Topic: Bigger carbs for CB350 (twin)?

[oconnor]

What works? CB450 carbs? Anywebsites listing carb sizes for different year/models?
My buddy has a Norton he thinks will stomp anything short of a four. I took that as a challenge to my little Hondas honor. I don't want to get into the motor if I don't have to and the Norton doesn't run all that great.

[RRRToolSolutions]

Which Norton? The 750's made more than 60 horsepower and your 325cc makes 36 at 9,000 (at best). You might need a supercharger or nitrous on the other side of those new carbs....

[CBGBs]

The CB350 twin is a great little bike. I love mine and I've been using CB500t carbs. The carbs are of the same size and carb body of the CB450 carbs. To make these fit you will have to get a pair of carb mounting boots from a CB360 and trim some of the boot to allow these larger carbs to slid in and seal properly. Then you will have to re-jet and voila, you have upgraded your carbs.

I would consider selling my setup to you. Clean working carbs with proper jets and the mounting boots.

[oconnor]

There is no freakin way this Norton makes more than 60 hp! Maybe 50.

CBCB, PM me your price so I can think it over.

[cb650]

The 350 should be 100# lighter so you wouldnt have match the HP.



                              Terry

[mlinder]

The 350 should be 100# lighter so you wouldnt have match the HP.



                              Terry

For top speed you would...

A well tuned Norton 750 should keep up with a cb750 with very little trouble.
a cb350 twin, well, I dunno, I don't see it happening...

[cb650]

I dont think you would.   More weight needs more power to push.  Now if your bike will red line in top gear no the weight isnt as much of a issue but if if it tops out at anything less lighter is better.
  Then lets include the drag of a bigger bike.   It might only be 2/3 hp in each but it adds up.   
Then lets think of 100# less in turns.




                  Terry   

[RRRToolSolutions]

Here is a 1971 article listing the available bikes and their stats. The 1970 CL-450 SS was the hottest twin Honda ever made. It was no match for the Nortons. I wouldn't expect it to be. The Norton's made more horsepower than the Honda CB750, their superior performance on the strip proves it. I just don't know why your neighbor's doesn't run better. If half decent, it will eat the 350 (and at twice it's size - should).

My best friend had a Harley ElectraGlide. 74 cubic inches of mass. No pwer, just mass. Now my CB350 would outrun him in every contest you could think of. The thing I'll never forget is that his was just about as fast with 2 people as it was with one. Put 2 on mine and he could leave me. It's all about power to weight. As a percentage, 2 people didn't change his much.

Enjoy the chart -

[mlinder]

I dont think you would.   More weight needs more power to push.  Now if your bike will red line in top gear no the weight isnt as much of a issue but if if it tops out at anything less lighter is better.
  Then lets include the drag of a bigger bike.   It might only be 2/3 hp in each but it adds up.   
Then lets think of 100# less in turns.




                  Terry   

Weight has nothing to do with top speed.
Top speed is a function of horsepower and drag coefficcient.
a 2000 lb bike with the same aero as a 500 lb bike, both with 50 hp, will reach the same top speed. The 500 lb bike will just do so more quickly.

[Peterbylt]

My friend had a 71 Norton Commando 650.
I have a 75 550four Supersport.
We used to run almost exactly even.

[cb650]

   

Weight has nothing to do with top speed.
Top speed is a function of horsepower and drag coefficient.
a 2000 lb bike with the same aero as a 500 lb bike, both with 50 hp, will reach the same top speed. The 500 lb bike will just do so more quickly.

     OK lets go extrems here.   My 360 will do 90 if I take the motor out and put it in my van it will do 90 still.
I dont believe it would with a 100 mph tail wind.    I understand what your saying but off paper in the real world it dont hold up.   Like all the test articles that calculated top speed 1/4 mile times.  Much diffrent than actually doing it. 




                                  Terry

[bill440cars]

           I'd like to know if the Norton is a Commando, Atlas, Dominator or what? Is it a 650, 750 or 850?
      All this makes a difference. What shape is it in. If it's runny "Crappy", He needs his Butt kicked for
      letting it get in such poor shape and still be riding it. The same goes for anyone who would ride a
      bike that is in need of repair.

                                                              Later on, Bill

[mlinder]

   

Weight has nothing to do with top speed.
Top speed is a function of horsepower and drag coefficient.
a 2000 lb bike with the same aero as a 500 lb bike, both with 50 hp, will reach the same top speed. The 500 lb bike will just do so more quickly.

     OK lets go extrems here.   My 360 will do 90 if I take the motor out and put it in my van it will do 90 still.
I dont believe it would with a 100 mph tail wind.    I understand what your saying but off paper in the real world it dont hold up.   Like all the test articles that calculated top speed 1/4 mile times.  Much diffrent than actually doing it. 




                                  Terry

No, because your van does no have the same drag coefficient. If it did, then yes, top speed would be the same. Paper, real world, both the same. Top speed is ONLY a function of drag coefficient, frontal space and horsepower. All things being equal besides weight, top speed is absolutely the same. Not paper. In real life.

/edit:

please see this thread: http://www.sohc4.us/forums/index.php?topic=12898.msg124798#msg124798

[dusterdude]

           I'd like to know if the Norton is a Commando, Atlas, Dominator or what? Is it a 650, 750 or 850?
      All this makes a difference. What shape is it in. If it's runny "Crappy", He needs his Butt kicked for
      letting it get in such poor shape and still be riding it. The same goes for anyone who would ride a
      bike that is in need of repair.

                                                              Later on, Bill

bill,calm down dude,it will get better

[cb650]

.

     OK lets go extrems here.   My 360 will do 90 if I take the motor out and put it in my van it will do 90 still.
I dont believe it would with a 100 mph tail wind.    I understand what your saying but off paper in the real world it dont hold up.   Like all the test articles that calculated top speed 1/4 mile times.  Much diffrent than actually doing it. 




                                  Terry

No, because your van does no have the same drag coefficient. If it did, then yes, top speed would be the same. Paper, real world, both the same. Top speed is ONLY a function of drag coefficient, frontal space and horsepower. All things being equal besides weight, top speed is absolutely the same. Not paper. In real life.

/edit:

please see this thread: http://www.sohc4.us/forums/index.php?topic=12898.msg124798#msg124798

I know drag thats why I added the 100mph tail wind or did you not see that.   Also with more weight you will have more resistance in bearings and tires. 



                            Terry

[mlinder]

I hate to put this off topic, but here is the deal.
It doesn't matter how light you make the CB. It will not make the top end any faster. period.
Top speed is a matter of HP and CDa
Acceleration (how long it takes you to get to top speed) is a matter of weight, CDa and HP.
Nothing you do outside of increasing horsepower or decreasing drag will give you a higher topend. If the CB weighed 1 pound, it would still not have a faster top speed than it does now.
Friction from tires and bearings are not really a factor in these kinds of applications, assuming tires and bearings are in good working shape and the tires are at good psi..
You CANNOT increase top speed in any measurable way by reducing weight. Not on paper, and not in the real world.

[TomC]

Hi
     Assuming that we are talking about top speed given all the room in the world. Not trap speed at the end of a quarter mile. Weight is a very small factor.
     The service column in Cycle World or one of there competitors wrote about this some time in the last year or so.

[oconnor]

I didn't mean to cause a stir guys. His Norton runs alright. I've only seen it run a couple times, he just bought it this summer. I don't know displacement for sure, I thought 650.