Motor Tune-up

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Tune-up VW EngineVW Motor (53882 bytes)

To get the most out of your trike and to make sure you get where you want to go, you should service your engine regularly. VW engines are very reliable and robust but that doesn't mean you should just ride them until they die.

Clean air, clean petrol and good oil make all the difference.  The ignition timing and valve clearance should be checked and oil changed every 5000km.  You will be amazed how many kilometres you can get out of the old air cooled VW engine if you give it just a little TLC.

Since different systems in a VW motor interact to affect overall performance, tune ups must be done in the following order:

  1. Valve clearance adjustment
  2. Ignition adjustment and timing
  3. Oil change and filter cleaning

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Valve Clearance

Make sure you know what motor you have in your trike.  Any HS3 built after 1999 should have a new motor and gearbox.  If your trike was built before 1999 you may have a rebuilt engine.

On rebuilt engines it is not hard to determine the valve clearance, but you have to find out if your engine has long or short rocker arm shaft support studs. 

Long or Short Studs?

Feel under the engine between the push-rod tubes for the bottom end of the stud.  If you can feel the stud, you have long studs.  If you can't feel the stud you have short studs.

NOTE: Check all 4 studs.  You could have an engine with long studs on one side and short studs on the other side.  If that's the case, it's time to see the professionals

Valve Clearance



Rebuilt - Short Studs

0.008" or 0.2mm 0.012" or 0.3mm

Rebuilt - Long Studs

0.004" or 0.1mm 0.004" or 0.1mm

New (Mexican) Motor

0.006" or 0.15mm 0.006" or 0.15mm

Start with a cold engine to avoid pain and secondly because the  expansion of the metal due to heat will give you wrong measurements. 

Make sure you do it right.  If the valve clearance is too small you can burn or distort the valves.  If the clearance is excessive you will have a very noisy motor and very little power.  A bit more valve play is safer than not enough.

Before adjusting the valves remove both rocket arm covers and the spark plugs.  This makes the engine much easier to turn by hand.  The plugs should be checked and cleaned anyway.  Turn the engine over and have a good look at the crankshaft pulley.  

measure_pulley.JPG (14471 bytes) There should be a mark or notch exactly 180 from the TDC timing mark.  If you can't find one - make one.  Measure across the pulley as in the picture below to accurately locate the mark.

To adjust the valves, turn the engine over so that piston No 1 is at TDC on the compression stroke.  You can tell this when the timing mark on the pulley lines up with the crankshaft seam and the rotor points to the notch on the distributor as shown.  

Do cylinder No 1 first, which is the right front cylinder.

Loosen the lock nut on the adjusting screw, insert the feeler gauge and adjust the clearance.  Tighten the lock nut and recheck the clearance, just to be sure.

Rotate the crankshaft pulley 180 counter-clockwise (backwards) until the mark you made lines up with the crankcase seam.  Now you can adjust the valves for cylinder No 2.

Rotate another 180 for cylinder No 3 and again for cylinder No 4.  When this is all done, refit the rocker covers with new gaskets.

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Ignition Adjustment & Timing


Remove the distributor cap and wipe off any dirt or corrosion (on the inside that is).  Pull out the rotor and check the contact.

If you look down in the distributor you will find a set of points.  If you don't, you would have electronic ignition and you can skip the ignition adjustment.  If you do have points (I like them better), then check them for signs of pitting and see if they line up nicely.  If they are pitted or don't line up, it's time to replace them.

Distributor2.jpg (65942 bytes)

Every 20,000km the points should be replaced.  To do this, disconnect the primary lead to the distributor and remove the points.  Make sure you remember how they are connected and install the new ones in the same way.  Check that the contacts on the points are properly aligned.

Rotate the crank shaft pulley until a high cam lobe opens the points to the maximum gap.  Loosen the screw holding the points.  Insert a feeler gauge in the gap and adjust to 0.016" or 0.4mm.  Tighten the retaining screw... and you have just adjusted your points.

Before you put it all back together add a bit of grease to where the points run along the shaft and place a drop of oil in the centre of the shaft where the rotor sits.

I always do a full turn and check again to make sure the adjustment is right.  Reconnect the primary wire, put the rotor back where it belongs and clip on the distributor cap.

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After you have done the points the next step would be getting the timing right.  There are two ways to do this.  The first and cheaper option is to do it with a "Static Test Lamp", which is your normal 12V test light which you should have in your toolbox anyway.

The other option, which costs a bit more but looks much more impressive with the girls is to use a "Stroboscopic Timing Light."  Of course, I'm in favour of the second option, but I will explain both.

Static Test Lamp Method

  1. Remove the distributor cap.
  2. Distributor (66468 bytes)Crank engine over by hand until the timing mark lines up with the crank case seam and the rotor points to the No 1 mark on the distributor housing rim. (see diagram to right)
  3. Loosen the distributor housing clamp screw.
  4. Connect one test lamp lead to the ignition coil terminal and the other lead to ground.
  5. Switch ignition on.
  6. Rotate distributor body clockwise until the contact points close (lamp off),  Slowly rotate the distributor counter-clockwise until the points just begin to open (lamp on).  Tighten distributor clamp screw in this position.
  7. Reinstall distributor cup and disconnect test lamp.

Stroboscopic Timing Light 

  1. Select the proper timing mark for your engine (as described in Valve Clearance above).  Mark the notch with white chalk or paint for better visibility.
  2. Connect timing light to cylinder No 1. as per the manufacturers instructions (The ones who made the timing light, not the trike.)
  3. Run engine at 900rpm.
  4. Loosen the distributor housing and turn it until the timing notch on the pulley, which you can see with the flickering timing light, lines up with the crank case seam.  Tighten the distributor in this position.

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Oil Change & Filter Cleaning

Time to change the oil?  It should be changed every 5000-7000km.  (Make sure you have a strainer gasket kit on hand before you start)

Oilstrainer.jpg (78682 bytes)I replace my oil every 5000km because we only run 2.5L and don't have a real oil filter (most of us anyway.)  The VW motor was designed over 60 years ago without an oil filter and has done fine without one for all these years.  But if you really want one, you can have it fitted at your local VW shop.

The best time to change your oil is when the motor is hot and the oil is thin,  Let it drain for more than 10 minutes.  

There are 2 types of oil strainer covers out there.  Type 1 has a drain plug in the middle and 6x10mm nuts around the outside.  Type 2 doesn't have the centre drain but looks the same otherwise.  I like Type 2 without the centre plug simply because you don't get tempted to do an oil change without removing the strainer cover and strainer and giving them the clean that they deserve.

When all the oil has drained, remove the nuts holding the oil strainer and remove the strainer.  Clean all parts in solvent (like kerosene) and reinstall the lot with a new gasket kit.  Make sure you don't over tighten the nuts or the centre plug.  

Time to fill the motor with new oil.  

2.5L will do the trick.  I buy oil in the upper price range.  Air cooled motors deserve a bit better oil considering you don't have to spend money on radiators, thermostats and water-pumps.

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Fuel Filter

I replace my fuel-filter every 5000km too.  They are cheap to buy and clean petrol can save you a lot of trouble and money down the road.

So far, we have done a basic VW engine tune-up.  Of course, there is a heap more we have to do to make sure we stay on the road hassle free and get lots of kilometres out of our trikes.  The tricky bits I leave to the specialists; people who have worked on VW motors and gearboxes for years.  You should only try to work on your trike when you feel confident you know what you are doing.  Services done by trained mechanics are well worth the money.

These pages will grow into a complete service and repair manual that we hope you will find useful... make sure you come back regularly to check out what's new, and to give us ideas on what is needed.

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