newbe needs help..

Hello everyone,
i recently was given a 1985 vf500c that was running but sat for a few years.. i cleaned the carbs, new battery, changed oil, drained fuel tank, fresh gas, etc. here is my problem, it starts on choke, then will only stay running at 3000 rpm minimum, that is when the throttle if feathered to keep it revving, once running the choke doesn't seem to make a difference. it won't idle at all and as soon as i let the throttle go it instantly dies.

in talking to the previous owner that gave me the bike, i found out before he let it sit he put a battery in it (hooked up backwards). he said it made a decent bang! when he touched the negative to the positive and blew the main fuse.

i have a decent amount of mechanical skills, to work on the bike, but i am not sure where to begin.

also i should mention, when i do get it to idle (at 3500-4000 rpm) it surges up and down.

i am thinking electrical more than fuel.

any help is greatly appreciated.
thanks.

 

carbs

My money is on the carbs. Did you remove the pilot jets and verify that they were not clogged ? When you cleaned what did you do?

 

sounds like a vacum leak ck your rubber boots between carbs and intake for tears and cracks.

 

i took them off and cleaned the bowls, and blew everything out, i did not dis-assembly them completely. and the boots do not look to be in great shape.

are these two problem areas?
is there anything else i should look at?

thanks for the quick replies guys. i am not looking forward to doing this job again. they are not easy to get on or off.

thanks.

 

disasemble carbs completely and clean well then really inspect the rubber intake boots for cracks and tears, replace if any.
should do it for you. good luck and keep us posted.

 

don't take them apart from the top plate. you'll find that you'll never get them back together right, plus they will leak. pull everything out of the carbs use ziplock bags for each carb.don't mix the parts. clean them with carb cleaner and compressed air. get every hole cleaned out. do some checking around there are other posts about the 500's

 

I agree.

Carbs Jets dirty
Carp boots cracked
Choke spring broken, or linkage bent
Air filter clogged or needing replaced
Fuel filter dirty

 

Thanks for the quick replies, guys. as an update, i wasn't able to tear into it this weekend, my daughters 2nd b-day party = huge cook-out and a weekend full of yard work.

anyways i did try and start the bike and it won't even start anymore and that familar stink of rotten gas has come back, so it appears i have work to do tearing her down again, the tear down starts tonight, will update when i get the carbs off. thanks.

 

Update.
i took the carbs off last night, air filter is clean, 3 carb boots are perfect (for being 23 years old). one of them is starting to crack around the edge, not down near the middle where it seals to the carb / head. i will replace this. onto cleaning tonight. i will keep you posted.

thanks.

 

Bingo - carbs clogged for sure. Make sure to clean out the pilot circuit really well!

 

Hey Guys, i would like to thank everyone for the advice, i am up am running. cleaned the carbs and found all four low speed jets were clogged. just finished putting it back together and she runs and idles like a champ. off to ride!!!

Thanks Again.