[rt]

this post is basically an extension of my crankshaft dynamic question,
secondly directed towards someone who has a lot of knowledge inside the 660 motor--

Heres the senerio(I haven't actually started yet): After very extensive head work and special cam :grin_nod:, Very aggressive port job...would nikisil be an idea for coating the exhaust ports (more for a smoother finish) or would a real good polish job be just as efficient, I say this because nikisil has very good cooling and low friction properties. Same thing in the intake ports but, its being slightly grooved(very small) and notched for a better fuel atomization effect.
The valves were also a concern as well, I wanted to go with titanium valves(to stay light) but the more I read up on them the more I wanted to stay away from them. the reason being I read here and there that they don't hold up so well for high hp 660 motors especially with the stronger springs needed. Again I read they work extremely well for about 2 or 3 races (the pros who use them) and are replaced if not more often. Can anyone verify this?

to the bottom end- taking a little weight off the fly wheel was first, secondly can the counter balancer be removed to get rid of rotating mass, I'm sure its going to vibrate more but is it going to bad enough that it'll start effecting or ruin the motor?

 

[scholle]

You are correct about the titainum valves. Kibblewhite or Ferrea valves are very good choices. There is no need for coating of the ports. Actually the stock exhaust ports are good to around 70hp.DO NOT slick the intake.Save the nikasil for the cylinder. Coating the piston and or the head chamber like HPC can't hurt either.The heat and friction coatings show up more in how long parts last vs actual power from my experience.
Trailtech offers a lighter flywheel for the 04,05 bikes -17oz. The L&A oneway clutch/gear is lighter than stock also.If you use an 01-03 flywheel with the L&A its within 3oz of the lightend trailtech version for the newer ones.
The crank can be balanced by Falicon, I had very good service from them. I also have run strokers that very closely trued and haven't had a problem not balacing them. There may be no real need if the crank is very true.The engine can be run with no counter. It will vibrate your teeth out! Unless you have someone make it a full circle crank and modify the cases (possibly) I would advise against it.
http://www.trailtech.net/atv_flywheels_1.htm
http://www.ferrea.com
http://www.blackdiamondvalves.com/

 

[rt]

just to clarify..I mean the weighted countershaft that runs separate from the crank..I said counter weight not countershaft, my bad..I'm not touching the counter weight ON the crank(except for balancing). There is a shaft that runs right beside the crank thats geared to it. It has a weight on it thats suppose to help with vibrations... Are you talking about the crank counterweight or the countershaft?? I should of been more clearer..

 

[scholle]

I was talking about the counter balance shaft(connects via gear to the crankshaft).It could be lightend but I would advise against removing it.