Quad bike maintenance guide Part 1

Posted by Tim Mckay on 26/09/2011

"I wonder", I thought to myself in a worryingly conversational manner, "how many of our readers know how to maintain a quad bike."

So .... how many of you own a quadbike? None of you? Really? Why not? Quads are great fun. A little unstable and certainly not without its dangers but if treated with care they can be one of the most enjoyable experiences to be had with four wheels.

Tell you what, I will wait until you have gone out and got yourself a quad bike before I continue. 

...

Got one? Good. Right! Here is how to maintain your newly purchased quad.

As we have unanimously agreed quads can be great fun. However they can be dangerous and unpredictable. Even a well maintained quad needs to be driven safely but a poorly maintained quad is an extremely dangerous vehicle.

Therefore, its worth performing routine maintenance as often is possible. As to how often that is depends on the make, how frequently its used and what its used for. Its best to check this when you are buying the bike.

Before you start with the quads service, make sure you are wearing protective clothing. Some of the lubricants can be very irritating if it makes contact with your skin. For this reason its also worth investing in a box of latex gloves to protect your hands. Also, I sometimes suggest using compressed air with an air gun. If you do one of these, I would put on protective goggles.

So lets start! The first thing I do is warm the quad bike up so you can drain the oil out. There are plenty of guides online telling you how to do this, and we might make one ourselves, but for now, I wont go into that much detail.

If your quad is fitted with an oil filter make sure you change it along with the oil. Several of the smaller quads don’t have an oil filter, they just have a gauze in the drain bung. If this is the case just give it a wipe down so its clean. Note: with some quads, when you change the oil, you are changing the engine and the gearbox oil where as others will have a separate gearbox level. You wont regularly have to change the gearbox oil but you will want to check its condition (It should look like new engine oil) and that its topped up. If you unsure which you have please consult the manual. 

A good thing to do next is to take the fuel tank off so we can clean the filter and to allow us to get to the top of the engine. To do this, you will need to remove the seat and any plastic panels that cover the fuel tank and then finally the tank itself. Note: Don’t forget to turn off the fuel tap and disconnect the fuel line before trying to lift the tank off. If this is not done you could cause damage to it or fuel might start leaking out.

If your tank is full of petrol, tip away at least half of it back into a can. Then you can turn the tank on its side and unscrew the two screws holding in the fuel tap. Slide out that assembly and in there you will see two small nylon gauze filters, one for the main and one for the reserve. Give them a wipe down, or if you have compressed air, use that. Note: Don’t get too close to the filters or you might blow holes into it. If its too dirty then it might be worth draining the tank right down, rinsing it out and disposing of the dregs inside it. Once you have done that you can put the fuel tap back in and put the tank to one side.

Next we are going to take the spark plugs out. Have a look at the tip of the spark plug. Ideally it will be a nice biscuit coloured brown. If its black then the fuel mixture is too rich and if its pale then its too lean. This can be resolved by tuning. If this is a service, then have a new one ready to go back in later, when we put it all back together.

With that done we turn to the air filter. Undo the screws and the hose clip that holds the lid on and pop the lid to one side. There are several types of filter that could be fitted; a sponge one, which can be washed out with some fuel and left to dry. Or a paper element type which can be cleaned with compressed air. Make sure the air gun is at a distance so it doesn’t damage it. If when trying to clean it with the air line, the dirt isn’t coming away, then you will need to change the filter.

Have a look at the bottom of the air box for a drain hole. Under here is usually a sealed bung. Give this a clean out as well. Once done you can leave the filter to one side.

Next we move onto the carburettor. At this level of maintenance there is not too much we are going to go through here. Clean away any dirt at the top of the carburettor with either air or carburettor cleaner. Look at the bowl at the bottom of the carb and locate the drainage tube. Sometimes these can be quite long so you will need to feel for where it goes. Put your waste bowl under where the tube ends. Then undo the screw on the side of the carburettor bowl to drain the contents of the bowl. This is important because water can often collect here, being heavier than petrol.

Finally for the keener mechanic, trace the choke cable from the handle bar into the carburettor. This usually screws into the top. Unscrew it, and gently lift out the choke slider. Give the slider pin and the opening in the carb a clean up with carburettor cleaner. We do this as this can seize up causing the choke to stick on. Then give it a light coating of a light oil such as WD40, and screw it back in taking care not to cross thread it.

Phew, almost done with the engine now. Before we finish this part though we are going to check the valve clearances. This is again, for the keener mechanic. Though it does need doing yearly (or the bike might not run). Unscrew two bungs on the top of the engine, one by the exhaust and one next to the carburettor. In there you will find the valve rockers. Ensure your spark plug is out for this next bit.

Start with the inlet valve nearest the carburettor. Turn the engine over using the electric start or pull chord, if fitted, until the inlet valve is fully closed. If your not sure when this is, let it cycle through a few times with the chord or start button so you can see the rocker moving up and down. You’re looking to stop with the rocker at its most upward point.

Using a feeler gauge of the correct width, as to the manufacturers specification, you are now going to measure the gap top of the valve and the bottom of the rocker and adjust accordingly. You should be able to feel just a small amount of resistance as you slide the feeler gauge in. If you cant get it in its too tight. And if you can still move the rocker up and down with the gauge in, its too loose. Now repeat this with the exhaust valve. 

We are now done with the engine so, take a look at the floor and look at the great job you did taking all the parts off. Now its time to put them back on. So put the valve back on, then the air filter and box lid, take note of any breather pipes you have moved out the way and make sure you aren’t pinching any. Refit the fuel tank and plastic panels but before fitting the seat lets take a quick look at the battery.

If your battery is a maintainable battery rather than a sealed unit check the fluid level. There is usually a level line on the side and the battery is often clear. Top up with deionised water. This should prolong the life of your battery. Check the terminals are secure and coat them with a small amount of grease to prevent the terminals corroding.

Then, you can replace the seat. And that’s it for part one of our Quad bike maintenance guide. To continue you will need to have a look at our second part (coming soon)

Hope you found this useful. If this sounds like too much to you, you could always just come and ride our quads.

Continued in Quad Bike maintenance part 2...