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10-18-2008, 09:18 PM | #1 |
Join Date: Sep 2007
Location: Bend, Oregon
Posts: 348
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GY5 swing arm mod
The GY5 has a design flaw that causes the chain to be pulled tighter and tighter as the rear suspension is compressed. Consequently the chain has to be adjusted very loose, 3.25" of play with no weight on the bike, which in turn causes a lot of slop in the drive train. Most or all other motorcycles have a different geometry so the chain gets looser as the suspension is compressed.
Today I removed the engine, swing arm, air box, etc.. and fixed the problem on my 07 GY5. The fix involved moving the swing arm pivot bolt down .5". First I welded steel plugs into the existing holes. I then added more metal to the bottom of the flange that supports the swing arm bolt and drilled new holes exactly 1/2" lower. After grinding things flat I painted it to match the existing silver color and reassembled. The result is that I can adjust the chain to 10mm play with no weight on the bike. Instead of the chain getting tighter as the suspension compresses, it gets slightly looser like other bikes. The slop in the drive train is gone and the drive is smoother and quieter. My conclusion is that the Lifan factory should improve the design by moving the swing arm pivot hole lower by 3/8" to 1/2". Q |
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10-19-2008, 08:07 AM | #2 |
Join Date: Jul 2008
Location: Wheeling, West Virginia
Posts: 683
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Did you tell "Super Dave" at A.L.?
Tigertamer
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07 H-D XL883C 06 LF 200GY-5 Yin and Yang CAUTION Obey The Traffic Regulation. Always Wear a Helmet. Don't Ride After Drinking Wine. Before Operation, Read The Owners Manual Carefully. |
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10-19-2008, 08:28 AM | #3 |
Join Date: Sep 2007
Location: Bevely Hills,Florida US of A
Posts: 138
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There is no way you could have improved that setup.Just ask the reps at the American Lifan forum.It is the best it can be, btw we can sell you parts......................someday. :roll:
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Lifan LF200GY-5 |
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10-19-2008, 08:42 AM | #4 | |
Join Date: Sep 2007
Location: Bend, Oregon
Posts: 348
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I posted the recommendation that the pivot be moved down on the Lifan Forum last year. Also posted about actually doing it yesterday in the Mods section. It's such a simple change that won't cost anything, you would think the factory would have done it by now.
Q Quote:
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10-19-2008, 11:34 AM | #5 |
Join Date: Jun 2006
Location: directly under the earths sun............NOW
Posts: 2,302
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I'm sure A.L. is very thankful to you and everything but they are still going to break your rice bowl for speaking up to them.They would have caught anyway....once they actually have an engineer there that starts working on these bikes.
A.L. will first ask this question :will improving the bike increase sales ? and what will the improvement cost ? will anybody really notice ? (they're thinking: drilling the hole in a slighty different spot sounds to expensive and dull----forget about it----up production.....) |
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10-19-2008, 01:08 PM | #6 |
Join Date: Sep 2007
Location: Bend, Oregon
Posts: 348
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Here's a picture.
Q |
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10-19-2008, 02:38 PM | #7 |
Join Date: Sep 2008
Location: Thorne Bay SE Alaska
Posts: 131
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Cool great mod idea thanks for the pic!
I fixed the html so the pic loads on this page
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Three Greys Lifan GY-5's |
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10-19-2008, 04:56 PM | #8 |
Join Date: Jun 2008
Location: wise va
Posts: 636
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boy, you guys sure are tuff on american lifan :wink:
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halls auto l coolster, modcycles, yanmar & zongshen, dealer fired roketa,lifan and jet moto and apollo quit me who's next |
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10-19-2008, 06:11 PM | #9 |
Join Date: Jun 2006
Location: directly under the earths sun............NOW
Posts: 2,302
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That is some nice and simple work to get the swingarm set right, good work Q.
So what is really needed is a kit. A kit that has a legal, registerable frame that is actually functional and sturdy and properly setup. A cycle kit that you can put various china bike and other assorted parts onto to make a very decent bike once its all together. I still think putting a new chinese engine into an old honda frame and resurrecting the bike is far better than buying a new china bike.(JMO) |
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10-19-2008, 06:33 PM | #10 | |
Join Date: Mar 2007
Location: Abbotsford, BC, Canada
Posts: 4,880
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