I tried to start my '78 the other day after a couple of months of sleep and it was dumping gas on the transmission, so I'm up against this, too. This is not the first time.
You say you put in "new needles and rings." I understand the new needles part, but I'm wondering what rings you put in. Do you mean bowl gaskets? O-rings between the individual carbs? Needle valves have no O-rings per se. They have rubber tips that seal when the floats raise them, hence the needle shape. New ones will seal, If you are leaking from the bowl overflow, it's because your floats are too high. Try putting a clear tube on the overflow, carb by carb, and unscrew the drain screw. Here's some advice I copied from this list a few years back: Run a clear vinyl hose out the back of the Carb Drain up to the Carb Body. Open the Drain Screw and watch the level of fuel in the vinyl hose. Adjust the Float Height so that the Fuel Level is even with the bottom of the lock washer on the Fuel Bowl Screws holding the Bowl to the Body. You are going to have to analyze where that leak is coming from. Me, I've learned to fill carbs with gas after a clean while they're still on my bench. If they leak, I don't put them on. You may have to take yours back off so see what's really going on. The other place they can leak is the fuel rail between the carbs. This will take new o-rings. To change them, you need to break the rack, something I'm personally loath to do, although I have. I have found that you can use O-rings from the nitrile o-ring assortment at Harbor Freight for this for cheap. You can also use the smallest o-ring in the assortment for the mixture screw. Just be sure to get the millimeter assortment. If your carbs themselves are not leaking, then fuel is dripping down from the petcock or leaking from the connection into the carbs, often between 1 and 2. Although I've never done it, people say you can drill out the rivets and replace the diaphragm inside your petcock, putting it back together with screws. I've never done it personally. Perhaps someone else can chime in on that. If your carbs are clean and synced and you have poor power above 80Km/H, except if you have the wrong size main jets, your issue lies elsewhere. Hope this helps. -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/nighthawk_lovers. For more options, visit https://groups.google.com/d/optout.
