First Build, 4-stroke 3.5 hp on a Schwinn Bike

Kristof,
I dont think its a mixture thing.
I have another MB using the BMP friction drive & Subaru-Robin 35cc & 1.25" roller. It can hit 34mph max with me in an aero tucked position. Was able to hit 36 when I had it set up as a vBelt drive.
Granted if the wind blows, it slows down some.
-lowracer-
 
lowracer said:
Kristof,
I dont think its a mixture thing.
I have another MB using the BMP friction drive & Subaru-Robin 35cc & 1.25" roller. It can hit 34mph max with me in an aero tucked position. Was able to hit 36 when I had it set up as a vBelt drive.
Granted if the wind blows, it slows down some.
-lowracer-
Click to expand...

So, what do I do?
-I have no idea...

By the way, I got an air filter from Kragen auto parts store. Let me go take a pic.
 
Note quite following your throttle setup Kristof. Looks like your governor is limiting your speed, which is usually about 3600 rpm on that engine. More detailed pic maybe?
 
Update 2.3

Air filter from Kragen Auto Parts Store

It barely fits, so whatever I guess it works... I wish K&N made air filters for small engines...lol, 0.25 HP increase!! lol

IMG_0097.JPG


IMG_0098.JPG


IMG_0099.JPG
 
wdbtchr said:
Note quite following your throttle setup Kristof. Looks like your governor is limiting your speed, which is usually about 3600 rpm on that engine. More detailed pic maybe?
Click to expand...

I have a cable running to the governor, which opens it full throttle.
I have checked out how it works, and the governor doesnt seem to be limiting the throttle.
 
LS614 said:
Looks good man! I can't wait to see a vid because I'm sure that pipe sounds sexy :D
Click to expand...

Ok, I will take a detour and gets some gas right now and I will make this vid...
Ive been pretty busy, so Im just gonna do it right now, cause Ill know ill be busy anyway later on...
 
That's great man! The exhaust sounds sexy. I might do a long pipe with a similar design for my HF build, I want a motorcycle sound :D Looks like a fun ride :) enjoy
 
LS614 said:
That's great man! The exhaust sounds sexy. I might do a long pipe with a similar design for my HF build, I want a motorcycle sound :D Looks like a fun ride :) enjoy
Click to expand...

Thanks. = )

The video wasn't great...but i guess it will do for now.
 
Well, if you want to do it without blowing up the engine, the best way to increase rpms is to get a large wad of money, and then take the engine to a professional engine builder to have it blueprinted, polished, honed, get the ignition timing changed etc. It's not work I would want to do on my own. Better to leave it as it is.
 
Kristof,
You can buy a different engine for $100 on eBay or tey sell them trhu Home Depot online. Bypass the governor like many do to squeeze a few extra rpms out.
Any speeds in the 40's range is plenty...
-Lowracer-
 
Gator Wrestler said:
If you have any plans to climb hills I think you will find that the gearing you have will not work very well. However it is simple to change the ratio by using a higher tooth count sprocket in place of the 14t that's driven by the clutch. If a 20t is used the ratio will be 12 to 1. You may even want to go higher for more hill climbing torque. I could be wrong I havn't used that engine. The 2.5HP HF works well with a 12 to 1 ratio but doesn't have hill climbing torque. YMMV.
Click to expand...

Do like this guy says. Change the 14t to a 15t first. That'll give you 9:1. Use sprockets with more teeth if 15t won't work for you.
 
Kristof said:
Update 2.3

Air filter from Kragen Auto Parts Store

It barely fits, so whatever I guess it works... I wish K&N made air filters for small engines...lol, 0.25 HP increase!! lol

K&N DOES make air filters for small engines. I have one on my 47cc Tanaka engine.
Click to expand...
 
LS614 said:
Well, if you want to do it without blowing up the engine, the best way to increase rpms is to get a large wad of money, and then take the engine to a professional engine builder to have it blueprinted, polished, honed, get the ignition timing changed etc. It's not work I would want to do on my own. Better to leave it as it is.
Click to expand...

lowracer said:
Kristof,
You can buy a different engine for $100 on eBay or tey sell them trhu Home Depot online. Bypass the governor like many do to squeeze a few extra rpms out.
Any speeds in the 40's range is plenty...
-Lowracer-
Click to expand...

5-7HEAVEN said:
Do like this guy says. Change the 14t to a 15t first. That'll give you 9:1. Use sprockets with more teeth if 15t won't work for you.
Click to expand...

Thanks for the info guys. =]

I think I'll stay with the engine that I have. I might do another project later on in life, then I'll buy another engine.

Putting a 15T sprocket won't give me more speed. It will lower my speed.
 
Unfortanetly, my axle bearings are trashed and they have locked up. So I had to carry my bike home =[. Today is the first day of spring break. Very disappointing day... after 2 months of hard work, headaches, blood(no joke), sweat, valuable time, and money this is what it came down to.
 
Lo siento mucho. Desfortunadamente los moto-bicicletas se murio con frequencia. Get yourself some tougher wheels or a better hub man. Sucks that it happened but there's nothing left to do but move on :( My heart goes out to you, these things are so frustrating sometimes :(
 
Sorry to hear that.
Definitely need good hubs for these MB's.
Bicycles aren't made for going this fast under this much load.
Some have used Moped hubs & I think that might be a great idea.
Heck might as well use the whole moped wheel & tire too DOT rated...
-Lowracer-
 
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