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Engine RPM'S at 50-100mph

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Tested out RPM'S today at 50-100mph,  beautiful day out,  minimal headwinds,  flat surface,   i stayed at every speed for about 1/2 a minute of so to keep it steady and get the right readings,  im using a TTO tachometer,  its very accurate.  reason for doing this is im in stock SM trim right now,  with stock SM gearing 15/41,  and just recently got a 39 rear sprocket to try out,  once i have that on the bike,  ill report back to show by how much it drops RPM'S at the same speed,  also,  the bike runs great now,  and im very happy that even doing 75-80mph if i WOT it,  it moves forward quickly,  if that goes away with the 39 rear sprocket,  its coming right off,   i do not want to lose power just to be able to do 75mph at a few hundred RPM'S less. 

 

this is the trail tech im using. 

 

3X3, UNI air filter, TT FCR MX-39, old school first generation 2003 stage 1 hot cams,  MRD/SSW shorty exahust. 

 

50 =4650

55 =5100

60 =5550

65 =6060

70 =6480

75 =6900

80 =7440

85 =7920

90 =8400

95 =8910

100 =9380

 

Flat surface,  all in 5th gear,  idle is at 1780

cockpit.jpg

riding game tt soccer.jpg

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Perfect! I've been waiting for someone to do this :) I now have the 39 installed in the rear and love it. What size do you have up front? 15 tooth? I have 17's on SM trim.

I can't wait to see the results. Thanks for posting!

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Perfect! I've been waiting for someone to do this :) I now have the 39 installed in the rear and love it. What size do you have up front? 15 tooth? I have 17's on SM trim.

I can't wait to see the results. Thanks for posting!

Yes,  15 up front,  17's in SM trim.

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Nice work Ron...But as you are using the stock instrument the speed is most likely going to have some error... :thinking:

Yes,  its about 5mph less in real life,  as shown by others on here with a GPS,  but RPM'S should still be very accurate. 

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You'll see a drop in performance with the 39 tooth.

I swapped my front sprocket to a 16T from the stock 15t (SM, w/ FCR, RS-2 pipe, KN filter).

Which would be swapping the rear sprocket to a 38T.

Top speed dropped (not enough power to pull) and acceleration dropped. 

More clutch slippage when starting out.

The nice thing about the 16T front is the lower highway RPM's and the mid-range acceleration seems better.

Cruise at 50 km/h and giver a whack of throttle brings it to 80 km/h in a blink, seems faster accelerating at those speeds.

I haven't hit the rev limiter in first (not wanting to) but first will take it up to about 60 km/h.

Also being able to drop it into 4th on the highway to accelerate and pass.

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You'll see a drop in performance with the 39 tooth.

I swapped my front sprocket to a 16T from the stock 15t (SM, w/ FCR, RS-2 pipe, KN filter).

Which would be swapping the rear sprocket to a 38T.

Top speed dropped (not enough power to pull) and acceleration dropped. 

More clutch slippage when starting out.

The nice thing about the 16T front is the lower highway RPM's and the mid-range acceleration seems better.

Cruise at 50 km/h and giver a whack of throttle brings it to 80 km/h in a blink, seems faster accelerating at those speeds.

I haven't hit the rev limiter in first (not wanting to) but first will take it up to about 60 km/h.

Also being able to drop it into 4th on the highway to accelerate and pass.

Yep,  i did the same,  changed the front to a 16 when i was in S trim,  so instead of stock 15/44,  i went to 16/44,  HATED IT,  not enough power to pull 5th gear at all,  lost top speed,  and it would just speed up very slowly,  could not wait to take off the 16t front,  one thing abut the 16/44 combo,  it turned 4th gear into a complete BEAST,  man 4th gear had tons of power and could get into the 70's in a blink of an eye,  5th gear however suffered way too much.

 

Thanks for the info Ron!!!

NP man,  glad some are finding this info useful,  it took a lot of time, to get allt his done believe it or not,  and after each speed i had to pull over and stop,  and write it down,  then start up and continue to the next speed. 

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Yep,  i did the same,  changed the front to a 16 when i was in S trim,  so instead of stock 15/44,  i went to 16/44,  HATED IT,  not enough power to pull 5th gear at all,

 

The S 18" rear wheel @16/44t .......would be like running 17/44t with a 17" SM wheel....

 

I run 15/41 on the E for road use (which is the same as 16/44) and pulls peak power in 5th no problem...The beauty of the added dimension a Big Bore provides...

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I can't believe my SM will make 100mph - 160kmh one day...not even 155kmh. May be 150 kmh but not yet.

 

I have acewell gauge. I believe it shows correct bec. when I measure distance, it shows %1 shorter. So, It calculates speed: distance/time, I think speed it true too... Uses front wheel.

 

I will write down my speed/rpm values later.

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If you guys haven't already done so, check out www.gearingcommander.com

Lets you see rpm/speed charts for any sprocket sizes

Edited by Gsxrstuntdrz
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I'm running 15/38 on my S with SM wheels, no complaints. FCR 39 (non-mx), Stage 2 Hot Cams, RS2 (open). Flat road, tucked, I can hit the rev-limiter in 5th gear, and I'm 250 lbs.

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Here we go,, I came from ride-highway.

 

My acewell says;

 

60 mph - 5900 rpm

70 mph - 6900 rpm

80 mph - 7900 rpm

85 mph - 8400 rpm

 

I can't go faster, mostly bike doesn't let me.  :naughty:   It is sad, I can't reach 9000 rpm and over... It was easier to reach(but can't pass) to 9000 before maintenance. I made valve clearance, carb cleaning and change main jet from 155 to 150 on maintanence.

 

What ever, my setup; 15/41 sprockets, 160/60-17 RScorsa rear tyre. And this "Gearing commander" says I can make;

 

61.7 mph @5900 rpm --- mine shows ~2.8% less

72.1 mph @6900 rmp ---   ""    ""         ~3.0% less

82.6 mph @7900 rpm ---   ""    ""         ~3.3% less

87.8 mph @8400 rpm ---   ""    ""         ~3.3% less

 

You have rev limiter @10.000 rpm(which we don't have on europe) so I suppose DRZ get in red line @9.000 rpm by myself  :rolleyes:

 

And I wondered what my bike can do maximum, and gearing commander says again;

 

94.1 mph - 9000 rpm

99.3 mph - 9500 rpm

104.6 mph - 10000 rpm

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Here we go,, I came from ride-highway.

 

My acewell says;

 

60 mph - 5900 rpm

70 mph - 6900 rpm

80 mph - 7900 rpm

85 mph - 8400 rpm

 

I can't go faster, mostly bike doesn't let me.  :naughty:   It is sad, I can't reach 9000 rpm and over... It was easier to reach(but can't pass) to 9000 before maintenance. I made valve clearance, carb cleaning and change main jet from 155 to 150 on maintanence.

 

What ever, my setup; 15/41 sprockets, 160/60-17 RScorsa rear tyre. And this "Gearing commander" says I can make;

 

61.7 mph @5900 rpm --- mine shows ~2.8% less

72.1 mph @6900 rmp ---   ""    ""         ~3.0% less

82.6 mph @7900 rpm ---   ""    ""         ~3.3% less

87.8 mph @8400 rpm ---   ""    ""         ~3.3% less

 

You have rev limiter @10.000 rpm(which we don't have on europe) so I suppose DRZ get in red line @9.000 rpm by myself  :rolleyes:

 

And I wondered what my bike can do maximum, and gearing commander says again;

 

94.1 mph - 9000 rpm

99.3 mph - 9500 rpm

104.6 mph - 10000 rpm

Thanks for the info,   we are running the same gearing (15/41) i wonder why your bike is at about 500 RPM'S higher then mine at the same speed?

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Different height-profile (Aspect ratio) front tyres ?

Hmm, i dunno,  the RPM tacho i have wraps around the spark plug wire and that is how it picks up engine RPM'S,    not sure why his is 500 rpm's higher then mine using the same gearing,  maybe rider weight?   :excuseme:

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Waiting on you to return.    :smirk:

chame sold his drz and bought an fz07. no idea why. he owned the drz and now hes financing the other bike. he doesnt even go anywhere anyway. so ill be the only one i know of out there with an sm. you'd be the next closest. the other guy i know had his stolen last year and the guy that chame rode with sold his too and bought the exact same bike as chame. $8200 for a bike seems too much for me. At least for now when i have no need for one. when i get back i'll be having to go to los alamitos to fly at least a couple times a month. it might be worth it then but i think id still get the fz09...

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