Technically challenged person over their head.

These folks know EVERYTHING you'll ever want to know;

Hit "Forum" at the top- http://www.sohc4.net/

My personal experience is that these bikes run much better with the stock airbox, but I don't know if you can replace a bad one. David Silver Spares in England has many what he calls "pattern" parts.

Hello Kevin,
I had the tiny CB 650 with the same type of underpresure carb set. But as I remember all 3 bikes were different in carb diameter and needle dimentions.
And all after some 80 - 150.000km needed beside the main jet and needle, new seels in the underpresure chambers and most of all the exallerator diafragma (the one that pushes a little off gasoline directly into the intake when you turn the throttle. When that pump doesn't work properly the hole ride starts to become nasty.
Other thing important is there may not be any false air coeming through the axle bearings of the chokes nor the flaps.
Syncronisation is not too dificult as long not any of the underpresure floats gets stuck or suck air.
There were 2 types delivered depending on the country. One style came with pistons with o rings =>might need some honing and one with diafragma. => one style which you might have the luck to be able to adapt the sice to your carbs.
Regards
Sven Peter

Question solved The parts that were broken on my 750 carbs were interchangeable with the 900 carbs so I just swapped out the broken parts on the 750 carbs. Then on the Honda CB 750 forum I got a reply from a person that has used the air filter pods and gave me the replacement jet sizes. Now all I have to do is rebuild 4 carbs. It is a long winter here in Maine.

Well, much of that is good news.
It is my recommendation to use Honda carbeuretor parts for jets and rebuild kit.
I've used Brand-X parts to save money, and ended up buying the Honda parts after all- they fit.

Good hunting and god luck ~

Kevin, You have mill and lathe?
Then I recommend to make new bushings and shafts for the air and choke flaps too.
I did that on a Chevrolet carb for my 1960 Willies and it made the big difference. The original rests in the "memory box" because that foolish design nearly burnt the Willies on its first day on the road again in December 1994.
Sven

Thanks for the info and suggestions guys.

I am going back to the original airbox, as suggested by Uncle Ernie and others on the Honda posts. I will look for some on E-bay. Unfortunately I have already ordered a cheap rebuild kit for the carbs...maybe I should see about sending them back with the pods...

I have no machine shop tools except a drill press and tap and dies Sven. I do know a guy that does work for $50/hr but that can get expensive fast. Very limited $$$$ working as a self employed fine art photographer here in Maine these days.

This is supposed to be my beater bike project , which I try to keep in mind but you know how it goes.... with a beater you still don't want to get left stranded in 10 degree weather on a back road so trying to put the $$$ where it counts.

....so trying to put the $$$ where it counts. ...
I know that one good for running a machine shop for 19 years now.
Kevin, then I want to recommend to go as original as possible. The individual air filters according to my experience always suck. Check the flap shafts and under presure pistons ,if you do see a feelable and visible play, then a little used carb battery very easily will be cheaper then a rebuild with doubtable results.
Sven

This guy puts together the best Honda carb rebuilt kits in the US. I've used his kit for the carbs on my GL1100 and I won't use anybody elses.

http://www.randakks.com/DOHC%20Four%20Page.htm#1

The days of multiple carburetors are fast going away. Virtually all of the new Japanese and other foreign bikes now have fuel injection. I even have fuel injection on my '04 Harley and I'm sure glad I do. It's absolutely unfailing.

I never even had any luck with just two carburetors on a British Triumph. I couldn't imagine having four or six carbs. There is always something wrong with at least one of them. From air leaks to leaking floats, clogged needle jets and on and on, ad nauseum.

I always though how nice it would be if a four-cylinder Japanese bike could have its carburetors replaced with either a single carb or two carbs with a special manifold. If it could be done, it would sure solve a lot of problems.

If I had a four cylinder Japanese bike, it would be a nice aluminum welding project. A good choice for a carburetor would be the Keihin CV 40 such as the ones used on a Harley or a Goldwing. When it comes to carburetors, one or two is a lot less trouble than four or six. When I say six, I'm thinking of a Honda Valkryie or CBX.

And the funny thing is that these carb batteries from Kehin nearly never failed,
something I could not say from (as you say brits) SU even as single carb on an Austin Mini was a pain,
or the Bing and Del Ortho.
I give you right with a single carb on a twin like in the Jawa, it failed less then on my first Honda with 2 carbs.
But the fuel injection on bikes has not been allways flawless.
You should have seen the pain on the first BMW K75 I rode in 85.
From that day on I got convinced that BMW only can build boxer engines. and reconfirmed recently.
Monday last week I saw 17 trafic patrol BMW K75 waiting for the junk yard.
For sure a good mecanic cold fix them, but public possesion is practically impossible to pass over into well carring hands.

So I am interested what others experience tell.
Sven

Peter Pan - 11/2/2009 8:57 PM

And the funny thing is that these carb batteries from Kehin nearly never failed,
something I could not say from (as you say brits) SU even as single carb on an Austin Mini was a pain,
or the Bing and Del Ortho.
I give you right with a single carb on a twin like in the Jawa, it failed less then on my first Honda with 2 carbs.
But the fuel injection on bikes has not been allways flawless.
You should have seen the pain on the first BMW K75 I rode in 85.
From that day on I got convinced that BMW only can build boxer engines. and reconfirmed recently.
Monday last week I saw 17 trafic patrol BMW K75 waiting for the junk yard.
For sure a good mecanic cold fix them, but public possesion is practically impossible to pass over into well carring hands.

So I am interested what others experience tell.
Sven

I think that even BMW has now got their Fuel Injection sorted out, at least according to recent Cycle World tests. The fuel injection is working very well on almost all modern motorcycles with which I'm familiar.

Beside Diesel engines the only injected vehicle I had was a 1300ccm Ford Festiva which had such a good engine I was very tempted to take its engine for a self constructed sidecar project.....
Until I gave it to my wife... Since then it sucks oil, but stays in the family at my brother in law now for 11 years.
My experience in Costa Rica with its abrupt height changes is that carburated engines with underpresure diafragmas have their troubles at high elevations and sudden elevation changes. That injected Ford engine never showed a lack of power, it simply adapted its mixtures to the conditions.
Sven

Peter Pan - 11/3/2009 8:23 AM

Beside Diesel engines the only injected vehicle I had was a 1300ccm Ford Festiva which had such a good engine I was very tempted to take its engine for a self constructed sidecar project.....
Until I gave it to my wife... Since then it sucks oil, but stays in the family at my brother in law now for 11 years.
My experience in Costa Rica with its abrupt height changes is that carburated engines with underpresure diafragmas have their troubles at high elevations and sudden elevation changes. That injected Ford engine never showed a lack of power, it simply adapted its mixtures to the conditions.
Sven

Well, if you are talking about automobiles, the fuel injection systems that are in use now are really faultless. I have a 1998 Dodge Dakota Pickup and a 2000 Ford Escort and both operate seamlessly. The car manufacturers have developed great fuel injection systems starting more than 25 years ago. I can't remember the last time I saw an automobile blowing black smoke as was common when they ran carburetors. There's nothing like fuel injection. Thankfully, you can't find a car without it anymore.

The EFI on my Harley is also superb. It starts quickly, idles well and is at good power at any elevation. You really can't ask for more. It's a blessing for a sidecar rig as well.

Yeah, carbs are pain.. but fun!
I need motorcycles not "appliances". (LOL)
What else should I fiddle and tinker with?
What happens to those old starting rituals? No choke? Oh no!

Seriuosly though, do you think FI repair kits or repro FI will be available 30 years from now?
I will keep my already 30 yr old motorcycles so I am fine but what about those people?