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
On May 25, 2009, at 9:10 PM, Dennis wrote: > My bike's been running a bit off for sometime now. A year ago, > when I first got it, I took it into the local shop and asked them > to change all the fluids, give it a tune-up and to balance the > carburetor vacuums against each other. > > When I got it back, they told me that they'd found junk in my carb > bowls and that they were pretty sure I had a problem with rust in > my tank. They wanted something like $700 to sort it out. Yow. I > said, "No thanks." I hadn't dealt with these particular folks > before so I didn't know if they were looking at me as a cash cow > customer or if they were telling me the straight stuff. > > The bike did run better when I got it back from them but it still > wasn't exactly right. I knew this because in addition to this '86, > I've also got an '85 700SC and it runs like a German clock so I can > tell the difference. > > About the time I got the bike back, Seafoam came up in conversation > on this group and I went down and got some and ran it through my > bike. It seemed to help. > > Well, it's been a year now that I've been riding the '86 since I > got it back from the shop. As I said, it runs OK but not > perfect. To me, it always feels like my carbs are not balanced > against each other and so when I'm running along without much > throttle, it feels like some cylinders are firing solidly and > others are weaker as if they're not getting as much gas. > > About the potential rust problem, I thought that if the guys at the > shop were right and I did have a problem, then sooner of later it > would come back and the bike would get worse. > > Well, about three weeks ago, it did get worse. It seemed like one > or two cylinders weren't hitting at all. I put more Seafoam in it > and ran it but it didn't seem to get better so I decided it was > time to dig into the problem. > > I've got a copy of the Honda Shop Manual for the 84-86 CB700SC > series. Today, I pulled off the gas tank and pulled my four carbs > out as a unit following the instructions in the manual. There > were a couple of parts that were a bit confusing but in the end it > all came out OK. > > So, I'm going to empty my tank and then swab around in the bottom > and see if I turn up any rust. > > I'm going to take apart the gas valve and diaphragm and see if they > look OK and I'm going to have a look at the fuel strainer and see > if I find any rust there. > > I noted when I took the small vacuum hose off the gas valve, that > it didn't have a ring clamp on it and the end of the hose was > partially split. That made me wonder if maybe insufficient vacuum > was getting to the fuel valve diaphragm and perhaps limiting the > amount of fuel delivered? > > I'm also going to check the carbs themselves out. Following what > the manual indicates, I'm going to check out all the stuff I can > check out with the four carbs still ganged together. Vacuum > chamber, float chamber, float levels, jets, etc. > > Talking about working on the carbs brings me to my real questions > here. > > I have a vague memory from reading along on this group that someone > (was it you, Dennis H?) said that it is unwise to pull the rack of > carbs all apart unless you have a good reason for doing so. > > But I'm thinking that if I find any grit in the fuel strainer or in > the carb bowls, I'll need to pull them apart so I can get in and > blow all the internal holes out with compressed air. Does that > make sense or can I do that with them still ganged? > > The other thing I'm wondering about is do I need to buy carb > rebuilding kits or not? I just looked on EBay and I saw a kit for > the 700SC for $29. http://tinyurl.com/oyyknv > > For four carbs, that's $116 plus shipping. Money's tight here now > and I'm wondering if these are essential or just nice to have. > What do folks who've rebuilt their carbs think about this? Am I > foolish to not buy and use a rebuilding kits? > > Any and all advice will be much appreciated. I've got a sheet over > the engine and the four carbs sitting on my bench and I'm ready to > wade into what ever's next. > > Thanks! > > Dennis Gallagher > - Seattle > - '86 CB700SC > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to nighthawk_lovers@googlegroups.com To unsubscribe from this group, send email to nighthawk_lovers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en -~----------~----~----~----~------~----~------~--~---
