31/01/2024
+++ ๐ฆ๐ฒ๐๐๐ถ๐ป๐ด ๐๐ฝ ๐ฎ ๐ฃ๐๐ฐ๐ต ๐บ๐ฎ๐
๐ถ ๐ฐ๐น๐๐๐ฐ๐ต +++
The spring inside the Puch clutch acts against centrifugal force and delays the point that the clutch begins to engage. By changing these springs, we can choose the point at which the clutch engages. Simply putโฆ The stronger the spring, the higher the RPM that the clutch engages.
๐ช๐ต๐ ๐ถ๐ ๐๐ต๐ฒ๐ฟ๐ฒ ๐ฎ๐น๐๐ผ ๐ฎ ๐๐ฐ๐ฟ๐ฒ๐?
The screw gives us a range of adjustment with each different spring, the further the screw is turned in the later the clutch engagesโฆ
๐ช๐ต๐ฎ๐ ๐ต๐ฎ๐ฝ๐ฝ๐ฒ๐ป๐ ๐ถ๐ณ ๐ ๐๐๐ฟ๐ป ๐๐ต๐ฒ ๐๐ฐ๐ฟ๐ฒ๐ ๐ฎ๐น๐น ๐๐ต๐ฒ ๐๐ฎ๐ ๐ถ๐ป?
If you go crazy on the screw it will reach the point where the coils contact each otherโฆ this locks the clutch solidโฆ It will not work! If the screw starts to get more than say 2mm below the surface, and you have not reached the revs you desire, it is time for the next stronger set of springs.
๐ช๐ต๐ ๐ฑ๐ผ ๐ ๐ป๐ฒ๐ฒ๐ฑ ๐น๐ฎ๐๐ฒ๐ฟ ๐ฒ๐ป๐ด๐ฎ๐ด๐ฒ๐บ๐ฒ๐ป๐?
Later engagement is desirable on tuned engines, which do not produce much power at very low RPM, indeed they may even be producing less power than the standard engine at say 2,000 rpm. If we allow the clutch to engage this low it will barely pull away, it might even stall the engine. If we make the clutch engage later rpm (when the engine is producing far more power) we will pull away smartly.
๐๐ผ๐ ๐ต๐ถ๐ด๐ต ๐๐ต๐ผ๐๐น๐ฑ ๐บ๐ ๐ฐ๐น๐๐๐ฐ๐ต ๐ฒ๐ป๐ด๐ฎ๐ด๐ฒ?
This is a difficult question to answer, so let us give two examples from our own test Maxis
Maxi 1 has a reasonably tuned engine, it has a 19mm carburettor Proma circuit exhaust and a 70cc barrel. This begins to produce its best power at 4,400 rpm, in this we have the ASP brace (Maybe not necessary, but as we make them why not!) our Kevlar lined shoes and the 50Nm set of springs, the screws are set make the clutch engage at 4,200 rpm, this machine steps away very well and then almost instantly accelerates very hard as the engine hits its powerband.
Maxi 2 is very highly tuned, with a 21mm carburettor, Polini Reed valve barrel and a Homoet 6p. exhaust, in this we have the ASP brace (definitely necessary, as this one revs to 12,000) our lightweight Aramid lined shoes and the 50nm set of springs, the screws are set make the clutch engage at 6,200 rpm, notice we still only use the 50Nm springs as the lighter clutch arms balance against this. Although we engage at 2,000 rpm before the power really gets going, this is deliberate because we had to think about how we are going to use the machine. We wanted a strong clutch set at the point to give us reasonable acceleration without having to ride through the town with a maxi that has to be screaming at over 8,000 rpm before it drives!
If Maxi 2 was used for sprinting where all that cared about was the maximum acceleration, we would be setting the clutch for engagement far higher, at the point where the engine really begins to hit the power, that would be 8,200/8,300 rpm, this would likely need the 100Nm set of springs.
Remember, unless you are racing, try and set the clutch engagement with how you want to ride. The higher the revs it engages at, the more annoying it can be in town and of course more wear involved. Our big Aramid friction area does a lot to mitigate the wear, but they are not magical, they will like all things, eventually wear out.
๐๐ ๐๐ต๐ฒ๐ฟ๐ฒ ๐ฎ๐ป ๐ฒ๐ฎ๐๐ ๐๐ฎ๐ ๐๐ผ ๐ด๐๐ฒ๐๐ ๐บ๐ ๐ฐ๐น๐๐๐ฐ๐ต ๐๐ฒ๐๐๐ถ๐ป๐ด?
The short answer is no, not really
We would recommend that unless you want the clutch to engage where it was, that if you are mild tune you start experimenting with our 50 Nm springs and the screw flat with the arm on standard shoes (about 4000 rpm?)
For those high rev pipesโฆ again start with 50Nm springs but with the lightweight arms (and donโt forget a brace!!)
