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Old 09-30-2008, 06:50 AM   #1
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Default Removing Ofna pull start from Hyper 21

Ok.....I need everyones help. I bought a used MBX5 from one of the forum members (thanks for the great deal Revo61!) and I am trying to put it all together. I have an0 Ofna Hyper 21 from an older monster pirate that I am stealing to put in this buggy. This engine is a pull start version and I need to convert it to a bump start version. When I take it apart I have the pull starter, the starter shaft, the back plate with the hole and the turbo fan/one way bearing. Looking at the parts diagrams, it looks like all I need to do is remove these items and replace it with the new back plate. Is this correct? It almost seems too simple. The turbo fan has a peg that goes in the rod end of the crank. Does anything need to go in there?

Also, I am thinking that since the turbofan no longer has to be spun by the engine that this conversion may effect the performance?

Any info would be appreciated.
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Old 09-30-2008, 07:30 AM   #2
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Yep, just pull all the old stuff off/out and put on the new backplate, nothing gets reused. Just be careful if the backplate sits into the motor that the piston is at TDC so you don't crack the piston skirt when you insert the backplate.
It's mine: http://au.youtube.com/watch?v=usYhSWbmx6s
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Old 09-30-2008, 11:29 AM   #3
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You will discard the Turbo fan, the starter shaft, the metal backplate, and the pullstart, and screw on the new bump start plate. Make sure you install it the correct way, the notch goes to the top, and Yes, your engine will have more power, and RPM, because it has less of a load to spin. Hyper .21 8-port is the best Engine for the money out there, 086 Pipe will bring it to full power
nothing to see here................................
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Old 09-30-2008, 12:29 PM   #4
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I'll keep the parts because I have a hyper 7 with the same engine with a tiger drive. I will keep the parts as backups. I am anxious to see how the mugen with the hyper 21 will perform compared to the hyper 7 with the pull start version of the motor.
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