas filter like the one recomended in the ggt 15 engine and the regular turnigy filter? they look similar but can not finde the mesh sizes..
many thanks