PES BSA B50 B25 B44 TR25W Vernier Timing Pinion Gear 41-0569 70-8040

So much better than the originals, these have five keyways instead of the one.

Made in the PES Factory to the highest standards as always

"How to set cam timing"

The first thing to do is to set the cam and piniongear to the standard marks

This is done to gain reference figures.

Next fit a protractor to the end of the crank and attach a pointer that can be moved for calibration.

As it's not possible to directly find TDC, we calculate the position. Using a DTI on top of the piston, first measure a point before TDC. Make a note of this. Then at that piston position read the number of degress on the disc and make a note of that.

Rotate the crankshaft backwards and find the same piston position coming up the other way. Note the degrees at that point.

Add these figures together and divide by two and you'll have calculated TDC Move the crank to this position then adjust your pointer till zero TDC is indicated. Then do it all again just to prove nothing slipped. Keep repeating till you get it right.

Oh BTW, I should have said that you should expect to take a day doing this the first time.

So that's the easy bit.

Next place your DTI in a push rod connected to the inlet cam follower. Rotate the engine in its normal direction, anticlockwise from the clutch side. Find the lowest point on the cam and zero set your DTI.

Slowly rotate the crank again until the DTI reads 0.040" or 1mm. (once you start using a unit don't change)

Note the degrees before TDC

Continue to rotate the crank until the dial almost stops moving then rotate back to find your 0.040" lift again from the opposite side of the cam lobe.

Make a note of the degrees After TDC.

The fun bit.

Add both figures together. Mine were 40 and 60. Add to this 180. Then divide by 2. Take away your opening figure from your answer. This gives you your full lift position of the inlet lobe.

So mine was 40 + 60 + 180 = 280
280/2 = 140
140 - 40 = 100 degrees

This was the spot of luck I had today as it was the figure that suits the MX cam for off road use.

The down side is, as it's what I was after I won't be showing you now how to correct the timing if it's not what you’re after.

Mark