replacing fuel petcock diaphragm - a big job? (from a newbie)

[mvukin]

Considering buying a 1999 gs500e which sounds to be in great condition except for a few small issues ....

The one I have question is described in the following remark; "He told me the diaphram in the fuel valve where you switch between RESERVE/OFF/ON has dried out.  He re-routed the fuel line and suggested that the valve be replaced.  I haven't done it because it runs fine the way it is."

The bike apparently was rarely ridden a few years and I assume this is why it dried out.  Any problems with having driven it this way?  I was told by some others there was a risk in doing this that engine oil would get into the gas tank.  Easy fix or expensive?  Anything I should be wary of before making this purchase?

Thanks!

Matt

[Trwhouse]

Hi Matt,

Welcome to our world.
Actually, the info you were given is backward.
If the vacuum petcock is not working and the petcock is left in the PRIME position, there is a chance that gasoline can get through the carbs and leak into cylinders, and the engine oil. That could happen if the carb floats were set too high or if the needle valves in the carbs are worn and allow fuel to pass through when it's not supposed to flow.
Engine oil can't get into the fuel tank this way.
What you need is a new fuel petcock, or valve. I don't believe Suzuki sells a new diaphragm for the fuel petcock. They don't sell replacement parts for the petcock, so you need to get a complete unit.
Others have blocked the vacuum port on the carbs and replaced the troublesome stock petcock with one from a Honda CR250F dirt bike. This will resolve the fuel starvation problem that is often found in these bikes.
Do a search here on the site for Honda CR250R and you will find those links.
It's not a bad job if you have some experience with basic hand tools, have some expertise and can work carefully and follow instructions.
Good luck.
Yours,
Trwhouse

   
replacing fuel petcock diaphragm - a big job? (from a newbie)
« on: February 11, 2009, 10:56:58 PM »
   Reply with quote
Considering buying a 1999 gs500e which sounds to be in great condition except for a few small issues ....

The one I have question is described in the following remark; "He told me the diaphram in the fuel valve where you switch between RESERVE/OFF/ON has dried out.  He re-routed the fuel line and suggested that the valve be replaced.  I haven't done it because it runs fine the way it is."

The bike apparently was rarely ridden a few years and I assume this is why it dried out.  Any problems with having driven it this way?  I was told by some others there was a risk in doing this that engine oil would get into the gas tank.  Easy fix or expensive?  Anything I should be wary of before making this purchase?

Thanks!

Matt

[fred]

Considering buying a 1999 gs500e which sounds to be in great condition except for a few small issues ....

The one I have question is described in the following remark; "He told me the diaphram in the fuel valve where you switch between RESERVE/OFF/ON has dried out.  He re-routed the fuel line and suggested that the valve be replaced.  I haven't done it because it runs fine the way it is."

The bike apparently was rarely ridden a few years and I assume this is why it dried out.  Any problems with having driven it this way?  I was told by some others there was a risk in doing this that engine oil would get into the gas tank.  Easy fix or expensive?  Anything I should be wary of before making this purchase?

Thanks!

Matt

Yeah, change the petcock, oil and filter and you should be fine... You might also need to clean the carbs if it has been sitting for a very long time, but no big deal. You can do it as a newbie, no problem. Save yourself some headache and grab a Clymer or Haynes manual to help you figure out what to do. Having someone to help out or read the manual to you doesn't hurt either...

[mvukin]

Thanks for your feedback .....

- so this isn't a dealbreaker that should keep me from buying the bike then, eh?

- what would be the problems with leaving the whole system as the seller describes?

[DoD#i]

Search here a little - there's a lot of info.

Basically, any problem with the float valves (a tiny pice of rust, etc) could result in an engine full of gasoline - which is not good, especially if you try to crank it while it's full of gasoline. If you are lucky and parked at a slightly different angle, you might "only" get a big puddle of gas from the airbox drain. You want a petcock that can be shut off.

There are instructions on here for modifying the stock petcock. Search for "Jenya"

You can replace the whole thing - parts are not sold to repair it, but Suzuki sells the entire thing, and it actually doesn't fail all that fast in use. The guys who mod it will now freak out in 1, 2, 3.... While this is not the greatest version of one, a vacuum petcock is handy when working, as you don't have to constantly remember to turn it on and off. Replace the vacuum line to it if you go this route.

Replace all the fuel lines while you are in there. 5 feet of 5/16 urethane fuel line will do it, including the upper vent hose.

[fred]

Thanks for your feedback .....

- so this isn't a dealbreaker that should keep me from buying the bike then, eh?

- what would be the problems with leaving the whole system as the seller describes?

Not a dealbreaker by any means. Perhaps an excuse to ask for a lower price, but from what you've said, it is all stuff a newbie could fix in a day with the right set of wrenches and a shop manual...

[Farakin]

I actually used a diaphragm from a rebuild kit for my 80 yama triple 850....works fine.  With a little trimming.

[Farakin]

Oh found this for you:

Ebay Item #  180327568154

2 petcocks

[simoniz]

Fixing the diaphragm is an easy job, just a couple of cross head screws to undo. If the seller was too lazy to do that job, what else did he skimp on? It's worth checking.