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float valves leaking on 97 VFR750

 
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brian13

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Since: Feb 08, 2004
Posts: 8



(Msg. 1) Posted: Sun Feb 08, 2004 11:34 pm
Post subject: float valves leaking on 97 VFR750
Archived from groups: rec>motorcycles>tech (more info?)

I think my 97 VFR750 has leaking carbs. No external leakage anywher,
but the bike gets crappy gas mileage and the oil sometimes smells of
gas. Also there is a strong smell of gas for hours after riding.

The bike has an electric fuel pump, so there's no petcock issue to deal
with. However, I've pulled the carbs and the floats do not have fuel in
them, the float needles look to be in good shape, and the float seats
are not replaceable. Also, the floats are not adjustable.

I don't know what to try next. I guess I will order some new float
needles, then maybe new floats?

Any other ideas or tests I should try?

Thanks,
Brian

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Kaybearjr

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Since: Jun 21, 2003
Posts: 661



(Msg. 2) Posted: Mon Feb 09, 2004 2:21 am
Post subject: Re: float valves leaking on 97 VFR750 [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)

 >From: brian brd5.TakeThisOut@yah00.com

 >Any other ideas or tests I should try?

Look at the needle valve seat with a magnifying glass. The tiniest bit of gun
on the needle seat will keep the needle from shutting off the flow of
gasoline...

Look at the needle itself with the glass. If there is no groove worn on the
needle, it should be OK. Some needles have a Viton rubber
tip, and if the rubber is OK, you don't need needles...

Sometimes you will find gum buildup on the sides of the needles, and that keeps
the needle from moving freely...<!-- ~MESSAGE_AFTER~ -->

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brian13

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Since: Feb 08, 2004
Posts: 8



(Msg. 3) Posted: Mon Feb 09, 2004 2:58 am
Post subject: Re: float valves leaking on 97 VFR750 [Login to view extended thread Info.]
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Kaybearjr <kaybearjr.TakeThisOut@aol.comical> wrote:
  >>From: brian brd5.TakeThisOut@yah00.com
 >
  >>Any other ideas or tests I should try?
 >
 > Look at the needle valve seat with a magnifying glass. The tiniest bit of gun
 > on the needle seat will keep the needle from shutting off the flow of
 > gasoline...

Hrm, the seat is recessed down in a hole. Kinda hard to get a good look
at it. Maybe I should just scrape them out with a small bit of
wood--toothpick, popsicle stick, or something.

 > Look at the needle itself with the glass. If there is no groove worn on the
 > needle, it should be OK. Some needles have a Viton rubber
 > tip, and if the rubber is OK, you don't need needles...

Yeah, these have a rubber, conical tip on them, so maybe they're not a
"needle" in true sense of the word, but I didn't know what else to call
them.

Thanks,
Brian<!-- ~MESSAGE_AFTER~ -->
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Burnout

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Since: Aug 16, 2003
Posts: 35



(Msg. 4) Posted: Mon Feb 09, 2004 4:22 am
Post subject: Re: float valves leaking on 97 VFR750 [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)

On Sun, 08 Feb 2004 22:34:10 GMT, brian <brd5.RemoveThis@yah00.com> wrote:

 >I think my 97 VFR750 has leaking carbs. No external leakage anywher,
 >but the bike gets crappy gas mileage and the oil sometimes smells of
 >gas. Also there is a strong smell of gas for hours after riding.
 >
 >The bike has an electric fuel pump, so there's no petcock issue to deal
 >with. However, I've pulled the carbs and the floats do not have fuel in
 >them, the float needles look to be in good shape, and the float seats
 >are not replaceable. Also, the floats are not adjustable.
 >
 >I don't know what to try next. I guess I will order some new float
 >needles, then maybe new floats?
 >
 >Any other ideas or tests I should try?
 >
 >Thanks,
 >Brian

How many miles are on the bike?
The rubber seals on the float valves wear with time and also from
sitting.
Also check the air filter and air box drain for clogs.
The plastic floats rarely leak but if they are holding fuel it's
obvious. You probably just need float valves.<!-- ~MESSAGE_AFTER~ -->
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brian13

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Since: Feb 08, 2004
Posts: 8



(Msg. 5) Posted: Mon Feb 09, 2004 4:28 am
Post subject: Re: float valves leaking on 97 VFR750 [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)

Burnout <acrispycritter.DeleteThis@hotmail.com> wrote:
 > How many miles are on the bike?

25,000.

 > Also check the air filter and air box drain for clogs.

Air filter was replaced at the 16k service last September.

 > The plastic floats rarely leak but if they are holding fuel it's
 > obvious. You probably just need float valves.

I'm going to order some tomorrow.

Laters,
Brian<!-- ~MESSAGE_AFTER~ -->
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brian13

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Since: Feb 08, 2004
Posts: 8



(Msg. 6) Posted: Wed Feb 18, 2004 7:46 am
Post subject: Re: float valves leaking on 97 VFR750 [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)

brian <brd5 RemoveThis @yah00.com> wrote:
 > I think my 97 VFR750 has leaking carbs. No external leakage anywher,
 > but the bike gets crappy gas mileage and the oil sometimes smells of
 > gas. Also there is a strong smell of gas for hours after riding.


So, in an attempt to find this fuel leak, I pulled the carbs and
replaced the float needles in the VFR yesterday.

Put her all back together last night, changed the oil this morning and
headed off to work.

As I pulled out of my neighborhood, I noticed a hesitation. On the
highway, that turned to stumbling, but never cutting out or shutdown.

Hrm, this is what I get for not doing a shakedown ride. I had to get to
work, and it didn't seem too bad, so I pressed on.

Up to about 4-5k rpm, it was fine, and from there up to 8k was just
wishy-washy. In high gears, full throttle would do nothing
acceleration-wise. I can be WOT in 6th and the bike does not accelerate
at all.

I did find that in 3rd, though, it would accelerate nicely from 8k to
redline. I cruised there and back mostly in 3rd and sometimes 4th gear.

My first thought was that the tank wasn't venting right, but I opened it
and filled up with gas and there was no woosh or sucking noise.

Aside from the float needles and oil & filter, the only thing I
(intentionally) changed is adding a longer hose to the carb overflow
vents. It had a short 3" hose that just dumped excess fuel onto the
engine. I ran a 2' piece out down the bottom of the bike where I can
see it with the bodywork on.

Fuel hoses and tank vent hoses are on correctly. Petcock is to full
"On".

Could there somehow be air in the fuel line, pump, or filter?

Any other ideas?

Thanks,
Brian<!-- ~MESSAGE_AFTER~ -->
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