Difficult is not the word for it Dennis. I have the carbs off my '86 700. I have two jets out of each carb soaking in carb cleaner overnight but it looks like there is a third jet that is pressed in (here we go again). I'm not looking forward to reinstalling the carbs and I may not do it today. The boots get a little more chewed up each time I do it.
Ahhhh Dennis, I don't think you want to connect your manometer to the bottom of your carb bowls but I'll let Dennis sort that one out, Graham On May 28, 2009, at 1:16 AM, Dennis wrote: > Dennis, > > Today, I loosened the screws on the butterfly plate and let it move > freely and then tightened it down again and it seems to have > improved it to where it looks like the other ones now. > > I also changed the spark plugs. I was amazed to find how loose > they were. All four of them took only the slightest pressure to > break free as if they'd been hand tightened. I can't imagine why > that should have been so. I've changed a few spark plugs over the > years and I've never found any of them to be anywhere near this > loose. The old plugs were the NGK -9 type which the manual > indicates are for very cold weather areas (bike was from > Indiana). The new ones are -8's which are the standard ones, I > believe. I put them in and tightened them down like I normally > would - between a quarter and a half turn or so past where the > washer begins to crush down. I gapped them as per the manual. I > took a photo of the old plugs. > > I was going to wade into the tank's valve, diaphragm and fuel > strainer but I discovered that all my gas cans are full so I had > nowhere to put the gas in the tank (it's full). So I decided to > skip this part for now. The tank comes on and off easily so I can > back track and do this later if I need to. > > I put the carbs back into the bike. Mmmmm. I suppose after > one's done that half a dozen times, they might have some tricks up > their sleeve. I had none and it was a complicated business. The > two throttle cables and the choke cables were fun to get > reconnected. A good test for patience and coordination. That's > some tight quarters. And then came the bit where you work to get > the carbs socketed into the front rubbers and then you have to > advance the air box forwards and line all of that up. I finally > got it all setup right but it took a good while. Graham, have you > found this difficult as well? > > I bought a length of new hose to replace the one that provides > vacuum to the tank valve diaphragm and two now clamps so I'll know > the vacuum there is solid. > > Tomorrow, I'll replace the battery and the tool containment parts > and the rest of the stuff and give it a try. I pretty much > suspect that it'll be the same as it was unless I get lucky. If > it is the same, then I think looking into the coils as you > suggested will be next up. > > I've just reread what you said earlier about taking a look at the > coils. I've also had a look at the schematic in the electrical > section. But I don't get what you were telling me about the > coils. Can you say it, perhaps, in different words? The manual > tells me how to measure the primary and secondary and I can do that > and I can certainly have a good look at all the wires for bare > spots or loose connections but I think you were telling me > something else but I didn't get it. > > Thanks for the picture of the quad manometer. So, when you told > me where to connect the manometer, you meant that I would remove > the screw at the bottom of the float bowl and that's where the > manometer hose and its fitting would screw into, right, as in my > second photo? > > Cheers for tonight. I'm off for a glass of Sake and a book. > Dennis Gallagher > - Seattle > - '85 & '86 CB700SC > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Dennis Hammerl > Sent: 26 May, 2009 21:30 > To: [email protected] > Subject: [Nighthawk Lovers] Re: 700SC carbs questions > > Excellent work, Watson. > The small phillips screws on the other intakes are where the vacuum > is measured at / from. (same place as take-off for the petcock) > There are screw-in adapters to attach the hoses to. (see attached > file) > > Rust is... yes, brownish. You have a very small amount for as bad > as you indicated. I'd clean the slow speed circuits just to be > sure. I've seen amounts as much as a spoonful in each bowl. What > might be putting you off is that it is very fine, almost like dust. > > The bent choke shaft was really somebody's carelessness. What did > the plug look like from that cylinder ? Any applied pressure to the > valve might allow it to bleed fuel in . > > Now the long part. I would expect to see some tiny variation in > openings from carb to carb. However... I have seen (too often) the > following; The throttle plates being off-center and incapable of > closing. This makes for a real PITA to sync. My buddy Rob was > pulling out what is left of his hair over his V-Max not syncing. > Hours of trying was getting him nowhere. We removed the carb bank > and I backed off the idle set screw and, using a flashlight, > checked for light around the throtle plates when completely closed. > When one wouldn't close even backing off it's adjustment... Ah Ha. > The throttle plate was off-center. I backed out the two screws > holding the plate and allowed it to center and retightened. Once > all the plates would close completely, the sync went fine. The V- > Max idles very smoothly and throttle response is... sudden. Easy to > check without disturbing the expensive sync job you paid for. Just > back off the main idle set knob and use a strong light to look for > light leakage around the closed plates. > > > > --- On Tue, 5/26/09, Dennis <[email protected]> wrote: > > From: Dennis <[email protected]> > Subject: [Nighthawk Lovers] Re: 700SC carbs questions > To: [email protected] > Date: Tuesday, May 26, 2009, 8:31 PM > > Dennis, > > Yes, I can see from your comments that I've probably let my old > suspicions about rust from a year ago color my trouble shooting now. > > But today, since I had the carbs out, I decided to have a look at > them. The primary thing I found was that all four float bowls > were pretty clean. There was some small amount of scum in the > bottom. It was reddish-brown and slightly gummy. I used the tip > of my pocket knife to gather it up and remove it. I'm not sure > I'd know what rust in the bowl would look like but this didn't seem > to be it to me. I'd expect rust to be small and particulate and > gritty. But I'm not sure. What are your thoughts? I've > attached a photo. > > I looked at the vacuum chambers and their diaphragms and they > looked OK to me. I pushed the slides up with my finger and they > all came down at the same rate and smoothly with the same slight > whoosh sound. > > I saw one bit of damage. The left end of the choke shaft was bent > down (see photo) and when the choke shaft rotated, the left-most > carb's choke bystarter valve was being engaged later than the other > three. I bent it straight again and now when the choke shaft > rotates, all four choke bystarter valves (whatever the heck they > are!) all engage at the same time. > > The manual talked about using the synchronization screws to make > the distance between the by-pass hole and the throttle valve equal > for each carb. I looked closely but this seemed pretty subtle to > me. The right carb and the two middle ones all looked about the > same to me. It looked like, with their butterfly valves closed, > maybe 1/4 of the by-pass hole was visible. On the left-most carb, > it looked like maybe 1/2 the hole was visible. But, as I said, it > seemed pretty subtle. I didn't try to adjust them with the > synchronization screws. > > Looking at how the butterfly valves mated with the walls of the > shaft, it seemed to me that three of the carbs joined very nicely > (the left, left-center and right). See the photo of butterfly- > rt.jpg for an example. But the right-center carb didn't seem to > join as tightly. See photo butterfly-rt-cntr.jpg for how it > looks. Again, all of this seems pretty subtle and maybe I'm making > something out of nothing?. You can see all four carbs at once in > the four-carbs.jpg photo. You can see what looks like a bit of > extra gap around the butterfly on the second from the left. > > As yet, I haven't messed with the gas tank. If my assumption that > the carb bowls were not messed up with rust is good, then maybe > there's no need to go messing with the tank and the fuel > strainer? Maybe I can put all this stuff back together and go > have a look at my coils? > > One last question on this long piece? I've seen carb vacuum > balancing discussed here on the list before. After I'd read all of > that, I decided that when I got that far, I was going to make a > home-brew manometer and try to do the balancing myself - > remembering all the comments about throttling down the gas flow so > it wasn't just bouncing up and down. But, now that I've had a > good look at my carbs up close and personal, the only vacuum I've > seen is the one that runs from the front rubber boot of the second > carb on the left back to the vacuum input to the fuel valve. > Where does one hook up to each carb to measure the vacuum it is > pulling? > > Oh, you asked why I didn't put an in-line fuel filter in long ago > if I suspected rust? Laziness, I have to confess. > > Thanks for all the help! > Dennis Gallagher > - Seattle > - '85 & '86 CB700SC > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Dennis Hammerl > Sent: 25 May, 2009 19:54 > To: [email protected] > Subject: [Nighthawk Lovers] Re: 700SC carbs questions > > > Whoa ! Too many, 2 much at once. first, Dennis.. did you rule out > the possibility of ignition failure of one system causing the loss > of two cylinders ? My suspicion would be that the bike was dropping > one first and then, finally two. The first one to go would have > been the one that has the current flow from ground to the center > electrode.(check the coil diagram and you'll see what I mean) It > was just a thought. The pair out would be the ones that don't drive > the tach. If you're sure that wasn't the case... Still easy to > check. Like maybe a bad coil ground ? They (?) did have the tank > off and all... > No, I still wouldn't separate the carbs. With all the float needles > out, air pressure applied to the fuel inlet would force any bits > out. Just a silly question, if you knew that this might happen, why > not have installed a good quality fuel filter in-line from the git- > go ? To run the way you say it did, there better be a ton of rust > in the bowls. Otherwise... back to the drawing board. > Rust bits will plug up slow jets first and cause poor response. You > sound as though it was much worse than that. Since you have the > carb pack out, check for that nice whoosh that healthy diaphrams > make. Lift each one and let fall. Whoosh ? All better be the same. > No clunks ! Again, don't remove unless you plan on replacing. > Large William.... > Tell me I'm wrong and we'll procede. > > > > --- On Mon, 5/25/09, Graham Rogers <[email protected]> wrote: > > From: Graham Rogers <[email protected]> > Subject: [Nighthawk Lovers] Re: 700SC carbs questions > To: [email protected] > Date: Monday, May 25, 2009, 9:49 PM > > Hey Dennis, I'm at the same stage with a NH700 S, and a CB750F. > So, I'll watch for answers. I haven't delinked the carbs and don't > see any reason to. If you've got rust in your tank, it at least > needs to be cleaned. It probably needs to be lined. I did a Suzuki > GS450 tank once. It turned out okay but was a > lengthy, messy job. The stuff cost $40 from JC Whitney. Since then > I've taken 4 tanks to a radiator repair shop and they did them for > $75.00 each. I'm glad to pay them to pressure clean, and line the > tanks. One of them was my CB700 tank. Cleaning the carbs of rust I > found to be simple on the CB700 and other carbs, Graham > > > > > > > > > > > > > > > > > > <Plugs-left2right.JPG><Connect-point.JPG> --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
