FQ101.co.uk
THE HOME OF MODIFICATION AND MAINTENANCE FOR YOUR SMART

Note: There is a lot of controversy over the accuracy of this guide. However, we have used this method on 5 engines with success every time. If you do experience any timing issues, please check that cylinder 1 is definitely at TDC with the timing hole on the cam sprocket in line with the top of the cylinder head.

Following any work to the engine which involved removing the cam sprocket (or crank sprocket), the engine must be re-timed.

Remove the inner wheel arch lining. Manually rotate the engine until cylinder number 1 is at top-dead-centre.

We found that a good way to do this was to remove all of the top spark plugs (which reduces the compression in the cylinders), and place a LONG thin screwdriver (or similar) in through the cylinder 1 hole.

Using a 15mm Ring spanner on the main crankshaft bolt rotate the engine in a CLOCKWISE direction (natural rotation of the engine).

Keep rotating until the screwdriver rises then slows until it is just about stationary (ie until it is just about to fall).

At TDC on cylinder 1 should cause a small notch on the main crank pulley to line up with the timing mark on the engine timing case. You can just see the timing notch approaching the timing mark in the circle below:

Please note for every 2 turns of the crank pulley, the cam turns once.
The cam sprocket can only fit on the camshaft one way (dictated by a notch on the sprocket). A visual check is that at TDC, the cam web for the exhaust valve on cylinder 3 is pointing straight up from the upper engine face. The alternative is the cam web for the inlet valve on cylinder 3 pointing at a slight down angle from the upper engine face.

You now need to check that the small timing hole is perfectly in line with the top edge of the engine face; i.e. you can see exactly half of the timing circle when you look at the engine on the side.

You will also note that the symbol which appears to be an arrow on the cam sprocket points vertically upwards. This is a logical check that all is correct. If the sprocket was supposed to face down (as shown elsewhere) there is no point in having it as it can't be seen!

If this is all in-line, then no adjustment is required.

If however, when the crank indicator is aligned, and the top hole does not line up, then you need to move the cam chain along one notch.
The amount and direction required depends on whether the crank indicator is in front or behind the mark on the casting mark.
If the pulley mark is behind the casting mark, the cam sprocket needs to move clockwise 1 notch with the chain in situ. We suggest only making 1 notch adjustments at a time to avoid over-compensating.

When testing, incorrect timing can be diagnosed through backfiring, misfiring, or very rough idling, which may start to smooth out at higher revs.

Member Login