83 Nighthawk 450 running poorly need help

[nerfherder81]

I'm working on a 83 Nighthawk 450, all stock. It seems to start hard and will not rev pass half throttle. It seems to be running rich.
Here is what I've done/checked so far -
Cleaned the carbs, and now cleaning them again
Checked the coil seems to be ok
Checked timing seems to advance as it should
replaced sparkplugs
Could this be a carb issue or ignition?? Help please :smiler:

 

[Element]

Are you running stock airbox and stock jets?

 

[Kamn]

How are you cleaning the carbs? With an Ultrasonic cleaner or just shooting carb cleaner at it?

 

[nerfherder81]

Stock jets and airbox.
welding tip cleaner, and carb clearner, now soaking in toluene. and tip cleaner.
I don't have an ultrasonic(would love to get one though)

 

[Element]

Careful spraying carb cleaner through the carb. It is powerful and will destroy anything rubber in the carb like o-rings, etc... Were there any holes in the diaphragms?

 

[nerfherder81]

didn't notice any holes in the diaphrams. all soft meterial Orings and such have been removed prior to toluene soak.

 

[Element]

Not sure. Sounds like an air/fuel issue to me. Perhaps one of the more experienced members familiar with this specific bike can chime in.

 

[Element]

How did the old plugs look before you changed them out?

 

[nerfherder81]

How did the old plugs look before you changed them out?

wet and sooty

 

[Element]

Have you tried re-jetting it yet?

 

[nerfherder81]

Have you tried re-jetting it yet?

No, I figured its all stock, there shouldn't be a need to.

 

[nerfherder81]

Could be the reason my bike isn't running? I believe thats where the secondary or primary Main jet goes. However the passage doesn't seem to lead anywhere or have threads?

 

[fresh_c]

I want to say there is supposed to be a little rubber plug in there? Your main and secondary are to the left.

 

[Bert Jan]

Eh.. i see two jets and a hole. What do you think when i poke a hole in you? Would you run far? I think you'll be wet and sooty too, and then die.

But serious. How many carbs does it have, and do they all have that hole? To me, it's not good. I'm not familiar with the 450 NH, but i know for instance 500f and 550f have the carb body casted so they can be used left or right. Maybe thats the problem here? I guess you should plug the hole no matter what.

If you poor liquid in the hole, where does it come out?

 

[fresh_c]

This link might be helpful.

http://www.cb750c.com/publicdocs/SeanG/Honda_Carb_Manual_revD.pdf

 

[nerfherder81]

This link might be helpful.

http://www.cb750c.com/publicdocs/SeanG/Honda_Carb_Manual_revD.pdf

Thanks fresh, I came across that link once forgot to save it. I've been looking for it.

 

[Element]

Based on web searches it looks to me like a jet definitely goes there, and if this is the case, it would run way to rich if the jet was missing. Is it missing out of both carbs? Can you take a pic of the jets that are in the carb?

 

[nerfherder81]

Based on web searches it looks to me like a jet definitely goes there, and if this is the case, it would run way to rich if the jet was missing. Is it missing out of both carbs? Can you take a pic of the jets that are in the carb?

I posted a pic of the carb, and 1 and 2 both are the same.
Side note my 550k1 only has two jets. a slow and a main but its not a CV stlye carb.

 

[cxman]

a rubber plug goes over the center slow jet

there is no second main jet in that year bike

it should have a 125 main and a 38 or 40 slow jet

 

[cxman]

here is some info on the carbs

http://www.hondatwins.net/forum/viewtopic.php?f=59&t=22566

if you need the plugs here is where i get them

http://www.siriusconinc.com/pro-detail.php?pid=&product_id=1104