Hello all, first post and kind of at a loss.
2004 Suzuki VS800 1100 miles
Backstory, picked this up from an old lady after it sat the last 10 years.
Wouldn’t idle. Rebuilt the carb and cleaned the tank. Didn’t clean tank good enough and had to redo it all again.
This time I rebuilt it and replaced the fuel lines, add a fuel filter before the pump and replaced the pump. Right now it will idle for an eternity, but while riding, it feels like it runs out of fuel and slowly comes to a stop.
You get maybe 60 seconds of riding before this happens. Doesn’t matter if you’re just creeping the throttle or going full send, it cuts off.
Bike will restart nearly immediately once it comes to stop and run fine after that for a short period.
Re: Dies while driving
Posted: Sun Oct 01, 2023 8:46 pm
by Herb
When you cleaned the carbs did you remove the float valve seats in each carb and verify that the filter screen under it was clean?
If it is dirty it can let enough fuel through to idle fine but it can restrict the fuel flow so that it runs out of fuel under load.
The part I am talking about is item 22 on this parts fiche.
The other place you could have a restriction is at the fuel tank petcock. If the filters on it are plugged or dirt got into the valve itself it can cause this issue.
Maybe try switching to reserve to see if it works better.
Re: Dies while driving
Posted: Sun Oct 01, 2023 10:21 pm
by sgtcall
Welcome!
Here are a couple of things to check out.
Also make sure the vent to the gas tank is clear. The vent is either in the gas cap or it has a vent line. If the tank can't vent the tank will build up pressure and not allow fuel to flow.
Also the fuel pump may be going out. Might need to bypass it or replace it.
Re: Dies while driving
Posted: Mon Oct 02, 2023 6:12 am
by Designer
Welcome New Board Member!
Your symptoms do seem to point to what SgtCall mentions about the Tank Vent being blocked and/or occluded.
When Air cannot enter the Tank to replace the outgoing gas, a partial vacuum is created which will cause the Fuel Pump to be starved of gas. Thus the Carbs not replenished with fuel, and a gradual lessening of Engine performance.
Re: Dies while driving
Posted: Mon Oct 02, 2023 10:15 am
by Brettm1388
I appreciate the replies, I’ll post results of cleaning the cap tonight.
Re: Dies while driving
Posted: Mon Oct 02, 2023 7:15 pm
by Brettm1388
Drove around with the cap loosely and put the filter on the pressure side, no change.
A little more info;
Slowly starts to bog down while cruising, then when you give it more than 50% throttle, it feels like you’re hitting the brakes and you get an air “whoosh” sound from the front carb.
When it dies and restarts, it feels like new and ready to go for maybe 60 seconds.
Re: Dies while driving
Posted: Tue Oct 03, 2023 1:30 am
by hillsy v2
Can you hear the fuel pump working? Might be defective/ intermittent fault. There is a volume test in the manual.
Also is it possible there might be a kinked fuel line somewhere?
Re: Dies while driving
Posted: Tue Oct 03, 2023 2:45 am
by Brettm1388
I haven’t done the fuel pump test yet, I can try that next.
No kinked fuel lines, checked that last night
Drove around with the cap loosely and put the filter on the pressure side, no change. A little more info;
Slowly starts to bog down while cruising, then when you give it more than 50% throttle, it feels like you’re hitting the brakes and you get an air “whoosh” sound from the front carb.
When it dies and restarts, it feels like new and ready to go for maybe 60 seconds.
As it starts to Bog Down while cruising, do you detect any misfiring of the Front Cylinder at either the Pipe of Inlet?
This "whoosh" sound is kinda peculiar. Does this sound happen just as you open the throttle more than 50%,....or just as the engine dies?
Also,...fuel pump related,...When you perform the restart after it died, does it need to be cranked over a lot?....does the Pump sound come on right as you restart, or is it delayed?
Drove around with the cap loosely and put the filter on the pressure side, no change. A little more info;
Slowly starts to bog down while cruising, then when you give it more than 50% throttle, it feels like you’re hitting the brakes and you get an air “whoosh” sound from the front carb.
When it dies and restarts, it feels like new and ready to go for maybe 60 seconds.
As it starts to Bog Down while cruising, do you detect any misfiring of the Front Cylinder at either the Pipe of Inlet?
This "whoosh" sound is kinda peculiar. Does this sound happen just as you open the throttle more than 50%,....or just as the engine dies?
Also,...fuel pump related,...When you perform the restart after it died, does it need to be cranked over a lot?....does the Pump sound come on right as you restart, or is it delayed?
It doesn’t feel like a dead miss. It feels like your bike is running out of gas and kind of sputtering and bogging down above 50% throttle.
I’m wondering if I goofed the floats when rebuilding the carbs.
Re: Dies while driving
Posted: Tue Oct 03, 2023 9:58 am
by Herb
That is possible.
In the manual there is a test to check the actual opperation of the fuel pump. All you do is run a hose from the outlet into a container and it is suppossed to pump a specific amount in a set time.
Re: Dies while driving
Posted: Tue Oct 03, 2023 9:17 pm
by navigator
Have you replaced the air filters?
I'd venture a guess that you have a huge mouse nest in the front air box.
You get maybe 60 seconds of riding before this happens. Doesn’t matter if you’re just creeping the throttle or going full send, it cuts off.
Bike will restart nearly immediately once it comes to stop and run fine after that for a short period.
.............I’m wondering if I goofed the floats when rebuilding the carbs.
Quite possible. but before you dive into all that work...let's keep working with the easier possible "fixes"
Re: Dies while driving
Posted: Wed Oct 04, 2023 6:27 pm
by Brettm1388
Alright so messed with the floats, rear carb measured in spec. Front carb was slightly out of spec.
Double checked the jets, didn’t see any issues.
While idling, if I twist the throttle, it’ll try to run but cuts off.
Holes / tears in the carb slide diaphragms perhaps?
Same with the enricher / coasting valves - they might be defective?
Definitely sounds like a fuelling issue.
Re: Dies while driving
Posted: Wed Oct 04, 2023 11:38 pm
by Lechy
For the small cost involved, replace the battery earth cable. A bad, dirty, frayed earth cable can cause a load of problems that appear to be fuel related.