A warning to those looking to mod their motorized bicycles:

Most, if not all, of the hacks and mods featured on this site were made by individual hobbyists. If you are new to working with 2-stroke bicycle engines, please by aware that there's a possibility that a mod featured on this site could seriously damage your engine. Please don't try any mod from this or any other site unless you fully understand what you are doing. The owner of this blog will not be held responsible for both material and bodily damage caused by performing a modification featured on this blog. Also remember that opening up your engine may void your warranty!

Sunday, September 18, 2011

Ethanol bicycle update

After reading around on the internets, I became very tempted to see if it's possible to clean up our china girls with E85(ethanol) fuel!  Few people have accomplished this; in fact I could only find one person who claims to run their motorized bicycle on E85.  I featured his video in an earlier post, although the video bears little information and I could not get in contact with the guy.  Never the less, I set out to see if I could replicate his results.

Today I picked up a gallon of E85 from a Conserv Fuel station, and some ester-based synthetic oil(as apparently regular and petroleum-based synthetic separates from the ethanol).  After tweaking the carb needle and replacing the float bowl gasket(which was melted by the ethanol), I got my bike running on booze!  Since it was night time I didn't want to take the risk of having the engine seize in the middle of the road, so I rode around my neighborhood for about 3.5 miles.  Ran pretty good, too!  I may still have to enlarge the jet in the carb, but with the needle at the 3rd position and with the choke on just a little, it seems to run just fine!  Even pulled me up some steep hills!

We'll see how this goes.  Tomorrow I'm going to ride further and continue to test out the E85 as bike fuel.  If I continue to get good results, I might make a video about it with more details.  But don't be shocked if my engine blows up sometime this week!

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UPDATE 2: I drilled the main jet with a #60 drill bit, but this may have been a mistake.  The engine now runs way too rich even with the needle at it's leanest setting.  This means that the engine does almost nothing but 4-strokes and it bogs down and it won't make it up hills.  It actually ran better with the stock main jet and the choke about halfway up.  Still, I want to get the most power out of the ethanol fuel, so my next plan will be to get an iridium spark plug since I think the problem might be that the normal NGK plug doesn't have a good enough spark to ignite the higher amount of fuel being squirted into the cylinder.  If that doesn't work, I'll simply have to buy a new jet and start again.  =/ That is if I could find a hobby store that sells a #65 drill bit so I can solder and redrill, which would be way easier.

UPDATE 3: I soldered and redrilled my jet with a #67(approx) from a Dremel drill bit set.  I've now got the bike running on ethanol with the slide needle clip on the second position, which is considered default.  No need for the choke anymore.  I'll wait for the plug to run a while to see if it's running too lean or not, but if this works out, the only things that would need to be changed to convert a bike to ethanol would be the main jet and some new gaskets.  The NGK B6HS spark plug works fine.  Turns out I got some gunk inside the fuel intake(on the carb) and not enough fuel was getting to the engine.  I also tried a Briggs & Stanton spark plug and that works well with it too.  Perhaps better, but I'll have to do more testing.  My muffler came loose during my last test run, and that caused my idle to go out of control and I almost went on Mr. Toad's Wild Ride!  Good thing my clutch and kill switch were hooked up properly!  Plus my gas tank has been leaking again and I'm pretty close to chucking it in the garbage.  I can't be riding around with fuel dripping on to a hot engine.  I promise to post a video once I am done fixing those few things.

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