Scooterotica

Ah bless ya mate

On the subject of Dyno graphs and lap times.....

1) do you have any Dyno graphs of your race scooter to post up here for analysis ?

2) what's your pal Charlie up to these days? Is he gonna race again? Be good for the king to come out of retirement and duke it out again with the current crop..,.lol

There is a graph posted on here somewhere. If not its in Scootering under smallframe dyno shoot out a couple of years ago. It was dynoed at diablo's for this feature.

Charlie ? Dunno really. He is pretty busy these days

drunkmunkey6969 wrote:

Darrell Taylor wrote:[ at these horsepower levels on an aircooled motor im probably finding out for the first time as to whether or not its sustainable at 42 / 45 / 47 i may have to liquid cool
ive just dynoed a late model cr250 with a road tyre fitted that did 43bhp this model had a 100% increase in radiator size compared to the year earlier so shows that they had cooling problems too even at 43 with liquid cooling

You are not wrong there Darrell, heat issues are the devil for these machines. But one thing is for sure, you have got more power out of your machines than any tuner (especially when taking RPM/spread of power and available torque into consideration). No one else is publishing power graphs at 47bhp. Figures in the 47+ bracket are very hard to come by, especially at sub 10k RPM....so good for you. If you solve the heat issues your engines will be a formidable weapon on the track.......

thanks for the encouraging words,lets hope i can sort the cooling,i only built it for sprinting but thought id see how it goes on track too
interesting point on power and rpm is the bmep figures that this air cooled motor is doing which is a good comparison to other motors,you can see its real close to the efficiency of a cr250 honda

the ts1225 did 125 bmep
ts1 245 does 117 bmep
the rb252 does 137 bmep std rb250 does 90bmep

honda cr250 143 bmep with

the improved bore / stroke and smaller capacity motors with better cylinder designs show better figures

the rs125 aprillia i tune do 170 bmep
the derbi 50 i tune do 170 bmep
the derbi 80 i tune do 161 bmep a drop as we go from near square on the 50cc to the big bore 80

and state of the art last generation 125 gp bikes 50bhp+
do 192 bmep

any more bmep numbers to add ,how do the latest generation off the shelf vespa gp / sprint kits do with the better bore/stroke combo

Darrell Taylor wrote: ts1225 did 125 bmep
ts1 245 does 117 bmep
the rb252 does 137 bmep

honda cr250 143 bmep with

the improved bore / stroke and smaller capacity motors with better cylinder designs show better figures

the rs125 aprillia i tune do 170 bmep
the derbi 50 i tune do 170 bmep
the derbi 80 i tune do 161 bmep a drop as we go from near square on the 50cc to the big bore 80

and state of the art last generation 125 gp bikes 50bhp+
do 192 bmep

any more bmep numbers to add ,how do the latest generation off the shelf vespa gp / sprint kits do with the better bore/stroke combo

Not sure...Tony is a Vespa man, he might know a few BMEP figures. Tony whats the BMEP of your race scooter?

The tuned RB252 i just did for John Bond in Group 6 is 114 BMEP, and that is hopefully going to be a 'full season' race motor (no strip downs)........lol.....but we'll see! (waiting for this statement to come back and haunt me at next race!) Its running a low-comp head, still using fan cooling and safe ign-timing and jetting. I hope he does a full season on it. (fingers crossed).

But although that BMEP isnt earth shattering, its the same amount that Charlie Edmonds won his BSSO championship with. Although Charlie's 36.75bhp Muggello was circa 45cc lower than Johns RB250.....but Charlies peak power was up at 10,300rpm.......Johns is at 8,200rpm. John therfore also gets a lovely 23.1ft-lbs torque.....Charlie was racing with 19ft-lbs.

Not that i'm suggesting John Bond is the next BSSO champion...lol, or that the bike we built could win the championship.....there are too many good riders and great machines out there for a novice to make an impact. I'm just throwing figures up there for comparison, its interesting stuff.

interesting bmep figures there

the bore /stroke of the group 4 motor is a better configuration
the smaller bore size leaves a more stable cylinder with more space to increase port widths before the studs get in the way,the case volume is greater vs cc ,the pipe size is bigger vs cc
there are also bare cylinder castings available and has been a few options on those too with extra meat here and there

tony wrote:In fact Paul would know for sure. Paul?

Most of the BSSO races are a 15 minute slot.... Which includes formation lap, start procedure and wind down lap

Tbh. You can throw all the figures out of the window unless you run the bikes on the same machine.

tony wrote:Tbh. You can throw all the figures out of the window unless you run the bikes on the same machine.

True. I always thought 33bhp was optimistic for a Vespa! Probably only about 25 on my Dyno...... Lol ;0)))

And Charlie was getting what? Maybe you should speak to him dan or maybe ask him to run one of your bikes to get a ballpark figure if you want to compare for real ?