Rob928
Member
Which carb did you order? the tanaka 15mm?
2-stroke/single-speed...operation for topend performance?
- Thread starter augidog
- Start date
D
duivendyk
Guest
If your aerodynamic drag is reduced substantially AFTER you have concluded your optimization, you have to keep in mind that this may invalidate your test results to a somewhat.Most 2 strokes have a rather pronounced drop off in torque(decline of power)beyond a certain rpm esp.those with fixed timing advance,the thing has prob. been engineered for a certain max, rpm.If you start revving it higher, for instance due to less drag,you might run into a "brick wall" because the torque drops of quickly.Then it could have been better to have less reduction (bigger front sprocket) and with it more speed.Engines vary a lot in that regard mostly because of differences in exhaust tuning (or the lack there of)
Eco Speeder
Member
- Local time
- 3:04 AM
- Joined
- May 11, 2008
- Messages
- 158
Augi,
Have you considered a velocity stack and exhaust manifold spacer? Could be the extra input of the hp carb might be enhanced with being aspirated and/ or is bottle-necking at the arse end of the engine.
Michael
p.s. They have E3 plugs in the lawn and garden centers of big box stores now.
Have you considered a velocity stack and exhaust manifold spacer? Could be the extra input of the hp carb might be enhanced with being aspirated and/ or is bottle-necking at the arse end of the engine.
Michael
p.s. They have E3 plugs in the lawn and garden centers of big box stores now.
Last edited:
yup, see my previous posts...matter of fact i was informed today that my new intake-stack is in the mail, yay!
and, there is some sort of methodology where i extend the "stinger" on the muffler, which i will experiment with later.
the E3 plug is doing fine, but i was warned about the gap expanding on it's own, that's happening...the electrode has almost too much quality to it...too much copper(?) makes it so pliable i can adjust the gap with my fingernails. not good, i'll be looking for something else.
duivendyk, i appreciate the input..den and i have come to the conclusion that the 32 will be able to "bull" it's way thru the 16 tooth with enuff fuel at the right mix.
and, there is some sort of methodology where i extend the "stinger" on the muffler, which i will experiment with later.
the E3 plug is doing fine, but i was warned about the gap expanding on it's own, that's happening...the electrode has almost too much quality to it...too much copper(?) makes it so pliable i can adjust the gap with my fingernails. not good, i'll be looking for something else.
duivendyk, i appreciate the input..den and i have come to the conclusion that the 32 will be able to "bull" it's way thru the 16 tooth with enuff fuel at the right mix.
Last edited:
shoot...got my HP carby (hi/lo 14mm) but the intake was the wrong one 
and i got my tach too...the bad baby will rev out at 14300! no-load but it's pretty lean & the small carburetor just won't feed it enuff power to pull. rich enuff to go anywhere takes me down to 12500 no-load.
i also have the 16 tooth drivegear, the 32cc pulls it (i wasn't paying attention to numbers tho)...gonna do some riding this weekend and start to compile some rpm/gearing stats.
i just made my deal for the paint: mopar green with red/orange lettering...wet-rub clear with more clear...you should see this guy's work
she may not be the fastest motorized bicycle (this year anyway) but she's sure gonna look the fastest
and i got my tach too...the bad baby will rev out at 14300! no-load but it's pretty lean & the small carburetor just won't feed it enuff power to pull. rich enuff to go anywhere takes me down to 12500 no-load.
i also have the 16 tooth drivegear, the 32cc pulls it (i wasn't paying attention to numbers tho)...gonna do some riding this weekend and start to compile some rpm/gearing stats.
i just made my deal for the paint: mopar green with red/orange lettering...wet-rub clear with more clear...you should see this guy's work
she may not be the fastest motorized bicycle (this year anyway) but she's sure gonna look the fastest
Last edited:
charting gears & rpms
temperature 53
winds from the n at 9mph
i'm only going to chart downwind...for reference, there's about a 2-3 mph difference. the tach refreshes every second, i'll give as accurate a number as i can remember. these are not my potential high numbers, the bike is about 15lbs heavier than when i'll be racing plus i'll have the bigger intake on.
12mm carby
champion plug .030
mixture 1 1/4 turns (factory rich, not extreme)
13 tooth
34.8mph
9370rpm
14 tooth
36.5
9220rpm
16 tooth
37.3mph
9200rpm
after while i'm going to chart the same specs using the E3 plug.
temperature 53
winds from the n at 9mph
i'm only going to chart downwind...for reference, there's about a 2-3 mph difference. the tach refreshes every second, i'll give as accurate a number as i can remember. these are not my potential high numbers, the bike is about 15lbs heavier than when i'll be racing plus i'll have the bigger intake on.
12mm carby
champion plug .030
mixture 1 1/4 turns (factory rich, not extreme)
13 tooth
34.8mph
9370rpm
14 tooth
36.5
9220rpm
16 tooth
37.3mph
9200rpm
after while i'm going to chart the same specs using the E3 plug.
Safety Disclaimer!
my bicycle is built to withstand the speeds i'm going, see the racing forum to learn more.
i always wear a DOT-helmet, goggles, and gloves, long pants & sleeves. i use a full-time lighting system with a 55W halogen headlight. i do my time-trials on a sparsely traveled 55mph stretch of road...
SAFETY FIRST!!
my bicycle is built to withstand the speeds i'm going, see the racing forum to learn more.
i always wear a DOT-helmet, goggles, and gloves, long pants & sleeves. i use a full-time lighting system with a 55W halogen headlight. i do my time-trials on a sparsely traveled 55mph stretch of road...
SAFETY FIRST!!
Last edited:
D
duivendyk
Guest
There is something amiss with you data.The road speed is proportional to engine rpm and to primary sprocket size,that is to the product of the two.So if you take the ratios of these numbers they aught to be the same as as your measured speed ratios,and they are not see table:
Teeth------Product of krpm&teeth---Ratio-----Speed-----Ratio
13------------------122.--------------------------34.8-------------
14------------------129.1-------------1.058------36.5----1.049
16------------------147.2-------------1.140------37.3----1.022
The first ratio in the 14T collumn is the 14/13 based ratio, the second the measured speed ratios,they agree reasonably well.but on the 16T line the ratio between 16/14 ratio(1.14) is way above the measured speed ratios only 1.022 !!.Something is rotten in the State of Denmark.I haven't a clue as to what is more accurate, the speed or rpm measurements,but it does not add up, regrettably.What is odd is that the first ratios are in the ballpark but the second ones are not, so it's not a systematic error,I'm puzzled.Even if you had a 15t instead of a 16 t,we're still way off.If you conduct tests you must be able to trust your numbers otherwise you are just wasting your time.
Teeth------Product of krpm&teeth---Ratio-----Speed-----Ratio
13------------------122.--------------------------34.8-------------
14------------------129.1-------------1.058------36.5----1.049
16------------------147.2-------------1.140------37.3----1.022
The first ratio in the 14T collumn is the 14/13 based ratio, the second the measured speed ratios,they agree reasonably well.but on the 16T line the ratio between 16/14 ratio(1.14) is way above the measured speed ratios only 1.022 !!.Something is rotten in the State of Denmark.I haven't a clue as to what is more accurate, the speed or rpm measurements,but it does not add up, regrettably.What is odd is that the first ratios are in the ballpark but the second ones are not, so it's not a systematic error,I'm puzzled.Even if you had a 15t instead of a 16 t,we're still way off.If you conduct tests you must be able to trust your numbers otherwise you are just wasting your time.
wait, i can't read that...i have no problem with the probability that i didn't remember a number right, the speed is easier to read and therefore accurate, the tach (1 second refresh) is a bit tough to pay attention to...but i still can't follow you...please clarify if possible.
Last edited:
Similar threads
