au117

My Feedback: (8)

64cc stihl 4 mix conversion in a balsa usa 1/3 sopwith pup
I did this conversion about 2 years ago I finally finished the pup and got 3 flights on it in October. In this video it is still rich on the high end. This was the 2nd flight, first flight it was windy and did not get it trimmed so this was a trim flight.

jtisch

Very nice! What are you using for a muffler?

J

erik58

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l'm in the process of converting a 4 mix what are you doing for a intake manifold ? I was thinking to use a rubber elbow and make a bracket for the carb is this how you did it? Thanks Erik

au117

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I have attached a picture that shows the exhaust and intake. erik58 I cut the stock rubber intake and clamped it to the intake. I made, then brazed a bracket to bolt it to the engine. jtisch its a copper 90 brazed no muffler if you are interested, I can show a pic of the silencer for my motorized bike that I used the 64 cc on.

au117

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this muffler- silencer slides in the straight pipe and is held by a screw
https://www.youtube.com/watch?v=CxtsmJUUePY

av8tor1977

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That is a very cool, "antique looking" bike, and it is interesting that you powered it with the Stihl! You should maybe add some "Steampunk" items to it, though it is really cool as you've made it. (I could easily visualize it with one of the old fashioned polished copper cylindrical fuel tanks with pointed ends in place of the "Super X" tank.)

AV8TOR

av8tor1977

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What speed and rpm do you have it geared to run at? Do you start moving by pedaling, then use the engine? Centrifugal clutch or one-way coupler on engine?

Thanks,
AV8TOR

au117

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Hi av8tor. Top speed is about 40 mph. 14 to 1 gearing and 26.5 tire hight, the math says about 7200 rpm. The pedals are 1st gear, 8 maybe 10 mph then give it the gas. It has a centrifugal clutch. It cruises nice at about 30 mph 5500 rpm. I have taken it on a 65 mile ride crusing. I ran it wide open for a 10 mile stretch, no problems. I wanted that board tracker look and super x was excelsiors race bike. They where owned by schwinn in the early 1900s. The frame is a 54 straight bar schwinn so I thought the paint scheme was appropriate. It was a fun project.

av8tor1977

My Feedback: (6)

Very cool and I really like it. You have done it pretty much just as I would have.

Regarding my experience with the Stihl Four Mix: Be sure to adjust the valves somewhat frequently, and I definitely recommend a top shelf, high quality synthetic oil at 40:1 instead of 50. I have seen a lot of these blown up due to valve and lube problems caused by the users. Be aware when you adjust the valves and replace the valve cover, it must be an airtight seal.

AV8TOR

au117

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Hi Av8tor. I have put new rings, bearings, seals, gaskets and lashed the valves on the 3 stihl 4 mix engines I have. Break them in on mineral oil 32 to1 and then switch to amsoil dominator 3 oz per gal. Adjust valves after 2 hours, 4 hours then every 5 hours. I did this to my kolm il100, stihl 32cc, stihl 64cc in bike and now on the 64cc in the pup.
This is not a conversion but it is a nice engine a video of my 1/3 d vii with the kolm il 100

av8tor1977

My Feedback: (6)

Very nice! Excellent wheel landings too! I want to scratch build a stand off scale Fokker D7 for my converted and test run Stihl Four Mix 36cc engine. One of these days....

AV8TOR