Go Back   EcoModder Forum > EcoModding > Motorcycles / Scooters
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 07-02-2020, 06:16 PM   #31 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,442

spyder2 - '00 Toyota MR2 Spyder
Thanks: 90
Thanked 267 Times in 204 Posts
Uh wait, how are emissions standards pushing compression ratios down? CBR-1000RR is at 13:1. NOx aftertreatment is mandatory, not an option.

I did forget the earlier bikes were carbed and have no cats, so that's one less handicap to make up for the poor fueling control. Still, if the ZX6R is making 200 hp/L, I was hoping for the same from the ZX25R. I guess it's hard to win against friction.

I would think that gear driven camshafts are actually more likely because the stroke is short. It probably has around 35mm stroke, 75mm of connecting rod, so it's around 115mm to the valves from the crank, which I would think you can span with a single gear.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 07-02-2020, 06:22 PM   #32 (permalink)
It's all about Diesel
 
cRiPpLe_rOoStEr's Avatar
 
Join Date: Oct 2012
Location: Porto Alegre, Rio Grande do Sul, Brazil
Posts: 8,118
Thanks: 0
Thanked 881 Times in 781 Posts
Quote:
Originally Posted by serialk11r View Post
I would think that gear driven camshafts are actually more likely because the stroke is short. It probably has around 35mm stroke, 75mm of connecting rod, so it's around 115mm to the valves from the crank, which I would think you can span with a single gear.
Considering that even Toyota 1HZ and 1HD engines which are considerably larger had only 3 gears for the valvetrain timing (OHC), it makes sense.
  Reply With Quote
Old 07-03-2020, 11:43 AM   #33 (permalink)
EcoModding flying lizard
 
Daschicken's Avatar
 
Join Date: May 2012
Location: Georgia
Posts: 723

Cibbie - '88 Honda CBR 250R
Motorcycle
90 day: 51.54 mpg (US)

Rarity - '06 Honda Accord EX V6
Team Honda
90 day: 38.1 mpg (US)

Baby viff - '86 Honda VFR 400R
Motorcycle
90 day: 42.15 mpg (US)

Latios - '08 Suzuki SV650SF
Motorcycle
90 day: 64.87 mpg (US)
Thanks: 561
Thanked 253 Times in 171 Posts
Quote:
Originally Posted by serialk11r View Post
Uh wait, how are emissions standards pushing compression ratios down? CBR-1000RR is at 13:1. NOx aftertreatment is mandatory, not an option.

I did forget the earlier bikes were carbed and have no cats, so that's one less handicap to make up for the poor fueling control. Still, if the ZX6R is making 200 hp/L, I was hoping for the same from the ZX25R. I guess it's hard to win against friction.

I would think that gear driven camshafts are actually more likely because the stroke is short. It probably has around 35mm stroke, 75mm of connecting rod, so it's around 115mm to the valves from the crank, which I would think you can span with a single gear.
Well, I suppose they could make it work with high compression, but I would expect a much higher HP number with higher compression. The top dollar bikes can get high compression. The CBR600 is sitting around 12.2:1. So the development goes where the money is.

Gear driven cams sound awesome, and are Uber reliable, but cancels any thought of head milling. So they are good and bad. I wouldn’t really mind either way, slight preference to gear driven cause I really doubt I would be tearing the engine down any time soon.
__________________
-Kaze o tatakaimasen-

Best trip in V6: 52.0
Best tank in V6: 46.0
Best tank in CBR: 61.3
Best tank in VFR: 62.5
Best tank in SV: 83.9

Quote:
Originally Posted by MetroMPG View Post
You can lead a fashion-conscious horse to unusual-looking water...

  Reply With Quote
Old 07-04-2020, 08:23 AM   #34 (permalink)
Master EcoModder
 
Join Date: Jan 2011
Location: Iowa
Posts: 1,129

Impala FFV - '10 Chevy Impala LT
90 day: 29.54 mpg (US)

XFE Coupe - '09 Chevy Cobalt XFE
Team Chevy
90 day: 37.68 mpg (US)

Penny's Rogue - '15 Nissan Rogue SL AWD
90 day: 29 mpg (US)

Cam's Rogue - '11 Nissan Rogue SV AWD
90 day: 26 mpg (US)

Elantra - '17 Hyundia Elantra SE
Team Hyundai
90 day: 44.68 mpg (US)

Cruze Limited - '16 Chevy Cruze Limited LT
90 day: 30 mpg (US)
Thanks: 268
Thanked 216 Times in 183 Posts
I wasn't aware of any gear driven OHC bikes except for VFR. And I think that only happened because they had some problems with how long the timing chain was for a V4. That stared in late 80's with the VFR750 later 800. I had a 83 V45 Interceptor a short time. Does you 400 have gear drive?
  Reply With Quote
Old 07-04-2020, 08:50 PM   #35 (permalink)
EcoModding flying lizard
 
Daschicken's Avatar
 
Join Date: May 2012
Location: Georgia
Posts: 723

Cibbie - '88 Honda CBR 250R
Motorcycle
90 day: 51.54 mpg (US)

Rarity - '06 Honda Accord EX V6
Team Honda
90 day: 38.1 mpg (US)

Baby viff - '86 Honda VFR 400R
Motorcycle
90 day: 42.15 mpg (US)

Latios - '08 Suzuki SV650SF
Motorcycle
90 day: 64.87 mpg (US)
Thanks: 561
Thanked 253 Times in 171 Posts
Quote:
Originally Posted by roosterk0031 View Post
I wasn't aware of any gear driven OHC bikes except for VFR. And I think that only happened because they had some problems with how long the timing chain was for a V4. That stared in late 80's with the VFR750 later 800. I had a 83 V45 Interceptor a short time. Does you 400 have gear drive?
Yes, both the 400 and my 250 have gear driven cams.

Some other bikes I know have gear driven cams:
1986-1997 VFR750
1998-2001 VFR800
1986-1996 CBR250 various models
1989-1990 CB-1
1986-1996 VFR/RVF 400 various models
__________________
-Kaze o tatakaimasen-

Best trip in V6: 52.0
Best tank in V6: 46.0
Best tank in CBR: 61.3
Best tank in VFR: 62.5
Best tank in SV: 83.9

Quote:
Originally Posted by MetroMPG View Post
You can lead a fashion-conscious horse to unusual-looking water...

  Reply With Quote
The Following User Says Thank You to Daschicken For This Useful Post:
roosterk0031 (07-07-2020)
Old 07-05-2020, 10:09 PM   #36 (permalink)
It's all about Diesel
 
cRiPpLe_rOoStEr's Avatar
 
Join Date: Oct 2012
Location: Porto Alegre, Rio Grande do Sul, Brazil
Posts: 8,118
Thanks: 0
Thanked 881 Times in 781 Posts
Quote:
Originally Posted by Daschicken View Post
1986-1996 CBR250 various models
I was only aware of these and the Hornet 250 fitted with the same engine.

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com