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Louie, Technician
Category: Motorcycle
Satisfied Customers: 12446
Experience:  25+ yrs. experience
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I purchased a 1994 cbr 900 with real 8.000 miles in

Customer Question

i purchased a 1994 cbr 900 with real 8.000 miles in california, used to work fantastic, even starting in cold whithout chocke, however the problems started when i first let sitting for 3 months, it started but leak gasoline in theleft side of the carb but riding the bike just gone...after 6 months...9 months and now is running in 2 cylinders only, then dies, i removed the carbs to clean, i expected to see a lot of dirt, deteriorated gasoline but everything looked clean and in very good condition, i removed floats, low and hight jets, needles, clean everything then started again a started to leak a lot of gasoline and work only in 2 i need a carb rebuilt kit made by K&L???do i need a dynojet kit?i never check the sparks plugs
Submitted: 9 months ago.
Category: Motorcycle
Expert:  Louie replied 9 months ago.

Hi and welcome to the site, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.

Initially and on "...running in 2 cylinders only...", which 2 cylinders?

Customer: replied 9 months ago.
running in 2 cylinders only. i touch the two central headers and are cold.
Expert:  Louie replied 9 months ago.

I understand.

Have you carefully checked for sparks? ...on all four?

Customer: replied 9 months ago.
Expert:  Louie replied 9 months ago.

Please click HERE.

Customer: replied 9 months ago.
all four has sparks
Expert:  Louie replied 9 months ago.

Interesting as in most instances, if 2 & 3 are cold then it would be an ignition issue; i.e. missing sparks.

However, that "...all four has sparks..." would point back to a fuel delivery/starvation issue.

Still, the description of "...started to leak..." would possibly point to a float/valve issue; either adjustment, stuck open and/or not sealing fully.

Consider replacement with a repair kit.

Customer: replied 9 months ago.
how can i repair the starvation problem?does the carburator floats has some kind of adjustment?which is best, ***** ***** kit like this: carburator kit like this: i replace the internal parts from the carburator, do i need to perform some adjusment or just replace the parts whith the ones in the kit?again, i test each sparkplug and all has spark.
Expert:  Louie replied 9 months ago.

Between these two (2), the product HERE appears to be best suited.

On "...need to perform some adjusment..." would depend on what type of float is used;

  • if brass, then the tongue can be bent to move the float valve closer to the seat;
  • if plastic, then replacement of the floats would also be needed.
Customer: replied 9 months ago.
the product you recommend does not include the nedless, do i should buy the needles or is not required?the floats are plastic and are attached by a metal pin. how can i test if are bad?
Expert:  Louie replied 9 months ago.

At this point that the performance of the Honda has not been tried with all cylinders firing, need for needle replacement can not be determine. It can only be 'felt' when everything else are working as expected. Hence not yet needed......and may even be not at all needed.

That the floats are plastic would mean that these can not be adjusted. If flooding, then automatically these plastic floats would have to be replaced. To my understanding, there is no test.

Customer: replied 9 months ago.
when the bike running in all 4 cyl and with new parts on the carbs, how i will determine if i need new needles?
Expert:  Louie replied 9 months ago.

With the carbs / bike running good BUT rise engine RPM seems to be slow or IF hesitancy when accelerating and/or a flat spot THEN checks / works needed on:

  • air/fuel mix;
  • possible air leak;
  • needle height adjustment or replacement.

Spark plug burn check would help confirm.

Customer: replied 9 months ago.
i install all the new parts. it sounds erratic. i purchased a vac adjuster. where i should connect the hoses? i do not see the connectors.
Expert:  Louie replied 9 months ago.

"... vac adjuster..." please provide a clear picture or even a LINK to the product description.


Customer: replied 9 months ago.
here is the carb sync i got, but i do not where to connect, and bring 4 cooper tubes.
Expert:  Louie replied 9 months ago.


There would normally be a connection port at each intake manifold or coupling covered with a rubber cap or a screw.

Customer: replied 9 months ago.
ok, i saw that, has a rubber cap each, the manual says that, connect tube #1 to master cylinder, which one is the master cyl?
Expert:  Louie replied 9 months ago.

Connect leftmost hose (#1?) to the leftmost intake manifold as this would be cylinder 1; then 2, 3 and 4 respectively.