creative carburation

[earthman]

Got an '80 Honda 650 4 today for $50. Hasn't run in years.
Last owner decided the carbs needed to be epoxied rather than using
gaskets. I don't want to buy a new set of carbs for a $50 bike.
The plot thickens. I intend to put a gas tank under the seat
like a Goldwing and i would like to have more space behind the
engine. I can fabricate intake manifolds out of tubing so does anyone have ideas about cheap and simple alternatives to the stock 4 carb setup? Possibly one or two small downdraft carbs / One larger side draft positioned off to one side / fuel injection ?
It is only 650cc so would a VW bug carb be too much?

 

[Unkl Ian]

An OEM aircooled VW carb might be ok,with an electric fuel pump.
They didn't make a lot of hp,so they shouldn't be too big.

If you are brave,maybe two,with a progressive linkage on a log manifold.
Mount the carbs up high,one on each side of the backbone.

The stock intake manifold is steel,easier to cut the flange off than make one from scratch.

I would definitely run a fuel pressure regulator,with an electric fuel pump.

Most motorcycle carbs are gravity feed,so they don't like a lot of fuel pressure.
An automotive carb should be able to handle a little more.

I'd pull the tank off first,before deciding what to do,the stock japanese frames can be pretty ugly.

 

[Unkl Ian]

Billy Lane used Stromber 97s on a couple of his bikes.

Might get some inspiration from some of his stuff,but I wouldn't copy all of it.

If you are really interested in the VW carb idea,remind me,
and I can ask for suggestions on a VW forum I frequent.

 

[earthman]

Thanks for the reply Unk. The backbone on this bike has a nice
arch. I will put up pix when i get it cleaned up. I am sure the dual VW carbs would be too much however cool they would look.
Really leaning toward the single VW (weber replacement $159). Would require four
pipes coming off the cylinders merging into one then curving to the side to clear the backbone. Downside is that it will take a lot of space. Any input from the VW board would be appreciated.

 

[chopper tom]

a jetted up harly carb might work better,or mabie one on each side ??????
S&S preferably.but take off harly carbs are easyer to find.
A word of advise ,dont spend much money trying to fix that 650 .Them bikes are notorious for bad electrical problems ,a little brain box on the charging are bad to go out on them.about 100 bucks to fix from what ive herd.
i had one once.but they do run good when ther right though.
the 70's bikes are easyer to full with i find,and some what cheeper .

 

[Unkl Ian]

The small HD Sportster motor is 883cc.Might be a possibility.

I've got an idea,will try and sketch it up,after I shovel some snow.

 

[motomech]

the buell blast is 500cc's........or a down draft weber w-40

 

[earthman]

Moto
Good thinking on the single carb on the Buell but i remembered
Suzuki still makes a 650 single. That should have the correct
cfm and no doubt cheaper than the Harley. Will see if i can find
it on the net.

 

[earthman]

Unk
ideas are good, unusual ideas are better!

 

[Unkl Ian]

http://www.jockeyjournal.com/forum/showthread.php?t=25412

Not sure if you need to be a member to view the pics there.

 

[earthman]

Thanks for the link Unk, got useful info from it. Got the stock 4 carbs apart after all. Now the practical thing would be to just use them but a log type manifold with a carb on each end would allow more space for the tank and be much more fun

 

[Unkl Ian]

Some Harley carb info:
http://www.sportster.org/tech/