Two Stroke Racelab

A couple months back I installed a fresh top end on a friend's bike, a '99 Cr125. The piston came without lubrication holes at the exhaust side. So, I thought it wouldn't make any harm to add a couple holes, quite the opposite I reckon. The piston was temporarily placed in the cylinder with the piston ring just above the exhaust port roof and the exhaust bridge layout was then scribbed on the piston skirt. Two marks were then punched on the piston, from memory it was about 8mm and 18mm below the piston ring. The punch marks were then spot drilled on the Dore Westbury miller and then drilled through with a 1.5mm drill.   The holes seem a little bit too large due to the chamfering. A drill of 1 or 1.5mm is adequate enough for this modification.  For more info on the subject, check out this older blog post 2t-racelab.com - piston preparation and also this nice article from the Wiseco blog blog.wiseco.com - relieving the exhaust bridge and drilling lubrication holes

I've been recently working on a Cr125 engine and the water pump shaft was in bad shape and didn't seal properly. The gear is a press fit and can be easily removed from the shaft. Two different ways come in mind for repairing the shaft. One is to turn down the diameter of the shaft and press fit or loctite a sleeve with the correct dimensions. Instead, I just tig welded the shaft with stainless wire (ER308 type, don't ask if it's the correct rod, it's the only one I had laying around). Then comes the lathe, turning the shaft diameter to it's correct dimensions. And here is the end result, ready to be installed on the clutch cover and hopefully serve for a few more years. Here are the dimensions, please note that this is for the CR125R 1998 model ONLY!

Another one rare PGM unit. This one is for a CRM250 MK3 and it's a CI659A Mugen PGM unit. Ignition side was repaired hence the messy look.

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