Fuel starvation problem, Honda GL650

('83 GL650)

My petcock was leaking a bit whenever I would flip the lever to
another position. The leak wasn't a lot but it was enough that I was
afraid of running on reserve for any length of time and dripping raw
fuel onto the engine. I purchased a rebuild kit for the petcock and
took it apart to have a look see. After fixing the leak and putting
it all back together, the bike was acting like it was fuel starved
at 70 mph and up although it was fine at slower speeds.

I wonder if someone who has taken these apart a few times can have a
look-see at my pics and tell me if I've reassembled it correctly?

http://home.comcast.net/~kenglong/honda_petcock/honda_petcock.htm

Tia,
Ken in Albuquerque

 

A fast way to check whether or not the petcock is allowing sufficient
fuel flow is to put the end of the fuel hose into a container and move
the level to the prime position. If there's a strong flow, you're in
good shape so far. If not, there's a problem.

Next, put the petcock into the On position and apply vacuum to the
vacuum hose. The fuel flow should be the same as on the Prime position
with vacuum applied, and nothing otherwise.

Your pictures look fine, though that large plastic piece may go in the
other way. It's either symmetrical and the spring is pushing it out, or
it's not symmetrical and the vacuum cannot pull it far enough out of the
way. I can't tell from here. HTH

--
Later,
John



'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.

 

Good idea but this tap doesn't have a prime position. Just On, Off and
Reserve.

I've been needing a reason to buy a vacuum pump. I'll try this if the
problem is still there. (I put everything back together this evening
after reversing that diaphragm and blowing out the screen.)

The picture shows a bevel that might indicate it's resting position
should be toward the spring. I think, since I reassembled it as shown in
the pic, it should require less vacuum to open the fuel path. (I'm
hoping anyway.)

It could also be that I was simply sloppy when I put it back together
the first time. I was much more careful this time.

Thanks,
Ken

 

Make sure that o-ring #14 is positioned correctly. There should be a groove
in the plastic fuel strainer for it.

I used a little vaseline to lubricate it on assembly.

 

You certainly don't need a fancy pump. If you're leery about applying
vacuum by mouth, a 100cc syringe should be able to apply enough vacuum
to do the job.

Yeah, as R. Pierce Butler pointed out, the alignment of the components
is pretty important in this application. You'll find out quickly whether
or not you got it right. Good luck.

--
Later,
John



'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.

 

That o-ring was missing when I first took it off the tank. I
reassembled it with an o-ring but there was no groove in the strainer
tube.

The bike still had the problem this morning after putting it back
together with the diaphragm reversed. I think I might remove the
o-ring completely and try it again...just to see what happens.

Ken
(Reply address works as is.)

 

Is there any differnce in symptoms if in the normal or reserve positions?

 

No difference. I rode it to and from work in the reserve position and
it still did it.

I need to verify one way or the other if the fuel tap is really the
problem. I think I can remove the seal from the plunger and test ride
it to check if the problem is still there. The tap should revert to a
non-vacuum type where ON is always on even if the engine is not
running. That should tell me if the problem is the vacuum-operated
valve in the tap or if, just by coincidence, I've got something else
going on.

Ken
(Reply address works as is.)

 

Try the old seal again and see if it still does it?
Holes may be two small in the new one?

 

Well.

Circumstances have conspired against me and the problem was actually a
very dirty air filter.

While at work today, I was thinking that I should get a new air filter
because the one in there was pretty dirty. Well, I took out the filter
after work for the ride home and wow, all the old power was back again!
It ran a bit lean with no filter at all but it was enough to tell me
that the air filter was my problem.

Ken