96 vs800 fuel pump circuit description

[69intruder]

I have a 96 intruder 800 I bought to restore, I have the factory manual but I'm finding it almost impossible to diagnose with the limited info in the factory manual. Following the wiring diagram leads into parts like the fuel pump that has no internal wiring shown so there is no way to follow power flow. I need to know how the pump interacts with the ignition. Also how the system should work so I diagnose it and repair it. The manual is very poorly written and much vital info needed is not in there. I also need to know where the mixture screw plugs are located on each carb. The manual only shows a screw no location on the carbs that have many plugs, I don't want to drill out the wrong thing. Thanks

[hillsy v2]

For the fuel pump all you really need is a switched power source - like from the kill switch. The pump is low pressure and automatically turns itself off when it is up to pressure (about 3psi). There is a relay either separate in the wiring or inside the fuel pump which is best bypassed as it is a known problem point.

Mixture screw plugs are on the side of the carbs near the intake port (head side). Pic here courtesy of lechy:

[sgtcall]

Welcome!
Here are a couple of things to check out.

INTRUDER MANUALS AND INFORMATION
viewtopic.php?f=19&t=14168

POSTING PICTURES ON INTRUDERS ALERT
viewtopic.php?f=19&t=13992

[69intruder]

Thank You very much for the info and Welcome. I think I found my trouble. Bike runs great EXCEPT a terrible hesitation right off idle, the engine pops and dies for a second then goes great. Wide open throttle it runs perfect, idle is perfect too. I checked the carbs for water-dirt and the float levels everything checked out great. SO I pulled the plugs out of the mixtures screws and found the front @ 1 turn and the rear @ 1 1/2 turns. I set both @ 2 turns for now it seems the issue is gone. Also I see the fuel lines are badly cracked, how many feet of line should I order? This is 96 vs800 with 18k on it. Thanks again for the wisdom.

[navigator]

Also I see the fuel lines are badly cracked, how many feet of line should I order? This is 96 vs800 with 18k on it. Thanks again for the wisdom.

Use a piece of string or soft wire to estimate lengths, but I think that a 10 ft. package of 5/16" fuel line should do.
I have found that fuel injection hose (high pressure) has a slightly smaller outside diameter, making it easier to fish around the frame.
JMO.

[69intruder]

I pulled the fuel mixture plugs and found the screws set @ 1 turn on rear carb 1 1/2 on the front. Reset them to 2 5/8 turn and it runs like it should. Tested the pump with the bike running and its pumping good. According to the info I found the pump should run when the starter button is engaged but it doesn't so there is something going on there,I believe thats why it can be hard to start cold. I'm going to convert it to a gravity feed system and see how it works. After looking at it carefully I can't see any reason it won't work. There is plenty of height and using 5/16 fuel line there should be plenty of flow and of course nomo having that crazy fuel pump circuitry involved in running the engine.

[Lechy]

All that is needed is to hook the hot wire of the pump to the orange/white going into the CDI box. The pump will activate off the key and for an emergency can be shut down with the kill switch.

[hillsy v2]

I pulled the fuel mixture plugs and found the screws set @ 1 turn on rear carb 1 1/2 on the front. Reset them to 2 5/8 turn and it runs like it should. Tested the pump with the bike running and its pumping good. According to the info I found the pump should run when the starter button is engaged but it doesn't so there is something going on there,I believe thats why it can be hard to start cold. I'm going to convert it to a gravity feed system and see how it works. After looking at it carefully I can't see any reason it won't work. There is plenty of height and using 5/16 fuel line there should be plenty of flow and of course nomo having that crazy fuel pump circuitry involved in running the engine.

If you really want to ditch the electric fuel pump - you could go vacuum.....

If you really want to do away with the electric pump another option is a vacuum fuel pump - similar to what they run on outboards. The carb'd versions of the Hyosungs ran them as well - I had a GT650 with the vacuum pump and it worked well.




https://www.ebay.com.au/itm/15454112083 ... R7yojMCvYw

[69intruder]

All that is needed is to hook the hot wire of the pump to the orange/white going into the CDI box. The pump will activate off the key and for an emergency can be shut down with the kill switch.

I have 4 wires going to the pump, I have no idea which does what. only thing I have figured out is the early intruders used a 2 wire pump and the electronics were separate in what most refer to as a "fuel pump relay". The newer 4 wire pumps have the electronics inside the pump and I can find NO info schematics anything about them even tried a local dealer. The dealer info only shows the 2 wire system. No info on the 4 wire system! frustrating because I'm not in the mood to fry anything or get stuck in TinBukTu or in the middle of the great plains.

[69intruder]

As far as a vacuum pump I have used them before and they are very unfriendly to backfires out the intake and this Intruder pops alot cold. What I don't get is why Suzuki made such a complicated pump circuit when a simple relay wired to the ignition coils would have worked just the same. And then don't let any info on the 4 wire pump out there??????? very odd. Great running bike but what a PITA.

[69intruder]

Thanks everyone for the help. I put the bike up for sale as I tried 2 dealers without any luck finding basic info on the fuel circuit. I just can't take a chance getting stuck on my trip without any support. Both dealers told me good luck getting the bike repaired any where because they will not work on the fuel system! Bike is too old and they only service fuel injected bikes. Crazy stuff wish I had known this before spending quite a bit to buy and service the bike with bags tires fluids and a windshield. Maybe i'll get lucky and someone will want to do a trade for something a little friendlier to get serviced.

[hillsy v2]

You got a 30 year old bike. Bike dealers don't want to know about you. That's why there's forums.

The fuel pump circuit only needs to be simple. Either find the power wire on your 4 wire pump or get a 2 wire pump and connect the positive to the orange and white killswitch wire then ground the earth. Done. Pump will turn off at pressure and when the killswitch is off.

Doesn't get much simpler and certainly not a reason to dump the bike.

[69intruder]

If it were a 4 wheeled vehicle I might but 2 wheels with me on it in traffic not my thing to risk that much. Plenty of other bikes out there to take a chance like that. Suzuki must have sold thousands of these bikes, hard to believe there isn't any info on how the 4 wire pump works. If there is I can't find it none of the dealer I called have it safe to say as much as I like the bike just didn't work out.

[Lechy]

Pump off a small Mitsubishi about $30 from most autostores. In/out line up with existing fuel lines, take note of the direction arrow on the base, cut off the mounting ears, pull the cover off to check which wire is power and ground, hook up as per hillsy's post.

[hillsy v2]

If it were a 4 wheeled vehicle I might but 2 wheels with me on it in traffic not my thing to risk that much. Plenty of other bikes out there to take a chance like that. Suzuki must have sold thousands of these bikes, hard to believe there isn't any info on how the 4 wire pump works. If there is I can't find it none of the dealer I called have it safe to say as much as I like the bike just didn't work out.

The 4 wire pump I believe has an inbuilt relay. You don't need it. Get a 2 wire pump like Lechy posted and wire it to switchable power. Or get a vaccum pump. They run them on Hyosung 650's and they work great. You run them off a small vacuum hose so they don't grenade with backfires. By the way - your Intruder "popping" isn't backfiring.

Either way - it's not a reason to ditch the bike. Heaps of different models around the late 80's early 90's ran low pressure pumps to feed carb set-ups. Shouldn't be a deal breaker and it's not that complicated.

[69intruder]

The 4 wire pump has a complete electronics package in it including a micro chip. There is no way I'm messing with that not knowing what it controls or how it works . BUT I found this https://www.ebay.com/itm/195412277117?e ... ition=3000

So if I simply unplug the fuel pump and the engine still starts and runs I can add this stock Suzuki vacuum fuel pump. Just need to find the factory manual for the newer vacuum system so I connect to engineerings design. This will save me from selling it. Bike is very quick and handles great to my likings. If I get this vacuum pump system up working good I'm going to install the taller 1400 final gear drive I bought off Ebay. I'm a little concerned that 1st gear will be too tall but I'll have to cross that bridge when I get there. Then I can leave the electric pump in place for back up. Thanks for the suggestions all.

[69intruder]

PS I don't believe the stock pump uses a point system to regulate pressure, I believe the electronics package inside it does that and other duties. I've dealt with low pressure contact point pumps before and they are EXTREMLY unreliable. The points wear quickly and pump fails miserably. Thats why I'm sure Suzuki in their wisdom went a electronic control that uses a micro chip with no moving parts to wear out.

[hillsy v2]

PS I don't believe the stock pump uses a point system to regulate pressure, I believe the electronics package inside it does that and other duties. I've dealt with low pressure contact point pumps before and they are EXTREMLY unreliable. The points wear quickly and pump fails miserably. Thats why I'm sure Suzuki in their wisdom went a electronic control that uses a micro chip with no moving parts to wear out.

How can you have a pump with no moving parts?

[69intruder]

Of course it has moving parts but the stock Suzuki pump uses electronics not points to operate. I think they are using the ignition to tickle a transistor in the fuel pump to operate it. But without any diagrams I can't prove it. How can I attach a picture?

[navigator]

Of course it has moving parts but the stock Suzuki pump uses electronics not points to operate. I think they are using the ignition to tickle a transistor in the fuel pump to operate it. But without any diagrams I can't prove it. How can I attach a picture?

https://intruders-alert.com/viewtopic.php?f=19&t=13992