Author Topic: Is this possible on a CB?? (Read 7779 times)

samfig · « **on:** January 04, 2007, 12:13:58 PM »

Hey guys,

I was looking around the web to get some ideas on how I want my 1974 CB 750 to turn into a cafe racer and I stumbled across this picture from BCR's web site. Its a Yamaha but I like what they did with the exhaust. Do you guys think this is possible to do with a CB 750 engine and frame? If so, have any of you guys seen any pictures of a CB with this type of exhaust modification or know of anyone who has done something similar to their CB??

I'm gonna play around on photo shop when I have a chance and see what I come up with.

I can't seem to add a picture so follow the link to see what I'm talking about.

http://www.benjiescaferacer.com/undrconstr.html

DammitDan · « **Reply #1 on:** January 04, 2007, 12:16:40 PM »

To add a picture type [ img]www.file's web location.com[/img ]

And yeah, I have seen it before although it wasn't quite as well executed as that yammy

If you're into that kinda modern sportbike look on a classic, go for it!

DME · « **Reply #2 on:** January 04, 2007, 12:24:22 PM »

Well, anything is possible.
You´ll have to relocate the battery, eletrical system, and oiltank though.
Could turn out rather difficult, but, anything is possible.....

Cheers
Daniel

ProTeal55 · « **Reply #3 on:** January 04, 2007, 01:17:16 PM »

As DME said, anything is possibile.
If I end up keeping the CB450, I plan to run an exhaust similar becasue now I have no
sidecovers to deal with !

I am sure jetting a bike with pipes like that is a blast

DammitDan · « **Reply #4 on:** January 04, 2007, 01:25:43 PM »

Superheated air from the pipes already circulating around the intakes... Hmmm....

736cc · « **Reply #5 on:** January 04, 2007, 01:32:19 PM »

Carpy did something like that....wild

eldar · « **Reply #6 on:** January 04, 2007, 01:47:51 PM »

Well as a question. Do the pipes need to be round? I mean why not move what you need to, figure out the routing then make the pipe oval or something where it can be placed closer to the frame. or even make it wide and almost flat. I mean, when you do something liek that, you are already bending the pipes around things, it would not really add any detrimental effects to flatten the pipe out to allow better fitting.

ProTeal55 · « **Reply #7 on:** January 04, 2007, 02:13:20 PM »

Oval exhaust is used allot on racecars and streetcars where ground clearance is an issue.
As long as the diameter of the pipe itself is the same, you should be ok..

samfig · « **Reply #8 on:** January 04, 2007, 03:33:48 PM »

Oval pipes ... flattening out pipes ... you guys are giving me crazy ideas for the drawing board. I'm going to have to sketch some stuff out before I really start anything, though.

Does anyone know of a shop in the Chicago land area that could custom make something if I gave them a sketch?

ProTeal55 · « **Reply #9 on:** January 04, 2007, 04:07:12 PM »

S & S Chassis in Franklin Park, IL
(5 Min from O'Hare airport)
847.678.3000
Ask for Nayel (like the river nile)
He is a good friend of mine, and built my old racecar from scratch...

He can build you whatever u want, from whatever u want (steel-chrome-moly-alum.-etc)
Good guy to know...

eurban · « **Reply #10 on:** January 04, 2007, 06:08:47 PM »

Anyone ever see that episode of Biker Buildoff where dreadlocked Billy Lane rode some serious miles on his chop with an underseat exhaust. His pants literally caught on fire a good ways into the trip. Undertail exhausts do look cool but may not be worth the work particularly if you are going to be spending a good amount of time in the saddle. I'm sure you could insulate the seat to a certain exent but this will add to an already complex project, and even so count on the boys being a being nice and toasty . . . .

aptech77 · « **Reply #11 on:** January 04, 2007, 06:15:21 PM »

It only take time, money and the balls to do WHAT EVER YOU WANT..............

paulages · « **Reply #12 on:** January 04, 2007, 07:34:16 PM »

i've thought a lot about making a similar exhaust on a sohc4, as i've seen a lot of the local formula 160 guys do this, and think it looks awesome. problem is, with a 750 the engine is so goddamn wide, you end up with some serious routing issues to clear the engine, carbs, and frame and still allow for leg room. i'd definitely use a 4-1 or 4-2 collector. heat? no problem---just wrap it. i still haven't given up on the idea, but might save it for a 550, rather than the 750 i'm working on.

mrbreeze · « **Reply #13 on:** January 04, 2007, 11:43:39 PM »

Back in the day,many a scooter had high pipes although the only ones that come to mind are twins. That one from Carpy just don't cut it with me but I'm sure something could be done with a 4 banger. I would just like to see someone come up with a low 4to4 stainless setup. I liked the Magnas with the 4 upswept tailpipes. Why can't someone make those to fit an SOHC so that we don't have to pay mega $$ to buy HM300&341's that will also turn to crap before thet should.

samfig · « **Reply #14 on:** January 05, 2007, 07:39:07 AM »

I figure its going to be a pretty penny but does anyone have a ball park on what something like this would cost??

burmashave · « **Reply #15 on:** January 05, 2007, 07:50:06 AM »

Quote from: eurban on January 04, 2007, 06:08:47 PM

Anyone ever see that episode of Biker Buildoff where dreadlocked Billy Lane rode some serious miles on his chop with an underseat exhaust. His pants literally caught on fire a good ways into the trip. Undertail exhausts do look cool but may not be worth the work particularly if you are going to be spending a good amount of time in the saddle. I'm sure you could insulate the seat to a certain exent but this will add to an already complex project, and even so count on the boys being a being nice and toasty . . . .

I remember that episode, and I was wondering about a new meaning for "hot *ss."

On the other hand, it seems that if you designed it properly, heat wouldn't be an issue. I don't have experience with something like this; however, if I were to design it, I'd try to keep metal between the pipes and seat to a minimum (mebbe use hangers and use holes in the seat pan metal through which the pipes would protude but not actually be attached to). That's likely why he's got the pipe fittings on the ends of the pipes. It seems that conceal the fact that the pipes are substantially smaller than the holes in the seat pan that they run through. Also, from the design in the pic above, it appears as if the pipes have good air space betwen the seat and pipes. Insulating material under the seat pan would help.

And if you guys have already figured this out, I apologize for stating the obvious.

ProTeal55 · « **Reply #16 on:** January 05, 2007, 08:13:48 AM »

Quote from: samfig on January 05, 2007, 07:39:07 AM

I figure its going to be a pretty penny but does anyone have a ball park on what something like this would cost??

It would just be a time(labor) & materials.
The more and more I think about this the more I wanna make something like this
work on my cb450 project...

paulages · « **Reply #17 on:** January 05, 2007, 08:39:18 AM »

there's probably another good reason why he has it wrapped...those are some hard welds to get good-looking. you can buy elbows and weld whatever angle you want (easier than bending, apparently).

Jinxracing · « **Reply #18 on:** January 05, 2007, 10:33:25 AM »

I think Benji's been lusting after Ducatis...

ProTeal55 · « **Reply #19 on:** January 05, 2007, 10:40:06 AM »

Quote from: Jinxracing on January 05, 2007, 10:33:25 AM

I think Benji's been lusting after Ducatis...

Their was one of these bikes at the Mods Vs. Rockers show this past summer.
Wicked design (especially the pipes)...

Rsnip988 · « **Reply #20 on:** January 06, 2007, 02:34:56 AM »

Quote from: DammitDan on January 04, 2007, 01:25:43 PM

Superheated air from the pipes already circulating around the intakes... Hmmm....

I was wondering the same thing, wouldnt there be an issue sucking in hot air or does the engine care as long as theres 02 coming in to mix with the gas?

Terry in Australia · « **Reply #21 on:** January 06, 2007, 05:06:10 AM »

Underseat pipes were developed for race bikes, to make it easier to change wheels iduring endurance races.

There was a dick on here a year or two back who hacked the frame around on a perfectly good Cb750 to make the worst monstrosity of an underseat pipe I've ever seen, he actually cut thru his frame rails forward of the shock mounts to make it fit, the moron.

While we're all individuals and can do what we like to our own machines that we've all worked hard to pay for with our own hard-earned moola, blahdy blah blah, there are those amongst us who should not be allowed within 500 yards of a hacksaw, by law.

If you're gonna do it, plan it, measure it, draw a scale picture of the planned mod and and err on the conservative side, or else other well meaning members here will say terrible things about you when you proudly post your pics of this major home-grown mod. Cheers, Terry.

BSA_Mikael · « **Reply #22 on:** January 06, 2007, 06:10:25 AM »

Someone said the impossible just takes longer time, I would add "And cost more" but then it is 100% true. Looks very "aggressive"!

Einyodeler · « **Reply #23 on:** January 06, 2007, 07:49:39 AM »

Quote from: Terry in Australia on January 06, 2007, 05:06:10 AM

There was a dick on here a year or two back who hacked the frame around on a perfectly good Cb750 to make the worst monstrosity of an underseat pipe I've ever seen, he actually cut thru his frame rails forward of the shock mounts to make it fit, the moron.

While we're all individuals and can do what we like to our own machines that we've all worked hard to pay for with our own hard-earned moola, blahdy blah blah, there are those amongst us who should not be allowed within 500 yards of a hacksaw, by law.

If you're gonna do it, plan it, measure it, draw a scale picture of the planned mod and and err on the conservative side, or else other well meaning members here will say terrible things about you when you proudly post your pics of this major home-grown mod. Cheers, Terry.

I saved a pic of said monstrosity.....WARNING.....don`t look at it too long or you will get retinal burn

DME · « **Reply #24 on:** January 06, 2007, 09:35:44 AM »

Why, dear God, WHY??

$:-\$

Couldn´t someone have stopped him before this?

News:

Author Topic: Is this possible on a CB?? (Read 7779 times)

eldar

BSA_Mikael