I haven't done any screw adjustments but I will start with the simplest - the petcock, etc. thanks, Graham
On Mar 6, 2009, at 8:31 AM, Creative Residential Designs wrote: > It sounds like it's not getting enough gas. Have you adjusted the > carbs with the screw adjustment? Have you checked the screen in the > petcock to see if there's any debris? Is the air filter clean? I > like to start with the little things before I go into major > surgery. HotrodMamma.. > ----- Original Message ----- > From: Graham Rogers > To: [email protected] > Sent: Friday, March 06, 2009 5:59 AM > Subject: [Nighthawk Lovers] Re: Nighthawk S starting problem > > This bike CB700) is on hold for a little bit. I'm having to make > the difficult decision to sell one of my Hondas. So I'm going to > sell my 1980 CB750F. But first I have a problem. I restored this > bike as much as I can (paint job, new decals, new seat cover and > detailed clean, including carbs). The bike runs good as long as I > keep the choke on some. The bike breaks up and dies if I do not use > the choke. Here's what I suspect may be the problem and this is > where I need help. I could not find a vacuum leak by spraying > around the carbs while it was running. The bike has a 4 into 1 > exhaust system. That's how I got it. Should the carbs have been > modified/adjusted for the change from the original exhaust system > and had they not, would that cause it to run lean and so need the > choke activated? If that's the case what do I need to do? > Installing stock exhausts/mufflers is too expensive. Thanks guys, > Graham > > On Feb 26, 2009, at 12:38 AM, Dennis Hammerl wrote: > >> They are your carbs. Investigate what passages are blocked. It >> would seem that you have sufficient intake vacuum, Hand choking >> increases that. If all was well, after hand choking, the plugs >> would be saturated. Because they aren't, the path from bowl to >> intake via choke valves must be blocked or the choke valves don't >> work properly. They can be removed without too much trouble. Very >> simple devices. >> >> --- On Wed, 2/25/09, Graham Rogers <[email protected]> wrote: >> From: Graham Rogers <[email protected]> >> Subject: [Nighthawk Lovers] Re: Nighthawk S starting problem >> To: [email protected] >> Date: Wednesday, February 25, 2009, 5:46 PM >> >> I cranked the motor over - it tried to start, at least on one or >> two cyl. Then I checked the plugs. They were dry on the tips and >> porcelain but a little wet on the rim of the plug. It didn't >> smell like gas however. I then tried to start the bike with my >> hand restricting the air flow at the air filter. It did start but >> died when I moved my 'hand choke' I probably could have gotten it >> started that way. So, it looks like the choke isn't working eh? >> Now what? >> Graham >> >> On Feb 25, 2009, at 12:21 AM, Dennis Hammerl wrote: >> >>> Spraying it optimizes the conditions needed for starting. >>> Which... means the chokes aren't working. If it has a strong >>> vacuum when cranking if you hold your hand over any carb throat, >>> the chokes aren't passing any fuel. WHY ? The "gas chokes" are >>> very simple valve devices. If they have access to fuel from the >>> float chamber and they are open to the bores when activated, all >>> should work. With the throttle plates closed, the high vacuum >>> (or , more properly, low pressure) should draw fuel up through >>> the choke circuits and into the motor. It's as simple as a >>> faucet. I don't want to get into any abstract at this point. Are >>> the plugs getting wet when you crank the motor with the chioke >>> operated ? Knowing that is a must before proceding. If they are, >>> we look elsewhere. If not, we stay in the carbs. >>> >>> --- On Tue, 2/24/09, Graham Rogers <[email protected]> wrote: >>> From: Graham Rogers <[email protected]> >>> Subject: [Nighthawk Lovers] Re: Nighthawk S starting problem >>> To: [email protected] >>> Date: Tuesday, February 24, 2009, 8:05 AM >>> >>> Tried starting the bike this morning and there doesn't seem to be >>> any improvement. It would 'bubble' along like it was trying to >>> catch (it acted like a weak spark) but again it took starting >>> fluid and the choke seemed not to play apart. Once it had >>> 'caught', restricting the air flow through the air filter with my >>> hand significantly increased the rpms. Maybe I should also check >>> the state of the battery huh? >>> Incidently I noticed the fuel gauge didn't work until I revved >>> the engine significantly and held the revs. That was a new one to >>> me, Graham >>> >>> On Feb 23, 2009, at 11:02 PM, Dennis Hammerl wrote: >>> >>>> Let us know how that works out. The neutral wiring is grounded >>>> and that's why it always shows N / green light. Let's get into >>>> that later. You have multiple issues. One at a time. >>>> >>>> --- On Mon, 2/23/09, kiwi <[email protected]> wrote: >>>> From: kiwi <[email protected]> >>>> Subject: [Nighthawk Lovers] Re: Nighthawk S starting problem >>>> To: "Nighthawk Motorcycle Lovers!" >>>> <[email protected]> >>>> Date: Monday, February 23, 2009, 1:16 PM >>>> >>>> Blasted those tiny holes that allow the gas through when using the >>>> choke with compressed air and >>>> spent 2 hours reinstalling the carbs. It >>>> still took starting fluid to get the bike started BUT, not very >>>> much >>>> and the choke worked a little. I'll see how it starts >>>> tomorrow when >>>> it is back to winter temperature. >>>> Second problem with this NH is the neutral/gear indicator. It >>>> reads N >>>> all the time and won't show what gear the bike is in. I found a >>>> little >>>> black box under the tail section that I think is part of the N/gear >>>> indicator system. Is there a way to check it? >>>> Third problem should be >>>> simple. The left front turn signal is >>>> 'bright' when ignition is on but will not blink when it >>>> should. The >>>> others work as they should. That left one shines a lot brighter >>>> than >>>> the right front when ignition is on. >>>> >>>> On Feb 22, 11:11 pm, Dennis Hammerl <[email protected]> wrote: >>>> > I will assume your carb clean was a complete operation. Let's >>>> examine >>>> how the choke works. The cable opens valves that will >>>> permit raw fuel to be >>>> sucked into the motor during cranking. Now, lets say that works >>>> fine.Your plugs >>>> should be wet after cranking for a short while. Y-N ? The most >>>> common >>>> cause of >>>> the plugs being dry after cranking is the throttle plates being >>>> open too far and >>>> causing insufficient vacuum. Same as opening the throttle while >>>> trying to start. >>>> When the intake air flow is too low, no fuel will be drawn in >>>> from the choke >>>> circuit. If the plugs are wet, you're flooding the motor. >>>> > We start >>>> here. Additional checks of compression and a leak-down may be in >>>> order. >>>> > This may take time to resolve. Get at it. >>>> > >>>> > --- On Sun, 2/22/09, Graham Rogers <[email protected]> wrote: >>>> > From: Graham Rogers <[email protected]> >>>> > Subject: [Nighthawk Lovers] Nighthawk S starting problem >>>> > To: [email protected] >>>> > Date: Sunday, February 22, 2009, 6:18 PM >>>> > >>>> > I have a 1986 Nighthawk S. It ran before I got it but always >>>> took >>>> > starter fluid in the air filter to get it going. I pulled the >>>> carbs >>>> > and >>>> thoroughly cleaned them and used to compressed air in all the >>>> > holes. However the bike still will not start without stater >>>> fluid >>>> > and even then it takes along time with the fluid. I noticed that >>>> > >>>> using the choke seemed to make no difference at all so, >>>> thinking that >>>> > perhaps the choke isn't working at all I removed the carbs again >>>> > (they are terrible to remove) and did what I could toi ensure the >>>> > choke was working right. The mechanism moves as it should and >>>> I used >>>> > compressed air in the holes to the where I >>>> presume the choke opens. >>>> > Now, before I reinstall the carbs, any suggestions? Could the >>>> > problem have been the choke or is there something else that would >>>> > cause the same problem. By the way, once the bike was warmed >>>> up, it >>>> > ran fine - just when it's cold I have to use >>>> starting fluid, Graham >>>> >>>> >>>> >>>> >>>> >>> >>> >>> >>> >>> >>> >>> >> >> >> >> >> >> >> > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. 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