Hi Guy's just having a go at posting pictures. Well here goes,
Owned her for about ten years now. had some great times. but most of that time big fueling issues !!!!
But I've been of late having a good think about my problem. So come up with a few ideas. Consisting of a fuel pump in place of the solenoid, a fuel regulator in line. with adjustable pressure.
So more photos to follow, and would be interested by your thoughts.
The following user(s) said Thank You: zed_thirteen
Fueling Problems- There have been a couple of members that decided to go ahead and install low pressure pumps on their bikes to overcome fuel delivery issues and I won't condemn them for it but I do feel it's unnecessary and complicates the system with more things that could break down and leave you on the side of the road. So here's a summarization of things that fail in the stock system and things to check. Fuel tank Venting- Fuel can't flow out of the tank if air can't get in to the tank and displace the fuel leaving the tank. It's extremely important that the fuel tanl vents properly, so here are some of the issues that have cropped up. Aftermarket Fuel Caps There are several aftermarket fuel caps available on Flee Bay as an example that have been manufactured and appear to fit the same but they are not identical with regard to marrying up the fuel tank vent line and because of this the fuel tank won't vent. There are a couple of posts on this site regarding the difference and things to look for. do a search and go back " to any date" Fuel Tank Vent Line- This is a 4mm? Capillary Line running from the bottom right side of the fuel tank up inside the tank to the fill opening of the tank. Several members have found that line plugged with debris and the easiest fix is to snake it out with a drill and an old piece of throttle cable and using a penetrating fluid like WD40 as a flushing agent. Carburetor Float Needle Seat Retainer Spring Clips- The aftermarket carb rebuild kits available come with new spring wire clips for the needle seats and the new clips appear to be similar but there have been several reports of the needles binding in the needle seats to to a bad fit of these spring clips. Usually carb flooding was the result but that's not to say that the clips won't bind in the opposite direction as well causing lack of fuel to the float bowls. Improper technique adjustment of carb float height- I've probably rebuilt 300-400 carbs in my lifetime and attention to detail is critical. Something I've come across more times than I can count are issues with carb float needles binding in their needle seats due to an improper adjustment to the tang on the carb float. It's critical that the tang on the float is perpendicular to the needle pin when the needle is in the closed position. Many people adjust the tang on the float by moving the end of the tang up or down and now the contact between the tang and the needle is angular instead of being perpendicular and that puts a side load on the needle instead of an upward force on the needle to close off the fuel. What ends up happening is there's a delay to open the needle and a delay to close the needle so the carb fuel level is constantly changing which in turn causes fuel lean, fuel rich issues.
Bottom line- Gravity fed fuel systems have worked since the inception of the internal combustion engine and we didn't have fuel pumps until we started putting the fuel tanks lower than the carburetors and then had to raise the fuel up to the carburetors.
The following user(s) said Thank You: scotch, biltonjim, z13phil, PaulD
Hi Kawboy, Many thanks for the reply, very informative. I have raised my problems in the past, but Im getting very tired now and need to try looking at the problem from a different angle. My carbs have now been off probably 20 times now in the past few years, I got that fed up i purchased a CBX !!!!
Carbs when bench tested are OK but put them on on the bike and it floods out normally number one, but some times number three. Original fuel cap either open or closed. Original Mikuni float valves fitted and new O rings. I have checked everything else on your write up on the previous page. But one thing interests me, is the shape of the Tabs on the float ??? from what you say this could be a problem. Would you happen to have a picture of a original float tab or the shape when you have set them.
The other annoying thing in the Genuine manual, no mention of a guide for the float height, but Im sure you know that. The other thing is i use a pingle tap.
Thanks again in advance.
The reference for setting the float height is a little difficult to find. There's a section on rebuilding the carbs starting on pg 49 and that section refers to pg 170 for setting the "Service Fuel Measurement"
Included is a pic of the float. Note the vertical rise and horizontal tab. I've seen tabs manipulated so bad that the tang no longer looks anything like the original. I'm going to suggest that if one finds it necessary to adjust the float tang radically, then the likely cause is that the Nitrophyl float has become saturated with fuel and no longer floats at the proper height. hence the reason Scotch started building "brass Floats" and making them available on our site.