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86 Rebel 450
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42 Posts
Discussion Starter · #1 ·
Hello! Was just wondering if anyone has successfully punched out their 450 engine to increase the power? With all these sportster kits converting an 883 to 1200/1250. I was wondering if anyone has jugs/pistons to have this engine make more power? I’m Just wondering! Sure would be nice to have more power knowing it’s got 450 stickers on it ;).
 

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86 Rebel 450 (blue w/title and Black no title yet)
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That’s a thought I’ve had a few times now. So far from what I’ve seen, there isn’t much out there for 450 upgrades.
 

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I’ve been wondering the same.
New to wrenching on bikes myself.
1986 Honda VT 500 is showing;

71.0 x 62.0 mm (2.8 x 2.4 inches) for bore and stroke and delivers 50HP with 10.4 compression.

450 CMX (Rebel) shows
75.0 x 50.6 mm (3.0 x 2.0 inches) for bore and stroke with 9.3 compression pistons.

Source:

You’ll need a shorter piston of slightly larger bore to increase the stroke.
No doubt there is a combination out there that will work. Pistons from one engine and crank or connecting rods from another.
I’m guessing slightly longer connecting rods with a shorter slightly oversized piston should work. But that’s a lot of calcumelations and I’m not that edumecated lol.
Honestly I’m a little surprised there isn’t a ready combo out there considering the 450 is from ‘86.
By my best math that’s 36 years to come up with something that works.
Like in the SBC world there’s 1000’s of combinations of this piston and this rod and this crank and this gasket will give you these #’s.
 

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86 Rebel 450
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42 Posts
Discussion Starter · #4 ·
Yeah man. I learned how to ride on a vt500 lol. I would just be interested in a piston/jugs swap. Other than that it’s staying the way it is lol.
 
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