These are our new 68mm big bore high port timing stock appearing Assassin cylinders. These cylinders are a new design from Driveline Performance which include 68mm Nikasil bore, triple exhaust ports, larger intake and transfer ports. We machine these cylinders in house on our CNC so we can ensure that all cylinder specs are proper for the +4mm long rod stroker crankshaft. Our cylinders are machined to specific heights so there are no spacer plates required a standard .020" base gasket is all that's needed.
The 421cc kit is designed to be used with a +4mm stroker crankshft with 115mm rods.
This cylinder kit has higher port timings for riders who are wanting more mid to top end power.
The port specs on these cylinders are 196 exhaust and 124 transfer durations. The exhaust port is much larger then a stock cylinder so peak H.P. will be much higher.
We have tested multiple exhaust manufacturers on our cylinders and most of them perform well, obviously the better the exhaust the more H.P. that will be achieved. Peak H.P. and power curves will also vary depending on the amount of compression and timing you choose to use along with the quality of reeds and carburetors that are being installed.
2 cylinders Nikasil plated to a 68mm bore size. We use Millenium Technologies for the Nickasil plating.
2 Wiseco forged 68mm Blaster style pistons with our custom intake window design, rings, wrist pins and circlips.
2 rubber water jacket plugs.
1 .020" base gasket
Posted by steven martinez on 11th Feb 2018
I ordered this kit and the crank as well as the stealth head and 19cc domes. I put it all together and took it down to a local shop to dyno tune it. They said the crush was ok but the compression was a little high but that's what I was shooting for with the 19cc domes. After they set up the jetsbon the 35mm PJs, the bike pulled 83hp at 6° advanced timing and CPI small bore pipes. I have since changed to Shearer small bore in frames and I can tell that the power band comes in sooner and holds longer but have not put it back on the dyno yet. I ride the bike out in the dessert and drag track. After 9 months or running it, I have had no issues at all. Soon I will tear down and see if I can open the ports a little before I hit the dyno again.