[Aufitt]

witht he new exhaust i can get up to like 21mph before needing to shift to 2nd

What has an exhaust go to do with 1st gear?,
It wont change the rev limiter lol.

As to gearing it up that would be a big step backwards, go the other way if anything... or.. leave it stock.

 

[Aufitt]

By putting a decent exhaust on the CBR250r it makes the engine breath better therefor revving faster and higher (you only need to see the Dyno to see that)

as for 1st gear if the engine is bogging down at a certain revs then curing the bogging will make the bike slightly faster even in 1st gear.

I must be reading the post wrong as I cant see that it would bog in first especially is as first is low geared anyway., or that it cant hit the limiter in any of the first 4 gears.. which is a waste of time anyway because max power is produced way b4 then anyway?

Any power mod wont give any more speed in first.. will just enable to change into 2nd at a lower speed and a quicker time if anything.

 

[Aufitt]

Anyone got a dyno graph for these things?
my wheelbarrow probably has more but I'd like to see where max torque, max power, and rev limiter are.

 

[Aufitt]

i would still like to know if i need to get a biger chain if im puting a 41 tooth rear sprocket on i cant figure it out

Measure 1 and a half chain links, (you are going from 38 to 41 teeth),
undo the chain adjusters and slide the axle all the way forward.

see if you can fold almost 2 links out of the now slack chain.

It will at least give you an Idea.

3 teeth is a fairly large jump.

 

[Aufitt]

You must have some **** serious engine mods to be able to pull taller gearing, It wont pull the stock gearing... All manufacturers do that to pass strict ride by noise tests.
I want one more tooth on the rear and it will be perfect, and 2nd gear starts a little easier, and it will slightly close up the gaps between changes.

 

[Aufitt]

So standard is 14T?

 

[Aufitt]

I need a 39 for the rear, are they available?

 

[Aufitt]

I'm adding a tooth to the rear.. bet it actually goes faster and gets there quicker.
And closes up the gaps 4th, 5th,6th where it spends its time.

 

[Aufitt]

Soul Searcher is that a misprint on the 39T line?

I'd like to know how many teeth more on the rear is the equivalent to going down to a 13T on the front? (would like to stay with 14T Front)

 

[Aufitt]

Aufitt, it looks like the 14/41t will fill the bill.

Thanks, I will select the 40T as a happy medium, our bike just cant pull the std gearing, 167kph indicated is still not even redline and needs a good downhill run to get there.

If I was lighter it might but at 80kg it struggles, 39T is not much of a change.

 

[Aufitt]

So which way would higher or lower gearing affect the speedo READING?

ie I'm getting approx 10,000 and its showing 166kph atmo.

 

[Aufitt]

Hit 100mph at 10 and a half K, thinking of going longer...

10,500rpm , That is amazing, whats your secret Tom?
-gearing?
-Break in?
-Tyre pressures?
-Slip on exhaust?
-Insert IN/OUT?
-Bazazz?
-Airbox lid ON/OFF?
-Your weight?

I edited my last post after a hard 200km run today as I'd read the Tacho wrong (hard to look at WOT)

Got home and checked both sprockets... 14/38T (Thought there may be a difference between mph bikes vs kph bikes due to our major speedo difference so its not that)

This was checked and double checked the whole trip, then as follows and checked with gearing commander putting in 14/38 gearing.

Uphills, 9,000rpm = 151kph indicated / Gearing commander = ~146kph
Flat road, 9,500rpm = 159kph indicated / Gearing commander = ~153kph
Downhills, 10,000rpm = 166kph indicated / Gearing commander = ~161.5kph

*Its not the speedo error I'm trying to sort here, is the gearing change needed to make the bike redline in top and less going back to 5th gear.

 

[Aufitt]

No good following trucks here either, speed limited to 100kph you're going to take all day to get where you are going.

 

[Aufitt]

Finally shattered my pb today for top speed by a long way.

Put all the road stuff back on after a caning at the track last week, filled it with standard 91RON BP instead of 98 premium.
Hot 37C degrees and only a slight downhill, no breeze.. 171kph! (flashed 172 for a second) redline top gear

Bike is absolute standard except Akrapovic slip-on and a minor secret intake mod.
Gearing is standard, way too high but the 40T rear will fix it.

 

[Aufitt]

Tried the 15 tooth front this weekend, and the results SUCKED!!! The motor will not pull it. Not even on a 2500 foot long straight. My 111 lbs. son on the bike, and it would not go past 8K RPM, and only hit about 83 MPH. Put the stock 14 back on, and we got the full rev out of the bike and hit 97 MPH. The Ninja's still pulled us hard down the straight, but the Honda handles the twisties way better. 4th in E Superstock, 3rd in F4, and 6th in Clubman. I will post some GoPro video of the race tomorrow in another thread.

Hey gofast have you been running the 38T rear the whole time?

 

[Aufitt]

Maybe the USA bikes have lower internal gearing?
It would explain the low top speeds and the high revving at only 80mph we hear about on here so often.
Mines a bit of a slug but if you take it all the way to redline in 5th then clutchless shift into 6th & hold it WOT for a few kilometres and get a good downhill run it will just touch the redline at 171kph indicated.
It will be faster when I get the 40T sprocket.

 

[Aufitt]

My bike never had the power to pull standard gearing despite getting to 171kph (redline) on VERY long downhill runs in perfect conditions.. I cannot fathom what it would be like to ride with even higher again.