Big Bore Kits & Cylinder

Installation instructions high compressed pistons and big bore kits

All engines with higher compression pistons (even if Big Bore kit or only High Compression pistons) need automatically different spark plugs to stock factory ones! The temperature range will change immediately. Therefor all engines need colder spark plug values!! And depending on the piston version, if piston deck is higher or not, the type of electrode is also different! Please consider that the minimum space between piston deck and electrode is 5mm and more (firing point)! Otherwise the piston will melt or crack! Furthermore please pay attention to the fuel grade (95, 98 or 100 octane. Depends on compression ratio) and air/fuel mixture (which has to be corrected for e.g. with a Power Commander). Please read the installation instructions, which are provided with the pistons or Big Bore Kit, carefully! If you have problems or questions please don’t hesitate to contact us.

• Here a list with spark plugs we advice
  

Attention! 900 '98 aso - 1000-1100 --- Attention cast-pistons !!! Please read informations below

All 2 valve engines 900 up from '98 (ie modells) and 1000-1100 got cast pistons, if you are a sporty rider, the pistons should be changed to forged Pistal pistons

CYLINDERS/BARRELS IN EXCHANGE -- NOTICE !!!

For our big bore kits we always take used cylinders, which will be bored and new coated. Becuase of their age and using, warm-cold while riding, the cylinders are "relaxed", means there are just very less tensions in the cast. That's the reason for better dimensional stability than new ones! It's a sign of quality, although it is more work and it is a little bit more expensive, but these "old " cylinders a much better than new ones with the point of view to measurements and dimensional stability!