How to get it running agaian..

[marco]

Hi just bought a 96 vfr750f 4th gen been stood 10 years! in great consdition but tank needs cleaning carbs removal and cleaning all cables locked up engine spins fine only 30.000 miles all original.Whats best way to remove carbs clean and setup and what to use to flush/clean fuel tank any advise would be great to get her back on road.

[Thumbs]

You need to read Joe’s write up with pics @ V4dreams.com for the carbs

 

The carb rubbers will be rock hard, particularly with the rotten weather we’re having, so make sure you warm them up 

This guy has a complete 4 carb set of O rings, jets, float valve etc for £15 delivered https://www.ebay.co.uk/itm/174527528066

 

First clean the tank out with white vinegar then depending on the state electrolysis with a battery charger will get you back to clean metal 

 

I put grey etching primer in mine and made sure it was in every crevice 

[marco]

electrolysis with a battery charger ? uhhh sorry im thick how to with batt charger? cheers .

[marco]

oh and grey etching primer ? is it like self etch and does,nt the fuel wash it all out ? all new to me.

[Thumbs]

Rust removal 

 

Etching primer chemically bonds to the clean steel, I’ve been doing this for years, personally I prefer painting the inside than putting a new epoxy liner in

I’ve recently been doing everything you’re about to start so have lots of other information and links .... good luck 

[marco]

ok would i get away without gettting carbs out? i dont think fuel pump working does it run when ignition on or buzz or click? ive got nothing tank off put my finger over inlet no suction any thing to try thanks got all the lights to work today so a start.

[DannoXYZ]

Maybe 2-5yrs is borderline for needing complete refurb and restoration of carbs. Here's carbs that's been sitting for 1.5-yrs before I bought bike.

 

 

And another set that wasn't working after 1-lap at Buttonwillow:

 

But after sitting 10-yrs, you really should refurb carbs completely. Not just remove and squirt useless "carb cleaner" through, but completely disassemble to every single last individual component: jets, washers, seals, O-rings, floats, slides, float-valves. Scrub every part until they're shiny factory-fresh clean.

 

Then scrub out all hidden petrol circuits. Ultrasonic soak in caustic radioactive solvents. Micro soda-blast. Then re-assemble with all-new rubber parts:  O-rings, float valves, maybe diaphragms.

[Cogswell]

If you want to see if you can get it running before going to the extent of tank cleaning, once the carbs are done you could use a portable gas tank boaters use with outboard motors.  If you know anyone with a small boat, it's possible they might have one to lend you.  Or, maybe find one cheap in the local ads. 

[squirrelman]

it's essential to have a clean fuel tank b4 hooking it up to carbs.  be sure to change the main fuel filter too. you're gonna need a copy of the honda service manual either in paper or a download.

[marco]

Cheers i think fuel punmp not working how should it run ? cranking over or buzz or something..

[Lannyl81]

The fuel pump pulses, does not run like a motor.  The FP pulses when the output line pressure is less than the internal spring...which is about 1-3psi.  So normal operation is the FP pulses, pushes fuel into the carbs, only when the carb float valves are open.

 

An easy test is to apply fused 12V directly to the fuel pump electrical connector with the output into a container if there is fuel at the inlet.  Need to be sure you have the polarity correct; Honda uses green wire insulation as the frame/ground.  Once again I suggest using an inline fuse, just in case; 10 amp fuse, nothing higher.  The FP will "buzz" if it is working.

 

I do not know what the flow rate of the FP is...probably in the SM somewhere. 

[marco]

cheers ill check seen cheapo for £22 ebay if i cant get it to work.Got fuel sender to work waiting for 20L white viniger get the tank sorted its a right mess in there try to prize the carbs of next..happy days

[Thumbs]

1 hour ago, marco said:

prize the carbs of next..happy days

Joe has a very helpful write up on that .... you really need 2 people to get them off

 

Don't forget to warm up rubbers up or they’ll just rip apart and that’ll really piss you off

[Lannyl81]

The cheapo fuel pumps on ebay lasts about an hour....get the K&L one.

[DannoXYZ]

7 hours ago, marco said:

Cheers i think fuel punmp not working how should it run ? cranking over or buzz or something..

Fuel-pump only runs when engine is spinning with ignition-pulses. Early '90s had change in FMVSS safety rules. Don't want fuel-pump running when you've crashed and trapped upside-down in car with fuel-pump merrily pumping petrol from ruptured fuel-lines onto hot exhaust pipes.

 

Easy test of fuel-pump:

 

1. connect IV-drip bottle to supply petrol to pump.

2. disconnect pump fuel-hose from carbs and aim into measuring-cup.

3. Crank engine for 10-seconds.

4. Measure how much petrol was collected in measuring-cup and

5. compare to number in manual. 

 

After you've got tank cleaned, do exact same test with petcock-outlet aimed into measuring-cup. Apply vacuum to petcock and time flow for 10-seconds.

 

There are multiple stages where fuel-flow can be interrupted. Clogged hoses, clogged filters, clogged carbs, clogged pump, clogged petcock, etc. You want to test and measure them all. While zero-flow from pump is obvious failure-sign, numbers will tell you whether fuel-system is running optimally. There's difference between 50cc/min vs. 250cc/min flow, and that'll make difference if bike runs or not (fantasy numbers, check actual # in manual).

[marco]

Hi got carbs off really easy after all... took pet cock off strainer looks ok ish cant get em anymore.. so hope its ok sucks and blows ok tank next to clean its dreadfull inside ive got another coming from ebay lovely clean inside but different colour as a back up also try fuel pump cheers for now.Herrs a couple pics of bike before i took apart hope one day when back together it runs and on the road! Got it for £550 so worth a chance.

[marco]

cleaned carbs up took bowl off in really good condition just needed a litte wipe around pulled jets not blocked loosened everything up ...looking good feeling good about it worst is tank and look at fuel pump then all fluids onwards and upwards!

[marco]

Hi again...fuel pump works a treat tank cleaning going well 21 l white vineger got fuel sensor to work petcock both out of tank and blocked off look like new cleaned with elbow grease fantastic stuff.after ive flushed out all the crap and used baking powder to neutralise acid aprt from gey primer i suppose to just swill it around is there any other products to use ..like POR15 or phosforus product or tank ok without just new petrol? all advise be great.

[marco]

just to add not keen on POR15 dont really want to line tank seen Phosphoric Acid adds a coat is it like grey etch primer ...

[scottbott]

£550 !!, blimey that was a good price, how good is the bodywork?, looks good in photo's, lucky you

[marco]

body work in superb condition the odd small marks all plastics no tabs broken or cracks tank was immaculate on out side but just yesterday i dropped something out of cupboard onto top put a little dent in it not bad but enough to pxxxme off after 25 years of no dents wish i covered it but there you go.Cleaning going well freed up rear brake new fluid all moves nice now soon the fronts if it was,nt that its been stood you would think its in daily use...was up for £700 still cheap i sold a cbr 600 f4 2 years ago and regreted it, it was immaculate with only 11.000 miles so i jumped at it.. know its worth alot more if it runs good which im sure it will, i will keep it and keep it fettled.

[marco]

Hi got it to run rear bank hot front bank not all with new plugs front did have spark all fuel bowls have fuel water circulating oil light out..need to see why front not fireing front exhaust cold so for some reason fuel not getting into cyclinders ...on we go any idears?

[Captain 80s]

Very likely, you did not get the carbs properly cleaned.  If you have spark and the ability to deliver good fuel to the carbs, that is pretty much what is left.

[marco]

ye have another go weekend 2 out of 4 not bad...not started for 2/3 years

[Captain 80s]

I know V4 carbs are not fun, but 2 out 4 is NOT GOOD.  If you are following the tutorial links provided, following the advice given and doing it correctly, it would be done right the first time.  Re-read the tutorials, re-read this thread, take your time, don't skip any steps.