Fuel System Info on 85 vmax

Get your questions answered here! Also be courteous and answer any you may know. Its a give and take kinda thing, we think you'll enjoy!
Post Reply
zeroburn
Posts: 5
Joined: Wed Jan 02, 2008 1:36 pm

Fuel System Info on 85 vmax

Post by zeroburn »

Since im new to the vmax i have a question on the fuel system that the vmax has. Now i see 2 fuel pumps, vent tubes that connect to the pumps and to the carbs. I just dont understand why or how that is supposed to work properly with the muiki carbs that are on it. Im just looking for info thats all so i can better understand what i have.
User avatar
Vmax540
Posts: 1521
Joined: Thu Jan 26, 2006 8:36 pm
Location: Shippenville Pa.
Contact:

Post by Vmax540 »

Yamaha's advertized logic was 2 fuel pumps insure needed fuel flow requirements ! Which, as we all know was unnecessary and not used on later sleds ! Altough, it works I have always wondered what happens to the engine if 1 pump quits working ?
Last edited by Vmax540 on Sat Jan 05, 2008 8:22 pm, edited 1 time in total.
https://www.youtube.com/watch?v=PFb6NU1giRA
"I prefer dangerous freedom over peaceful slavery." Thomas Jefferson
User avatar
tyler440
Posts: 692
Joined: Tue Jan 24, 2006 12:47 am
Location: Clarion, PA
Contact:

Re: Fuel System Info on 85 vmax

Post by tyler440 »

zeroburn wrote: vent tubes that connect to the pumps and to the carbs.
your not getting confused witht the pulse lines that connect the pumps to the crankcase are you?
My airbox is held on by one screw, not because Im lazy but because it is less weight!

Any questions or comments about this site itself can be directed to me at tylerochs@hotmail.com
zeroburn
Posts: 5
Joined: Wed Jan 02, 2008 1:36 pm

Post by zeroburn »

Nope, i have 2 fuel pumps, they have intake from the tank, then the pulse line and then the feed side goes to the carbs with T fittings that go back to the tank. I just dont understand the reason for this? Does anybody have lets say a diagram of how the fuel system for the 85 is to be routed?
opsled
Posts: 214
Joined: Mon Dec 18, 2006 9:50 pm
Location: Burlington Wi.

Post by opsled »

There should not be an Tee's in the feed line to the carb. The line should go straight from the outlet side of the fuel pump to the carb. If you have Tee's in there that are returning fuel to the tank someone has been messing with the sled. Remove them.

opsled
User avatar
tyler440
Posts: 692
Joined: Tue Jan 24, 2006 12:47 am
Location: Clarion, PA
Contact:

Post by tyler440 »

agreed, the only t's in the fuel lines should before the pumps for the oil injection
My airbox is held on by one screw, not because Im lazy but because it is less weight!

Any questions or comments about this site itself can be directed to me at tylerochs@hotmail.com
zeroburn
Posts: 5
Joined: Wed Jan 02, 2008 1:36 pm

Post by zeroburn »

Well ill remove them and see what happens. I just could not understand why the fuel would be routed like that made no sense to me. Thanks Guys!
Post Reply