40mph speed secrets revealed

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foureasy

foureasy

New Member
Jul 9, 2009
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tucson
foxy,
i'll post a pic of the finished chamber tomorrow. it matches the dome of the piston just fine. you have to buy a top end from me or do the math yourself. then you have to build a pipe, it takes too much time to go through all the trial and error. they are chamfered but definitely not radiused. lets hear some of your secrets? clay
 
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bandito

New Member
May 22, 2009
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colorado
That cheese head is a great concept but Id worry about heat disipation from it. Most motor builders put thin fins on the head and motor to increase the surface area to disapate the heat. Four do you have an infrared temp thermometer? Id be curious as to the op temp of the cheese head vs a stock head.
 
N

noco

New Member
Sep 9, 2009
343
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fort collins colorado
hey thanks for sharing...i do think that milling fins would have been beter than the cheese head...it is cool though...and by the way that was fun to read...what is the internet for right, slandering each other anomomously...hahaha...if you dont got something nice to say then say it on the internet
 
FileStyle

FileStyle

New Member
May 27, 2008
719
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Decatur,IL
let me just say that 40mph isnt impossible with internal modifications! I have "80cc" kings motor purchassed in may 08 I now have over 3000 miles on it and it runs good still. I havent done any mods to the engine other than a expansion chamber, a shorter intake with better air filter on stock carb and upgraded plug and wire and a 35t sprocket. my frame is aluminum (GT Agressor) with 26" maxxis holy roller tires and my top speed of the day of the rally on flat ground was 41 mph! so yeah Iam in the 40 mph club! I think if I had a mikuni carb with hi/lo settings I believe I could get 45mph! but we all must keep in mind that we are dealing with bicycles not motorcycles! bicycle frames were not intended for the vibrations that these motors put out (harmonic vibrations) and due to stresses and torque on the frames and wheel that constant pm will have to happen to keep yourself safe! when at those speeds I wear a helmet, glasses, and gloves to help keep me safe (just in case) and I spoke to a new friend from waukeagan IL about trying to make a 2 stroker go 60mph! and that can be done! all it takes is the gearing, intake, and exhaust! thats when I will modify the internals of the motor.
 
Venice Motor Bikes

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,337
1,981
113
Los Angeles, CA.
Many of us have been able to hit the magic 40MPH mark with a HT engine... It's a little scary going that fast on a bicycle!

The new magic number is 50MPH... Who will be the first to prove it??
 
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noco

New Member
Sep 9, 2009
343
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fort collins colorado
i have some ideas that could get us there....the question is are we brave enough and will we let our china girls tack as high as this will take...we do not get as many rpm's out of that small stroke that we can...will it shatter to pieces...i dont know...there is only one way of finding out...lets advance our timings and go
 
foureasy

foureasy

New Member
Jul 9, 2009
478
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tucson
everyone calm down, someone that says is all right in my book. anyone can get any top speed, it's how fast you get there. ill be at the death race next year, and encourage everyone to smoke me at the track. anyways, i had to work on site today and couldn't make it to the shop for a chamber pic, so the suspence continues. about the cheese head, i have reached the conclusion that it is only slightly better than stock as far as cooling goes, but i have had zero warping issues (which was a problem i was having with the increased compression and the mid day heat of tucson). but the advantages were not enough to offset the amoung of time to build one. i have a head coming in the next few days from another application that i think might be an excellent solution, ill let you know.
 
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foureasy

foureasy

New Member
Jul 9, 2009
478
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tucson
Foximus said:
Foureasy, have you ever seen a slant head? how is the squish on them? just as bad as the centerfire heads?
Click to expand...
i have not seen a squish band on any head yet, but i have not seen a slant chamber either. im not so concerned with the chamber as i am with the cooling capacity, because i can build up and machine the chamber however i want. anyways, this is a pic of the head from the first few posts, the cheese head has the same size/shape chamber, but is still on the bike. i told the ol lady i was gonna be defying death at the death race. yaaaayyyyyyy!


 
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Foximus

New Member
Sep 28, 2009
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Orlando
foureasy said:
i have not seen a squish band on any head yet, but i have not seen a slant chamber either. im not so concerned with the chamber as i am with the cooling capacity, because i can build up and machine the chamber however i want. anyways, this is a pic of the head from the first few posts, the cheese head has the same size/shape chamber, but is still on the bike. i told the ol lady i was gonna be defying death at the death race. yaaaayyyyyyy!
Click to expand...

Ah! See heres the chamber you welded at another angle. You did indeed not deck it perfectly flat, there is a squish. Thats what I originally was discussing.


As for the chamber and cooling capacity, those are almost directly related. The smoother the chamber is the less heat soak it is subjected to, so the less heat it absorbs. (and there is no offense inteded by this...) And really your chamber is far from smooth. Really you should get in there with a fine grit ball stone or perhaps even a sanding barrel. Also make a decent chamfer radius on the transfer from the chamber to the squish. Doing both these will make your engine more efficient by turning more energy into kinetic energy as opposed to heat energy.
 
S

stv1jzgte

New Member
Feb 11, 2009
489
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australia
Of the 2 motors i have both the pistons are flat. dead flat, have a slant head motor and a normal centre fire. the slant head has a "squish area" cut at about 10-15degrees the centre fire is cut at about 30-40degrees
I have a spare piston that is domed and looks to fit the slant head pretty well so this combo would have a "Squish band".
 
markeatmark

markeatmark

New Member
Jun 17, 2009
182
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0
jacksonville NC
The idea behind the fins is to increase suffice area. If you total the Cheese Head suffice area. It looks much greater. there is only one way to find out if it works.

Don't die at the death race, wish i was going Mark
 
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