Big Bore Kit

25 replies to this topic
  • Rich_Rohrich

Posted May 30, 2005 - 07:11 AM


The dyno runs I posted included runs with California spec pump premium. That engine was also setup with 14:1 compression and had no issues with the pump fuel. It had better response with the good fuel, but pump fuel didn't cause any issues. In fact right after it left the dyno Bill took the bike and rode about 1500 miles with it on pump fuel in Baja (on his honeymoon :) )

I wouldn't suggest running as high as 14:1 on pump fuel unless you really stay on top of the jetting, but slightly less compression (12.5 - 13:1) is easy to deal with running pump fuel .

  • drewpeacock

Posted May 30, 2005 - 01:28 PM


please explain?? aside from racegas why wouldnt you want to use one??


  • ISBB

Posted May 31, 2005 - 03:48 PM



If built properly reliablity shouldnt be too big a issue?

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  • drewpeacock

Posted May 31, 2005 - 06:02 PM


I'm not trying to be a jerk with this question but on mine I blew out my head gasket and also found a break in one side of the (new in rebuild) timing chain with the 2mm overbore and high compression piston. I did not do the engine work so do you think it was the mechanic or a reliability issue. Also, I did not feel a real big difference in power. At least not enough to justify my reliability. :)

  • beezer

Posted May 31, 2005 - 06:11 PM


I have had pretty good luck with Forward Motion. They don't try to ram high dollar crap down your throat.

If it didn't work I don't think Eric Gorr would sell it.

I have put in 2 big bore kits from them and had great results.

  • Rich_Rohrich

Posted May 31, 2005 - 08:05 PM


If built properly reliablity shouldnt be too big a issue?

My experience has been that reliability is the same as the stock engine if it's put together correctly.


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