Fuel Pump Needed?

[Glyn Pickering]

Just wondering how neccessary the vacumn operated fuel pump is on the Vision. The 400 model did not have one fitted. Am finishing off the manifolds on my weber carb conversion and wondered if I need to plumb in a vacumn pipe for the fuel pump. Has anyone ever used the 550 without a pump? Perhaps the fall between the tap and the carb is not sufficient to provide full supply at max revs? Alot of older style middleweights did not have fuel pumps in the past tho'?

Cheers
Glyn ???  

[louthepou]

Hi Glyn,

Yep, if I remember correctly (from reading a post a few weeks back), it was indeed because the carb for the 400 is sitting lower with respect to the tank that it worked without a fuel pump.

Louis

[fiddlesticks]

I know of a forum member who removed it and has had no problems.You just have to reroute the linesand bypass the pump. If mine ever brakes I think I will do the same. I would think you would just loose your reserve, and would want to stay on the high side of half a tank.

[Rick G]

I would only do that if I enjoyed pushing the bike, after it started hacking and coughing from fuel stavation.

[Walt_M.]

I agree with Rick, you probably wouldn't get 60 miles from a full tank before it started to starve for fuel. If you don't like the vacuum pump, see if you can find an electric one. I've looked but haven't found anything promising yet.

[Brian_Matthewson]

Not true..I get 250km (about 150 miles) before I even start to worry about running out of gas. I removed the fuel pump 4 years ago with no regrets!

[h2olawyer]

With the rebuild kits available, why not just rebuild it & keep using it?  Seems to me Yamaha put it there for a reason.  Could have built it without the pump 7 still sold it for the same $$ so why would they cut into their own profits by putting on a part that serves no useful function?

Just my opinion - for what it's worth.

H2O

[Walt_M.]

Brian, not to doubt what you are saying but, how do you get the fuel to run up hill?

[Rick G]

I'm afraid that 150 mile range is not sufficient for my usage , I ride off the beaten track and far from gas stations . That last 50 is very necessary for my well being! LOL

[Superfly]

I get about 150 also, but that is taping into the reserve...

[jasonm.]

I have seen 150+ a few times before hitting reserve(45mpg). There are Yamaha electric fuel pumps all over ebay. They fit Vmax's, Ventures, R1, R6 pre-efi etc. They have a built in regulator. All you need to do is the plumbing and a relay so they are not on all the time. They draw only 1 amp. This is the best bet for a bad pump replacement.

[Brian_Matthewson]

Walt...
The fuel doesn't need to run uphill...the petcock is higher than the inlet to the carb...gravity works flawlessly!! ;-)
Brian

[jasonm.]

Well, if my pump ever goes bad. I'll try the gravity...but when you are down on reserve for 30 miles a pump may be needed for those last few ounces..

[QBS]

A year ago my 85k mile '83 started having fuel starvation issues after 90 miles on the tank.  Also, for the first time, experienced fuel starvation symptoms at 10K rpm in 5th gear.

Carefully cleaned the petcock to no avail.  Replaced the petcock with a spare, no help.  POR 15ed the tank just in case.  No change.

Checked fuel flow from the fuel return.  Got a steady dribble.  Put on spare fuel pump and checked return line flow again.  Same steady dribble.  Lowered seperate gasoline source to below carb level.  Pump would lift from there and provide the same steady dribble and would even produce a spurt of pressure if the hose was pinched off.  No help with fuel range or high speed starvation, however.

Considered fitting an electric fuel pump, but decided that 85k of trouble free miles was acceptable service out of the stock set up, which also had the benefit of already being installed.  Bought $15.00 US Keyster fuel pump rebuild kit.  Replaced the two thin rubber gaskets and the two large plastic diaphrams inside the fuel pump.

This afternoon, took 98 mile shakedown ride.  No signs of fuel starvation.  Held 10k rpm in 5th gear for mile and a half.  No signs of fuel starvation.  Bike runs very well with no stumble or hesitation and a perfect idle.  Instant hot start and four crankshaft rotation cold start.

Recommend anyone experiencing half tank fuel starvation should replace the thin rubber gaskets and large plastic diaphrams in their fuel pumps.  Cheers.

Note:  The Keyster kit also provides replacement small plastic discs for the pumps internal valves.  I didn't replace these because the process looked like it would more distructive than productive.  And my OEM valves discs appeared to be in like new condition.  The large plastic diaphrams, on the other hand, were bowed out and distorted.