Hello, I have gotten myself a 62mm crank and could do with some infomation and any hints or tips.
It has a standard con rod 107, does this need changing to a longer one so the piston skirt doesnt catch at BDC?
is it best to get the bigend pin tigged because so close to edge of crank web
If I'm going to this effort how much extra to change to eccentric pin to stroke it to 64/65mm
Engine cases, I'm guessing a groove is required to give conrod clearence, does ali welding have to be done for reinfocrement
barrel, I have a ts1 barrel I was thinking of using, is this possible or does it have to be fitted with iron liner to get correct port timings or should I get a rapido 250?
Thanks Dave
62mm crank infomation needed
As far as replacing the con rod, it really comes down to the top end in question and whether the port timings would line up, etc. Same goes with the stroke question. There are a number of different opinions regarding welding up the pins. This may help keep the two halves together but you'd better hope you don't spoil a big end bearing. There is a lot of work that needs to be taken into consideration when fitting a crank with a longer stroke (say 62+) as it will most likely require extra machining to the crankcase. This means the crankcase may get nice and thin and go boom or lots of welding. I just came across this same problem while setting up my Rotax motor. Decided it wasn't worth the extra work for the 4mm stroke and opted for a 60mm stroke crank and will machine the barrel to suit. Good luck and keep us posted!
-Ryan
-Ryan