tap-tap-taperoo

**Akzle** · 7th June 2012, 09:38

so my fuel tap (or pet-cock) only wants to work on reserve. this isn't a new fault, but i dismantled it the day other and nothing looks wrong...
FWIW it's an on-res-prime vacuum type.

so my question is: WTF? ideas on problem and how to fix?

**Haggis2** · 8th June 2012, 17:02

Sheesh, don't all answer at once...

Sorry, me not know

**Maha** · 8th June 2012, 17:35

Bike needs replacing.

**FJRider** · 8th June 2012, 17:41

Originally Posted by Akzle

so my fuel tap (or pet-cock) only wants to work on reserve. this isn't a new fault, but i dismantled it the day other and nothing looks wrong...
FWIW it's an on-res-prime vacuum type.

so my question is: WTF? ideas on problem and how to fix?

Check by taking off the vacuum hose at the lower end, then remove fuel hose from pet-cock. (with tap set to run/on) Then suck on the vacuum hose ... and then fuel should flow as you do. (put a large cloth under the pet-cock to catch any fuel)

If it does flow ... give it another check with it connected with the engine running .... as the problem is not at the pet-cock.

It doesn't take much to jam/block the vacuum flap.

**kiwi cowboy** · 8th June 2012, 17:56

Originally Posted by FJRider

Check by taking off the vacuum hose at the lower end, then remove fuel hose from pet-cock. (with tap set to run/on) Then suck on the vacuum hose ... and then fuel should flow as you do. (put a large cloth under the pet-cock to catch any fuel)

If it does flow ... give it another check with it connected with the engine running .... as the problem is not at the pet-cock.

It doesn't take much to jam/block the vacuum flap.

Have hilited text that should not be used in the same message please.

**ducatilover** · 8th June 2012, 17:57

The spring in the diaphragm may be munted, or you're not getting vacuum to the tap.
If the diaphragm looks fine, it probably is.

Does it have an O-ring in the housing on the vacuum side? That may be leaking too.

**kiwi cowboy** · 8th June 2012, 18:02

Originally Posted by Akzle

so my fuel tap (or pet-cock) only wants to work on reserve. this isn't a new fault, but i dismantled it the day other and nothing looks wrong...
FWIW it's an on-res-prime vacuum type.

so my question is: WTF? ideas on problem and how to fix?

hey bud just a thought but check the arrow on the fuel tap as some the arrow points the opposite way to others wich may mean you are actualy on the main tank with the res filter part in the tank blocked.

**FJRider** · 8th June 2012, 18:28

Originally Posted by kiwi cowboy

Have hilited text that should not be used in the same message please.

honda riders were never known for their spilling skills ...

**kiwi cowboy** · 8th June 2012, 20:34

Originally Posted by FJRider

honda riders were never known for their spilling skills ...

year and a half in high school wassnt enough???.

**FJRider** · 8th June 2012, 20:47

Originally Posted by kiwi cowboy

year and a half in high school wassnt enough???.

My apologies .... I was sure it would be less ...

**Akzle** · 9th June 2012, 10:30

Originally Posted by FJRider

Check by taking off the vacuum hose at the lower end, then remove fuel hose from pet-cock. (with tap set to run/on) Then suck on the vacuum hose ... and then fuel should flow as you do. (put a large cloth under the pet-cock to catch any fuel)

If it does flow ... give it another check with it connected with the engine running .... as the problem is not at the pet-cock.

It doesn't take much to jam/block the vacuum flap.

will try that... but surely the vacuum from engine will be greater than i can draw? --cheers.

Originally Posted by ducatilover

The spring in the diaphragm may be munted, or you're not getting vacuum to the tap.
If the diaphragm looks fine, it probably is.

Does it have an O-ring in the housing on the vacuum side? That may be leaking too.

it does have an O ring, but it's on the (valve stem?), diagphram looks OK.

Originally Posted by kiwi cowboy

hey bud just a thought but check the arrow on the fuel tap as some the arrow points the opposite way to others wich may mean you are actualy on the main tank with the res filter part in the tank blocked.

yeah. nah. appreciate the thought, but i did check!!

**ducatilover** · 9th June 2012, 11:29

Tried taking it off and blowing through it with compressed air?

**Akzle** · 9th June 2012, 11:52

Originally Posted by ducatilover

Tried taking it off and blowing through it with compressed air?

i dont have enough electricity to run my compressor ><

**FJRider** · 9th June 2012, 18:21

Originally Posted by Akzle

will try that... but surely the vacuum from engine will be greater than i can draw? --cheers.

[/COLOR]

Actually ... it doesn't take very much. It takes less draw, than is required to drink a milkshake.

It's not sucking fuel through to the engine ... just opening a small valve (read spring loaded flap) It's usually a gravity fed system on the older bikes ... but later bikes have electric fuel pumps.