Potential New VF Owner

Check the vacuum valve on the fuel petcock.

Easy to do - use a Mityvac, connect to the vacuum hose to see if the diaphragm is working.

 

What a clean bike, wow!

Make sure the hose isn't kinked! If it isn't you could have a bad fuel pump or a petcock diaphragm issue. Both can be resolved without any $ invested. The fuel pump can be pulled & pitched, and the petcock diaphragm can be cut to allow fuel to flow through it when it's turned on. I'm on my way out the door right now, but I'll check back here when I get back. Someone will likely post before then though.

Other possibility is poorly adjusted floats, but it seems unlikely that they are all off.

 

Made some progress today. Removed the tank, found that all the fuel hoses are pretty rotten, cracking and brittle. The vacuum line from the intake adapter to the petcock diaphragm is rotten and won't hold vacuum. I installed a temporary line on the petcock, put vacuum on it, fuel flowed from the petcock just fine. Connected the tank back up to the carb and I have hoses leaking. I am going to go ahead and remove the carbs, give them a cleaning and replace all the hoses, should solve the fuel problem. Checked the fuel pump relay and pump, working OK. The clutch was rubbery feeling so I cleaned out the master and flushed the system, clutch feels like it should, disengages cleanly with the bike in gear. I think sometime next week I might be able to take 'er fer a spin.

 

Nice to read a post like this.

Thoughtful step by step inspection is the way to go on any vintage bike with an unknown service history.

If I could make a suggestion, while you have the carburetors removed - this is a great time to remove the valve/cam covers and visually inspect the condition of the rockers and cams along with checking the valve lash.

The VF500F's valve train requires careful maintenance to insure the engine's longevity.

Keep us posted on the progress.

 

Good point on checking the valve lash and condition, I will definitely do that. Thanks.

 

+1, and remember, don't separate the carbs from the plate!

 

+1 on the +1

Keeping the throttle bodies mounted to the plate is best - unless you have logged some serious V-Four carburetor rebuild time and you don't own a cat or a dog that can jump up on the workbench.

 

Or just:

Daugherty Motorsports - Tank Valve Petcock Modification

That's been the permanent fix for my bikes!

 

Well guys, looks like I need some help. I thought that the carb for # 4 cylinder had a float needle problem, was leaking. Turns out that the plastic fuel connector tube between the carbs is leaking, I'm assuming that there is an O-ring involved. Since one is leaking, I intend to separate the carbs and replace all the O-ring seals. Are there any pitfalls that I need to know about before I pull them apart, like maybe a net to catch flying parts?

 

Separating the throttle bodies from the mounting plate is not for the faint of heart. You are on the right track with having a few safety nets.

Before diving in, I would recommend purchasing a copy of Mike Nixon's guide to V4 carburetor rebuilding. This is a must read, IMO, before you start the disassembly.

The Motorcycle Project Book Nook

 

It's very possible that the plastic fuel T is cracked. They are very brittle and are easily broken. I would suggest getting new ones on order - if they aren't broken now they very well might be once you start separating the carbs!

 

Thanks very much ic, I will order that right away. On closer inspection of the assembly, it looks like there are two springs missing on the throttle adjusting screws. Are there supposed to be two springs, one under the adjuster screw head and another between the two tabs? Hopefully, Nixon's book will show whether or not this is the case. The float bowl seals are pretty hard and flattened, do you have a source for new seals and other carb parts that I may need?

 

I think you will find Mike's tech manual very helpful.

Billy Carr offers very good pricing on float bowl gaskets. I believe these are aftermarket but of good quality.

Billy C's more or less complete price list

If you run into trouble with your rebuild I have a spare set of very clean '84 VD-B carbs. VD-Bs are the Canadian issue '84 VF500F carbs. They have a 32mm throttle bore with #102F and #105R main jets, #38 slow jets and 2VG jet needles front and back. I was going to hold onto these but I have two sets already and only have so much room on the parts shelf. Please feel free to send a PM if interested.

Good luck with the rebuild and let us know how you make out.

 

Hit me up if you want a pair of stock mufflers.

Good luck with getting the bike running.

 

I forgot to mention that I had the engine running on Friday. I had filled the bowls with Seafoam, let it sit overnight and then drained them. I had also poured a bit of Seafoam into the spark plug holes. Since I had determined that the petcock is OK, I connected the tank directly to the carb fuel inlet bypassing the filter and pump. After a few sputters, the engine fired up, idled smoothly and with the choke 1/2 way on, took throttle very well (lots of smoke at first, cleared up) I didn't hear any rocker arm clatter at all (don't know at this point if that is good or bad) was stoked to hear the engine run so well. I ran it about 3-4 minutes, shut it down. I now have the carb assembly removed, will be ordering some bowl gaskets and I'm pretty sure that I can get the O-rings I need at the local NAPA, they have a very large selection. Thanks much for all the help and advice so far. slowbird....thanks for the offer on the mufflers, can you email some pics?

 

I've had a VF and a VFR that have had cam wear but ran well and quiet. I didn't know until I had the bike opened up.


These are the cans.


They have a few scuffs and scratches. PM me your e-mail and I'll get you more pics.

Mind you....I loved my F1r pipes.

 

So just think how happy you would still be if you never opened it up! You'd still be contently riding around the 500 for years to come. Too bad VF Guru told you about it when you did the lash adjustment...

 

I have just been revived after pricing the Honda OEM carb gasket kit. After some thought, I am going to try to make my own bowl and flange gaskets from a DIY O ring kit. You slice the proper length off a straight length of the proper diameter O ring material and glue the ends together with the supplied cement. Anyone done this? Found a clutch slave kit here CLUTCH SLAVE CYLINDER REBUILD KIT for HONDA VF500 VFR700 VFR750 VFR800 CB1000 CBR1000 ST1100 GL1500

 

No need! You can find an o-ring that is already the correct size. In fact, one from the $25 VF500 seal kit that I offer is probably the same size. Shoot me a PM and I can do some checking if you are interested.