First, I'd like to give a special thanks to those responsible for teaching me how to complete my first valve adjustment: countless calls to Brian @ WPP Racing when I would have questions, and of course, Rob's site: Rockin Horse Web. This information is really courtesy of those two resources...I am just taking the time to put this information into detailed text and picture form for others.
Second, this valve adjustment "How-To" was meant to be very detailed and in-depth. It was meant to show everything about the process of adjusting the valves in a TRX450R. So, no whining about how LONG it is!
Third, I assume NO RESPONSIBILITY for your ATV and or parts if you screw them up. Conduct this adjustment AT YOUR OWN RISK!
Fourth, PLEASE do not use any of these pictures without my knowledge or consent. PLEASE do not copy this write-up and pass it off as your own. These are my pictures, and my own words (except where given credit)...Please treat them as such.
Fifth, I'd like to give credit to those who helped me out by proof reading this long article: Lumi, Ryan, Chino, Sam, and Greg. Thanks fellas!
You can visit MY 450R PAGE by clicking here.
Tools you will need to complete this job.
An extra set of hands to help. (one of the most important tools)
Feeler Gauges. (both straight and angled...these can be found at your local SEARS...Craftsman brand)
Needle Nose Pliers.
3/8" Torque Wrench.
Gloves.
Loc-tite. (RED)
Motor oil.
Zip-ties.
Very small Flat Screw Driver.
Flat Screw Driver.
Hot Cams Shim Kit or a local Honda dealer that has 9.48mm shims. (I prefer the HC's shim kit)
Digital Metric Caliper. (possibly to measure the shims...there are other methods provided to get around using this tool)
Metric Socket Set.
Metric End Allen Sockets.
Metric Allen Wrenches.
Metric End Wrenches.
Cutters or Razor Knife. (To remove Zip Ties)
Pencil and Piece of paper. (To record measurements and shim sizes)
IMPORTANT NOTE! (From Rob at RockinHorseWeb.com):
If there is more then one bolt holding anything on that you are removing follow this procedure. Example: There are 3 bolts holding the valve cover on, put your socket on bolt #1 and barely break it loose, then bolt #2, then bolt #3, then remove bolt #1, then #2, and finally #3. DO NOT remove #1 before you break #2 and #3 loose. If there are 4 bolts follow the same procedure using a crisscross pattern. The same goes for tightening, install all 3 bolts and hand tighten, then cut the torque spec in half and start with #1, then #2, finally #3. Then reset your torque wrench to the full amount and repeat. If the torque amount is high, like 40 ft/lbs, then start at 10, then 20, 30 and finally end at 40...Do not just cut a large amount like that in half. Use this procedure anytime there is more then 1 bolt…it may take a little longer but not in comparison to a broken bolt or stripped threads.
Checklist:
- Have all the tools outlined above out and ready to be used.
- Read the important note by Rob...this is very important and will minimize the likelihood of broken bolts or stripped threads.
- It may also be wise to have a Service Manual handy while completing this adjustment. The service manual can be downloaded here.
- Make sure the ATV is clean so that minimal dust will enter the engine when the valve cover is removed.
- Be sure to complete this adjustment within a garage or shed with minimal dust circulation.
- This adjustment must be completed when the engine is COLD.
- Take your time and be careful...especially if this is your first adjustment.
Down to Business:
STEP 1:
Before tearing anything down, first I like to get organized so that nothing is lost. I clear a space in my garage to put the larger parts such as the Rear Plastics, Seat, and Tank. I also put down a sheet of carboard with several paper towels on it. On these paper towels, I lay the various bolts and small parts in the order they come off the quad. Below, you can see a picture of what I'm talking about.
(Click the picture to enlarge)
STEP 2:
Remove the seat from the ATV by pulling up on the lever located on the underside of the rear of the seat. Then simply pull the seat towards the rear of the ATV so it will slip out. Refer to the picture below to see the seat lever.
(Click the picture to enlarge)
STEP 3:
Remove the rear plastics from the quad by completing the following tasks: Pull the kick start lever out off of the plastics into the starting position (This is so the plastics do not get hung up on the lever while trying to pull the plastics off). Pull the plastics out of the 3 rubber tabs. One rubber tab is located on either side of the quad, directly below the gas tank (Show in the first picture below). They can sometimes be tight, but should pull right out. The last tab is located on top, directly behind the gas tank and right above the intake snorkel (shown in the second picture below). Next, remove the two bolts (10mm) on top of the plastics which are located above the airbox assembly (Bolts are shown in the 3rd picture below, circled in GREEN). Then, remove the four remaining bolts (10mm) holding the plastic in place. Two bolts, on either side of the ATV, are located on the underside of the rear plastics (Bolts are shown in the fourth picture below circled in RED). Lastly, remove the rear plastics by lifting them up and off the ATV; place them somewhere out of the way. The ATV should now look like the fifth picture below.
(Click the pictures to enlarge)
STEP 4:
Remove the tank from the quad by completing the following tasks: Pull the gas cap breather hose out from inside the steering stem hole (shown circled in GREEN in the first picture below). Turn the Petcock to the OFF position (refer to the second picture below). Remove the fuel line clamp using needle nose pliers (shown circled in RED in the picture below). Pull the fuel line off of the gas tank's fuel line fitting (the fuel line can be stubborn sometimes, and be careful, there is a little bit of gas left in this line). Remove the two "tank-to-frame" straps which are located on each side of the ATV (shown circled in BLUE in the fourth picture below). Next, remove the two bolts (8mm), one below each of the front fenders (shown in the fifth picture below circled in GREEN). Remove the four bolts securing the front plastics to the tank and frame, two bolts (8mm) on each side of the ATV, one holding the plastic to the tank, and one holding the plastic to the frame (shown circled in RED in the sixth picture below). Remove the two tank bolts securing the gas tank to the frame. One bolt (8mm) on each side of the frame. You will need to pull the front plastics back to remove these bolts (shown circled in BLUE in the seventh picture below). Lastly, lift the tank off the ATV and place it somewhere out of the way.
(Click the pictures to enlarge)
STEP 5:
Remove the heat shroud by completing the following tasks: Remove the three black plastic tabs (shown circled in GREEN in the picture below). You will need to use a Flat Screw Driver, and pop the snap tabs up, then use the screw driver to pop the whole tab out of the frame and plastic shroud. After removing all three tabs, pull the three wires up and out of the heat shroud so that there is plenty of slack in the wires. Then, pull the heat shroud up off of the frame, and carefully maneuver it out from under the wires (Be careful that you don't pull a wire out or kink a wire). Place the heat shroud somewhere out of the way.
(Click the pictures to enlarge)
STEP 6:
Remove the valve cover by completing the following tasks: Zip-tie the two wires on the right hand side of the bike (from the rear) to the plastic snap tab hole on the frame (shown in the first picture below). Zip-tie the one thick wire on the left hand side of the bike (from the rear) to the frame (shown in the second picture below). This will keep those three wires back of the way so that you may work on the cam assembly without any interference. Next, loosen the clamp on the valve cover vent hose (your hose will be black with a small clamp (USE needle nose pliers), not pink like mine) with a flat screw driver or needle nose pliers (shown circled in BLUE in the third picture below). Pull the hose off of the valve cover fitting, and push it towards the rear of the bike so that it is out of the way. Remove the spark plug boot (shown circled in RED in the third picture below) by pulling up on the boot; push it towards the front of the bike to keep it out of the way. Then remove the spark plug from the engine using a spark plug socket and long ratchet extension. Remove the three valve cover bolts (shown circled in GREEN in the fourth picture below) while keeping Rob's method outlined at the top of the page in mind. Now the valve cover is ready to be pulled off. Lift up on the valve cover on both sides and slowly lift the valve cover off the head. Be sure that the gasket stays on the bottom of the valve cover, as it can be re-used several times. After completing this step, your bike should look like the fifth picture below.
(Click the pictures to enlarge)
STEP 7:
Set the engine to TOP DEAD CENTER (TDC) by completing the following tasks: Remove the Crankshaft Hole Cap (10mm allen wrench) on the bottom right side of the engine (near the transmission fluid check hole). Inside the crankshaft hole, use a 8mm allen wrench to rotate the crank manually to line up the timing marks on the sprocket and case (shown in the first picture below circled in GREEN). Or, you can roll the bike forward (this will manually rotate the engine - make sure the bike is in gear) until the mark on the crank, and the arrow on the case align (shown circled in GREEN in the first picture below). Also, after setting the crankshaft marks correctly, check to be sure the timing marks on the cam assembly, and cam chain sprocket are aligned properly (shown circled in RED in the second picture below). Finally, if all the timing marks line up, the cam lobes should be pointing towards the rear of the quad, and slightly up as shown in the third and fourth pictures below. This means the engine is now at TOP DEAD CENTER, and you are ready to check your clearances.
(Click the pictures to enlarge)
STEP 8:
Before checking your valve clearances, you must first know what the clearance specs are for the cam you are using. Most cams, for example: STOCK 04/05/06/07, 04/05 HRC, 06/07 HRC, 04/05/06/07 CRF, Hot Cams Stages 1, 2, and 3 all have an intake valve clearance of .006" (+/- .001") or .16mm (+/- .03mm) and an exhaust valve clearance of .011" (+/- .001") or .28mm (+/- .03mm). To find out what your cam's clearance specifications are, contact the cam manufacturer or your builder. Now, you may be wondering, what does the "(+/- .001")" or the "(+/- .03mm)" mean? This is the allowed variance to the clearance specification. Example: If the intake valve clearance spec for your current cam is .006" (+/- .001"), and your measured clearance is .005", .006", or .007", then your are still within spec. Same goes for the Millimeter measurements. If the exhaust valve clearance spec for your cam is .28mm (+/- .03mm), and you measure a clearance of .25mm, .26mm, .27mm, .28mm, .29mm, .30mm, or .31mm, then you are still within spec. The first picture below shows the location of the four valves. The two intake valve clearances are measured between the "bucket" and cam lobe (circled in BLUE below), and the two exhaust valve clearances are measured between the rocker arms and exhaust valve shims (circled in RED below). First measure the two exhaust valve clearances. Use a straight feeler gauge (shown in the second picture below), and slide it in underneath the rocker arm, and above the exhaust valve shim (shown in the third picture below). Try different feeler gauge sizes to see which feeler gauge gives you the best feel. You are looking for a snug fit, but you should still be able to move the feeler gauge around freely while it's between the shim and rocker. Be sure to record your measurements on what clearances you have for each valve on a piece of paper for reference. Next, check the two intake valve clearances. It is very important to get an accurate feel for the intake valve clearances, so I stress that you use ANGLED feeler gauges as shown in the fourth picture. Slide the feeler gauge under each of the two cam lobes, you are feeling for the clearance between the cam lobe, and the bucket under the cam lobe. Refer to the fifth picture below to see how to properly check the intake valve clearance. Again, you are looking for a snug fit, but you should still be able to slide the feeler gauge back and forth while it's between the lobe and bucket. Be sure to record your measured clearances for each intake valve. If one or more of your valves is not within the manufacturer's specifications, continue on to Step 9; you DO need to make adjustments to your shim sizes. If all four of your valve clearances are within the manufacturer's specifications, you DO NOT need to make any shim changes. Begin reassembling your bike by reversing the previous steps. Torque specifications for the Spark Plug, Valve Cover Bolts, and Crankshaft Hole Cap are outlined in STEP 10.
(Click the pictures to enlarge)
STEP 9:
To adjust your valve clearances, you must change the thickness of the valve shims. To make shim changes, you must remove the cam sprocket and the cam carrier/assembly. NOTE: You may want to put a large rag in the open area of the engine (left side of the engine if you are looking at it from the rear) just to make sure no small parts fall inside. First, break the two cam sprocket bolts loose (shown circled in RED in the first picture below), but DO NOT remove them YET. I highly suggest using gloves when breaking these bolts loose, as they are held in place with RED loc-tite and require a lot of force to loosen. In breaking the cam sprocket bolts loose, you will need to keep the cam assembly from turning. The method I use is to put the bike in gear, and have your helper step on the rear brake, or the rear tires. You could also try holding the crank still with an allen wrench...or find your own method in keeping the assembly motionless while breaking the bolts loose. To keep the machine in time, be sure to leave everything at TOP DEAD CENTER before removing the cam chain sprocket, and the cam carrier. Zip-tie the cam chain to the cam sprocket (shown circled in GREEN in the first picture below), to be sure the timing stays straight up. Now (for the 04/05 machines), remove the cam chain tensioner bolt (8mm), and use a small flat screw driver to screw the small cam chain tensioner screw all the way in - clockwise (shown in the second picture below). Be careful, this screw is spring loaded. With the cam chain tension screw all the way in, remove the two cam sprocket bolts that you broke loose earlier. Be careful not to drop these bolts down into the engine. Pull the cam sprocket off the cam, and zip-tie it to the frame (shown in the third picture below). After you have the cam sprocket securely zip-tied to the frame, you can now slowly back the cam chain tensioner screw out. This will put tension back on the cam chain. DO NOT just let the screw driver go, as this tensioner is spring loaded. The cam chain tensioner mechanism is a little different on the 06/07 machines. No screwdriver needed, just loosen the two small 8mm allen head bolts until there is no more tension on the chain. Then zip-tie the cam sprocket to the frame, as mentioned earlier in this step. Remove the four cam carrier bolts (shown circled in GREEN in the fourth picture below), remember to use Rob's method for removing these bolts. Now lift the entire cam assembly up and off of the head (shown in the fifth picture below). You may have to wiggle the assembly a bit to get it to pop off. Be careful that you don't drop the small shims down into the engine, sometimes they like to stick to the rocker arms or the buckets (the buckets are the "lifters" that cover the intake valve springs, they are shown in the sixth picture below circled in RED). After lifting the cam assembly off, the top of the head should look like the seventh picture below, note the shims circled in GREEN.
(Click the pictures to enlarge)
STEP 10:
The disassembly part is pretty much finished. Now, you just need to make your shim changes (the shims are shown in the first picture below circled in GREEN), and put it all back together. On a side note, keep this LOGIC in mind: If the spec. valve clearance is .006", and your current valve clearance is .004", you need a SMALLER number shim to increase the size of the gap. If the spec. valve clearance is .006", and your current valve clearance is .008", you will need a BIGGER number shim to decrease the size of the gap. Another IMPORTANT NOTE: Before installing any new shims, be sure to coat them with oil, DO NOT put a dry shim into the engine. Measuring and changing the shims can be pretty tricky. If you already KNOW what size shims are in your bike, this will be one of the easiest steps (Sometimes you can still see the small 3 digit number printed on the shim, IE: if the number is 170, it is a 1.70mm shim). If you do know what size shims are in your bike currently, just use this calculator to calculate what size shims you need for each intake valve, and each exhaust valve. The valve shim calculator is in MILLIMETER measurement! So, if you took your measurements in thousandths of inches, as many people do, you will need to convert your measurements into millimeters. EVERY .001" is equal to ABOUT .025mm. So .002" is ABOUT .050mm and etc. Therefore, if your spec intake valve clearance is .006", this converts to .16mm. Likewise, if your spec exhaust valve clearance is .011", this converts to .28mm. So to use the calculator, enter your spec valve clearance in the appropriate calculator (either intake or exhaust), put in your current valve clearance which we measured earlier with feeler gauges in STEP 8 (if you took your measurements in standard, you will need to convert them to metric), and then enter in your current shim thickness (example: 1.65 - this is the three digit number printed on the shim, it is measured in millimeters). Then press the "Calculate New Shim Thickness" button, and voila! That's the shim thickness you need. Repeat this step for each shim that needs changed. Now, if you DON'T know what size shims are in your bike, there are two methods you can use in figuring out what size shims you need. The easiest method, is to just use a digital caliper to measure the shim, as shown in the second picture below (the caliper shown below is a standard analog caliper, it is not digital. Digital is highly recommended). Then use the valve shim calculator to calculate the correct shim thickness (how to use this calculator is outlined earlier in this step). The last, and most time consuming, is the "guess and check" method. If you don't know what size shims are in your bike, and you don't have a caliper to measure the thickness of the shims, you will need to put shims in, which you know the thickness of, and take new valve clearance measurements. Here is what you will need to do. Put a 1.95mm shim in BOTH exhaust valves, and a 1.65mm shim in BOTH intake valves (Be sure to make a note of this, as you will need these shim thicknesses for your valve shim calculator). Reinstall the cam carrier and the 4 bolts, and torque the bolts back down to 10 ft/lbs, remember to use Rob's method (you do not need to re-install the cam sprocket or anything yet, just the cam and carrier). Be careful when re-installing the cam carrier, as the buckets can fall down into the engine. Also be sure that the cam lobes are facing towards the rear of the quad, and slightly up in the TDC position when re-installing the cam assembly (Just like you removed it). Re-measure the valve clearances (as outlined in STEP 8), and record the measurements. Remove the four cam carrier bolts (remember to use Rob's method), and remove the cam assembly (as outlined in STEP 9). Now, use your new shim thicknesses, and clearance measurments and plug them into the valve shim calculator to get the correct shim sizes (how to use the valve shim calculator is outlined earlier in this STEP).
(Click the pictures to enlarge)
STEP 11:
Record your shim sizes and put everything back together! Make sure you record on a piece of paper, what size shims are in which valves for future valve adjustments. Reverse step 9 to install the cam carrier and cam sprocket: Install the Cam Assembly (be careful when installing it so that the buckets do not fall into the engine), be sure that the cam lobes are facing towards the rear of the quad, and slightly up, in the TOP DEAD CENTER position, the same way you removed it from the head, and torque the four bolts to 10 ft/lbs (Use Rob's method at the top of the page). Then RE-CHECK YOUR CLEARANCES JUST TO BE SURE EVERYTHING IS O-K! Re-install the cam sprocket and bolts. Be careful with the cam chain tensioner, as you will have to screw it all the way in again (clock-wise), install the sprocket, and then back it out slowly to put tension back on the chain. Before installing the cam sprocket bolts, be sure to clean all the old loc-tite off the bolt threads, and re-apply RED loc-tite to the bolts (allow the loc-tite 20 minutes to set up before starting the quad). Torque the cam sprocket bolts to 14 lb-ft (Use Rob's method at the top of the page). Be sure to remove the zip-ties from the cam sprocket and chain (be careful when removing these, do not let them, or any pieces fall down into the engine). Before installing the valve cover, turn the engine over manually, either by using the crank, or pushing the quad while its in gear, just to be sure the cam and timing chain are moving correctly. Reinstall the valve cover (make sure the gasket is properly seated), and torque the bolts to 7 lb-ft (Use Rob's method at the top of the page). Reinstall the sparkplug, and torque it to 17 lb-ft. Re-install the Crankshaft Hole Cap, and torque it to 11 lb-ft. Reassemble the rest of the quad by reversing the steps above, but be sure to put everything back the way it was! Take your time, and double check that everything is in place.