very new to this motorbike thing with a few questions

Yes, the nuts on both of my 48cc engines are a 10mm, the first is a grubee and the other is a BGF. I thought it would help identify his engine. If you look at his pics it looks like the head and intake and clutch lever nuts are the same, all on mine are 10mm.

Bro-die, If your engine is new it will get better after your break-in miles. On my first build it was around 300 miles or so when the bike started climbing the hill that until then I had to pedal to keep the engine from dieing. So if it is running well as you say just keep on riding. MERRY CHRISTMAS

Hey BD,
I'm trying to figger what u mean, 'died out on the hill'.

Mine barely makes it up some small rises, at little more than walking speed, but does plug right along. Sometimes I pedal a bit, but never very much.

You'll need to make a choice between going for top speed, or conquering that hill you spoke of.

The option here is to get a shifter kit.
Most reports regarding them are good.

The button to push on the carby... it's only for bleeding air out of the input line... that is, if you DO have an NT... NT uses a choke for cold start enrichening.

Tell us more abt this hill, and more abt what 'die' means and details...

...I got hills around here I just don't even attempt to conquer! lol

Best
rc

Merry Christmas to all !

bro-die said:

It running right and I ride it almost everyday. I also ride at night. I just want a little bit more speed and conquer that hill because if I do ill make it my dialy ride to work. hehe save some money on gas.

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Don't get discouraged, I started out the summer at about 225LBS and my bike could pull me up a steep hill without pedaling. From a pedal start at the bottom of a hill the motor would get me up to about 20MPH going up the hill without pedaling. (this is a steep hill but not a suicide hill!) Average flat land high end speed is around 30MPH, but at times I had been getting more around 35MPH.
Just break in your motor and get on a regular mix, then tune the carb a bit and you should have what you are after...

bro-die said:

It running right and I ride it almost everyday. I also ride at night. I just want a little bit more speed and conquer that hill because if I do ill make it my dialy ride to work. hehe save some money on gas.

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With a shift kit, you will conquer most hills. This depends on your overall gear ratio.

With a 36-tooth rear sprocket, your ratio is 14.76:1. Not too good for climbing hills.

With SBP shift kit and the lowest gears possible, you might want to use all 8 speeds.

The engine has 4.1 built-in gear reduction and 10t gear. Connected to a 17t jackshaft (4.1 x 1.7 = 6.97:1).

The second jackshaft sprocket can be 9t or 10t. Connected to a 44t chainring sprocket, that gives you 37.173 or 33.456:1.

Using a 30t chainring sprocket and a 32t first gear on your cassette gives you 39.65:1 or 35.69:1. That's equivalent to a 97-tooth rear sprocket or a 87-tooth rear sprocket.

The lowest gear ratio I can calculate would be with (4.1 x 1.7) x (48/9) =
37.173:1. Then using SBP's smallest 24t chainring and the largest (most) available 11t/34t rear cassette, you'd get

37.173 x (34/24) = 52.66:1, which is equivalent to a 128t rear sprocket.

The 8th gear in this combo is 17:1, equivalent to a highway 42t gear.

With a 10t/48t chainring, it'd be 33.456 x (34/24) = 47.4:1, equivalent to a 116t rear sprocket.
The 8th gear in this combo would be 15.33:1, equivalent to a 37t rear sprocket.

A good all-around combination would be using a 30t bicycle chainring, that'd give you a 42.13:1, like a 103-toothed rear sprocket for first gear.
The 8th gear in this combo would be 13.63:1, equivalent to a 33t rear sprocket.

BTW, the first gear on my Tanaka engine/shift kit is 46.36:1, like a 113t rear sprocket.

My 8th gear is 15:1, equivalent to a 37tooth rear sprocket. Since my Tanaka 47R engine can pull higher rpms than a Happy Time engine, 15:1 in 8th gear is not an issue. In fact, in cruising speed, I am in 7th gear @ 17.73:1, like a 43t rear sprocket.

In first gear, my MB climbs hills like a dirt bike.

Just food for thought at low end and high speed.

BTW, even with stiff gears, I still get 125mpg.

Whew!

I'm gonna have to read THAT one over again.

...Lotta info there!

rc

I am long winded.

Greg58 said:

Yes, the nuts on both of my 48cc engines are a 10mm, the first is a grubee and the other is a BGF. I thought it would help identify his engine. If you look at his pics it looks like the head and intake and clutch lever nuts are the same, all on mine are 10mm.

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I don't know, the 4 acorn nuts on top of that head look larger to me than what's on the intake/exhaust, hard to tell from a pic though.
Maybe this is a good way to tell 48cc from 66cc, cause all the 66cc motors I have seen have had much larger studs and nuts on the head than the intake/exhaust (13mm or 14mm vs 10mm). I am still having a hard time believing the head studs and the intake/exhaust studs are the same size on even a 48cc, but you've got the wrench there and the motor to fit it on so I guess I have to trust you on that one. You can trust that what I am saying about the 2010/2011 Grubee 66cc is correct, the head studs and nuts are larger than the intake/exhaust...

bro-die said:

What I mean by "dying out on the hill" is that itll die out in th middle and since its a sigle speed its really hard to pedal so I walk the other half.

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When it dies out on the hill is it because there isn't enough power to pull you and your speed decreases until you are going so slow that it stalls, or does it die out on you when you have good enough speed to stay running if not for being on the hill?

It could be that the going up a hill puts the carb on an angle that makes it hard to run, you might be able to adjust the float in the carb a bit to eleviate that problem and make it run better when on an angle going up a hill if that is the case.

Don't give up it will get better, I thought it looked like the bgf kit I built.

Get a short aluminum billet intake to improve carburetion and motor performance- under $20 shipped

You may also want a newer 66 speed carb- also about $20 shipped- look for shutoff valve on the carb and the word "Speed" or "66 carb" in the ad- it's got a bigger bowl, a bigger port area and a larger jet to let in more gasoline. But the billet intake really makes a bit more difference if you have to choose

Narrow tires will give you a better roll, a lighter bike and less vibration- you can get 26" all the way down to 1.25 inches these days, but those are rare and more expensive. An older !.75 style tire is out there that doesn't cost much and has a nice road tread for a decent roll, or more expensive and generally smoother 1.50 tires are more polular with all cyclists these days . If your rims are alloy and not steel- the general rule is probably look for tires with the size described in decimals like 1.75 and not fractions like "1 3/4"

I've got narrow 27" and 700c tires on my two cruiser builds, generally about 1 1/4" wide- like an older ten speed road bike, while I use a modern lightweight cruiser frame for motor, tank and chainstay clearances

http://motorbicycling.com/showthread.php?p=351395

bro-die said:

I took a size 10 socket to confirm and it is a size 10. Overall its a fun bike I never thought Id go back into my childhood years and have fun with these things.

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I think the consensus then is that you probably have a BGF 48cc motor there...
Does anyone know if a BGF 66cc has 10mm nuts on the head studs, or larger? (Cause the 10mm head studs is what is making me guess its 48cc)

I know what you mean about feeling like a kid again on these bikes, it's just too much fun! Keep it up, she will run better as she breaks in, and better as you move to the regular fuel mix. After riding and tinkering for a while you will get the hang of it and will probably find several ways to increase your speed and ability to pull up hills.

I have a BikeBerry black 66cc motor I bought three years ago, and it has 10mm nuts on the head. So I don't think head bolt size is a very good indicater of displacement. The motor looks like a 66cc, with the square head, my 48cc has a some what smaller head that is more rounded looking. Just my 2 bits on the subject!

Most of the newer 66cc have larger studs and nuts, I was just comparing his to my 48cc.




http://motorbicycling.com/album.php?albumid=264

Regarding that hill- in Tonasket, there is 4rth street going from main uphill to the high school. We live in a ravine that is called a valley- you go either direction perpendicular to the river and soon you are going uphill. Unavoidable. The aforementioned 4rth street is right on par with the best San Fransisco has to offer for 6 blocks. My rig is a monospeed Cranbrook with a 48cc motor. I am 57 years of age with a heart attack 4 years ago on the 23rd of this month, weighing in at 200 pounds.
I can make it to the top without stalling.
Wasn't the case at first... it became a challenge to me. Took me a while to master it, but persistance paid off... leaving me to look like a rather STUDLY senior citizen! My wife was born the same year I got my first FFL, 1975- I had just turned 21 that year. Oh Yea, Mama Likes!!!! Mama Likes her washboard!!! You're concerned about weight? It ain't the calories you put in, it's the calories you do or don't put out! This bike is your ticket to a new body- make good use of it! Trust the Old Sgt. on this one or I'll come over there and drop you for pushups!
Gregory F. (the Old Sgt.) Howard

tim turbo said:

I have a BikeBerry black 66cc motor I bought three years ago, and it has 10mm nuts on the head. So I don't think head bolt size is a very good indicater of displacement. The motor looks like a 66cc, with the square head, my 48cc has a some what smaller head that is more rounded looking. Just my 2 bits on the subject!

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OK, so maybe the consensus is that the motor he has is older (manufactured a while ago) rather than being a 48cc (since the head bolts are 10mm). I just started this hobby this spring, and all I have seen are newer motors manufactured in 2010/2011, they all seem to have larger head studs than exhaust/intake studs.