| | | High Performance Bicycle Engine Tips We all want our bicycle engines to push our bikes faster. Get exclusive engine modification tips and suggestions from us. | How fast can your 80cc really go? Discussion at Motorized Bicycle Engine Kit Forum in the High Performance Bicycle Engine Tips forum. Originally Posted by Phatman Motors
,and long plastic intake runner[gas can nozzle]cut to 5"...
ummm yeah, not ...  | | 
02-06-2009, 10:44 PM
| | Motorized Bicycle Member | | Join Date: Feb 2009 Location: Seattle
Posts: 32
| | Re: How fast can your 80cc really go? Quote:
Originally Posted by Phatman Motors ,and long plastic intake runner[gas can nozzle]cut to 5"... | ummm yeah, not sure if that's a great idea. | 
02-07-2009, 04:03 PM
|  | Motorized Bicycle Member | | Join Date: Dec 2008 Location: florida
Posts: 24
| | Re: How fast can your 80cc really go? Quote:
Originally Posted by runslikeapenguin ummm yeah, not sure if that's a great idea. | whats up with that? | 
02-07-2009, 11:11 PM
| | Motorized Bicycle Newbie | | Join Date: Feb 2009 Location: Benton,arkansas
Posts: 1
| | Re: How fast can your 80cc really go? When I get speedometer will post mines got 80 cc | 
02-17-2009, 01:34 PM
| | Motorized Bicycle Newbie | | Join Date: Jul 2008
Posts: 14
| | Re: How fast can your 80cc really go? Like Phatman Motors, my 80cc (mallory power cell [gives our cdi's a stronger spark, speed increases 3-5 mphs fits bikes perfectly], msd 8.5 plug wire, bosch platinum size 4302 [it has two ground electrodes=more sparks=more power], 27 sprocket [main modification increase speeds up 10 mph from kings sales and services], and an uncorked original mufffler (increase power about 5 mph alone)...I've gone 48.5 mph drafting a delivery truck and I was gaining on it pretty qucikly had to slow down. I also cruise in the 40's about 95% to full throttle. The kind of bike you use also matters because of weight. Mine is like Lance Armstrongs bike but the cheap end a trek 370 with thin tires. Man guys, my rides are an adrenaline rush now because I ride my MB to work and back. One way is about 33 miles so about 66 miles total trip. Peaple just look at me like I'm crazy or amazed at the speed I'm going. I stress wearing helmets going at these speed even wearing a motorcycle helmet. And I give the mopeders a run for their money. My next add on is an engine sprocket with 11t. This will push me in the 50's and probably cruise at 45. I will finally catch this guy with a sooped up moped going 50 mph +. One last thing, I use premium unleaded gas with octane boost and 16:1 to 24:1 oil/gas mixture. If you got 16:1 [more oil in gas] lean out your idler screw, turn it clockwise for leaner gas and versa counter clockwise if you use 24:1+ [less oil in gas]. Guys/gals try these tinkering ideas and post your outcome...remember use helmets. | 
02-17-2009, 02:06 PM
|  | Godfather of Motorized Bicycles | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 7,081
| | Re: How fast can your 80cc really go? Hate to burst your bubble.... that mixture screw is only an idle speed adjustment and doesn't do anything but change idle speed when you turn it.
Two electrodes won't give more spark, just more places to jump spark to.
Boosting octane with these engines is a waste of time and money, since they don't have high enough compression to need anything higher than 87 octane.
Gearing to infinity? Since speed is a function of horsepower, not total gearing, and these engines only make about 2.5 horsepower, 3 at best, gearing higher has it's limits.
Finally, leaning out a mixture of 16:1 over 24:1 is bad advice, the 16:1 mixture is already leaner (more oil=less gas in the fuel to air mixture) than 24:1. Not to mention that 16:1 is ridiculously over oiled to begin with.
__________________ If it ain't broke, and you mess with it long enough, it will be.
Last edited by Bikeguy Joe : 02-17-2009 at 03:03 PM.
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02-17-2009, 02:54 PM
| | Motorized Bicycle Newbie | | Join Date: Jul 2008
Posts: 14
| | Re: How fast can your 80cc really go? Hate to burst your bubble.... that mixture screw is only an idle speed adjustment and doesn't do anything but change idle speed when you turn it. This is correct Joe. I got stuck last night because my oil and gas mixture was too mush around 16:1. I tried numerous times, each time trying different methods of starting and I found the only way TO START and KEEP THE ENGINE GOING was to lean out the gas; therefore less oil in gas and air mixture better ignition.
Two electrodes won't give more spark, just more places to jump spark to. I completely disagree. But I do agree with "just more places to jump spark..." equals to more power.
Boosting octane with these engines is a waste of time and money, since they don't have high enough compression to need anything higher than 87 octane. You might be right on this but I like to think it give my engine more boost.
Gearing to infinity? Since speed is a function of horsepower, not total gearing, and these engines only make about 2.5 horsepower, 3 at best, gearing higher has it's limits. "Gearing to infinity..." is probably true but trying is believing and there is a big difference from 44t to 27t in speed. Again please try it.
Finally, leaning out a mixture of 16:1 over 24:1 is bad advice, the 16:1 mixture is already leaner (more oil=less gas in the fuel to air mixture) than 24:1. Not to mention that 16:1 is ridiculously over oiled to begin with. Refer to my first rebuttle.
Peaple trying is believe...isn't that what tinkering with these engines is all about? | 
02-17-2009, 02:58 PM
|  | Godfather of Motorized Bicycles | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 7,081
| | Re: How fast can your 80cc really go? You are correct on the corrections on all accounts.
__________________ If it ain't broke, and you mess with it long enough, it will be. | 
02-17-2009, 03:02 PM
|  | Godfather of Motorized Bicycles | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 7,081
| | Re: How fast can your 80cc really go? Yes, I concur, changing the 16:1 to 24:1 will improve performance.
Still the idle screw is only called a mixture screw in some incorrect instructions. Turning it in will increase the idle because it opens the slide more.
Octane booster can cause an overly rich mixture to lean out, making it run better, but there are better (an cheaper) ways to correct the over rich condition.
Finally, going from a 44T to a 40T or even a 27 t will lower cruise rpm, and give a marginally hight top end speed, especially when going down hill or drafting (don't try that one at home kids) but as stated, ultimately, top speed is governed by horse power.
Are we on the same page now?
__________________ If it ain't broke, and you mess with it long enough, it will be. | 
02-17-2009, 09:26 PM
| | Motorized Bicycle Member | | Join Date: Feb 2009 Location: Seattle
Posts: 32
| | Re: How fast can your 80cc really go? two things,
1. with the ignition on these engine any kind of platinum plug, multi prong plug or any of those fairly debatable upgrades is useless on these engines. if the coil isn't throwing the spark then its not going to be connecting with all the points. the most we can hope from with these coils is a spark that will bridge a decent gap.
people always have this idea that some how if they find the right plug its going to give an engine all this power. if there isnt enough spark being thrown in the first place then your just wasting money.
2. Octane booster is hard on any engine being that its normally an Alcohol based product and secondly if your not getting Detonation then you have no reason to run higher octane gas. in fact in most cases people who decide that they are going to dump some VP 110 into their car for the one day they go to the drag strip find that it actually slows their car down. this is true because all a higher octane number represents is how resistant to burning the gasoline is to make sure its not ignited by the cylinder pressure instead of the spark. so initially it will rob power if its not burning fast enough to get all the possible energy out of the fuel.
in a nut shell for optimum performance you want to run a fuel that will not detonate even under full load. if your running flat out on your engine and its not detonating then go down and Octane level, if its still not detonating then go down some more.
i could run a highstrung VW 1600 that was running at 10.5:1 compression and reved up to 6K without detonation on 89 octane so i doubt we need 91 in our engines let alone any kind of additive booster | 
02-18-2009, 02:03 PM
| | Motorized Bicycle Newbie | | Join Date: Jul 2008
Posts: 14
| | Re: How fast can your 80cc really go? To Joe...yeah we're on the same page.
To runslikeapenguin...lets stay away from car tuning, too expensive for me but I what learned from it was by increasing the ignition output will increase torque and power. So that's why I installed a mallory power cell to increase the ignition capacity of my cdi and also use a better plug wire and plug to carry out a much stronger spark. AGAIN THIS IS WHAT MY EXPERIENCE HAS BEEN since I've tinkered with these MB engines. | | Thread Tools | | | | Display Modes | Linear Mode |
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