Author Topic: Project cafe-matic  (Read 2061 times)

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Offline j4hfr34k

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Project cafe-matic
« on: May 27, 2010, 11:03:55 AM »
First off id like to apologize up front  if some of my terms are wrong im not sure what  certain things are called so please bear with me.


I Have been reading a lot  lately about the success of hondamatics in drag racing and have been looking  at a bunch of 750 cafe's and even though its not really my style, decided i want to build one. I have a 76 750a that i ride daily, but i also have a 77 750a that was purchased from a guy that drag raced it. The 77 wiring was shot when i got it, and after purchasing  a new wiring harness and  other parts, i moved out of state, and shortly afterward bough the 76, (less work and didnt have to transport the  77) I recently HAve means to bring the 77 over and  was contemplating building a cafe or street-able dirt racer with it. either way it goes i guess what im wondering is  any suggestions or recommendations on different performance parts for the hondamatic and what other options are available. another option i considered is a dirt drag bike or something. Im not meaning to be rude with all the questions and i am  still  looking online and elsewhere on the forums as well, but i know and respect the experience and wisdom of the members of this forum and wondered what you would do. I have no clue the cost of doing  some of these things and i know  pretty much anything can be donee   with enough money but im looking for suggestions on things you know work, and what kinds of things are best bang for the buck so to speak. i know i was wanting to go with a big bore kit and wondered how big i could go realistically before it causes problems, i read that the bigger you go  it can cause problems with the gaps between the cylinders being so thin.

ideally what id like to do engine wise

bigger pistons
have the engine ported
have the crank stroked
modify the torque converter for a little higher stall
figure out a way to add another gears between the high and low or a couple gears (i dont know  anything about transmissions so am not sure if this is even possible but would love to be able to shift down from high  for passing without tearing up the engine.)
new carburetors or a fuel injection conversion.
and fabricate a forced air intake (make a hot rod style intake with moving butterfly's, and put on either side of the engine with each one linked to the two carbs on that side)

as far as non engine
air forks and air shocks for rear
dual front disks or a twin piston caliper
76' cb750 Hondamatic
77' cb750 Hondamatic
78' cb400 Hondamatic

Offline KB02

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Re: Project cafe-matic
« Reply #1 on: May 28, 2010, 03:45:07 AM »
I don't really have any suggestions for you, but I'm liking the way you are thinking. :) It will be great to see this project get going.

Check out the High Performance/Racing board. Some members are building a Hondamatic Dragger. Not a whole lot of info on it yet, but it's a great thread.

- - - Edit - - -
Just read that post and see that you have already found it.  ;D
« Last Edit: May 28, 2010, 04:07:21 AM by KB02 »
1978 CB750K Project
2000 Ducati ST2
...and a pedal bike

Join the AMA today!!

My project thread Part I: K8 Project "Parts Bike"
My project thread Part II: Finishing (yeah, right) touches on Project "Parts Bike"

Offline j4hfr34k

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Re: Project cafe-matic
« Reply #2 on: May 28, 2010, 06:37:58 AM »
Now i justy need to get the bike over here lol, i thought i had lined up a truck to bring it over when i go over there in a couple weeks but now looks like ill be doing a little more waiting but that just gives mee more time to plan etc. until thenhere are some before pics of how it was before storing it.
76' cb750 Hondamatic
77' cb750 Hondamatic
78' cb400 Hondamatic

Offline captaincrash80

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Re: Project cafe-matic
« Reply #3 on: May 28, 2010, 07:05:39 AM »
Interested to know what you have planned out for the force air system

Offline j4hfr34k

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Re: Project cafe-matic
« Reply #4 on: May 28, 2010, 08:15:30 AM »
I don't really have any suggestions for you, but I'm liking the way you are thinking. :) It will be great to see this project get going.

Check out the High Performance/Racing board. Some members are building a Hondamatic Dragger. Not a whole lot of info on it yet, but it's a great thread.

- - - Edit - - -
Just read that post and see that you have already found it.  ;D
That thread is partly what got me thinking seriously about this project
76' cb750 Hondamatic
77' cb750 Hondamatic
78' cb400 Hondamatic

Offline j4hfr34k

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Re: Project cafe-matic
« Reply #5 on: May 28, 2010, 09:48:39 AM »
Interested to know what you have planned out for the force air system
I'm making a custom "assisted ram air" intake aftyer  further research online of what i was wanting to do, i found out that's the closest thing to call what i am planning. I have the design of the inlet and ducting but need to talk to some people that know more about the scientific parts of it like how to best funnel the intake air into the carbs, whether its from a manifold type intake or to make separate ducts to each individual carb. I plan on having the inlets be in front of and under the gas tank and run the ducting along the bottom edge of the tank.

My design #1 is for two separate inlets one on each side with a 2 1/2 to 3" aluminum tubing run along the bottom edge of the gas tank tucked underneath close to the frame. and build a manifold to connect all for carbs together and have the tubing connected and sealed to each side. i need to figure out what angles and baffles to make in the manifold to direct the air properly into each carb. I build custom computers for a living as well, and considered putting in a couple fans to help the airflow which could be switched on or off.  of course i have to find out what to do to the engine to let it take advantage off the extra air as well if i can get the funds wrangled up I might even make a prototype one for  the 76 and see how it does. if i out it on the 76 though ill be mounting the inlets to the top of the highway bar. if i add the fans i need to  figure out what the optimal airflow would be and i can set them up to match that and if it should be turned off  at higher speeds or increased as speed increases. all that math is  gonna take more researching though, anyone  that knows about airflow etc feel free to pm me or add in here. 
76' cb750 Hondamatic
77' cb750 Hondamatic
78' cb400 Hondamatic

Offline j4hfr34k

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Re: Project cafe-matic
« Reply #6 on: June 09, 2010, 12:10:41 PM »
after talking with some of the more knowledgeable members of the forum and discovering i have access to a guy that has built hundreds of racing motors right in my back yard, i have ditched the ram air idea, however i am going to go with a turbo. i am going to get an 836 kit and have the head machined. hes gonna build the engine and help with the custom turbo ducting. i will get pictures as soon as i start getting parts.
76' cb750 Hondamatic
77' cb750 Hondamatic
78' cb400 Hondamatic