fuel leak

[rdoldtimer]

hello guys i have a annoying problem . can any one tell me whoowns an rd 500 why a carburretor wont stop dribbling fuel even though i think im right fuel is only pumped through when the engine is running un less it s been left in the prime position , because one carb on my bike emptied fuel all over my garage lst night whats the likely cause
leaving my moble no if any uk guy has an idea .. 07449004269,,

[Vin]

Common issue on these unfortunately, the fuel tap rubber seal deteriorates and passes fuel through to carbs and another common issue is failing float valves which causes them to over flow.

Some people have fitted a type of stop valve between the tap and carbs for added security to stop the tank emptying or you can buy fuel tap rubber repair kits still I believe? but you will still need to buy or at least clean the float valves. buying genuine is the way to go even though they are expensive.

Also make sure fuel has not entered into the exhaust pipes as this can happen also!

[rdoldtimer]

Yes thank u I've ordered a fuel tap repair kit of yambits £20 a new tap I've seen £127 next step is why one carb others are fine thanks any way

[rdoldtimer]

Would it hurt or damage if I shot a blast of high pressure air up the overflow pipe !! Or would I make it worse

[Vin]

This wouldn't help as you need to get to the float valve, not a massive job and you will be able to check the float post for breakage at the same time.

[rdoldtimer]

yes i thought was a bad idea ta ..............

[giron]

you can also replace the fuel outlet under the tank by using the petcock under the tank from a TZR250 3MA. It fits without any modification and if you ever need to remove the tank. You can shut the fuel off.

[rklages]

You may have 2 issues, the first is what VIN mentioned is that your petcock is definitely letting fuel past when the bike is not running. The petcock uses vacuum to allow fuel flow, but the seal on the front side of the petcock has probably worn or deteriorated and is letting fuel through even with no vacuum (as Vin mentioned, very common problem). The second issue you have is that since that is happening, fuel is being provided to each carb, but the leaking one is letting fuel past the float valve, so it may not be sealing properly or have dirt in it (it could also just be the lowest point in the system and getting a little more pressure from the fuel if it is the lowest carb on the kickstand side).

Rob

[rdoldtimer]

Ta rob all useful stuff it s actually the highest carb on right side of bike I've ordered a complete carb kit now an petrol tap repair kit will keep u up dated ok thanks all

[pstamper]

Install a secondary shutoff and never worry about it again. I have been told of homes burning to the ground. gas leak, water heater lights and history.

[Speed Freak]

Same on my RD350.
After the first winter i wanted to drive to the next gas station, but after the first corner the engine shut down.
Over winter the whole fuel was lost.

I tried it with a fuel tap repair kit but it did not work, still fuel leaking out when no negative pressure applied.
I guess the O-ring of the plunger is too hard in this kits.
Using a stronger spring would solve this issue but I don`t know if the negative pressure of the engine is still strong enough to open the fuel tap at full load (open throttle = less negative pressure).
Wouldn`t be a good idea to cut off the fuel at full load on a 2-stroke

In the end I mounted a second on-off fuel tap from a lawnmower, no problems since then.


Leaking needle valve can be fixed by polishing the sliding surfaces of the needle seat and the needle.
Just needs some ear cleaners and a bit of polishing paste, costs nearly nothing and worked several times without replacing the expensive parts.

[s4oz]

Leaking needle valve can be fixed by polishing the sliding surfaces of the needle seat and the needle.
Just needs some ear cleaners and a bit of polishing paste, costs nearly nothing and worked several times without replacing the expensive parts.

Agree 100%, used Keiser and original parts, needle valve continued to leak intermittently. Polished all bits (except the rubber tip of the needle) carefully with a SS polishing paste and ear buds and has sealed properly ever since.

[rdoldtimer]

Actually today proved to be a good day ok finally resolved my leak was a new tap repair kit resolved it from yam bits

[rd84]

Hi,

Well after 31 years I need to either replace my fuel tap or install a repair kit. So far so good, but the repair kit diaphragms don't have the black plastic spacer / gasket between them that the original does - any ideas how I can install the spacer / gasket ? - does the repair kit diaphragms assembly pull apart easily ? - It looks very easy to damage if any force was used.

Thanks.

Cheers
Paul

[rdoldtimer]

Paul here's my mobile no if u wanna discuss it better 07449004269 uk based ALANS my name