I would be tempted to say adjustment rather than accelerator pump, but I'm a novice when it comes to carburetors, but the reason I would suspect tuning is because the carbs were sourced from another bike in which the mixture profile would likely be different than the 450NH.
As far as I know, the accelerator pumps are more so for "acceleration" when you twist the throttle they spurt gas to offset a sudden leanness, other than that they shouldn't do much. The flat spot could be related to missing a accelerator pump or tuning, but the surging would be due to how the carbs are tuned. If the carbs were off a 400, even though it may not sound like a lot, those missing 50cc's would call for a different mixture than 450. I'd say, pull the plugs and look at the ends, that would be an indication of how it's been running and then that can help determine what needs to be done with the carbs. I didn't think an accelerator pump was "make or break", older bikes got by alright without them, I don't know if it was intricate to 450Nh's though. On Apr 26, 7:42 pm, Joey Kelley <[email protected]> wrote: > Hello All, > Wanted to introduce myself, my name is Joey and I ride a 1982 > CB450SC with just over 13,000 original miles. (Just rolled over last > week!) Up here in Maine, where the riding season varies from three > months to six each year. This year we've gotten a good start already - > the end of April and I've been riding for two weeks. > When I bought my Nighthawk nine years ago - the carburetors > were deemed plugged up beyond repair. A replacement set of carbs was > salvaged from a 400 of unknown vintage and installed. She's had over > 9,000 miles on her since. Spent the past five years in my Dad's shed > and like all good Hondas, started right up with the old gas still in > it. > After nine years and 9000+ miles I'm getting annoyed by the > constant surging under partial throttle and flat spot between 3,000 > and 4,000 RPM. > So here is the question, is this surging and flat spot caused by the > lack of the accelerator pump on the 400 carbs that I have installed, > or is it some problem or adjustment that can be made to the ones I've > got? > 50 Degrees and highway speeds makes for a cold ride home! > -Joey > -- > -Joey Kelley > > -- > You received this message because you are subscribed to the Google Groups > "Nighthawk Motorcycle Lovers!" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group > athttp://groups.google.com/group/nighthawk_lovers?hl=en. -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en.
