[JRM7997]

Hello all

i just pulled my carb off a 2004 AC ATV 400 4x4 auto. Since I bought it it’s been hard starting and the previous owner didn’t take good care of fuel management.

With the choke on it would start but you couldn’t touch the throttle or it would stop. To keep it running i had to keep using the primer lever. To me this it means it’s not getting fuel or running lean. Once warmed up it ran and started fine. I’ve pulled the carb and spent a lot of time reading posts.

at this point I have two questions. Three.

A good place to buy a carb rebuild kit? I see lots of them but the prices and comments are all over the place. Even the number of parts in the kits vary greatly.

while pulling the carb I found out the fuel shutoff valve leaks. It has torn and disintegrating seals. I’ve looked and found a few on Amazon and eBay. I’m wondering if anyone has bought a rebuild kit or found a good one? Again comments and pricing are all over the place.

lastly, I’ve watch a couple videos on doing the cleaning and rebuilding. There has been a couple comments about a post that has “initial carb settings”. I’ll record what they are as I pull it apart but I’d like to see the arrtival And I havnt been able to find it yet. I’ll keep looking but if someone knows where it’s at….. .

ive Attached a couple pictures of the carb as an FYI.

Thanks in advance.
jim

 

[Farrix]

Ok, if you have a dealership nearby I wouldn't buy a "rebuild kit" for that carb myself. I have a 2004 400 FIS similar to yours, 8500 miles on the clock and unknown hours of abuse and nonsense.

You can buy a fuel shutoff/petcock online from alot of places, I've never had an OEM one go bad before but OEM isn't unreasonably priced ($65 cad I think?) I wouldn't rebuild, just replace it and the seal. fairly easy to do, drain and remove tank, unbolt, replace, rebolt, done.

Your carb sounds like it's probably just dirty and needs cleaned, if you've watched a bunch of videos etc, you've read alot of guides, and you can also read the guide that I have on this site pinned (no pics just words) you're off to a great start, I would definitely read the guide i've got here because it talks about ensuring you don't strip the screws, or wreck the carb if you do strip a screw.

Most common mistake made during carb work, stripped screw, followed by drilling it out, don't make that mistake.

For "rebuilding" the inside, the couple of parts you may need to replace, the bottom "o ring" gasket, the float valve, and MAYBE the needle. The jets usually just need cleaned with a fine pin/staple and some chemical. Rarely you may need to replace the diaphragm spring in the top, or the diaphragm IF it has a hole/tear in it, typically not common.


Float Valve $50 (there are difference sizes over the years, be careful to get the right one definitely replace this while you are in there)
Needle (unlikely to need replaced I'm on my OEM needle still
MAYBE diaphragm.
MAYBE $30 Diaphragm spring
MAYBE base seal (IF it's leaking)

You SHOULD buy a 1/4" plastic inline fuel filter from a Gregg distributors or similar, a decent quality one. The Canadian Tire plastic fuel filters almost burned my machine down twice, don't buy them utter trash.

Replace your fuel lines with modern ethanol safe lines if they haven't been, typically 1/4 and I clamp them a bit tighter. the OEM fuel lines rot out with ethanol gas and start shedding rubber chunks into the carb to cause extra cleaning.

Where in Canada are you located? I may be able to offer suggestions on supply locations.


As you mentioned make a note of how many turns the pilot screw is from all the way in before removing it. mark the starting point, turn it in all the way counting rotations, mark the finish point, then remove it for cleaning.

Sorry I can't offer better advice on kits and such, just never ran a carb kit in my 400, just replace the float valve every couple years, and keep riding it.

 

[JRM7997]

Im in the Vancouver area. Surrey BC.

I’ve got a1970 CT90 I’ve been trying to resurrect so I have already invested in a set of JIS drivers. I’ve also seen a few techniques for loosening screws so totally appreciate the care to loosen the screws, I’ll be careful. I hope.

When I removed the carb and drained (caught the outflow of fuel) I got a ton of junk in the container I used. Unfortunately, it could have been from inside the carb or sitting on top of it. My helper dumped the container before I had a chance to see what it was.

I’ll pull it apart then see what parts I’ll need. By the sounds of your reply I’ve already read your post but will do more spare search.

I started putting filters and running Chevron high test, on all my small engines starting about six or eight years ago. I think it was a local lawmower dealer started me on this when I bought a new weed eater And blower. I’ve got a filter and new fuel line ready to go.

thanks for the reply I really appreciate where your knowledge comes from.

 

[JRM7997]

I forgot. International motor sports in Langley is the closest , only??? AC parts supplier near me.

 

[Farrix]

Oof might be better to order online then, worth a call to price.

If a dynojet kit comes with a new float valve etc it might just be worth the buy online.

Just an FYI 91+octane will actually reduce your power quite a bit vs 87 octane.

Unless you advance the timing or increase the compression that machine will run better on 87 octane, idle more stable and make more torque and power. I gained mph when I swapped to 87 octane from 94 I used to run.

 

[doorfx]

X2^^^

 

[JRM7997]

seems like my reply went the way of the dodo bird. I’ll try again.

I’ll look up dynojet. I’m looking at doing the carb this weekend. Hope its warm enough to work in the garage.

thanks

 

[doorfx]

seems like my reply went the way of the dodo bird. I’ll try again.

I’ll look up dynojet. I’m looking at doing the carb this weekend. Hope its warm enough to work in the garage.

thanks

????

 

[JRM7997]

[
????
[/QUOTE]

Just commenting to Ferrix's reply.

I looked up Dynojet and it looks like its a kit for rejetting after having changed in the breathing/exhaust of your machine. Not something I'm interested in doing.

I was just looking up prices from a local AC parts supplier. The fuel shut of is between $38 and $70 bucks CDN depending on the model. I think i need to find out if my ATV is an MRP, TBX etc. I've just done a VIN search but i think there is a digit wrong its showing up as a 650cc. Ill go buy and check it today on my way home.

In the meantime it looks like its going to warm up enough to work in the garage.

 

[Farrix]

@JRM7997 Ok, lets identify your model quick.
Is it long with a dump box? (Dump Box is TBX model)
Does it have independent rear suspension (FIS Fully Independent Suspension)
Does it have a solid rear axle? (no additional FIS)
Does it have Modular Multi Piece Rack System? (MRP - Modular/Multi-Rack Pack)

With a quick search 0470-445 is the P/N for almost all 2004 ATV's and i believe all 2004 400 ATV's (MRP, FIS, TBX, TRV)

Your Vin will start with a 4 (4wd) UF 04 (2004) ATV then a bunch of other numbers.

 

[Farrix]

In 2004 there is only 1 concern really when ordering parts, be careful with your suspension components, 2004 was a split year on A-Arm design, early 2004 had the 2003 400 style, late 2004 had the 2004-2013 style, I believe in the fiche it says (VIN Ending is 225000 and Up)

 

[JRM7997]

@JRM7997 Ok, lets identify your model quick.
Is it long with a dump box? (Dump Box is TBX model)
Does it have independent rear suspension (FIS Fully Independent Suspension)
Does it have a solid rear axle? (no additional FIS)
Does it have Modular Multi Piece Rack System? (MRP - Modular/Multi-Rack Pack)

With a quick search 0470-445 is the P/N for almost all 2004 ATV's and i believe all 2004 400 ATV's (MRP, FIS, TBX, TRV)

Your Vin will start with a 4 (4wd) UF 04 (2004) ATV then a bunch of other numbers.

sounds like a great idea. it isn’t a TBX. No box

It has front and rear FIS.
It has front and rear MRP with a front lockable box.
I looked up TRV and I can’t figure out the big difference. Is the seat made for one or two? I can’t tell But I’m pretty sure you could seat two.

so it’s a 2004 AC ATV 400 (meaning 400cc) 4x4 (or 2 WD on the fly) FIS with MRP. And the vin is 4UF04ATVX4T254278.

The last 6 are over 225000 so I should expect the suspension components to be the newer style.

thanks Farris for the info and part number. I’m going to wait until after disassembling the carb before ordering parts. Just in case I break something.

 

[Farrix]

TRV is the two up version, the wheel base is longer, has extra foot-rests for the second person, 2004 the TRV only came in the 500 I believe, 2005 the TRV came in the 400. If you had a TRV you would have about 8-10" longer frame, longer wheel base, extra foot rests, and a backrest. I've always wanted to find a 2005 TRV chassis with a torched motor, do a gear reduction and put my 400 engine into it.

just so you are aware the 400CC engine in 2004 is actually 375 or 376CC on paper. with a 0.5MM overbore it's a 381CC.

 

[doorfx]

400 trv came with 4.0 gears 😊

 

[JRM7997]

TRV is the two up version, the wheel base is longer, has extra foot-rests for the second person, 2004 the TRV only came in the 500 I believe, 2005 the TRV came in the 400. If you had a TRV you would have about 8-10" longer frame, longer wheel base, extra foot rests, and a backrest. I've always wanted to find a 2005 TRV chassis with a torched motor, do a gear reduction and put my 400 engine into it.

just so you are aware the 400CC engine in 2004 is actually 375 or 376CC on paper. with a 0.5MM overbore it's a 381CC.

Than definitely not a TRV. Too short and no extra pegs. Only 375cc OMG. ripped off again. My CRV Is supposed to be 1500cc but it’s only 1498cc ripped off again

 

[JRM7997]

Well, the carb looks pretty good inside. Needle seats look hardly used. It only has a few hundred miles on it so i shouldn't be surprised. Except..... lots of fine grit. I think ill flush out the tank a few times and put a good filter inline. I'm heading out to watch the grey cup at a friends so will clean and put it back together tomorrow.

So im not going to order a kit but will definitely be replacing the shut off.

 

[Farrix]

Yeah, something as small as fine grain pepper can fudge a carb so quickly. Glad you found a potential cause inside, worse when you see nothing.

 

[JRM7997]

I’ve put the carb and it’s parts through a sonic cleaner and Have a tip for you. I thought I’d lost a small washer that goes with a jet o-ring. I found it stuck to the inside of the float bowel. My brother suggested that in the future use a zap strap or wire to make the part look bigger

on the grit question. I flushed the fuel tank (plastic tank) with some gas and poured it into a coffee filter. Nothing gritty. But, a lot of water came out. I’m thinking the grit might have been from the outside of the carb even though I’d cleaned it before starting but….

as for the water, that may have been why it wouldn’t start. and also a good reason to drain the carb once in a while. Water goes to the low point. So I rinsed the tank out with methyl alcohol (it mixes with water) then I’ve let the tank dry. All good

I’ll get to rebuilding the carb within the next couple days. Looks like we are going to get some snow so maybe they will declare a “snow day” and I’ll do it then.

For those Americans reading this, good luck kicking Iran’s soccer/football butt today At the World Cup.

 

[JRM7997]

So its all cleaned up and almost fully assembled. I have run into a problem. I found out that the ATV is a MRP so should have an CVK32 carb on it. However, in the manual I downloaded for this unit the carb shown below doesn't have the manual primer lever/system that mine does. So it has me wondering if my carb is a 32 (pictures on first post).

It isn't a real problem as all the information I have found says the carb float setting should be 17mm. So my real problem is setting that 17mm. I've watch soooo many videos and read a lot of information on this. The problem is seeing the float arm touch the needle and to try and measure at the same time. I've also tried the method of blowing air into the fuel intel and listening for the shut of them measuring the height. A lot easier but it isn't the method I'm supposed to use.

The manual says to do

NOTE: Check float arm height by placing the car-
buretor on its side w/float contacting the needle;
then measure with a caliper the height when the
float arm is in contact with the needle valve. Float
arm height should be 17 mm (0.7 in.).

Actually, reading those instruction again sounds easy. Maybe another attempt. But in the meantime any advice or direction to a better method?

 

[Farrix]

You have a cvk 34 which is the correct carb for that machine, cvk 34 has the primer pump.

The diagram you are showing is not for an FIS (fully independent suspension). If you have rear A-arms you have an FIS.

MRP only changes the rack design.

I believe you mentioned in an earlier post you didn't have a rear swing arm.


I'll see if I can find the float height guide that I used a few years ago, it made a huge difference in my brain wrapping around measuring it. I'll post if I do.