blaster detonation

[bdrak11]

Bought an 88 blaster from friend. Said it was a family members and knew nothing about it. I tore down the top end and everything was brand new. The cylinder was at1mm O/S and it had a brand new wiseco. Put it back together and ten minutes into the ride at pismo, it detonated on my son. Took it home and started on the rebuild. New wideco piston, thank god almost no cylinder damage only needed hone. I figured it only needed to be richened up a little, so i went from the 250 main that was there to a 280 main. As i was slapping her back together, i noticed that the head was shaved. I thought i could get away with doubling up the head gaskets, so i did. At pismo, i was able to beat my record of ten minutes and detonate in three. I have since bought a stock head from ebay and attempting another rebuild. Hopefully threes a charm. Can anyone help me with jetting because inside the cylinder it was DRY and the PLug was dry and WHITE.

The bike has the following mods:

 

67mm wiseco piston,K&N airfilter with outerwear, open lid,Old school cobra exhaust system, stock pilot jet and main is at 280, oil injection removal kit. I mix at 32:1 with castor 927.

Any help anyone can give would be greatly appreciated.

[wayfst]

put a new cdi box on it, check the timing.

[rocketboy]

if its stil l doing it on the stock head than id say you have ignition issues as wayfst has stated ,the timing is to o far off

[bdrak11]

it has stock timing, not advanced at all

[wayfst]

just to rule it out, new cdi box

[pimpeinkc]

if the head was shaved, it needed race fuel... my whole crew has melted pistons,,, if you put it back to stock compression you should be fine....

[RATBIKE0130]

If the squish band was not properly cut adding a second head gasket could cause it to detonate quicker. If you want a reliable machine I would return the head to stock and don't run any sort of special piston (Vitos). If it hasn't been done already disable the oil injection system and start premixing the fuel.

[bdrak11]

If the squish band was not properly cut adding a second head gasket could cause it to detonate quicker. If you want a reliable machine I would return the head to stock and don't run any sort of special piston (Vitos). If it hasn't been done already disable the oil injection system and start premixing the fuel.

 

 

If you wouldnt mind, could you explain why it would detonate in a little more detail. Thank you