Conversion parts for Honda clone motors

Discussion in 'Battle Scooters' started by Woodsrat, Dec 6, 2009.

  1. Woodsrat

    Woodsrat Gone ridin'

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    I'm a big fan of getting older horizontal motored bikes back on the road by using the inexpensive Chinese clones based upon the Honda 50/70 motor. Recently while cruising eBay I found a brackets for these motors that can be used to build an engine stand--or to adapt these motors to another frame. I ordered up a pair and I'm extremely impressed at what I got for $21 delivered. My next project is to set up a CT-90 frame to accept the 50/70 style motor and these will simplify the process greatly. They're eBay item #330328288514.

    Hope the mod doesn't think I'm pimping these critters (I'm not)--I just wanted to share this with you since this has been a popular subject here.
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  2. hugemoth

    hugemoth Long timer

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    Looks to me like they would complicate the installation rather than make it easier. I've put 2 Lifan 110 engines in CT90 frames and found that a little grinding with a small angle grinder and drilling a couple holes is all that is needed.

    Q
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  3. Coopdway

    Coopdway Curiouser

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    Appreciate the info Woodsrat!
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  4. 2speed

    2speed Puching adventurer

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    Doesn't Dratv have some kind of bracket to do this?
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  5. Woodsrat

    Woodsrat Gone ridin'

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    Dunno. Just what I've observed using a set of Z-50 cases for mockup use on the 90 frame the 50/70 motors don't fit it very well without some serious modification. Dr. ATV has his own brackets he offers for the conversion that probably work okay but just don't melt my butter. Since the 50/70 engines are narrower than the 90/110's--and the lower mounting point doesn't even come close--how did you get yours to work with just grinding and drilling? If I can save some work I'd be all for it, lazy and cheap as I am.

    Pics from Dr. ATV's site about a Lifan conversion for the CT-90:

    http://www.dratv.com/ct.html

    There's a picture there of the Lifan fitted into the CT chassis that shows just how far off they are.
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  6. hugemoth

    hugemoth Long timer

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    What I did was to hang the engine by the top mounting bolt then take a felt pen and mark the frame where it needed to be ground so the engine could be rocked back far enough for the rear mounting hole to be drilled in the frame. Once you get the frame ground, drill the back/bottom hole in the frame. I used a stack of 4 or 5 thick washers per side as spacers to align the sprockets. I glued them together to make it easier to hold them in place while pushing the bolt through.

    On the foot pegs I used the stock setup but used the grinder to cut the welds on the mounting tabs, moved them into the correct position, then welded them back on.

    For the carbs I cut the manifold that came with the Lifan engine in half, filed it smooth, then used a piece of 1" automotive radiator hose and a couple hose clamps to position it. Used ABS plumbing pipe to make an air box with a foam unifilter attached. BTW: gasoline has not affected the radiator hose in the 2 years since I installed it.

    I also used the stock exhaust with a little grinding, cutting, and welding.

    Used the existing rear brake lever as a clutch lever. Made my own clutch cable from a bicycle brake cable and throttle cable from a bicycle shift cable.

    Other than the $200 cost of each engine the only other expenses were a hardware store bolt for the engine mount, unifilter, a couple 90 degree ABS plumbing elbows, fuel filter, fuel line, plastic fuel shut off valve, and bicycle cables.

    Q
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  7. Bladeforger

    Bladeforger Been here awhile

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    What if you didn't have an exhaust from the old engine? Think you could make one? I was thinking a flat piece of steel welded to some tubing bent to fit and wrap it with muffler tape up to a small muffler of some kind from TSC. What do you think?
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  8. hugemoth

    hugemoth Long timer

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    Yes, making an exhaust system wouldn't be too difficult. You could probably make one from 3/4" conduit bent with a conduit bender.

    Q
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  9. Woodsrat

    Woodsrat Gone ridin'

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    ...or use one from an XR/CRF-50 or 70. They're plentiful and cheap/free from the pit bike racers. I had to weld a mounting tab on the Passport but a 50 pipe worked great. You might have to devise a heat shield because these pipes were designed for single-shock bikes and when you rotate them out to clear the shocks you've got a hot pipe to burn yourself or a passenger on.

    I've picked them up locally and on line for less than $20 in new condition. One fellow in SF, CA sent me one for a 70 and paid the freight!!! I favored him with a Starbucks gift card for his generousity but it just amazed me that he refused to take any money for it.

    I personally like quiet bikes and these pipes will give you that and a durable exhaust that you can replace easily and cheaply. Highly recommended.

    Edit: The 50 exhaust is smaller in the headpipe diameter to about halfway down to the muffler before it gets bigger but still works fine on motors up to 88cc or so. The 70 pipe is large all the way and it's muffler is larger than a 50. I've used the 70 pipe on 125cc motors and they work fine although I have a CRF-100 pipe that's going to donate it's muffler to the modified 70 pipe that's currently on my BBR bike to let it breath a bit better and still be quiet as stock. eBay is your friend.
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  10. Bladeforger

    Bladeforger Been here awhile

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    :clap Thanks!!!!!!!:ricky
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  11. YamaGeek

    YamaGeek Ancient trailbike padwan

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    I used the stock pipe from my Yamaha YG5-T bike, I cut away the header pipe part and made a new pipe from 3/4" thick conduit. I wanted some seriously sharp radiuses in the section from the engine to the muffler, so I cut slight angled pie shaped cuts 3/4 through the conduit and rewelded them shut. It was a lot of welding and it's not pretty, but it's been darn durable and I believe that the engine is breathing better than it would have with some after market pipe.

    It is a two stroke muffler, so there's a bit less backpressure, but no real big noise issue. The big initial scare with it was that it smoked like the engine had just broken it's oil ring for about 10 miles when I took it for it's first ride.
    #11