[QUOTE=husaberg;12 pounds of it they must have thought it was worth it[/QUOTE]
From what i remember reading at the time it brought the bike up to the FIM minimum weight - 2 birds with one 12lb stone....
Low personal B.M.E.P.
[QUOTE=husaberg;
From what i remember reading at the time it brought the bike up to the FIM minimum weight - 2 birds with one 12lb stone....
Long Haired Yobbo
Smart place to put extra weight!Originally Posted by Grumph
Heinz Varieties
elbow down dreamer
Forum whore
.......
All two strokes .... and the gaggle of FXR's chasing them is no where to be seen.
Fixers 50 ran well to, the race I saw he finished 1st with a best lap time of 31.44 and that puts him in the A grade F4 time bracket along with the hot FXRs, not bad for a 50.
All the results for round 7
Pretengineer
elbow down dreamer
Haha good call. Gary on the MB100 actually finished second in the second points race. He unfortunately didn't finish the first race.The top 3 are all RS chassis
Interesting note on the MB100 is that it has RS wheels, RS forks and fork clamps and has a NF4 RS style rear shock modification. I think it's brilliant although it clearly is still not an RS125 chassis.
Forum whore
Hmmm true and the consistent front runner is 80-85cc it must mean something.... just not sure what....The top 3 are all RS chassis
Pretengineer
They're a great chassis those RS chassis and surprisingly work very well as a bucket racer on our tight tracks!
I'm envious of that RS80.
Forum whore
Here we have a water cooled 80-85cc (Derbi?) followed by three air cooled 2Ts, a 125cc Kawasaki farm bike, a 125cc Suzuki farm bike and a 125 Honda commuter bike engine, all consistent front runners.
2 smoke lover
I am pretty shore mb's can not be taken out to 125 without going thou the sleeve.
Compare Pornography now to 50 years ago.
Then extrapolate 50 years into the future.
. . . That shit's Nasty.
Forum whore
Yes my bad .... its a MB100 so 100cc commuter bike engine.
This one is in its original frame but with up rated suspension, I am not sure about its capacity but your right, its probably not going to be 125.
Forum whore
TeeZee I think your bmep for the RGV Aircooled is a bit high, your numbers would translate into near on 40 RWHP.
Pulling the proposed numbers back to around 12 Bar is still a tough ask, but more doable I think.
Going too radical is just going to create transfers that will loose excessive velocity/stream control - even with a good powervalve setup it will
drop the mid power too much.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
Anorak
There is a cylinder available for them for the full 125.....
Search 57mm MB8.........
Kinky is using a feather. Perverted is using the whole chicken
Hardcore Biker
FUEL DROPLET SIZE REALITY CHECK
Some pages ago, there was some discussion on fuel droplets. Got me thinking as to what size a fuel droplet might be.
So, using the RSA 125, 54 hp @ 12,000 rpm as an example. Rounding numbers as we go, this equates to 40 kW. Referring to an SAE paper 2004-01-3561, the instrumented dynamometer performance of a Honda RS125 engine was measured and compared to various computer predictions. This showed a best BSFC (brake mean specific fuel consumption or basically fuel mass flow rate per unit of power) of 400 gm/kWhr. Using this figure as a general guide, we can calculate a fuel flow rate of 40 * 0.4 = 16 kg/hr = 0.27 kg/min = 270 gm/min.
At 12,000 rpm, this gives us 0.023 gm/cycle. Using a fuel density of 0.74, this gives us a fuel volume per cycle of 0.031 mm^3.
If this was a cube of fuel, it would be of (0.031)^0.333 = 0.31 mm per side or if a spherical droplet, it would be of (0.031 *3/4 * π)^0.333 = Ø0.4 mm.
Pretty small stuff really, not something like the Ø3 -4 mm as one might imagine a droplet might be.
Taking this one stage further, if the A/F ratio was 12:1, this would mean 0.023 * 12 = 0.28 gm air was entering the engine per cycle. Using an air density of 1.2 kg/met^3 (at sea level & 15 deg C), this would give us a volume of air entering the engine of 0.000233 met^3 = 233 cc. From this the Delivery Ratio can be calculated at 233/125 = 1.87 : 1. This is pretty good, and sort of correlates with the DR indicated in the SAE paper of around 1.4 : 1, this engine under their test conditions was around 30 kW, not the 40 of the RSA.
Comparing the 233 cc to the volume in the cylinder at the time of exhaust port closure. This (trapping) cylinder volume at the time of exhaust port closure (based on a 120 mm rod, 54 stroke and 192 exh open duration, gives a stroke of 27.45 mm from port closure to TDC) would be 63 cc.
So, ignoring all temperature rises and pressure variations, this means we are stuffing 233 cc of air into a 63 cc volume, a ratio of 3.7 : 1. Some time ago on pitlane.biz, Frits (I think) stated that Jan Thiel took the entire exhaust off the RSA engine and tested it. Would have been a tad noisy I’d imagine. It obviously would have had no benefit of any harmonic supercharging (as with the expansion chamber) and resulted in a power output of 18 hp, compared to the 54 hp which is 3 times the power. Sort of matches the 3.7 : 1. Tells you just how useful the expansion chamber exhausts system.
There you go, a bit of rough trivia.
Ken
"Success is the ability to go from one failure to another with no loss of enthusiasm.”
Hardcore Biker
i wonder how many pebbles the front tire flipped into the cylinder
https://www.youtube.com/watch?v=P-O9nDNzPKM
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