ATV Answerman: Clogged Carburetors, CV Joint Issues and More

Have an ATV or side-by-side tech question for the AnswerMan? Send an e-mail with your name, vehicle year, model and a detailed description of the problem to editor@off-road.com, Attn: ATV AnswerMan.

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No Instructions
I have a BMX UTV 500 4x4 that I kind of inherited with no manuals. I was wondering how to adjust the parking brake? The UTV still rolls when the brake is set. I am also wondering where the air filter is. I see a large 3 or 4 inch inlet that goes underneath and was wondering if the filter is further inside and underneath the engine compartment or did it fall off the inlet hose? Any help would be appreciated. It has other idiosyncrasies but this would be a good start. And is there any dealer in USA and how can I get a manual on the machine, including maintenance, type of gasoline, oil, etc.?
Chickenman555

It seems you have inherited someone else’s problems. These machines are typically non-serviced, meaning there is no legit shop you can take them to and get qualified repairs. Most mechanics can work on them but become frustrated when they cannot get repair parts. It seems I have found a company who not only carries some parts but a service manual of sorts to boot – your lucky day I guess. The site is at http://www.bmxutvparts.com/, so that would be the first place I’d call. As far as the parking brake goes, it must have an adjustment close to the caliper/hub, but because I have not seen this machine before, ever, I’d refer to a service manual from the website above.

Sitting Cat
I recently bought a mid/late ‘90s Arctic Cat 400 4x4 manual shift. The last owner let it sit for about 1-2 years. It started but will not stay running, runs for about 20 seconds max while choke is on. If choke is moved it still cuts out. If you attempt to give it gas it cuts out. I have tried many different things to keep it to stay running. I removed the carburetor and brought it to a small engine repair shop. They cleaned it out and said it was really bad. Once I placed carburetor back on it and put in fresh gas it still does the same thing. Opinions?
John

This is such a common problem with machines that get parked for long periods or even with the ethanol-infused gas we are offered now it can be as little as a couple of weeks. The issue is most likely still in the carb. This machine should have a Keihin CVK style carb on it. If it were me I would go to the local dealer, purchase every jet that comes in the machine from the factory and just replace them all. You will have a main jet, primary and needle jets. This will most likely clear up your problem quite a bit, but also run some fuel system cleaner such as Ethanol Equalizer through the first couple of tanks. Good luck and be sure to ride that beast, as it’s not made to sit in the barn collecting dust.

Popping Ranger
I have a 2013 ranger crew and the front end seems to crack and pop when I start forward or backwards. I cannot figure out where the noise is coming from, but my buddy says he thinks it is the axle. I do not think it is. I have noticed it when I turn my steering wheel sometimes but mostly when I start off.

This could very well be the CV axle joint, but I would check a few things first. The bushings in the upper and lower control arms seem to wear quickly on these machines, and especially if it has been lifted or the tire size has been increased. Pull on the parking brake and jack the front of the machine up enough to just get the wheels off the ground. Be sure to chock a wheel or two so the big rig sits still. Take one hand and place it on the top of the tire and the other on the bottom. Try rocking the tire in and out from bottom to top. This should reveal any issues not only on the A-arm bushings but the ball joints as well. If any of this is loose or moves it needs to be inspected or replaced. Get a good service manual and you could probably replace these items yourself.

No-Name 50?
I bought my son a small 50 size ATV that I think is an Aldy? It has a Herchee engine I think. I cannot get it to stay running. It ran great for just a few hours but now seems to have lost power. We have been mixing the gas because we were afraid the oil system didn’t work. Help, my son wants to ride but I’m no mechanic.
Linda

It helps to know the maker on these machines and include them with the question, but I am very familiar with these so I will give you some things to consider. First off, you say you’re no mechanic and that’s going to be a problem. Most dealerships will begrudgingly work on the off-brand ATVs, but as I said they won’t like it. As for the problem, I would start with fuel. These carburetors have a lot of very small holes inside that get plugged up with varnished that is produced by our problematic fuel these days. The carb probably needs a good thorough cleanout, and this will get the engine running better. However, with a two-stroke mini quad you also have reeds that control the engine’s power output or at least can restrict how much you get out of the engine. If these reeds get worn they get flimsy, and this is where you will see a lot of power loss. If I were you I would find a kind and understanding dealer to sweet talk into repairing the machine. 

Screeching Sounds
Have a 2000 Polaris Scrambler 2x4 that is making loud screeching and the chain will not stay tight. It sometimes feels like the brakes are on full blast and I want to ride. Can you help?
Stan

This machine has an axle-bearing carrier that has bearings on both sides as well as seals. Take a good look at the back end when the chain is loose and see if you notice the right rear wheel moved forward more than the left. Typically the bearings on the chain drive side will wear faster as the engine pulls hard on the chain. Jacking the back of the quad up with the wheels off the ground should reveal the issue even better. This can be a complicated process to repair if you have no experience but it is not impossible. One thing to keep in mind is that the brake disc is hard mounted to the axle and if it begins to get out of shape from side to side the disc will literally lock itself up on the caliper and that could be why the brakes feel like they are stuck on.

Not Running
LTR450r will not run without the choke and it seems to be getting worse. It acted bad at our riding spot so I pulled the fuel filter out because that’s what my buddy told me to do. Now it is really bad and I want to race it but it’s not running right.
Dave

Well, I’m sorry to hear you will not be able to race your machine, and the fact that you let your buddy, who I hope is not your competition, talk you into removing a critical component of the fuel system is sad. The fuel filter is there for a reason and that’s to keep all of the bad junk in your race gas can from clogging the system, but most importantly from clogging the fuel injector itself. Might as well pull the air filter off now, right? You could have a severe issue in that the fuel injector has slowly become clogged with debris. That’s a dealer item and would need to be serviced by a dealer or a smart mechanic because one more miscue and that LTR is junk. Take the beast to the dealer for further inspection.

It’s funny how we thought when we were young we knew it all. Off-road vehicles are complicated machinery, and to think we should understand them is also a misunderstanding. Keeping fuel and air clean as well as doing regular oil changes will keep the biggest issues away from your toy, so be sure to take good care of the machine you own. If you’re not going to ride for a while, drain all of the gas from the carb by simply turning off the fuel and letting it run until the machine cuts off. This could save you a lot of misery when you decide to get back on the trail.
RS

Have an ATV or side-by-side tech question for the AnswerMan? Send an e-mail with your name, vehicle year, model and a detailed description of the problem to editor@off-road.com, Attn: ATV AnswerMan.

Previous ATV AnswerMan Columns
July 2014

June 2014

May 2014