Topic: Carb Bowl Gaskets

[Tdinova]

It is now winter here in Nova Scotia and my sons 80 cb650 is still not running tip-top, It still bogs out some mid range . I did get to work better than early summer by buying new needles for the carbs. I adjusted the float heights (12.5mm) but 1 carb would not stop leaking gas, so I had to lower it some. I just found a site that sells a gasket set
http://www.newmotorcycleparts.com/fuel_system_parts/bowl_gaskets.html .

good price The gasket will also fit:
CB550 '77-'78
CB650 '79-'80
CB750K '77-'78
CB750F '77-'78
CB750A '76-'78

So I done some ebay searching and found these:
http://www.ebay.com/itm/HONDA-CB750-CB750F-CARB-FLOAT-BOWL-GASKETS-1977-1978-/220891431298?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item336e27c182

I may save some money but buying ebay parts. 

Did anyone else try the cb750 gasket set in their cb650?

[bollingball]

No but I have used the SCI brand and they worked good on my 750

[Trav-i]

I have those same Ebay ones on my bike right now.  Never been a problem with 'em.

[Tdinova]

I put the gaskets in today and works great. I am still waiting the small washers and O rings on the pilot screws. I did find 1 slow jet plugged. (Fingers Crossed)

[Tdinova]

All went well, I have the washers and O rings in. I set the pilot screws to 1 7/8 turns. I had the figure wrote down 3 years ago. I did find the # 2 slow jet plugged, I got that unplugged by using air and sea foam. I checked the height of each float and put them to 12.5 mm. I then check the gas height using the clear tube method, but # 1 needle was not seating. I had to remove the bowl/needle and clear out the dirt. I put the carbs back on annnnnndddddddd she fired up smoothly. I went for a run in the sub-division and it did not bog out or even skip. I think it is fixed. BUT I need several days of good runs before I'm convinced. 

[Tdinova]

Here is the height of the gas with the floats measured across the main jet to the base. (12.5mm)

So far so good. Fingers crossed

[lucky]

Something is wrong. That float level is way too high.

No wonder you have gas leaking.

Better check the float the way the book says and use new float needles.
also since you live where it is so cold make sure that the pick up tube in the float bowl is not cracked.

[Tdinova]

That float level is way too high.

At what level should the gas be? I thought even with the bowl gasket.

[KeithB]

That fuel level is high!
It's my understanding that the 12.5mm is measured from the notch on  the sides of the carb where the original Honda tool would have rested.
The only  question I have is, do you measure to the bottom of the float when it is just resting against the fuel needle valve or do you gently push it to take up the spring tension in the valve?

[Bob Wessner]

Measure when it is just resting, apply no pressure.

[Tdinova]

I found this picture on the net. You measure at the point of the curve 12.5 mm, I was measuring from the main jet

[Tdinova]

Well the verdict is in ' She's Alive' After readjusting the float height to 12.5 mm on all 4 measuring from the end of the float not near the needle. The pilot screws are set at 1.75 turns. Lots of power, smooth idle, no bogging out. Here is a picture of the gas on all bowls.

[lucky]

It is now winter here in Nova Scotia and my sons 80 cb650 is still not running tip-top, It still bogs out some mid range . I did get to work better than early summer by buying new needles for the carbs. I adjusted the float heights (12.5mm) but 1 carb would not stop leaking gas, so I had to lower it some. I just found a site that sells a gasket set
http://www.newmotorcycleparts.com/fuel_system_parts/bowl_gaskets.html .

good price The gasket will also fit:
CB550 '77-'78
CB650 '79-'80
CB750K '77-'78
CB750F '77-'78
CB750A '76-'78

So I done some ebay searching and found these:
http://www.ebay.com/itm/HONDA-CB750-CB750F-CARB-FLOAT-BOWL-GASKETS-1977-1978-/220891431298?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item336e27c182

I may save some money but buying ebay parts. 

Did anyone else try the cb750 gasket set in their cb650?

You say you bought some new needles.
Slide needles or float needles??

Changes everything.

[Tdinova]

It is now winter here in Nova Scotia and my sons 80 cb650 is still not running tip-top, It still bogs out some mid range . I did get to work better than early summer by buying new needles for the carbs. I adjusted the float heights (12.5mm) but 1 carb would not stop leaking gas, so I had to lower it some. I just found a site that sells a gasket set
http://www.newmotorcycleparts.com/fuel_system_parts/bowl_gaskets.html .

good price The gasket will also fit:
CB550 '77-'78
CB650 '79-'80
CB750K '77-'78
CB750F '77-'78
CB750A '76-'78

So I done some ebay searching and found these:
http://www.ebay.com/itm/HONDA-CB750-CB750F-CARB-FLOAT-BOWL-GASKETS-1977-1978-/220891431298?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item336e27c182

I may save some money but buying ebay parts. 

Did anyone else try the cb750 gasket set in their cb650?

You say you bought some new needles.
Slide needles or float needles??

Changes everything.

New Bowl gasket, new float needles, new Pilot screw washers and O rings.
I learned alot about these carbs and how they work

One thing was # 2 slow jet was partially plugged. I turned the carbs over and put 3 inches of small hose over the small jet brass tubing and poured gas in the tube. If the gas went down = not plugged, gas stayed up = plugged. A long slow battle..

[harisuluv]

Those gaskets that sci sells in my opinion are k&L gaskets. They come in the same exact bag but without the blue cardboard packaging. There are even staple holes where the k&L packaging has them.