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Within about 50 miles, I was getting a bad popping coming from the swingarm area upon initial drivetrain loading. After reading up I realized the tires, clutch kit, and lift were probably all causing a ton of strain on the u joint. So after some reading I decided a 450 swingarm swap was what i needed. Plus the 28s were rubbing the plastic, and one day I'd like to have 30s on the bike so this would give me some additional clearance later. So I ordered parts based on what I read online. I bought a 450 Swingarm (used off ebay $50, part# 52100-HN0-670), 450 driveshaft ($50 new OEM Honda), 450 foot brake cable ($15 new OEM Honda), All Ballz SwingArm bearing kit (Part# 28-1056 02-04 tapered style bearings) and I bought a Moose Racing U joint for extra strength (part# 1205-0201). Here's the goods:
Close up comparison, Moose on top, OEM Honda 500 on the bottom:
Let's examine these joints a little closer. Moose overall width dimension: 2.112
Stock Honda piece is 2.021
Bearing cap O.D. on the Moose unit: 0.746
Bearing cap on the OEM unit: 0.667.
500 swingarm on the left, 450 arm on the right. I did a quick sand blast and repaint to it as some of the powdercoating has some rust.
Honda 500 DS 6.25 long, 450 DS is 8.75, so about 2.5 inches longer here also...meaning drive clearances should stay the same.
Back of the 500:
The swingarm must be cut and re-welded to do this swap correctly IMO. I snapped a pic of the cuts I made. The first bend with be the bring the passenger side of the arm closer to the centerline of the bike and the cut towards the bolt holes will be to straighten the arm back up so it will align with your bolt holes on your axle tubes.
Installation is the reverse of removal. And, a highlifter 2 inch lift will still work and put you back to basically the original height but with a much more favorable u joint working angle. I made no changes to their lift EXCEPT remaking the outer brackets because one was found to be broken (after 100 miles). I will be contacting them about this failure as it in unacceptable in my opinion.
I did originally file the OEM plastics some because the 28s were rubbing slightly, now, 30s will fit with room to spare:
Looks like your back is gonna get slightly dirtier.
Bad news is the foot brake cable for the 450 is exactly the same length as the 500 meaning it did not fit. The hand brake cable had no trouble reaching. Questions, comments........
So i did this conversion years ago and don't remember having any issues. BUT now im doing to an 2007 Foreman 500es using 01 450 parts. Cant get past the ujoint hitting the inside of the swingarm housing. Everything works fine but its loud. The distance are different where the swing arm bolts to frame. At this point im going to just cut and extend by 2 or so inches and use 450 driveshaft. Ive researched this but no one ever states having this problem.
Never done any mods to bikes, or wanted to. If the ditch is too deep for the bike, don't go into the ditch.
However, the UJ spider has to be bang on the centre line of the swinging arm bearings, otherwise the geometry doesn't work. I would assume the UJ assembly is the same for 450 as 500 (because the old 300 had exactly the same joint as the 500) so, it won't be at that end there is a problem, unless you are using the bigger Moose joint. So, either drive shaft length doesn't quite make up for the difference and the UJ is floating about, or that spring on the end has broken, allowing for movement.
Not an easy swap this time. Did this 10 so years ago and don't remember this issue. So here's the pictures of how I completed this time. Hopefully this helps some one in future. I would recommend buying all the parts previously listed for this swap. And just cut and paste or weld. I will be able to make foot pedal for rear brake work some said extended lines but I won't need that.