Two Stroke Racelab

Time goes by like a two stroke motorcycle and this blog is now seven years old. Cheers!

Όπως και κάθε χρόνο, κλασικά κόβουμε τη πίτα μας και αυτή τη φορά θα πάμε προς Βόρεια Προάστια. Χαλαρό ποτάκι - μπυρίτσα και μπόλικη διχρονοκουβέντα δίπλα στα καμάρια μας. Για ετοιμαστείτε...    Mέρος : Cinecitta Pub, Πίνδου 50, Ανω Πεύκη Μέρα & Ώρα : Κυριακή 12 Φεβρουαρίου, 18:00   Περισσότερες πληροφορίες για το μαγαζί : cinecitta.gr facebook.com/localpubcinecitta

Electronic gremlins are so unpredictable. I've been working on a few Honda Rs250 PGM units this week, one for Olivier(FR), one for Colin(GB) and three units for Nicola(IT). You think that you know enough, you've seen common patterns, electronic parts that are regular suspects. Then one day you receive five PGM units from three different people and three different countries. Four of the PGM units have similar issues. Similar issues that I haven't encountered in the past even though I've repaired quite a few of them. How bizarre is that? Is it like a new PGM disease or something? Three of them are now repaired, two more to go. It will be a long night...

A few photos of some footrests that I turned on my metal lathe for the Tz125 bike. Parts were made from 25mm billet aluminum rod. Brake and shift pegs.  The footpegs now complete, side by side with the old ones. Before & after pics...

When time permits, I make some progress on my '91 NF4. This time I ended up refurbishing the dash. New panel from high density foam sheet. After dismantling the tacho, I used some emery cloth on the plastic panel. And then some polishing compound on a dremel tool with a polishing wheel. The end result looks nice and clocks are already installed on the bike.

Excellent craftsmanship and a work of art on two-stroke exhausts. Visit Tony's(UK) site at tonygreenracing.com

Time goes by like a two stroke motorcycle and this blog is now six years old. Cheers!

Today I was working on a Yamaha DT200 YPVS controller, that belongs to Joel(NZ). This curve opens the exhaust valve at 4.620rpm and the cycle is completed at 8.640rpm. If you check the blog post that I did a couple days back, you may notice that Yamaha uses the same closing time for the 125cc model as well. Though the curve starts opening the valve earlier on the bigger capacity bike. This is something to keep in mind when tuning other bikes as well. It does help to use an exhaust valve curve that delays the opening of the valves on bikes with weak mid range or tuned for higher revs.  Here is how to set the DIP switches.

I have repaired and modified a YPVS controller for Kire(DEU) and found yet another one YPVS curve that was previously unknown to me and might be a good suggestion for all 125cc bikes, including the TZR125 models. This curve is opening the exhaust valve at 4.800rpm and the cycle is completed at 8.640rpm. Here is how to set the DIP switches. P.s Check the below post for another one DT125 YPVS curve. DT125 LC MK3 '87, YPVS Curve