86 Honda VF700C Magna - New to Bikes

[crwallaceva]

I just aquired a 1986 Honda VF700C Magna ($200). It looks good, has 7K miles on it - but didn't run when I got it. This is my first bike and I am mechanically inclined (torn down engines and the like on cars).
Loaded on a trailer on Saturday and started to take an assesment of the 2 issues below:

Issue # 1. Gas tank had about 1 gallon of what used to be gasoline. A lot of rust "sluff" and I cleaned it out. Next step is to fill with some bb's and kero or mineral spirits and see what else I can get off of the interior. Not sure what to do after that - either epoxy the insides or just keep an eye on the fuel filter?

Issue # 2. Carb is gummed up, throttle didn't turn very easily initially. Spray the carb down with carb cleaner (while still on motor) and then some starter fluid. I cranked the bike and it has spark - a good thing! Last night the throttle was a bit easier to turn, but still sluggish. I had a lawn mower gas tank that I threw onto the fuel line and started it up. It took a few cranks but it started and sounded pretty good, but an aweful lot of smoke coming from the exhaust, which is probably in part due to the floats being gummed up and running rich. Not sure if I should remove carbs and spray them down more thougholy or just rebuild with a $27 kit (x4). I did notice an L shaped fuel tube coming up from the carb and was not attached to anything - it was dumping gas - kind of like a vent or overflow tube, if anyone has any ideas as to why it is pushing fuel out, would be good info. I looked everywhere to see if it connected to something, but didn't see anything. It also looks as if it never had a hose clamp on that end. If I can take a picture - I'll post it.

Other than changing out the other fluids, such as oil and shaft should I be looking at something else.

This bike looks like it has a lot of potential - first thing I want to do when I get it in running shape is change the square headlamp with a round one - any advice whould be great to this newby at motorcycles.

Chris

[DrBob]

I'd bet money that the inside of your carbs look exactly like the junk that came out of the gas tank. Take them off and clean the heck out of them. Stuck floats, needles, and jets will cause it to run poorly and dump gas out the vents. new floats might be in order- check them for leaks.

New fuel lines might be in order, and also hoses, as rubber tends to deteriorate when a bike sits for a long time. Check the tires also, not only for visable dry rot and cracking, but also for the date of manufacture- if they are more than 5-6 years old they are probably unsafe and should be replaced. Change all the fluids, and then treat it like a new bike: change the oil and shaft drive oil again in 600-1000 miles. Make sure youflush the brake lines well, as the master cylinders probably look like mud from the old fluid, and that gunk will clog up the small passages and hoses.

As for the tank, a good cleaning should do it. You might add a canister fuel filter somewhere right after the petcock (if it does not already have one), and if it starts catching a lot of junk then get some of that gas tank sealing cream to prevent further rust.

[Tab B.]

Originally Posted by DrBob

I'd bet money that the inside of your carbs look exactly like the junk that came out of the gas tank. Take them off and clean the heck out of them. Stuck floats, needles, and jets will cause it to run poorly and dump gas out the vents. new floats might be in order- check them for leaks.

New fuel lines might be in order, and also hoses, as rubber tends to deteriorate when a bike sits for a long time. Check the tires also, not only for visable dry rot and cracking, but also for the date of manufacture- if they are more than 5-6 years old they are probably unsafe and should be replaced. Change all the fluids, and then treat it like a new bike: change the oil and shaft drive oil again in 600-1000 miles. Make sure youflush the brake lines well, as the master cylinders probably look like mud from the old fluid, and that gunk will clog up the small passages and hoses.

As for the tank, a good cleaning should do it. You might add a canister fuel filter somewhere right after the petcock (if it does not already have one), and if it starts catching a lot of junk then get some of that gas tank sealing cream to prevent further rust.

What he said. New floats may indeed be in order. Also, be as anal as you know how, on the cleaning of the carbs. Take all of the jets out, especially the pilot jets. They are the smallest and usually the first to clog. Look at them with a magnifying glass. Pilots, you can clean with strands of copper speaker wire. Just find some strands from a small enough wire gage, that will fit. Make sure all of the passage ways that the jets access are clear also.
If the floats are a black rubber looking material, then definately consider replacing them, as they can become saturated with fuel, and no longer "float". If they are white plastic, have no cracks or splits,,, and you can't see any fuel sloshing insde them, you should be fine. Fuel needle valves and seats can be cleaned with a Q-tip, and get this, tooth paste. Basic tooth paste is a very fine abrasive, and won't harm the seating surfaces. Rinse thoroughly and enjoy the minty freshness.

[crwallaceva]

Thanks for the tips.

I pulled the carbs. Took a peek in one and found that the Jet needle was gummed up, almost like tree sap on the end. I was reading in the Clymer book to not mess with the pilot jets unless absolutely necessary and that they needed to be in the same exact position as they came out. I'm worried that I won't be able to do this exactly the same 4 times. I am wondering if soaking them in carb cleaner will do the trick. It also says the pilot jets can be removed while the carbs are on the bike or off. I did remove the main jet and the slow jet as well as the main jet holder - they looked varnished, but the ports looked open.

I also wonder if I should just spend the $25/carb rebuild kit (x4 - $100) instead of trying to clean up the parts. The carb rebuild comes with all the stuff - floats, jet needle, etc... The floats are opaque/yellow (not the black ones) and they don't have gas inside of them. Except for the float bowl gasket, which is needing replaced, I am debating whether if I clean everything up - is it worth the trouble of taking the carbs back out if that doesn't work?

I'm thinking I need to just buy the kits!

[Tab B.]

The kit isn't a bad idea, but if you can get away without it, money saved. I think what Clymer was talking about was the pilot "screws" being messed with. As a general rule, you shouldn't mess with them. BUT, from the sounds of things, you may end up messing with them anyways. The pilot screws, or fuel screws are the fine/final adjustment for the pilot circuit. I would take the pilot jets out. They should be right next to the main jets. Here are some problems to be aware of. Since they are tiny, if they get gunked up, you can bugger them up just trying to get them out,,,, and not get them out. That REALLY sucks. As a couple of precautions, I would get some penetrating oil of some kind, and let that stuff soak for a day or two. Then use a screw driver that fits the slot of the pilot jet as snugly as possible. Just before that, I would warm up the carb with a blow dryer. Aluminum expands more than brass when heated, so that should help ease the jet's removal. Once you get them out, then you can decide to clean or replace them.
If the pilot jets look awful, then the rest of that circuit isn't going to look good either. That means you should consider taking out the screws. Not a huge deal,,, IF,,, they have had the access plugs removed. Pretty much all m/c carbs from the early 80s onward, have brass or aluminum plugs over those screws so a nimrod like myself, won't mess with them. If the plugs have been removed, first, you should slowly turn the screws inward,,,,, carefully counting how many turns it takes to seat them LIGHTLY. Write down what you get for each screw. Then you can take them out. That is what you will set them to when you put them back in after you give the carb body a good cleaning/soaking. If they aren't the same, don't sweat it. The factory can be really anal because emissions rules. Take note of the highest and the lowest screw setting that you find. As an example, say one screw is at 2 turns from seated, and another is at 3 1/2 turns, either one can be your base for all four carbs. You don't have to be as anal as the factory. If you set your screws to the smaller number, the bike might be a wee bit cold blooded, and fussier on cold days until it warms up. If you set them to the larger number, they should be a wee bit less fussy. Once you have all of the jets removed, then a good soaking of the carbs in some mannner of carb cleaner will do its' best. I've usually cleaned my carbs at work, so I have access to good degreasers, and compressed air. Hmmmm, you may want to go out and pick up the premier issue of "Motorcyclist Retro". It is put out by the folks at "Motorcyclist" and it is going to cater to older bikes like yours {and mine, 86 GSXR}. They also happen have a good article on,,, you guessed it,,, carb cleaning. Please forgive my being long winded here. We enthusiasts can be that way sometimes.