Points Setting

[bullylover]

One good thing to do if you own a Bultaco is to grind/ file the width of the feeler gauge down so it fits in the slot easily. As soon as I buy a set of feeler gauges this is the first thing I do. File or grind the .40mm one down. Your bike should spark fine with the points set at .40mm no matter where the timing is. They do like a small plug gap though. Bultaco recommended a .40mm plug gap as well. So I think Guys might have a good point above. Graham.

[bultacosd]

Hi everyone,

I have fitted points and adjusted the timing on a fair number of Bultaco's over the past 25 years. Last year, for the first time, I encountered the same problem that many of you have experienced. i.e. not enough adjustment on the ignition plate to set the correct timing position. I also noticed that on a couple of my bikes that it was difficult to get the points to open wide enough.

Now, this is just a theory, but I think the points supplied to me are not the same as the original. In particular, the length of the arm from the fulcrum to the block in contact with the cam. The difference is slightly less than 1mm but it's enough to cause trouble. If anyone is able check this then that would be a weight off my mind and it may be worth letting BultacoUK know that there is an issue.

My solution was not to complain or make a fuss (I don't know where i'd be without Bultacouk) but I simply used a Dremel to increase the 3 slots on the ignition plate. This job took about 20 minutes to complete and the results are good.

I set up the timing by playing around with the points gap initially but I was worried that with such a small gap that the points would be more prone to closing up during use = no spark.

Let's get to the bottom of this lads....or 2.5mm above top dead centre...

[lbhbul]

Have noticed a problem with after market points here, in that the rub block is so much longer than my originals

that it is necessary to grind the block to match (close enough) in order to be able to utilize the eccentric adjusting

screw, don't have any new points on hand so cant help there, however the new Femsa condensers for me are a

no go.

Someone will know for sure on the length. Interesting though.

Larry

[bultacosd]

I managed to compare a set of reproduction points with a set of original and I believe I have tracked the problem down.

I compared the length of the lever to the fulcrum and they were identical...however, I noticed that the rub blocks were in slightly different positions./

The rub block on the original points are riveted flush with the end of the points lever, on the new set they extend past this edge by about 1mm. This does not seem to be much of a difference but I had to extend the 3 tracks on the back plate by about 10mm to enable me to retard the ignition down to 2.5mm whilst retaining the 0.45mm points gap.

Extending the back plate slots is relatively easy.

Remove the plate. Use a marker pen to to plot the extensions to the slots. Use a Dremel with a small milling attachment. I managed to do this with the coils in situ but if you are in any doubt it would be wise to remove them first.

Good luck one and all...and kick out kick back.

[feetupfun]

The 0.35 to 0.45 mm point gap is there so the points open on the steep part of the cam and not the shallower, top part of the cam.

When they open on the steep part, in other words, when the points open quickly, you get the best spark and the least chance of burned points.

At least thats what they teached me at school a long long time ago...

Yes that is a good reason.

Another reason is that the gap between the faces, and the diameter of the faces, determines the size of the charge that the capacitor is required to store (the points gap and the diameter of the contacts are tuned to the size of the capacitor)