VF400F carbs

I have managed to get a workshop manual for the VF, the Carbs look a bit tricky to get at and since it hasn't run for 5 years they probably will need ultrasonic cleaning or I might try just dropping the needles & jets in some STP carb cleaner to see if that works first.

Any advise is welcome.

 

Not sure if they have it in the UK, but soaking the carbs in Pine Sol works really well and doesn't leave any residue. I did this with my Ducati carbs and seemed to do the job. Here's a link to more info...
http://www.advrider.com/forums/showthread.php?t=560117

Cheers.

 

Never heard of Pine Sol but thanks for the info.

 

^^ makes 'em real shiney but does not clean clogged passages or clogged jets and is only the beginning of a proper carb cleaning.

 

Thanks I'll do a bit of Googleing to see if it over here..

I have found it on sale at Amazon but which one I'm assuming its the original as there are loads of products from Clorox..

 

I would try some Sea Foam first (see ebay) then buy the guide from Mike Nixon if you plan to overhaul: http://www.v4hondacarbs.com.

I only use the fancy Shell unleaded with the additives.

 

Okay Paul I'll look in to Sea Foam, isn't it free on the beach..:wink: Thanks for the link.

 

Carbs need a proper hand-cleaning, not just a simple chemical dip. :bull_head:

 

Hi

The carbs need a proper clean as mentioned.

Just busy getting my 83 Interceptor running after a period of probably 4 years and have done my carbs. There will be lots of old fuel and sticky varnish deposits in the gubbins that need proper cleaning and dismantling of the carbs to do properly.

Will post a how-to shortly - it's not all that difficult but, from what I found in mine do not spray anything into the carbs until you have removed the vacuum diaphragms.

Better still, set aside an afternoon and get a 7mm, a 10mm socket, a star and a flat screwdriver together.

On mine all the original parts were serviceable and re-usable although I replaced them all as matter of course (except the diaphragms which are hard to find and expensive to ship out here so its best to take care to preserve them)

Also get some lacquer thinners and carb cleaning spray, some old cleaning cloth and some ear cleaning sticks together.

Remove the carbs from the bike in the interim but do not take them off the lower air intake plate. It's easier to work on them mounted on that and everything you need to get at at first is accessible.

Only ever work on one carb at a time. It's an easy process really and straightforward.

Will post the process later today.

Cheers

 

Thanks for the input. All sensible suggestions 7mm socket! I'll have to see if I have that size as its an un-usual size.

 

"Only ever work on one carb at a time."

Mix and match as necessary. I clean idle jets and main jet tubes all together. Only necessary (maybe) for vacuum slides to go back into the same carbs they came from; all other bits and pieces should be interchangable, with proper and accurate float setting. Even idle mixture screws could be interchanged IF factory idle drop procedure was done or optimally tuned by ear.

 

VF Carb cleaning how-to

V4 carb cleaning - a how to as promised.

Just finished mine so here goes.

CAVEAT: I had no option but to do my own carb cleaning, setting and adjustment. This was because the expertise of professionals suggested on this forum (who I suggest you engage to re-build your carbs if you can afford the US$250-300 fee) was prohibitive given the distance and costs involved in shipping my carbs to the US. In addition, the risk of the items being stolen when shipped back to Africa is high so I opted to clean them myself.

If you can, and you are in the UK or USA/Canada, I would suggest that your best option is an economy carb re-build from one of the suggested specialists used by other forum members.

If you opt to clean them yourself then please understand that “your mileage may vary” and results may not be optimum as compared to a professional rebuild.

The procedure here is suggested for carbs that have sat for some time with fuel in them without the engine being run and where float levels and other settings have not been tampered with.

WARNING: Solvents must NOT get into contact with the diaphragm in the upper carb assembly. Squirting volatile aerosols, carb cleaner or other gunk into the carb without dis-assembling it is not a good idea.

WORK AREA: Make sure you have a clean work area and that all tools and cloths used are clean.

CLEANERS: Lacquer thinners, gasoline, 1200 grit sand paper (For exterior polishing of vacuum domes ONLY) Carb cleaner spray, DUST-OFF or similar compressed, filtered air.

TOOLS: Flat screwdriver, star screwdriver, 7mm socket and 10mm socket, 10mm paint brush, old plastic bowls, old (clean) glass coffee jar, clean cloth.

SPARES: K&L or similar re-build set with O-rings, float bowl gaskets, jets etc. Approx US$30 each or some E Bay sellers sell 4 for US$100. Search around.

You CAN re-use old parts but yet again, your mileage may vary.

THE CLEANING

WORK ON ONE CARBURETOR AT A TIME – DO NOT MIX-UP PARTS - While they may be interchangeable I tend to be conservative - if it worked with them there before...

To start with, you do not need to remove the carbs from the lower air intake plate. If you have done this already, put them back to save too much fiddling about. The plate makes it easier to handle the carbs and gives more leverage for unscrewing bits.

Photos are labelled steps 1 through 12 and should follow the text.

DIAPHRAGM AND NEEDLE SLIDE
Unscrew the top 4 screws around the vacuum dome. TIP: Remove the screw next to the little indentation first. If it, or any other one is reluctant to come loose, remove the others and then turn the dome a bit (Only a few mm as you do not want to damage the spring inside under the dome). Usually this loosens a stubborn screw.

Lift off the dome and remove the long spring you will see (It usually pops right up and you cannot miss it.) Set these parts aside in a plastic bowl or other suitable clean container.

Nor carefully lift the edges of the diaphragm away from the carb body – do this gently as you do not want to damage the diaphragm – if yours are already deteriorated (tears, splits, holes) then you must replace them – tough break. Mine were all fine – not bad for 30 year old parts!

Carefully lift the diaphragm and slide out of the carb body. Usually, if the bike has sat idle for a long time, you will see varnish on the needle. This can be carefully cleaned by wetting a cloth with thinners and gently rubbing the needle down to remove the varnish. Do not get thinners on the diaphragm! NoW set this assembly aside in a clean container of its own.

If you are going to replace the needle, then this is done by pressing down slightly on the clip inside the top of the slide and turning a few degrees. Then the needle and retainer can be removed. Assembly is the reverse process (Hee-Hee!)

FLOAT BOWL
Remove the 4 cross head machine screws on the float bowl. Usually, on carbs that have sat for ages, the float bowl needs a light tap with the handle of a screwdriver to dislodge. Do not use a mallet or hammer – not advisable. Light tapping and patience eventually releases the bowl. Do not try and lever it off with a sharp edge.

Remove the bowl and set aside – inside you are likely to see residue of old fuel – ranging from heavy varnish deposits to light rust or even green dye residues.

Now look at the float chamber – you will see the plastic float. It is attached with a slip-in pin. On the outer carbs simply slip it out and place in your container of bits. With the middle carbs the linkage bar has holes and slots drilled into it to help remove this if you position it properly while you slide the pin out.

Now you can carfeully lift the float bowl and shut-off valve from the fuel inlet that is just below the hinge area of the float. DO NOT PULL on the float as the metal strip that hooks under the attachment to the shut-off valve determines the float level. If you bend this then you will have just complicated the cleaning/rebuild by a factor of 10x.

You can slip the float out towards the front and then try and wiggle the shut-off valve out if it is reluctant. Mine came out without a fight.

Once you have done this, a 10mm socket is used to remove the inlet tube and screen.

If not replacing the inlet screen, tube and washer, (most kits have them new) you can use gasoline and a brush to clean this out – DO NOT USE THINNERS HERE, you will melt the plastic cage and inlet screen.

Once you have cleaned this with fresh gasoline, use the compressed air to blow it clear from the inside. If there are heavy varnish deposits in the tube, then use cotton buds dipped in thinners to clean the tube – remove the screen first (Be gentle as they get brittle.)

Make sure the seat inside the inlet tube against which the shut-off valve rubber will push is free of grit (Cotton ear buds are great to get in there and clean it properly.)

Replace the inlet tube and screen.

REMOVING MAIN JET
Use a flat screwdriver to remove the lower part of the main jet. It usually screws out leaving the main jet behind but some may come out together.

Use a 7mm socket to remove the main jet.

Drop the jet and inlet screw into your coffee jar with some thinners in it to soak for a few minutes.

CLEANING MAIN JET ORIFICE
While the coffee jar is doing its thing, you can blow carb cleaner down the main jet tube, the slow jet and the others. Wipe up any excess.

Use the compressed air to blow down the jet tubes and then the vacuum tube at the top of the carb to make sure it is clear. (That is the little orifice in the semi-circle under the indent on the dome cap around which the diaphragm locates.)

Once the carb cleaner has dried, use the compressed air to blow through the main and other jet orifices as well.

REMOVING VARNISH DEPOSITS/CLEANING FLOAT CHAMBERS
Wet a cloth with thinners and then wipe the varnish away. It may take a few wipes but eventually it will come up clean. Use cotton buds to get into crevices.

CLEANING MAIN JET
Remove the main jet from the thinners.

Now grab the main jet so as to cover the one end with a finger. Now spray carb cleaner into the other end and make sure it sprays out of all the holes on the jet. There are two rows down each side and two small holes at the top. Repeat until they all let spray through.

Allow to dry then blow out with compressed air.

Do this to the main jet inlet screw as well.

Now re-assemble by using the 7mm socket to screw in the main jet.

Replace the inlet screw.

CLEANING THE OTHER JETS
Only one of these is easy to clean. It is the only othe rone with a slot in it. Use a flat screwdriver to remove it and follow the same procedure as for the main jet.

RE-ASSEMBLY
Replace the jets, float (ensuring wire hook is around the metal tab), float hinge pin and then replace the float bowl after replacing the gasket.

Use the new machine screws provided in the rebuild kit.

Carefully replace the diaphragm ensuring the needle drops into the main jet orifice in the middle of the carb body.

Carefully align the diaphragm tab with the vacuum hole and place it in position around the vacuum tube.

Replace the long spring.

Replace the dome cap ensuring the spring is seated around the retainer in the underside of the cap and that the indentation is over the vacuum hole.

Replace the machine screws one by one – do not over-tighten them though, When they feel like they are tight, give them just the slightest of added torque. The dome cap seals against the cap and will have some "give".

Carbs 2-4
Repeat steps as above.

AIR AND FUEL CROSSOVER TUBES.
There are two metal fuel crossover tubes that use O-rings on either end. Loosen the carbs from the support plate until you can get the tubes out. Replace the O-Rings and re-install the tubes. Use a little bit of motor oil to lubricate the O=Rings when re-inserting the tubes.

The fuel supply tube T-inlet is a cruddy plastic job that is either cracked and leaking or is yet to crack and leak. I suggest you buy one of the aluminium ones on E-Bay or make your own one up at an engineering firm. If in the US it's only US$30 for a ready made one off E-Bay. The genuine Honda one – if you can find one – is more! (Out here anyway) I made one myself in about 30 minutes with the help of a mate's lathe to cut the O-Ring recesses.

Replace this T-Piece or re-new the O-Rings if you must re-use the old one.

Replace the O-Rings on the air crossover pipes as well (Tube runs from the airbox to two plastic tubes linked by a slightly fatter pipe at the top of the carbs near the dome cover.

TESTING
Replace carbs in the frame by re-installing the lower airbox plate as if the carbs are being re-fitted and connect up the fuel feed. Do not worry about fitting carbs into the intake boots yet.

Make sure the kill switch is off. Switch on the bike. You should hear the fuel pump operating for a second or so then stop. If so, be happy. If not, you have other fish to fry and may need to clean/service the fuel pump.

Assuming the pump operated, switch off the ignition and leave the carbs overnight to check for leaks from the float bowls or cross-over pipes.

If no leaks, refit carbs and see how she goes.

If you have leaks, trace and rectify as needed.

If you get lumpy running or hesitation on acceleration there may still be blockages, If the job is done correctly and you have not upset the float levels then it should work fine.

If you need to re-set or check the float levels then follow the procedure in the dealer service manual available in the downloads section of this site. (Great item to have )

POLISHING DOME COVERS
If the dome covers are cruddy, use the 1200 grit paper (wet) to polish them up while they are off the carbs. (A before/after effect can be seen in one of the shots where the one on the right has been cleaned up and the other still has to be done.)

Hope this helps you.

Good luck

 

Brilliant and very useful indeed, although some important details were perhaps omitted and you covered nothing that wasn't in the Honda service manual, but thanks for your time anyway.

There are at least 6-8 similar carb cleaning tutorials on this forum and thousands on other fora, but each one may have something unique to contribute, hope i have.

As for SPARES: round float bowl O-rings--easily fitted--sell for about $1 each if you have the specs and a source. Only the criminally insane would pay $100/4.

New carb fettlers must always be cautioned: first time carb virgins need to be reminded how brittle and fragile carb alloy can be: a fall off a workbench or drop may ruin something or anything over-tightened like jets can be a disaster. Don't re-install any screws that have the heads gouged out.

Test float valves (and crossover tubes) for leakage--as described above--and proper slide diaphram operation before installation.

Hardly needs repeating--i hope--that before connecting up carbs, the fuel tank needs an inspection (for rust) and a proper flush to expel any sediment. IT's a must-do if you don't want to clean the carbs again in a couple weeks.

This is a fragment of my carb experience (over 40 years): don't assume any jet orifice is perfectly clear until you've passed a wire through it. "I saw light" is no indication that a jet hole is perfectly clear. Emulsion tube holes need a quick wire treatment too to clear built-up deposits.

 

Thank you Squirrelman.

Warning about tank rust and the need to work carefully so as not to drop or bump the carbs are all on point. Apologies for not adding that - having done work on engines for decades I assumed that was obvious.

As to rust, my tank had been drained and the attached photo shows what came out just by shaking the obvious stuff out.

You can imagine that will quickly kill the fuel filter and crud-up the tubes, age the pump (if not block it totally) and bung-up the carbs if not dealt with.

Various methods exist, no doubt, for tackling this.

First, I removed the tank float/level guage sender unit.

THen after shaking the loose crud out seen in the photo and blowing out with an air line, I put clean pebbles in the tank with fresh gasoline and shook it about (repeated many times) until the fuel coming out was clear and flake-free. Inside of the tank is now shiny again.

Also put in fresh gasoline and pumped out once or twice through outlet tube until it was all clear.

As for the seals, the carb kits I mentioned at $100/4 include the O-rings for various bits, including the crossover tubes and idle jets, new idle jets, machine screws for the dome cover and float bowl, springs for the choke, new inlet tube and filter screen plus other sundries.

All of the essential bits (O-rings, new screws etc) can be purchased at other sources - I got machine screws, springs and O-Rings from a local motor parts store. Once again shipping-in the kits would have made it even crazier in cost. The Flaot bowl seal was, as gleaned form one of your earlier posts, simply a suitable diameter O-Ring pushed into place. (Thanks for that tip).

As to using a wire, Squirrelman, that has merit but I read caveats about that so went for the spray until it is clear method. Each works I guess but if it is really gummed-up a wire will be needed.

Our VF400 owner cannot say he has no options!

 

Wha?? So you never tried it but derived your suspicions via some ancient wisdom attributed to an uncertified, uncredentialed person through an online source claiming no particular authority?? You're too smart for that !

Use chemicals and compressed air all you want, some deposits need the application of wires for a properly- cleaned carb. :clown:







Sorry i misunderstood your spares details above.
:embarrassed:

 

Use chemicals and compressed air all you want, some deposits need the application of wires for a properly- cleaned carb. :clown:

I had the wire on stand-by in case the other method failed though...as said, if it is really gummed-up, I agree that a wire is needed. Guess I got lucky (Probably because the tank and carbs were drained before the long sleep.)

If a bike has stood with float bowls of fuel for ages, no doubt wire is the way to go as your experience proves.

I have always tried the least intrusive approach before bringing in the artillery though.