DIY Two-Stroke Engine

This thread is going all over the place - so here goes.

Consider building a Kemp G2 replica. If you can do that there might
even be others that would want to buy them.

2 cyl - 4 cycle low end HP.

On Mar 20, 9:00*pm, bizguy wrote:
This thread is going all over the place - so here goes.

Consider building a Kemp G2 replica. *If you can do that there might
even be others that would want to buy them.

2 cyl - 4 cycle low end HP.

http://bourkeengine.net/home.htm

http://www.rogerrichard.com/14507.html

Another very interesting project worthy of following.

your too late,, Mr. Chotia made an engine for the weedhopper that is exactly
what you described..you can go to the weedhopper site and buy one for under
a hundred bucks...........try,,,,you'll be surprised
"durabol" wrote in message
...
For the last few years I have toyed with the idea of building a
homemade two-stroke engine for UL use. What keyed my interest was
reading about homemade model aircraft engines and reading and watching
a re-enactment of the Wright brother's first flight with a replica
engine (not a two-stroke engine).

Has anyone made a 2-stroke engine from scratch? One may need to cast
aluminium, may need a lathe and milling machine with boring head and
hone or perhaps the boring and honing of the cylinder and bearing
journals could be farmed out. A commercial carburetor and piston could
be used. Two-stroke engines seem simple enough that home construction
may be possible, if not practical.

A direct drive engine will be that much heavier when you take into
account the weight of the drive reduction system. I have calculated
the weight of an 80x80mm bore and stroke 2 cylinder opposed engine and
it was a bit under 40lbs which should give about 1hp/lbs. I used 10mm
cylinder and crankcase wall thickness and a 1.25" dia crank.

I have got some idea of port-time-area from the freeware computer
program called "BiMotion". I'm not sure how good the data is for
lowish speed engines but I guess it is a start. I have also worked up
a spreadsheet for similar information.

I don't think a reed valve system is needed for this engine since it
is only going to operate at a fairly narrow rpm range and the port
timing isn't critical. Piston ported valves offer similar performance
to other induction types but only over a narrow rpm range which is
what I have planned for the engine. I plan to build an engine with a
restrictive exhaust to ensure no fuel escapes. I have heard that
piston ported engines can spit some fuel out of the carb at idle but
this doesn't seem like a major problem. Rotary valves via crank shaft
induction (disk or drum valves as well) is an interesting idea but I
don't think I need the critical timing they provide.

I was planning on using the largest two-stroke piston (not a diesel
piston) I could find and using the largest stoke that was reasonable,
something like 90x105mm

Brock

wesley marceaux wrote:
your too late,, Mr. Chotia made an engine for the weedhopper that is exactly
what you described..you can go to the weedhopper site and buy one for under
a hundred bucks...........try,,,,you'll be surprised


I was surprised - to see that the site hasn't been updated since 2005...

I didn't see anything about an engine for under $100 either.

On Mar 27, 4:18*pm, cavelamb wrote:
wesley marceaux wrote:
your too late,, Mr. Chotia made an engine for the weedhopper that is exactly
what you described..you can go to the weedhopper site and buy one for under
a hundred bucks...........try,,,,you'll be surprised

I would indeed be very much surprised to find such an engine
available
for that price, unless it is a very simple model engine, as opposed to
one that might be used on a weedhopper.


I was surprised - to see that the site hasn't been updated since 2005...

I didn't see anything about an engine for under $100 either.

There are least three (3) weedhopper Yahoo groups:

http://groups.yahoo.com/group/weedhopper/

http://groups.yahoo.com/group/WUPA/

http://groups.yahoo.com/group/Weedhopper-Ultralights/

The third appears to have fallen victim to spam, but there
may be something of interest in the earliest postings.

--

FF

On Mar 27, 4:18*pm, cavelamb wrote:
wesley marceaux wrote:
your too late,, Mr. Chotia made an engine for the weedhopper that is exactly
what you described..you can go to the weedhopper site and buy one for under
a hundred bucks...........try,,,,you'll be surprised
...

I didn't see anything about an engine for under $100 either.

Perhaps he was looking at a weedwhacker website...

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Ff