I've had both and the OS seems to make a little more power on the same muffler. I never had problems with the TT but the machining is not OS quality. I ran both on the rich side and they still made more power than the OS 61 that I had. If I could have a choice I would go with the OS but do not run the 70 lean. Hope this helps. Sam
I have the os 70 in my Raptor 60. Works great only complaint is that it has so much compression its hard to start. My starter has more than enough torque. I have even damaged the bearings in the clutch once. Now I just loosen the plug a little to start it. It should loosen up when I get more time on it. Once started its great with lots of power. Easy to tune with 3 needles. I had a used but very low time TT 70 once but it had been damaged and I was never able to make it perform well. It was going to cost too much to have it serviced so I bought the os. I went with the os because I thought it would perform better and be more reliable. I like the 3 needle carb and I think OS has better customer Service.
i had this same exact issue...I opted for the Align starter since mine is 12 years old ziptied with 2 old NIMH batts...i got sick of the zipties diggiing into my cold hands trying to start the 70..BWT the align starter turns it with ease...
It ran great..except last Sunday my clutch shoe and Piston went..but i hear the piston has been beefed up in the newer os.70 since mine was bought... Waiting for piston and ring
I am flying a TT70, but I couldn't make the carb work. I put on an OS 2 needle carb and it works great! Any OS carb with a .590 throat OD is better than the TT carb.
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