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What's necessary for converting to bump start?

What's necessary for converting to bump start?

Old 11-30-2013, 02:41 PM
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Default What's necessary for converting to bump start?

Hi.

I'm trying to convert my pull start nitro engine to a bump start with a box. The flywheel is fairly small, and from the searching around I've done, I've found that I either need a new flywheel with a bigger diameter or I need to lower the engine with thinner engine mounts so that the bump wheel will be able to reach the flywheel. Since I'm relatively inexperienced with bump starters and flywheels, I have a couple questions.

a) Are flywheels for 1/8 engines (mine's a .28 SH) universal? In other words, can I buy any generic flywheel and expect it to fit?

b) Are 1/8 scale engine mounts universal? IE, can I go buy Traxxas or Losi engine mounts that are smaller and expect them to lower the engine?

c) Are 1/8 scale starter boxes pretty much universal? I have no idea what type of box to purchase.

The pull starts are frustrating and constantly break, so I figure it's time to try something else. This is the one thing on an engine that I've not build or modified. I would most likely just leave the pull start backplate on and not have any string or a handle if I chose to do this.

Thanks!
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Old 12-01-2013, 06:27 AM
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starter boxes are universal. motor mounts are not but some might fit other brands. It would be better if you can find non pull start end cap for your motor. Flywheels are universal also just find one that is the size you need.
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Old 12-01-2013, 06:52 AM
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What's the direct advantage to having a different backplate?
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Old 12-01-2013, 07:46 AM
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It allows you to lower the motor. I had to do this EXACT thing to my RTR losi truggy back in the day.

Get the right back plate and lower the engine then the flywheel will be low enough in the chassis so the bump box can get on it. More than likely you don't need a flywheel. I have no idea the vehicle you are working on or how it's built, but I ran into this problem once before and this how I solved my issue.
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Old 12-01-2013, 11:57 AM
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indeed, pretty sure your flywheel is Ok, but your engine has been fitted higher to allow for the pull start mechanism. A picture will allow for readers to confirm.
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Old 12-01-2013, 10:31 PM
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I use to have a Thunder tiger EB4 S3 i converted to bump start, in that case i could get lower engine mounts, bacically as you mentioned to get the flywheel low enough so the starter wheel can reach it. From memory it dropped about 5mm.
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Old 12-02-2013, 07:12 AM
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Okay, so that makes sense.



It's a Redcat Hurricane, with an SH .28 engine.

Edit: is the image not showing up?
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Old 12-02-2013, 07:40 AM
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Another advantage to a bump start is it eliminates the one-way bearing in your pull starter, which is connected to your crankshaft, the one-way bearing is like turning your a/c on in your car, by adding another pulley, or bearing in your case, takes away engine performance. This is why you don't see the pros using pullstarts.

Sounds to me you just need to find a lower engine mount. However I'm not really familiar with Redcat rc products.
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Old 12-02-2013, 05:25 PM
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Originally Posted by kylehirano View Post
Another advantage to a bump start is it eliminates the one-way bearing in your pull starter, which is connected to your crankshaft, the one-way bearing is like turning your a/c on in your car, by adding another pulley, or bearing in your case, takes away engine performance. This is why you don't see the pros using pullstarts.

Sounds to me you just need to find a lower engine mount. However I'm not really familiar with Redcat rc products.
I have some experience in this matter
u probably need a. 36 or. 38 mm flywheel
if u would like to discuss it further
pm me pretty sure we can figure it out
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Old 12-02-2013, 06:11 PM
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Cool. Thanks guys. Finding a backplate seems tough since they're all specific
.. Or are they? The engine is generously powerful, so while I see it taking away some performance, it's not really a super highly competitive buggy, so I'm not too concerned with that. But yeah, are backplates standardized?
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Old 07-18-2018, 12:56 AM
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Default Need to know a nice size for a fly weel on a 1/8 truggy for a start box

Whats a bigg size diameter for a flyweel theres 34mm 35mm 38mm please help
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