Porting a china girl

[HeadSmess]

i know for a FACT that one of my engines has done at least 300km/h.

at least, i was told it was air mail... par avion!

 

[skyash]

I have asked this question before but no one answerd. I was driving I saw a stock 66cc pulled along side him and he was doing 57kmh so if he got a carby and muffler and ported it and a head and what ever. What speed wood he get.

 

[butre]

I have asked this question before but no one answerd. I was driving I saw a stock 66cc pulled along side him and he was doing 57kmh so if he got a carby and muffler and ported it and a head and what ever. What speed wood he get.

depends on what carb, how it's jetted, what geometry the expansion chamber is, what timing the ports are at, the size, shape, and clearance of the squish band, the displacement of the head, the quality of the whole ignition system, how in-balance the crank is, what the gearing is, etc.

you can't say "yeah a vm18 gets you an extra 3 mph" it's a system of parts and how they go together makes way more of a difference than what they actually are.

all the bolt ons in the world won't get you past 40 though, not with stock gears.

 

[skyash]

Just sounds like a lot of work money and time for 5 kmh more someone has to make a better motor just not right my 49cc can do 50 and the 66 cc hits 57 it's massive compared to the 49 cc but not power wise. Thanks for the reply

 

[HeadSmess]

someone already does make a better engine...
http://www.denardisengines.com/40cc.html

just seems that barely anyone will take the plunge on a quality race engine that pulls 7hp...

just think,no need to spend money on "bling", no modifications other than the mounting issue, if you ever require parts, they are interchangeable...no strange hybrid things without part numbers...warrantied... etc etc etc...

after blowing 5 china engines at $150 a pop, the 5-600 price tag is relatively CHEAP.

whats the saying? "i am too poor to by cheap tools"

wish i had a denardis

i wonder why KTM is willing to use them in their lil ring ding kiddies bikes? along with several other companies...

 

[johnsteve]

for a second motor what would be the recommended motor, thatsdax, arrow, or denardis? Just courious what would be a good quality motor with nice HP that would make a nice upgrade?

 

[Frankfort MB's]

I'd look into the 50cc 2 stroke ktm engines that are making 9 HP with almost 12,000 RPMs.... I like the little HT engines but it's hard to make a powerful power plant out of a throw away engine.... I know there is some HT engines that are pretty powerful for a 80$ engine but whether or not they will last is another story.... I have a MB that has at least 1000-1500 miles on it that's been ported polished and matched with a tuned carb but the stock exhaust and it's about shot... When it gets about half speed it starts "machine gunning" at full throttle and won't go any faster, I thought it might be the cdi so I replaced it and still does it so I was figuring it was either magneto or crank bearings or piston rings, I only have 150$ in the entire bike so I figured I'd get rid of it for cheap (I don't like fixing 5 or 6 15$ parts on a engine that only costs 80$ for a new one) lol sorry that's such a long post

 

[johnsteve]

thanks for the update. I agree also. I think it was more of a couriousity porting this 2 stroke, but now I am thinking about a 50cc motor for my new build

 

[Frankfort MB's]

Any comments on what might be wrong with my ported 80???? Could I have ported too much???

 

[butre]

it's the jetting it sounds like. running rich.