Mixtie frame and bullet train - will it fit
- Thread starter thxcuz
- Start date
wheelbender6
Well-Known Member
Unfortunately, I think your questions can only be answered by trial and error. I have seen quite a few successful builds on the forum on step through frames.
-Changing wheels sizes from stock can make it tough to mount the right rim brakes. You may need to use a universal caliper brake mount if you change wheel sizes.
-Changing wheels sizes from stock can make it tough to mount the right rim brakes. You may need to use a universal caliper brake mount if you change wheel sizes.
Citi-sporter
Active Member
There's these newer unitized head and cylinder, 66cc engines now for about ~$130 that run smoother and better than the older separate head/cylinder ones.
. https://www.amazon.com/dp/B071YQ8CR6/ref=dp_prsubs_1
You're still going to have issues mounting these in frame engines inside the tiny space afforded by a mixte frame, plus the fuel tanks are made exclusively for men's frames with a single 1"~1.125" top tube. You're efforts would be better rewarded using a late 1980's MTB bike with good componentry.. If this is your first motorized bike build it's always best to just build up a standard framed bike to see if you even like how the engine works. These CG engines can occaisonally have tuning problems with carburetor and ignition timing, you need to fine tune the main jet and make sure the engine has the magneto rotor on the correct direction.
This is my 63 year old J.C. Higgins with a 48cc CG engine
Last edited:
thxcuz
Active Member
Not my first build.
My first build was a weird frame that was kind of mixtieish (see my avatar)
I would love something smoother, that’s why I was considering a 4 stroke. But if I can get less vibes from a 2 stroke I’m in.
I’ve pretty much abandoned the mixtie idea and I HATE the look of the stock tank. Absolutely can’t stand it. There are other options I plan to pursue.
My first build was a weird frame that was kind of mixtieish (see my avatar)
I would love something smoother, that’s why I was considering a 4 stroke. But if I can get less vibes from a 2 stroke I’m in.
I’ve pretty much abandoned the mixtie idea and I HATE the look of the stock tank. Absolutely can’t stand it. There are other options I plan to pursue.
Citi-sporter
Active Member
Well for smoothness my 48 cc engine is pretty darn good, and it pulls 6 percent grades with my 155# weight at 20 mph, all day if needed. But it's really detuned to run better at midrange and have a broad torque curve.
What makes these engines really vibrate is that they don't supply them with an output sprocket that is concentric! Nearly all of them have some out of roundness, mine was especially bad and I ended up grinding it lower on the roller lands parts of the sprocket's high spot, filling in the low spots with hard stainless TIG weld filler, and then carefully hand filed the concentricity back into the sprocket.
That's a lot of trouble to go through, but it's eliminated what was the worst vibration my engine produced, the lower frequency, output shaft sprocket eccentricity judder. You can buy new sprockets.. I've found that out of 4 that I bought, none were much better than the stock one.
What makes these engines really vibrate is that they don't supply them with an output sprocket that is concentric! Nearly all of them have some out of roundness, mine was especially bad and I ended up grinding it lower on the roller lands parts of the sprocket's high spot, filling in the low spots with hard stainless TIG weld filler, and then carefully hand filed the concentricity back into the sprocket.
That's a lot of trouble to go through, but it's eliminated what was the worst vibration my engine produced, the lower frequency, output shaft sprocket eccentricity judder. You can buy new sprockets.. I've found that out of 4 that I bought, none were much better than the stock one.