Oversized bore/piston options for 400
Posted June 20, 2006 - 07:41 PM
Posted June 25, 2006 - 12:13 PM
Posted June 25, 2006 - 02:56 PM
as far as i know, the sleeve and coating process is far more involved than what we may assume.
I have researched getting my 400 barrell bored and recoated, (electrosil/nicosil) and have had some mixed feedback over recoating.
apparently the nicosil coating aids in the heat dispersment function of the barrell and i would only recommend using the nico/electrosil method due to the high temps our bikes run at.
the only other alternative is a 426 barrell from yamaha, approx $550 AUS.
hope this helps.
Posted June 25, 2006 - 06:00 PM
I've used big bore kits from both Gorr and Lukes on my bikes, and have had no trouble with them. When adding up the cost of new piston, rings, pin, gaskets, and the machine work necessary to fix a buggered up cylinder, either by sleeving or welding up and re-grinding, the Big Bore kit wins by about a Benjamin...with, at least from my experience, no decrease in reliability. The only advice I would give (besides do it)is to order an extra set of gaskets and rings when you buy the kit. That way, you will have them available when it's time to re-ring, and not have to remember who's stuff you used and what the part numbers are to order from the TT store; and to make sure they are legal for the class you are racing (if you're a racer).
One more thing about running the 444 kit with the hot cams...the hot cams tend to rev a little bit quicker (ok...a lot quicker) than the stocker. The big bore kit revs a little bit slower due to the added weight of the piston, so the powerband is somewhat of a middle ground between the WR and YZ, just with a whole lot more of it.