Valve / Tappet Clearance Inspection |
This DIY illustrates the Valve / Tappet Clearance Inspection. It does not cover the shim adjustment / replacement procedure. |
Acknowledgments |
A big thank you to a few individuals who were instrumental in the making of this DIY. Allwak, who is my original hero of the Burgman 650 family on BUSA. His original Valve / Tappet Inspection was very critical to get me started on doing my own inspection. Allwalk’s Original Valve / Tappet Inspection Buffalo, who is a constant dedicated contributor on BUSA with great insight into all things mechanical and motorcycle related. He was kind enough to answer my questions and steer me in the right direction. Many thanks to all and others who contributed in other ways |
Basic Information |
A bit of basic information about valves, camshafts and what not for those that aren’t dedicated full time DIYer or trained mechanics. I am not a mechanic by trade and have done most of my learning over the years via the gracious tutelage by others far more knowledgeable than me and now days with the amazing vast pool of information available online. Rather than me trying to explain engine combustion and why valves need to be adjusted, I thought I would just point you to a great source online that was put together by a very savvy individual: Dan’s Online Motorcycle Repair Course Please support his site if you find the information useful. Below are a few excerpts from his excellent Valve Clearance Adjustment article: "Valves ? I have no problems... mine are nice and quite. Maybe and maybe not. As we know, metal expands and contracts as it heats and cools. Because of this there needs to be some clearance for the metal to expand into. Sometimes it's a little and sometimes it's a lot. So what happens if there is too little clearance ? Well, for one thing the valve loses most of it's heat through the valve seat. If the valve doesn't seat fully it will start to get hotter and hotter. Sooner or later the valve starts to melt or burn. Not good ! Now if the clearance is too much the valve train components will be hammered every time the valve opens. Again, not good but better then too hot. To prevent these problems some engines use hydraulic tappets which pump up with engine oil while the engine is running and keep the right clearance. Now for some reason everybody thinks valves loosen as the miles pile up but they don't, at least they don't unless you have lubrication problems. ( So change your oil, OK ? Well, at least check it now and then... maybe ? ). If an engine is running right the valve will slowly wear its way into the engine, taking up clearance until the valve is held open and burns. So you need to check the valves at regular intervals until you find out at what rate they are wearing. You can use your shop manual as a guide to how many miles to go between checks but, you will need to check several times to know for sure. Shim Type Adjusters Shim type adjusters are supposed to extend the valve check intervals. However, when it comes time to change things it can get expensive. Each shim is a certain thickness. If you need more valve clearance, you put in a thinner shim, at $10 to $15 per shim. Let's see... a 4 cyl, 4 valve engine has 16 shims... WOW, that adds up fast. AND you are replacing good parts. For the shims rarely wear out. Good news is you can swap shims between valves, tight one for a loose one, and save some money there." |
Recommended Service Intervals |
The owner’s manual calls for a valve / tappet clearance inspection every 14,500 miles or every 24 months. It’s a good idea to adhere to the recommended service / inspection intervals by owners so they can keep an eye on the wear and tear on their shims and minimize the risk of suffering any major valve breakdowns. I personally didn’t do mine until the 54k miles while I was rebuilding my CVT and had the engine out. I think every owner should decide for themselves what is the best way to keep their ride in perfect riding conditions. Checking the valves every 14500 miles may sound a bit excessive, especially considering the reported number of out of spec tolerances by those that have done it. However, no two machine are alike and there is no way to assure that the wear and tear on internal parts occurs uniformly on identical models. I personally plan on doing an inspection every 30k miles from now on. |
Terminology |
Some basic terminology to help clarify things. Below are a few pictures of the 650’s camshafts from the Service Manual:
Basic camshaft verbage:
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Preliminary Steps | |
You will have to remove some tupperware in order to gain access to the the front of the engine where the cylinder head cover is located which has to be removed in order gain access to the Intake / Exhaust valves. Foot Board (you can skip this one if you can easily access the valve timing inspection cap) I performed my valve inspection while I had the engine separated from the frame during my CVT repair project. It gave me easier access to the cylinder head cover, especially with the frame out of the way.
DIY Valve - Tapper Clearance Inspection Video | |
Step | Service Manual Tappet Clearance / Inspection Data |
The tappet clearance values / specifications are different for the Intake and the Exhaust valves. They should be checked and adjusted accordingly at:
The inspection should be performed on a cold engine. Below are the normal standard clearance value ranges for the tappets: DATA: Tappet clearance: Standard: IN..: 0.10 - 0.20 mm (0.004 - 0.008 in) EX.: 0.20 - 0.30 mm (0.008 - 0.012 in) | |
Tappet Clearance / Inspection in a Nutshell | |
The entire tappet / valve inspection procedure can be broken up into the following basic steps: There are 8 valves total, 4 per cylinder, 2 Intakes and 2 Exhausts. The cylinders are referenced as #1 and #2. The #1 cylinder being on the left side of the engine where the oil filter is located, the #2 cylinder is on the opposite side of the engine.
You will need the following tool to perform the clearance inspection: 00900-20803: Thickness Gauge When inspecting the clearance, start with the smallest thickness gauge and work your way through the gauges until you encounter a gauge that is too thick to pass between the top of the tappet and the head of the lobe. Never force a gauge between the tappet and the lobe, it should just slide in and out with very little effort. Use this worksheet to keep track of your inspection values for each valve: | |
Tappet / Valve Clearance Inspection | |
The steps below contain the original instructions / pictures from the service manual, followed by additional comments, pictures and videos as I performed the inspection. | |
1. | Remove the spark plugs. You must remove the spark plugs first.
Tool: OEM Spark PLug Tool / 14 mm socket
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2. | Remove the cylinder head cover The pictures below show where the cylinder head cover is located with multi-views from different sides.
Tool: 6mm Hex Key / Socket
Note: Make sure that the spark plugs have been previously removed. |
3. | Remove the gasket. The gasket will remain attached to the engine casing. It has to be removed for the reassembly as there is no gasket track / groove on the engine casing.
Note: If you are not replacing the gasket, place it in a plastic bag to keep it from drying up or getting damaged. |
4. | Remove the valve timing inspection cap The timing inspection cap is located on the right side of the engine, right past the CVT Assembly. Tool: 10 mm hex key / socket
Once the cap is removed, you will be able to see the 14 mm crank shaft bolt. |
5. | At this point you need to turn the crankshaft to align the valves per cylinder to perform the tolerance check. The alignment process is performed by lining up the notch mark on the crankshaft with the notch mark on the engine case, and checking the markings on the camshaft wheels for the proper alignment for each cylinder. There are two punch marks, A and B, which will serve as the visual guide for the valve inspections. The pictures below will help identify cylinder #1 and #2, and the Intake and Exhaust valves:
The alignment process basically consists of turning the crankshaft bolt and lining up the respective punch marks and then checking the A and B punch marks on the camshaft wheels. The A/B punch marks should be upright for cylinder #2 and inverted / upside down for cylinder #1. Below is the description from the service manual: Turn the crankshaft to bring the “Top” line on the starter clutch to the index mark and also to align the notches (A) on both ends of each camshafts with the “1” mark (B) on the exhaust sprocket to the positions as shown.
You basically need to make sure that the punch marks A/B are upwards on the camshaft wheels and the vertical punch marks line up with the edge of the engine casing as seen in the pics below:
Note: If for whatever reason the markings don’t line up accordingly, you can turn the crank shaft bolt again until they do. |
6. | In this condition, read the tappet clearance at the valves (In and Ex of No 2)
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7. | Turn the crankshaft 360 degrees (one rotation ) to bring the ‘TOP” line on the starter clutch to the index mark of the valve timing inspection hole and also to bring notches (A) to the position as shown.
The pictures below show how everything should be lined up:
Note: If for whatever reason the markings don’t line up accordingly, you can turn the crank shaft bolt again until they do. |
8. | Read the clearance for the remaining valves (In and Ex of No. 1) and adjust the clearance if necessary as shown below.
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9. | If the clearance is out of specification, adjust the clearance as shown below.
DATA: Tappet clearance (when cold): Standard: IN..: 0.10 - 0.20 mm (0.004 - 0.008 in) EX.: 0.20 - 0.30 mm (0.008 - 0.012 in)
Here are my clearance / inspection values at 54k miles. This was my first check: IN..: #1 12 mm / #2 12 mm / #3 14 mm / #4 14 mm EX.: #1 14 mm / #2 14 mm / #3 19 mm / #4 19 mm |
Cylinder Head Cover Reassembly | |
The reassembly process is pretty straight forward. I would highly recommend that the gasket be removed from the engine casing and remounted on the back of the Cylinder Head Cover which has a built in groove for holding the gasket. If you leave it on the engine, it require a lot of effort to line it up as it will slip and sag since there is no holding groove on the engine casing. I had ordered a new gasket for my cylinder head cover as I didn’t want to run the risk of developing any kind of leaks in the long run. The one that I took off the engine looked very good and came off without tearing and could have been reused. You can order the gasket from any outfit / dealer that sells Suzuki OEM Parts. The part # for my standard 04 Burgman 650 was: 11173-10G00. Price: $25.00
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99000-31230: Suzuki Bond “1216B” Note: Do not remove the dowel pin at the backside of the cylinder head cover since it is embedded.
Engine Oil
Cylinder Head Cover boltt: Light tightening: 10 N-m (1.0 kgf, 7.0 lb-ft) Final tightening: 14 N-m (1.4 kgf, 10.0 lb-ft)
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The following is provided as a courtesy for those that may need to perform a shim adjustment. It is a verbatim recitation of the shim adjustment / replacement steps from the service manual. | |
Step | Tappet Clearance Adjustment |
The clearance is adjusted by replacing the existing tappet shim by a thicker or thinner shim. | |
1. | Remove the Intake or Exhaust camshafts (3-12) |
2. | Remove the tappet (1) and shim (2) using your fingers or a magnetic grab tool. |
3. | Check the figures printed on the shim. These figures indicate the thickness of the shim. |
4. | Select a replacement shim that will provide a clearance within the specified range. For the purpose of this adjustment, a total of 25 sizes of tappet shim are available ranging from 1.20 to 2.20 mm in incremental steps of 0.05 mm. Fit the selected sim to the valve stem end, with the numbers facing the tappet. Double check the shim thickness with a micrometer to ensure its accuracy. Refer to the tappet shim selection table for details. Note: Be sure to apply engine oil to the tappet shim top and bottom faces When seating the shim, be sure that the face with the printed figures faces the tappet Caution: Reinstall the camshafts as per the recommended specifications (3-72)
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5. | After replacing the tappet shim and camshafts, rotate the engine so that the tappet is depressed fully. This will squeeze out oil trapped between the shim and the tappet that could cause an incorrect measurement. Check the clearances again to confirm that it is within the specified range |
6. | After finished the valve clearance adjustment, reinstall the following items: Cylinder head cover Spark Plugs and plug cap Valve timing inspection plug |
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