Motorized Bicycle Engine Kit Forum  

Sponsors



Go Back   Motorized Bicycle Engine Kit Forum > Bicycle Motor > High Performance Bicycle Engine Tips and Motorized Race Bicycles

High Performance Bicycle Engine Tips and Motorized Race Bicycles We all want our bicycle engines to push our bikes faster. Get exclusive engine modification tips and suggestions from us. Also check out some of our racing members builds

Reply
 
Thread Tools Display Modes
  #1  
Old 01-06-2017, 07:44 PM
BlazeAZ314 BlazeAZ314 is offline
Motorized Bicycle Newbie
 
Join Date: Dec 2016
Location: AZ
Posts: 3
Default Cant seem to pass 30mph

i have this engine kit
http://www.bikeberry.com/gas-engine-...-2-stroke.html

I have removed my airfilter which gave me a few mph i also whiched to a 36t sprocket

Im wondering how much speed porting my engine would give me.

I just orderd this
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I havent recived it yet but will it give me any more speed?
Reply With Quote
  #2  
Old 01-06-2017, 11:13 PM
ultralight01's Avatar
ultralight01 ultralight01 is offline
Motorized Bicycle Elite Member
 
Join Date: Oct 2016
Location: Hood River, Oregon
Posts: 335
Default Re: Cant seem to pass 30mph

You removed your air filter? That will destroy your Carb and hurt your engine. Unfiltered air is like sandpaper to an engine. Put a metal mesh filter on it.

The performance muffler will help. There are a ton of mods available. but don't expect over 35-40. There is a peak engines hit and once they're there it's hard to go faster without a jackshaft kit and lots of mods and $.

These bikes are often only legal if they stay below or at 20mph. If you want to go fast, like 50mph, buy a jackshaft kit to use the bike gears or get a different engine AND a jackshaft.
Reply With Quote
  #3  
Old 01-06-2017, 11:21 PM
Venice Motor Bikes's Avatar
Venice Motor Bikes Venice Motor Bikes is offline
Custom Builder / Dealer/Los Angeles
 
Join Date: Mar 2008
Location: Los Angeles, CA.
Posts: 6,127
Default Re: Cant seem to pass 30mph

What ratio are you mixing your gas?
__________________
For motorized bicycle sales, service & engine kits in Los Angeles, please visit us at- www.VeniceMotorBikes.com

Follow VMB on facebook>>> facebook.com/VeniceMotorBikes

Follow VMB on Instagram>>> instagram.com/venicemotorbikes
Reply With Quote
  #4  
Old 01-07-2017, 07:37 PM
TheNecromancer13 TheNecromancer13 is offline
Motorized Bicycle Elite Member
 
Join Date: Jan 2015
Location: Portland, Oregon
Posts: 552
Default Re: Cant seem to pass 30mph

Quote:
Originally Posted by BlazeAZ314 View Post
i have this engine kit
http://www.bikeberry.com/gas-engine-...-2-stroke.html

I have removed my airfilter which gave me a few mph i also whiched to a 36t sprocket

Im wondering how much speed porting my engine would give me.

I just orderd this
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I havent recived it yet but will it give me any more speed?
First off, don't run it without the air filter. Second, that expansion chamber you bought looks rather tiny. You'd be a lot better off making one yourself.
__________________
125cc lifan build 79cc predator series
There's no replacement for displacement. Bigger is better, and too much is never enough.
Reply With Quote
  #5  
Old 01-08-2017, 09:35 PM
sbest's Avatar
sbest sbest is offline
Motorized Bicycle Elite Member
 
Join Date: Nov 2015
Location: Nova Scotia
Posts: 340
Default Re: Cant seem to pass 30mph

I was able to get just barely over 40mph with the 44t sprocket and stock carb.
1) port match the exhaust pipe flange and gasket to 19mm (pipe pictured not so great)
2) Modify the head to have a 2mm squish band right out to the outer diameter.
3) Eliminate the headgasket with teflon tape and shim the basegaskets to get 0.030" squish.
4) Widen the bottom of the intake port window and the top of the exhaust port a couple of mm on each side.
5) run your chain just barely loose and as straight as you can.
6) Tune your main jet to get the plug a nice tan colour, and your needle to suit.

This will put you pretty close to 40mph and plenty of power on the hills.
Go careful, the proof is in the details.

Steve
__________________
That's a mighty noisy bike you got there, it must haul a lot of ass?
Reply With Quote
  #6  
Old 01-15-2017, 03:11 AM
Tyler6357's Avatar
Tyler6357 Tyler6357 is offline
Motorized Bicycle Elite Member
 
Join Date: Mar 2012
Location: Santa Barbara, CA
Posts: 715
Default Re: Cant seem to pass 30mph

Quote:
Originally Posted by TheNecromancer13 View Post
First off, don't run it without the air filter. Second, that expansion chamber you bought looks rather tiny. You'd be a lot better off making one yourself.
I was going to say the same thing, that expansion chamber looks small with a long header, it might help on the low end but I don't expect to get much on the high end with that thing.

Reply With Quote
  #7  
Old 01-15-2017, 09:56 AM
mike carter 2 mike carter 2 is offline
Motorized Bicycle Elite Member
 
Join Date: Nov 2011
Location: west virgina
Posts: 122
Default Re: Cant seem to pass 30mph

that is the same chamber that came with my gasbike gt80 kit .its junk, the flange (the part that bolts to the exaust port) is way to small.about half th size it needs to be .i first cut it up and tried to use just the chamber part useing 1 inch conduit bent and shaped for my header.i also dremmeled out the flange to make it larger.it helped but still not rite .i ended up modding a 1979 suziki rm 80 chamber using a cr machine header,made all the differance in the wourld.went from about 25 to around 40 instantly. before you install it look at how porely it matches to the exaust port
Reply With Quote
  #8  
Old 01-15-2017, 09:56 PM
mike carter 2 mike carter 2 is offline
Motorized Bicycle Elite Member
 
Join Date: Nov 2011
Location: west virgina
Posts: 122
Default Re: Cant seem to pass 30mph

im sorry i was so blunt earlyer . didnt mean to seem like that.i did a lot of reasearch on this website to make my desions to build the way i did.there are a lot of people on this site that take no greater pleasure than helping people like us,newbies.my advice is to read as much as you can on this website ,figure out who have the knowldge you need and talk to them , pulse a big shout out to all the people that helped me without even knowing it !!!!!!!!!!! m carter
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:59 AM.


Sponsors

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
MotorBicycling.com