Suzuki king quad 300 idles great but Boggs when you apply throttle

[97kingquad]

Between the carb jets. The fuel pump and the cheap pieces in the carb. I think it's an aftermarket carb. Buddy said he replaced it last year when I asked him if he had the old parts. 

 

Also new thing. I'm going to trace the wires but thought I'd ask. 

I took it out for a run tonight and it ran well. I just couldn't go past half throttle but I could cruise around 60 at peak. But I got home and went to park it and I switched from neutral to reverse then it died. So I put it back into neutral and I had no lights at all. No green no reverse red and no headlights. I'm thinking maybe the regulator got fried? I put a small temp battery on and it is still fine but not big enough for a permanent position on the bike. But everything worked great up until that point. 

Would that be a wiring issue or is there a fusebox on this thing?

Just now, 97kingquad said:

Between the carb jets. The fuel pump and the cheap pieces in the carb. I think it's an aftermarket carb. Buddy said he replaced it last year when I asked him if he had the old parts. 

 

Also new thing. I'm going to trace the wires but thought I'd ask. 

I took it out for a run tonight and it ran well. I just couldn't go past half throttle but I could cruise around 60 at peak. But I got home and went to park it and I switched from neutral to reverse then it died. So I put it back into neutral and I had no lights at all. No green no reverse red and no headlights. I'm thinking maybe the regulator got fried? I put a small temp battery on and it is still fine but not big enough for a permanent position on the bike. But everything worked great up until that point. 

Would that be a wiring issue or is there a fusebox on this thing?

Sorry I should clarify the battery was on the whole time and it ran well. It's out of the lt-f4wd I have 

 

[Mech]

I use engine oil of air filters.

The wiring, check the battery has voltage, then check both the small wires and the cable from the battery are making good connection to the negative battery terminal and frame/engine and that the small wires from the battery going to the fuse and switch have a good connection  and that power is getting to the fuse then the ignition switch. Pretty sure they will be red all the way. It needs testing/tracing with a test light really.

If there is no battery voltage then unplug the regulator and try recharging the battery. The regulator can discharge the battery.

 

The red wire that goes to the fuse and switch also goes straight to the regulator without going through the fuse or switch..  You could check for direct voltage to there with or without the key on..

At least, that's what I think it will be wired..  that's pretty standard for the lt300f etc

[Mech]

And there's a bullet connector in the small red right near the battery, and that's the wire going to the fuse and key..

[DayBreakJim]

Also a good option

https://www.amazon.com/dp/B0BHYW1PBF?psc=1&ref=ppx_yo2ov_dt_b_product_details

[Mech]

Right Jim..  I'd thought of flexible drive but it seemed too hard..  That's cool though.

[97kingquad]

22 hours ago, Mech said:

And there's a bullet connector in the small red right near the battery, and that's the wire going to the fuse and key..

So it was the 20amp fuse in the headlight lol luckily my parts bike had two brand new ones on it 

Just now, 97kingquad said:

So it was the 20amp fuse in the headlight lol luckily my parts bike had two brand new ones on it 

Of course I tore the whole rack off and front plastics chasing the wiring harness thinking it was a fuse box further in

[Mech]

you love it.... 

[Gwbarm]

Good you are riding now, been away a little bit and missed a few things, trying to catch up, one of the OEM carbs i had didnt have any numbers on the jets either, so i replaced them with a kit, suposedly a good kit, All Balls, kind of a strange name but had good ratings, should have bought OEM suzuki jets , if i had it to do over i would and still might. But they are 30.00 each kind of pricy for jets.

[Mech]

And they may not fit Gw..  I know some of the aftermarket carbs have different idle adjust screw threads, and needle shape.. And jets come in different threads..

Unless the carb body is worn out I reckon it's always best to do up the OEM.

Or seized in idle screws I guess too  haha..

[97kingquad]

8 hours ago, Mech said:

you love it.... 

Yeah... I do lol the 4 hours I've rode and 40+ I've worked on it, I at least know whatever breaks I am pretty capable of fixing it or at least limping home which is nice. Lol but when I take it out my upset is just loaded with tools. Just incase 

[Mech]

And so is it still not maxing out ? The reason I was saying to move the needle was because apart from possibly being all that was needed, it is a test..  If it improved things then we are on the right track, if it made no difference or made things worse then it's something else.

The charging system can fail in several different ways, and sometimes they cause a ignition cut a lot like rev limiting in cars, but they can also start putting a huge strain on the engine, so it feels like it's seizing as the revs go up, but then freeing up as soon as you let the revs drop slightly.

You should test the power wire to the regulator, it has a join inside the wiring loom, and you should check all the earths. Resistance in any of those wires  can cause problems. There are seven and five wire regs and some have more than one 12v connection, one being a switched 12v.

[Gwbarm]

I agree i would never try to rebuild an aftermarket carb, the kit you buy for OEM would not fit correctly, but i am just assuming that i have never tried and never seen a kit that specifically stated for Niche, Kipa or any of the aftermarket ones. The kit i bought for my suzukis OEM carb fit it good and the jets had the correct numbers on them, still thinking i would like to measure them next to the jets that came out and see if they are the same, or worn, but havent got to it yet.

[97kingquad]

I fixed it!!!! I bought a carb rebuild kit and found I had a broken jet inside and an o ring was torn in the forks that hold the main jet.

The only issue now is getting it to run perfect. 

I took it out on a trail ride today and it will go wide open now but stumbles a slight bit from not moving to moving. Then the power band picks back up. I think it has to do with the air fuel screw mixture so I'm gonna play around with it tomorrow but thank you everyone for your help. I now have a mint bike for 800 bucks plus 250 for the registration and trail pass 

3 minutes ago, 97kingquad said:

I fixed it!!!! I bought a carb rebuild kit and found I had a broken jet inside and an o ring was torn in the forks that hold the main jet.

The only issue now is getting it to run perfect. 

I took it out on a trail ride today and it will go wide open now but stumbles a slight bit from not moving to moving. Then the power band picks back up. I think it has to do with the air fuel screw mixture so I'm gonna play around with it tomorrow but thank you everyone for your help. I now have a mint bike for 800 bucks plus 250 for the registration and trail pass 

 

[Gwbarm]

Yes that would do it 

[Mech]

Make sure you're adjusting the idle mixture with the throttle backed off as fas as possible. Adjusting the idle mixture with the idle speed too high gives that bad takeoff/flat spot.

[97kingquad]

6 hours ago, Mech said:

Make sure you're adjusting the idle mixture with the throttle backed off as fas as possible. Adjusting the idle mixture with the idle speed too high gives that bad takeoff/flat spot.

The carb comes out to adjust 

[97kingquad]

11 hours ago, Gwbarm said:

Yes that would do it 

There was also an o ring that was busted and almost missing. I think that was causing a lot of the blowback into the air intake

[Gwbarm]

The o rings seem to get brittle over time that and your broken jet fixed you should be good to go

[97kingquad]

On 8/5/2023 at 4:07 PM, Gwbarm said:

The o rings seem to get brittle over time that and your broken jet fixed you should be good to go

Everything is running fine now. Now my only issue I'm working on rectifying is It stumbles when taking off in first. If I choke it about halfway no problem but without it Boggs until it catches throttle then it's perfect like 0-1km/h

[Mech]

If it's less than about 1/4 throttle then it's in the idle circuit.. probably just the adjustment. You really need to adjust the idle speed and mixture hot and running.

[JustRandy]

So a broken jet was the problem?

Awesome you fixed it but seems strange a jet would suddenly break on the trail with the guy that sold it to you lol

21 hours ago, 97kingquad said:

Now my only issue I'm working on rectifying is It stumbles when taking off

Turn the idle speed back up some then adjust the mixture until it idles at the speed you want and the stumble should go away.

Often a stumble is found in the transition between the pilot circuit and the needle circuit (see pic below).

Turning the idle speed down as far as possible while adjusting the mixture is a good way to create a stumble if the carb isn't absolutely perfectly designed.

 

[97kingquad]

27 minutes ago, JustRandy said:

So a broken jet was the problem?

Awesome you fixed it but seems strange a jet would suddenly break on the trail with the guy that sold it to you lol

Turn the idle speed back up some then adjust the mixture until it idles at the speed you want and the stumble should go away.

Often a stumble is found in the transition between the pilot circuit and the needle circuit (see pic below).

Turning the idle speed down as far as possible while adjusting the mixture is a good way to create a stumble if the carb isn't absolutely perfectly designed.

 

I think we both know by the shape of that jet. He had tried to fix the issue before but I don't think he had much experience fixing things as he did mangling them 

[1998Zuki250]

I am battling this issue on my 1998 250. I will definetly be montiroing this post. 

[97kingquad]

7 hours ago, 1998Zuki250 said:

I am battling this issue on my 1998 250. I will definetly be montiroing this post. 

I got the issue fixed but there are some other nit picky things I need to get it perfect. What's the issue with your 250? I have a quadrunner 250 also

On 8/8/2023 at 6:02 PM, 97kingquad said:

I think we both know by the shape of that jet. He had tried to fix the issue before but I don't think he had much experience fixing things as he did mangling them 

I think the petcock and fuel pump are the issue, they both are messed up and I think it's not getting enough fuel until I give it throttle 

[Mech]

Here's how to test the fuel pump..  And you do need to check it's working as the load comes on the engine and the vacuum drops..

To test the fuel pump you lay the fuel hose to the carb into a bottle. Lay it on it's side with the hose laying flat. If the hose is dangling down you won't see the fuel pumping out properly. Then suck hard two or three times on the vacuum hose going to the pump, and then let the vacuum off suddenly. You should see a single slug of fuel come out of the fuel hose. The slug should be full diameter of the hose and about ten mills long. If that works then your pump is ok and will work if it's getting good pulsating vacuuum.

To test the vacuum you reattach the vacuum hose and start the motor and let it idle. It should pump fuel out of the fuel hose into the bottle at full diameter of the hose and slugs about eight mills long. If that works then the pump is working and it should start and idle at east.

Then you need to check the vacuum is still strong enough when the motor is under load. To check that you leave it all as is but sit on the bike, put the brakes on hard, engage first gear and open the throttle until the motor starts straining against the centrifugal clutch. As the motor starts to labour the pump will likely slow down it's delivery of fuel, but it should keep pumping some. If it stops pumping then you have weak vacuum or a malfunctioning pump.

The vacuum has to be strong, and pulsating when it gets to the pump. If the vacuum hose has been swapped with some soft thin walled stuff the pulsations can get lost as they suck the vacuum hose flat and then let it out again. Low vacuum can be caused by low compression, tight valves, or air leaks. Low vacuum at high revs can be caused by a blocked exhaust.

 

[97kingquad]

27 minutes ago, Mech said:

Here's how to test the fuel pump..  And you do need to check it's working as the load comes on the engine and the vacuum drops..

To test the fuel pump you lay the fuel hose to the carb into a bottle. Lay it on it's side with the hose laying flat. If the hose is dangling down you won't see the fuel pumping out properly. Then suck hard two or three times on the vacuum hose going to the pump, and then let the vacuum off suddenly. You should see a single slug of fuel come out of the fuel hose. The slug should be full diameter of the hose and about ten mills long. If that works then your pump is ok and will work if it's getting good pulsating vacuuum.

To test the vacuum you reattach the vacuum hose and start the motor and let it idle. It should pump fuel out of the fuel hose into the bottle at full diameter of the hose and slugs about eight mills long. If that works then the pump is working and it should start and idle at east.

Then you need to check the vacuum is still strong enough when the motor is under load. To check that you leave it all as is but sit on the bike, put the brakes on hard, engage first gear and open the throttle until the motor starts straining against the centrifugal clutch. As the motor starts to labour the pump will likely slow down it's delivery of fuel, but it should keep pumping some. If it stops pumping then you have weak vacuum or a malfunctioning pump.

The vacuum has to be strong, and pulsating when it gets to the pump. If the vacuum hose has been swapped with some soft thin walled stuff the pulsations can get lost as they suck the vacuum hose flat and then let it out again. Low vacuum can be caused by low compression, tight valves, or air leaks. Low vacuum at high revs can be caused by a blocked exhaust.

 

Okay but I appreciate the effort but that's not the issue, I know what the problem is and my parts arrive Tuesday. The diaphragm in the fuel pump is rusted through and there are a few holes in the gasket. 

And the petcock had a hackjob or a gasket maker seal which plugged half the holes and ruined the gasket for it  

[Mech]

Oh. I thought you'd ticked those off on page two, and again a few pages back.

I thought 1998 at #293 might have found it useful to check his system.. 

[97kingquad]

2 minutes ago, Mech said:

Oh. I thought you'd ticked those off on page two, and again a few pages back.

I thought 1998 at #293 might have found it useful to check his system.. 

I did check them. I believe it was you who told me what to check (the flow and whatnot) but also advised I don't remove them or open them up to clean. Which I ignored and found these issues

[Gwbarm]

I have expierience in that area, more than i would like to have, actually. When it comes to fuel delivery and electrical problems i dont mess around, been put down to many times and i always say when will you learn, i finally did. I would replace the fuel pump it really looks bad. The vacum fuel petcocks are troublesome the vacum assembly swells up after time and restricts fuel flow. I have rebuilt them with a kit but they never seem to last. Both of the bikes i am working on now had their petcocks replaced with manual ones, i like the manual ones because i can turn the fuel off and run the carb dry if its not going to be used for a while, but if i were doing it i would have gone back with original thats what they were set up for. Just my opinion. 

[97kingquad]

3 minutes ago, Gwbarm said:

I have expierience in that area, more than i would like to have, actually. When it comes to fuel delivery and electrical problems i dont mess around, been put down to many times and i always say when will you learn, i finally did. I would replace the fuel pump it really looks bad. The vacum fuel petcocks are troublesome the vacum assembly swells up after time and restricts fuel flow. I have rebuilt them with a kit but they never seem to last. Both of the bikes i am working on now had their petcocks replaced with manual ones, i like the manual ones because i can turn the fuel off and run the carb dry if its not going to be used for a while, but if i were doing it i would have gone back with original thats what they were set up for. Just my opinion. 

I have gotten OEM kits for everything. Because I intend for it to last, not gonna lie though these bikes are really fun. I actually ended up sinking it today, I was creeping through a foot of water and it just dropped off to 3½ feet  got into the intake. 

So I had to pull the bike out (water went down the exhaust too) I got the bike pulled back (soaked myself) 

Then pulled the plug and turned it over a few times and drained the carb then she fired right back up and I was on my way lol