MotoSport









FUNDRAISER!
We need to cover DirtRider's expences
for the next year.
Every little bit helps!



80cc Dyno Charts Here

nikki

Moto Junkie
Joined
Apr 21, 2000
Messages
5,802
Likes
0
#1
All of these debates about the 80 motors are getting a little old. I think looking at the dynos of each 80 should help show which are good for low-end (mainly KX and RM because of powervalves) and which are strong mid and up. These dyno charts are from the FMF site - www.fmfracing.com

The blue line is the stock pipe/silencer and the red line is with the FMF REV pipe and silencer.
 
Q: Where are the best deals on moto gear?
- a d v e r t i s e m e n t -

nikki

Moto Junkie
Joined
Apr 21, 2000
Messages
5,802
Likes
0
#6
So... just based on the FMF dyno charts ONLY, here are some raw numbers:

Most HP at:

6k RPMs - RM/KX/YZ (5 HP)
7k RPMs - RM/KX/CR (6 HP)
8k RPMs - KX (11 HP)
9k RPMs - YZ (15 HP)
10k RPMs - YZ (18 HP)
11k RPMs - RM/KX/CR (19 HP)
12k RPMs - CR (18 RPMs)

Least HP at:

6k - CR (4 HP)
7k - YZ (5 HP)
8k - CR (6 HP)
9k - CR (12 HP)
10k - CR/KX (16 HP)
11k - YZ (18 HP)
12k - YZ (12 HP)

Greatest Peak HP - RM/KX/CR all 19 HP @ 11,000 RPMs

So just some numbers to throw out there. :confused:
 
Q: Where are the best deals on moto gear?

HiG4s

Subscriber
Joined
Mar 7, 2001
Messages
1,308
Likes
0
#9
Interesting but not really applicable to any thing but the Honda.
All the Dyno runs are on 80s, Kaw beefed up their engine up to 85cc two years ago and the RMs and YZs went to 85cc this year so all this data is presumably from the 2000 models or at the latest the 2001s on the RMs and YZs.
This is the reason I won't buy a pipe for a new mini, they obviously do not do any research on the minis the year they come out so it is quite possible the stock pipe is as good or better than the after market.
 
Q: Where are the best deals on moto gear?
- a d v e r t i s e m e n t -

Joined
Dec 2, 2001
Messages
1,512
Likes
0
#11
"Interesting but not really applicable to any thing but the Honda."

2 cc's arent going to make any difference whatsoever!
 
Joined
Apr 10, 2002
Messages
322
Likes
0
#12
sounds like nikki knows what she's talkin about hehe most girls dont even know what a frickin spark plug is :) i had a 99 yz80 it was a good bike it just lacxked alot of low-end power but top end overrev, outstanding, the bike had to be revved out alot and the clutch had to be fanned alot to keep the rpm's up
 
Q: Where are the best deals on moto gear?

HiG4s

Subscriber
Joined
Mar 7, 2001
Messages
1,308
Likes
0
#13
Originally posted by dell30rb
"Interesting but not really applicable to any thing but the Honda."

2 cc's arent going to make any difference whatsoever!
First that is not true, but assuming you meant "any APPRCIABLE difference whatsoever" with no other changes you may be correct, but with both Yamaha and Suzuki making porting and pipe changes along with the 2cc's my statement stands as dyno runs on 2000 80cc machines may very well have little relation to 2002 85 actually figures.

Also what year did Kaw add the power-valve to the mini, 'cause that KX80 graph looks a lot like a non-power-valve profile.
 
Last edited:
- a d v e r t i s e m e n t -

OKKX'er

Lifetime Sponsor
Joined
Sep 10, 2001
Messages
713
Likes
0
#14
The rules for the 80 class have always been 85cc (to allow for boring cast liners in the olden days), and the bikes have been 83cc since the nikasil liners stock. Our '01 YZ80 is 82.9cc. The 85 bit is all PR.
 
Joined
Nov 17, 1999
Messages
93
Likes
0
#15
Nikki, I think the only chart that is valid is the cr80 one.
okkx'er, the yz80 and the yz85 are very different motors:

ALL New for 2002!

Engine:

The industry’s mightiest mini gets an all-new lightweight, liquid-cooled two-stroke engine’s capacity increased from 83 to 85cc (bore x stroke = 47.5 x 47.8mm) to deliver even harder-hitting, moto-winning power throughout the RPM range.
Crankcase features reshaped scavenging port for reduced horsepower loss and improved mid-range and top-end output.
Crankcase reed valve induction and 28mm Keihin flat-slide carburetor ensures seamless throttle response across the powerband, while all-new, aluminum carb body helps reduce weight.
New-design digital CD ignition system puts out a more precise spark and monitors engine speed to ensure optimal timing for quicker, stronger response during hard acceleration.
Smooth-shifting, 6-speed transmission features new-design main and drive axles, while all-new, heavy-duty, multi-plate clutch delivers maximum hook-up for outstanding acceleration and corner-exiting power.
All-new, involute spline set-up in clutch means smoother shifting under power with greater durability at competition-level usage.
All-new clutch cover features a sub-cover for easy access during maintenance.
Gearbox features a new-design shift shaft for smoother shifting feel with no spring friction.
All-new, lightweight radiator has larger cores and more louvers, while retooled water pump features a cast aluminum (vs. resin) impeller to ensure maximum cooling efficiency — and minimal horsepower loss.
New, lightweight exhaust system design with a reshaped tapered section helps create a broader powerband with stronger low-end punch.
New airbox design with reshaped filter ensures greater air cleaning performance and easier maintenance.
Primary kickstarting features a reshaped lever with a sealed pivot to keep out water and mud, enhancing durability.
 
Last edited:
- a d v e r t i s e m e n t -

Q: Where are the best deals on moto gear?