720 big bore kit

10 replies to this topic
  • crowboy15

Posted August 15, 2005 - 05:26 PM


has anyone heard of a 720 big bore kit seems like i saw one these in dirt bike magazine several years ago any imformation will be appreciated :D

  • wr450fyamaha

Posted August 15, 2005 - 06:02 PM


yeah, i seen one thing on a web site.....720 cc.......dont remember where tho sory.

  • Supplicate

Posted August 15, 2005 - 06:18 PM


that just seems like too much IMO. Like you would be risking way too much reliability.

  • Mikie1

Posted August 16, 2005 - 08:46 AM


There's no way the cylinder is thick enough to go that big. 680cc is already getting pretty thin. Maybe with a stroker crank, but then I think it would be very slow-revving. The 680 already makes TONS of torque- any more would be overkill, IMO.

  • wr450fyamaha

Posted August 16, 2005 - 08:52 AM


i think it was a new cylinder that i seen (very expensive like 2000 bux) that was made to 720. i think just a high compression piston, exhause, carb, and what not is good enough.

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  • TimBrp

Posted August 16, 2005 - 11:47 AM


I believe Baja Designs was designing a big bore kit for the 650R. It was a 710cc or so.

  • mikekay

Posted August 16, 2005 - 06:34 PM


yeah BD had 710 kits--so did a german motard outfit...

having done the 680 mod--i am a big fan of more...i do know of one guy who had issues with the 710 at Vegas to Reno 3 years ago...might want to go easy on the compression.

  • tzsr1

Posted August 25, 2005 - 08:13 AM


A place called LA Sleeve did (still do?) a 720 kit for the 650L. It was tested in the January 1998 issue of Dirt Bike. Back then the kit cost $350 (piston kit, gaskets, and sleeve) and machine work was $305 (had to machine the cylinder & cases). HP went from 34.6 to 41.4 (no other mods were done on the test bike).

  • wr450fyamaha

Posted August 25, 2005 - 09:39 AM


wow, thats a bit of a jump.......what was the torque increase?

  • tzsr1

Posted September 04, 2005 - 08:37 AM


They didn't give any #'s on torque which seems really strange. You'd think the torque would be impressive as well...

  • bork

Posted September 04, 2005 - 09:11 AM


I emailed laseeves and got no response back approx 8/15/05.

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