« previous next »
Pages: [1]   Go Down

Author Topic: CB350F vs. CB400F  (Read 3196 times)

0 Members and 1 Guest are viewing this topic.

Offline andyman

  • Full Member
  • *
  • Posts: 60
CB350F vs. CB400F
« on: May 21, 2018, 03:43:32 AM »
Hi Guys!
I am Andy from Austria and i have build a 350F Racer by myself. The competitor has CB400F Stock engines with open carburettors and open Megaphones 4 into 4.

My engine is a CB350F with open carburettors and also the same 4 into 4 open Megaphones as the 400F, but modified by head tuning and a WebCam Stage1 Camshaft.
Pistons are original standard. So what do you think, could i have the same hp as the stock 400F or maybe more?

Thanks and greets!

Andy
Logged

Offline Old Scrambler

  • My CB750K3 has been in 39 States & 5 Provinces
  • Old Timer
  • ******
  • Posts: 3,807
Re: CB350F vs. CB400F
« Reply #1 on: May 21, 2018, 06:48:25 PM »
The 400 has larger valves so I would GUESS it will have more power than the 350............
Logged
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
'73 750K3 Owned since New
'77 750F2 Cafe Project
2020 ROYAL ENFIELD Himalayan

Offline turboguzzi

  • Old Timer
  • ******
  • Posts: 4,084
Re: CB350F vs. CB400F
« Reply #2 on: May 22, 2018, 02:53:28 AM »
not sure you like to hear this, but unless you are limited by 350 displacement or some cut off year for your class, most people would opt for the 400 as a base for a race motor.... has also 6 gears too...
as a 350 it will be spanked by the well developed and light 350K4 twins, no wonder nobody races them.
i think only Hansen honda build a serious 350-4 but it was more of a "Hailwood" parade bike

http://www.teamhansenhonda.com/hailproj.htm
 
Logged

Offline Sam Green Racing

  • Moderator
  • Really Old Timer ...
  • *****
  • Posts: 16,068
  • I REALLY? hate black rims.
Re: CB350F vs. CB400F
« Reply #3 on: May 22, 2018, 06:22:56 AM »
Like the guys say here Andy, I doubt you will get anywhere near some of the serious teams.
But saying that, depending on how good the cam and head job are, you could be close to the stock motor CB400.
Your motor when stock was only 3 bhp down on the stock 400 and stock, the 350 was about 34 lbs lighter.
Higher compression pistons will help also and shouldn't break the bank.
If you're new to racing, good luck mate and ride safe.

Sam. ;)
Logged
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline andyman

  • Full Member
  • *
  • Posts: 60
Re: CB350F vs. CB400F
« Reply #4 on: May 22, 2018, 09:22:06 AM »
Thanks for your answers!

The cam is for using stock valve springs, headwork was a lot of hours. I will see it on Racetrack next time.

Yes the 350K Twins are very quick i know, i have also a Twin but nearly stock engine. A little bit more compression and headwork, bigger carburettors and bigger exhaust than stock.
The Twin is about 20kg lighter than the Four.....
Logged

Offline carnivorous chicken

  • Master
  • *****
  • Posts: 1,837
Re: CB350F vs. CB400F
« Reply #5 on: May 22, 2018, 09:37:31 AM »
Quote from: turboguzzi on May 22, 2018, 02:53:28 AM

i think only Hansen honda build a serious 350-4 but it was more of a "Hailwood" parade bike

http://www.teamhansenhonda.com/hailproj.htm

That is one nice looking 350F!
Logged

Offline andyman

  • Full Member
  • *
  • Posts: 60
Re: CB350F vs. CB400F
« Reply #6 on: May 23, 2018, 09:16:51 PM »
Yes this Four is a beautiful bike, but there was a lot of work i think.

When i understand this they use a 400Four crankcase with a 350Four cylinder and head.
Logged

Offline innovativems

  • Expert
  • ****
  • Posts: 1,029
    • Innovative MotoSports
Re: CB350F vs. CB400F
« Reply #7 on: May 23, 2018, 09:24:07 PM »
The other item is the transmission is better in the 400.  That extra gear helps


Sent from my iPhone using Tapatalk
Logged
2007 KTM 990 adv
2003 Honda RC51
2000 Yamaha YSR50
1978 Honda Express
1975 Honda CB400f
1974 Honda CB350f
1974 Kawi H2
1974 Honda CB550f
1971 Kawi h1
1973 Kawi h1
1974 gt 550
1974 gt550

Offline andyman

  • Full Member
  • *
  • Posts: 60
Re: CB350F vs. CB400F
« Reply #8 on: May 24, 2018, 06:55:47 AM »
Yes it is, but the 5Speed 350Four gearbox holds more power because the gears are wider.
Logged

Offline innovativems

  • Expert
  • ****
  • Posts: 1,029
    • Innovative MotoSports
Re: CB350F vs. CB400F
« Reply #9 on: May 24, 2018, 09:24:05 AM »
Quote from: andyman on May 24, 2018, 06:55:47 AM
Yes it is, but the 5Speed 350Four gearbox holds more power because the gears are wider.

The six speed allows you to keep the motor in the right rpms better.  With the smaller cc they like to stay I. Their sweet spot vs lugging them and driving out.  It's the same for people with the cb500 vs cb550 racers back in the day.


Sent from my iPhone using Tapatalk
Logged
2007 KTM 990 adv
2003 Honda RC51
2000 Yamaha YSR50
1978 Honda Express
1975 Honda CB400f
1974 Honda CB350f
1974 Kawi H2
1974 Honda CB550f
1971 Kawi h1
1973 Kawi h1
1974 gt 550
1974 gt550

Offline turboguzzi

  • Old Timer
  • ******
  • Posts: 4,084
Re: CB350F vs. CB400F
« Reply #10 on: May 24, 2018, 10:30:07 AM »
the intention was good but both the 500 and 500 have 5spd boxes ;)
andy, in theory you are right, in practice, the 400 6spd is a fine box.
we had a few tuned, pumped to 500c.c. 400F in our championship and never seen one out with gearbox issues even with all the extra power.
the rods are the 400F weak point, seen at least two explode, in one case even went through the oil cloud myself when following with my 500-4 :) can still remember the sound of the 400 engine shrieking in front and then go trr-trr-trr! like bones of a skeleton being crushed.... 
Logged

Offline andyman

  • Full Member
  • *
  • Posts: 60
Re: CB350F vs. CB400F
« Reply #11 on: May 24, 2018, 12:59:18 PM »
So another question.

I have another 350F engine. The plan is to put on this 350 engine a 400F cylinder and head with 466ccm big bore kit, headwork and a WebCam Stage1 camshaft. Is that possible?
Logged

Offline turboguzzi

  • Old Timer
  • ******
  • Posts: 4,084
Re: CB350F vs. CB400F
« Reply #12 on: May 24, 2018, 01:51:26 PM »
ttr400 is a member here and super knowledgeable about 350s too. PM him or go to his site: ttr400.com
Logged

Offline jakec

  • Master
  • *****
  • Posts: 2,075
Re: CB350F vs. CB400F
« Reply #13 on: May 24, 2018, 02:06:55 PM »
Quote from: turboguzzi on May 22, 2018, 02:53:28 AM
not sure you like to hear this, but unless you are limited by 350 displacement or some cut off year for your class, most people would opt for the 400 as a base for a race motor.... has also 6 gears too...
as a 350 it will be spanked by the well developed and light 350K4 twins, no wonder nobody races them.
i think only Hansen honda build a serious 350-4 but it was more of a "Hailwood" parade bike

http://www.teamhansenhonda.com/hailproj.htm

This has been for sale in my area for a while:

https://vancouver.craigslist.ca/rds/mcy/d/honda-rc162-tribute/6593001317.html
Logged
1970 CB750 K0
1977 CB750 Chop
1997 XR650L

Offline andyman

  • Full Member
  • *
  • Posts: 60
Re: CB350F vs. CB400F
« Reply #14 on: May 31, 2018, 06:18:47 AM »
So guys another question. Is it possible to put a 6 speed 400 gearbox into the 350 crankcase?
Logged
Pages: [1]   Go Up
« previous next »