VF500: Only runs if I rock it back and forth

1984 VF500F- 40k miles, fuel pump delete, stock jets & exhaust

Hasn't seen much use the last year. Ran great when parked. Carbs synched, idle set, etc. Purred like a kitten. Went to start it and it revs up and then dies. Pulled the carbs and cleaned them. Some of the jets were definitely clogged so I thought the problem would be solved. I was wrong. On full choke it fires on the first try, revs up to 4-5k, then dies. However, if I rock the bike side to side while starting and keep rocking it, the revs stay up. Any ideas? Float issues? Thanks

 

I'm thinking you need to clean the tank and the rest of the fuel supply system too. Fuel may be partially gelled in the tank.

Good luck. :mechanic:

 

Previous fuel was 5 months old with stabilizer. Nothing nasty in the tank. Fresh fuel in there now. Will pull the carbs again and have another look. thanks

 

Carbs won't clog if you drain the float bowls before storage or non-riding periods, and that takes less than 2 minutes, compared to how long to clean carbs again ??

As solo says, drain, flush, clean fuel tank and check for rust. Coat tank if rust is present.

 

Ice-Munchin knows his viffers:smile: I hate creaming gas tanks, dont twist dat chit into some perverted stuff yah sodomites! I am keen on using the acid etching and cleaner from KREEM...Me thinks you can use muriatic acid too, but me is unsure...

I have seen coated gas tanks give up and they yielded a floating douche bag inside dah tank...food for thought...thats all. :evil:

 

Epoxy-coated tanks (Plating Kits Electroplating Kits Aluminum Anodizing Kits Powder Coating Systems Metal Polishing And Buffing Supplies - Caswell Inc ) don't come apart, and the exterior of the tank is likely to rust away before the impervious coating goes to shit.

 

Yours runs and you actually rode it home from the seller and you complain ?? That's rare!! Do you know how lucky you are that it runs at all compared to so many thousand others ??

 

Huh? It runs a little if i violently shake it side to side while standing next to it. I have owned for 5 years. It has had its ups and downs but overall not too bad. This issue is a new one.

 

squirrelman I am one of those thousand lol. I have had issue after issue for almost three years never been able to ride it on the rode as it would not pass inspection first leaky carb for eeevvvveeerrr no matter what I did then it just stopped all by its self one day lol. Now working on taking the engine off as to replace head gaskets the guy that had the bike before me said he had done them but I have had nothing but coolent leaking into the oil so I am doing them again. I have really high expectations with this bike after I fix everything. The little bit I have rode it have made me not be able to let it go. I MUST FIX EVERYTHING WITH IT! lol its very slow but Im getting close to a rode ready bike finally.

 

Somone's personal dedication to the project, hard work and $$$ to get it back on the road is the only way to preserve these near-gems for the more classically-oriented riders of 2020 and beyond......:biggrin::soapbox:


The main caveat for VF ownership is that you always need to have another bike to ride so you're a motorcycle rider, not just an owner.

 

The first year of ownership was hell. Way more time fixing than riding. The second year was great, just regular maintenance. Then things started breaking again in the third
year. There is definitely a pattern of one good year then a bad year. When it is running right, riding the bike is so rewarding. It is a fun bike and there is a satisfaction knowing that I brought it back from the dead (most years). Anyway . . .

The tank and fuel line are clean and clear. I am actually amazed at how clean the inside of the tank is. Had the carbs off and cleaned the jets again. Refilled with fresh fuel and started it up. Let it warm up and took it off choke. Idle was a little rough but right around where it should be. Throttle response was okay. Shaking the bike back and forth didn't change the RPMs. So far so good. Went to get my gear and take it out for a test ride. Just as I was about to take off, the idle started jumping between 3,000 and 5,000. Then the revs climbed to 6,000 and are pegged there now. Adjusting idle knob does nothing to change RPMs.

Hooray for this.

 

this sounds like your carbs have passages blocked. even simple carbs (of yours are not) have small passages that get clogged and make life hell. The rocking was most likely a float issue or a vent issue. now I would say you have fuel poring into the engine and the lack of air is keeping it from running away. Put a small inline cindered bronze (not the paper one) fuel filter between the tank and the carbs. this will catch just about everything that cant pass through the carbs including varnish in the fuel (get a can of premium and fill your tank from dry). If memory serves your carbs have a diaphram on them for automatic altitiude changes, thi means you would have a seal that could be leaking or a set of vents that are plugged. time for a complete carb tear-down.

Carbs = simple+reliable+fun+proper_storage/ missery+wrenching+time+money+improper_storage
from this we can see making sure the carbs are drained and the chance of fuel leaking in to them is removed we can remove the storage parts as well as money and a portion of the wrenching.

I like to turn off and remove the fuel line and then run the carb on my 200 dry, wait half a beer and try to start it again with full choke, when it no longer starts then they are as dry as they will get without removing them. beer is optional but greatly helps the seperation anxiety.

now jokes and half assed advice over, looks/sounds like you will need to take them right down to nothing and soak them, its a long and time consuming process, see if squirrelman has a gasket kit. and while your at it might consider a full rebuilt and jet tune depending on altitude you ride at.

 

thanks for the reply. Carbs are off again getting ready to be disassembled and soaked. The jets are still clear so the issue is somewhere else. It did have a fuel tank vent issue. The bike doesn't have a fuel pump so the petcock has been modified as shown on Jamie D's website. The vent hose loop was loose and had some fuel. Cleaned it out and secured with better clamps. The bike didn't conk out so soon but still ran poorly. Hope the soaking and closer inspection will have some positive results.