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  • In this video we'll show you how to adjust the valves on your 4-stroke motorcycle ATV.

  • We'll need a few different tools to complete this job.

  • First we'll need a feeler gauge so we can measure the clearances.

  • And Rocky Mountain has a few different options for you.

  • Next we'll need a few standard tools, so we can get to the valves.

  • But most importantly we're going to need our service manual.

  • This contains the very important, very specific specifications you need for this job.

  • It's also very helpful to have a caliper to measure the thickness of each valve shim.

  • We're also going to need some valve shims.

  • Rocky Mountain has these available in shim kits with numerous different sizes, or you

  • can buy them individually if you know what sizes you're going to need.

  • But we'll get to that a little later.

  • It's a good idea to start with your piston at top dead center.

  • Refer to your service manual for this, but most of the time there will be a mark on the

  • flywheel that needs to be lined up with the mark in the top hole.

  • You'll see our piston is currently at top dead center.

  • So first things first: we're going to want to start with a clean bike.

  • It's always easier to work on a clean motor, and also keep in mind that each machine is different.

  • This process will vary from machine to machine.

  • Today we're working on a 2007 Yamaha WR250F.

  • The first thing we're going to remove the seat and the tank.

  • After that is the spark plug cap, and the valve cover breather hose.

  • After that we're going to remove the two bolts from the valve cover.

  • Usually there are just two of these bolts, but sometimes you'll find three.

  • And once those are removed we can just remove the valve cover.

  • And that will reveal the valve train.

  • Now we can start measuring our valve clearances.

  • We're going to need our feeler gauges now and, to measure the valve clearance is simple.

  • All we're going to do is take the appropriate feeler gauge and slide it in between the camshaft

  • lobe and the valve bucket, which is also known as the tappet.

  • You want the gauge to feel almost sticky underneath the cam lobe.

  • If the clearance is bigger than the gauge it will slide in and out easily.

  • If the clearance is smaller than the gauge you'll know because the gauge won't slide in at all.

  • For illustrating purposes we've removed our cylinder head from the bike

  • to better show the adjustment process.

  • So removing the head is not required, and the steps that are shown will be the same

  • as they would with the head still on the motor.

  • We need to refer to our service manual and figure out what our valve clearance service

  • limits are and that would tell us what size feeler gauge we need to be using.

  • As you can see the service limits for this WR are .1 to .15 mm for the intake, and .17

  • to .22 mm for the exhaust.

  • Most all motors will have service limits similar to this motor.

  • So we're going to start with the exhaust side.

  • We're using our .20 mm feeler gauge, and as you can see it's sliding in under both of

  • the lobes, but not very easily.

  • So we're going to grab out .18 mm gauge, which is a little smaller and try that one.

  • You can see that it's a little sticky and that's exactly what we want.

  • So we're going to record that measurement because we'll need it later on.

  • With the right side measuring .18mm and the gauge went a little easier on the left side,

  • so we're going to record that as .19 mm.

  • Now we can start measuring the intake side, and we're going to start with our .15 mm gauge,

  • because it's the top for our service limit for our intake valves.

  • As you can see it slid into the right side just fine. Moving to the middle valve you

  • can see that it won't slide in at all, and the same case for the left intake valve.

  • So we're going to move to our .13 mm gauge and it looks like it's fitting perfectly in the right side.

  • The left intake valve and the middle are still not fitting, so we're going to record the

  • measurement for the right intake valve now at .13 mm.

  • Now we're going to go to a little smaller gauge to see if we can't find the clearance

  • for the left valve. We're using a .06 mm gauge and that slides in just fine; but the .07

  • mm gauge fits perfectly.

  • So we can record that clearance for the left valve now at .07 mm.

  • After that we're going to take our two smaller gauges and see if there's any clearance in the middle valve.

  • As you can see nothing is fitting between the lobe and the bucket, so we can record

  • the middle valve as having zero clearance.

  • So now that we've got our clearances measured and recorded we can begin removing the camshaft

  • so we can get to the valve shields.

  • The first step would be to remove your cam chain tensioner.

  • Keep in mind that yours will most likely be a little different than the one shown in this

  • video, so refer to your service manual for proper procedures.

  • The next step is to tie a wire around the cam chain so it doesn't drop down into the

  • motor when the cam shafts are removed.

  • We can tie that up around the handle bars.

  • And now we're loosening the cam shaft cap bolts.

  • Remember to loosen these in a criss-cross pattern to prevent causing any damage.

  • After the bolts have been removed we can pop the cam shaft caps off.

  • Remember there are usually a couple of aligning pins in each cap and an aligning clip that

  • need to be removed to prevent them from falling down into the motor.

  • After we've removed the caps we can go ahead and remove both the intake and exhaust camshaft.

  • Doing this will reveal the valve buckets.

  • The next step is to remove the valve buckets and shims.

  • A magnet works best for this, and ensures that you don't drop anything down into the motor.

  • Remove each bucket and shim and organize them on your table so they won't get mixed up.

  • Sometimes the shim will stay kind of stuck up inside the valve bucket, and other times

  • it will stay sitting down in the spring retainer, so pay attention so you don't lose it.

  • So we have got both exhaust buckets and shims removed and placed on the table.

  • We're going to do the same thing for the intake side.

  • Just grab the bucket with the magnet and make sure you have got your shim as well and then

  • place them on the table.

  • You want to make sure you're keeping everything organized between your motor and the table

  • during this whole process.

  • This is a very critical part to a valve adjustment.

  • Now we're going to clean everything up with a rag really quick to make it easier to work with.

  • It's time to refer to the specs from our service manual, and once again you'll see that the

  • intake is .1 to .15 mm, and the exhaust limit is .17 to .22 mm.

  • We need to check the clearances we've recorded and see which ones are still in spec and which

  • ones need to be adjusted.

  • As you can see both our exhaust valves are still in spec at .19 mm and .18 mm which is

  • right in the middle of our bracket.

  • And the right intake valve is still in spec as well at .13 mm.

  • So now we need to look at our other two intake valves and figure out the correct size shim

  • to install to get our desired clearance.

  • To figure that out we need to know what size shim were in the head.

  • This is where our caliper comes in handy.

  • All valve shims have their size printed on them, but sometimes that number can get worn off,

  • so if you're unsure of what size the shim is simply measure it with the caliper.

  • As you can see our left intake valve shim is measuring 1.7mm, and our middle intake

  • valve shim is measuring 1.63 mm.

  • So we're going to write that down.

  • With our left valve we need to go down on the size of the shim to get more clearance,

  • because right now it's at a .07 mm and it needs to be between .1 and .15 mm.

  • So if we get a 1.65 shim, which is 1.65mm thick, the difference between that and the

  • 1.70 mm that was in it is .05 mm.

  • If we add that clearance to our current .07mm of clearance we should get .12 mm, which is

  • in spec so we'll swap that 1.70 shim out for the new 1.65 shim.

  • And since our middle valve has zero clearance, we're going to use the biggest service limit

  • for the intake, which is .15 mm, and subtract that from the shim size that was in it.

  • So 1.63 minus .15 mm equals 1.48 mm, and since they don't make a shim that size we're going

  • to use a 1.50 shim.

  • So we can go ahead and swap that shim out.

  • Okay, so now we've done the math to get our new shim sizes on the two intake valves that

  • needed adjustment, and we need to put our cams back in to check those clearances again.

  • Now we're reinstalling each shim and bucket back into their correct location.

  • When installing the shim be sure it seats down all the way to the end of the valve,

  • and then slide the bucket down over the shim.

  • Repeat this process for all the valves.

  • After that we're ready for the cam shafts and cam shaft caps.

  • Don't forget the locating clip and make sure your dowel pins are in place as well.

  • Do this for both cams, if applicable, and make sure everything seats correctly.

  • We can reinstall the cap bolts and tighten those down.

  • It's a good idea to refer to your service manual for this to avoid causing damage.

  • You'll want to tighten these bolts in a criss-cross pattern.

  • After you get those tight make sure the camshaft rotates smoothly.

  • If they do we can rotate the lobes back up to where they sit at top dead center.

  • This will allow us to get an accurate clearance reading.

  • We're using our .13 mm feeler gauge and it seems to fit about perfect with our left intake valve.

  • But it still won't fit under the middle intake valve.

  • But if we drop down to a .07 mm gauge it fits.

  • So at least it's measurable now.

  • So now the new measurement for the left intake valve is .11 mm, which is in spec.

  • And the new measurement for the middle intake valve is .07 mm which is still not in spec.

  • So if we swap that shim for a 1.45 shim the difference of those two is .05 mm, and if

  • we add the current .07 mm clearance to that it equals .12 mm of clearance,

  • which is right in spec.

  • We need to remove our cam shaft cap again, and remove our intake camshaft one more time

  • to swap the middle valve shim out for a new 1.45 mm shim.

  • So after we've removed the 1.50 mm shim from that we're going to set that 1.45 mm shim

  • down into place and replace the bucket on top of it.

  • After that we can reinstall the cam shaft and cam shaft cap, and once again tighten those bolts down.

  • Then we'll measure it again and it should measure something like .12 mm which it does.

  • So now all of our valve clearances are within spec, so we can start putting the motor back together.

  • The first step to that is timing the motor.

  • So we need to remove the engine plugs from the left crankcase cover.

  • The bottom plug is so you can get a socket in there and turn the motor over if needed.

  • The top hole has the aligning mark and shows the mark on the flywheel and as you can see

  • both marks are lined up telling us the piston is at top dead center.

  • If you don't see the mark on the flywheel you need to turn the motor over until both marks line up.

  • You're going to want to pop your cam shafts out one more time and apply a little assembly

  • lube to the lobes and journals of each camshaft.

  • We need to refer to our service manual for proper timing instructions.

  • As you can see each cam sprocket has timing marks on them.

  • So we're going to need to refer to our service manual to get the cam shafts in the correct position.

  • It's important to start with the exhaust cam and pull the cam chain tight up off the crankshaft

  • so there isn't any slack.

  • Align the timing mark where it needs to be and then run the cam chain over the intake

  • cam and align those marks accordingly.

  • It's basically starting at the front of the motor and then working your way back.

  • The slack in the cam chain will be taken up by the tensioner.

  • So we have our camshafts installed and timed using the mark on the flywheel and the marks

  • on the cam shaft sprockets.

  • Go ahead and double check your work according to the service manual.

  • Make sure everything is how it should be.

  • Remember the cam chain tensioner will not be installed until a little later.

  • So now we're going to install our camshaft caps.

  • First we set the locating clip down onto the bearing.

  • Be careful not to drop it.

  • And then make sure we have our two dowel pins still in the cap and set that down onto the camshaft.

  • It should just pop into place.

  • And then we're going to do the same thing for the exhaust side.

  • Sit that locating clip down into the groove on the bearing, and then set the camshaft cap down into place.

  • Then we can put the cam shaft cap bolts into place and begin tightening those down.

  • Again, we need to tighten these and torque these bolts in a criss-cross pattern to avoid causing any damage.

  • Refer to your service manual for proper torque specs.

  • So after those have been properly torqued we can go ahead and put those two engine plugs

  • back into place and tighten those down.

  • Now that those are tight we can install the cam chain tensioner.

  • Remember that your tensioner may require a little different install than this one did,

  • so be sure to refer to your service manual for this.

  • The next thing we're going to do is apply a light coat of silicone to the cylinder head surface.

  • That's going to help the valve cover seal a little better.

  • And then we can just set that valve cover up into place.

  • You'll notice we've already got the gasket on the top part of it.

  • Then we can reinstall the two bolts on top and tighten those down.

  • The next thing we're going to do is reinstall our spark plug cap.

  • Now we're going to slide that cylinder head breather hose down into place and route that accordingly.

  • After that we're going to reinstall the tank, tighten those bolts down.

  • And once the seat's installed we're done with this valve adjustment.

  • If you have any questions call in or visit our website. Rocky Mountain ATV/MC is the

  • leader for parts, accessories, and apparel for your UTV, ATV and motorcycle.

  • Thanks for watching!

In this video we'll show you how to adjust the valves on your 4-stroke motorcycle ATV.

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B1 中級 美國腔

如何調整摩托車或ATV上的氣門------------------------------墊片類型 (How To Adjust Valves On A Motorcycle Or ATV - Shim Type)

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    Syuan 發佈於 2021 年 01 月 14 日
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