Which is better if there is such a thing? Any downsides with one or the other? Im going to be going yoshi z450 stroker kit, exhaust, webcams blah blah blah...just need to know which carb to order...Do you notice a performance diff with a 40 over 39 or vice versa? Do I also need a Dyno jet kit to rejet or can i just screw dials on the fcr? thanks

 

is the motor ported and polished?. I run a 41 mil on mine and what a difference it makes
and it also depends on where you order the carb from. some places will have it jetted close to where you need it
you will have to check the jetting to make sure its ok. i'd go for the 40 or a 41 mil
and yoshi might know what jetting to use on it

 

No port and polish but should I have it done if I put in the 450 kit? Will I notice a diff if I didnt get port and polish? This is gonna be my Christmas present to myself (gonna buy it all probably early dec.) and I want to have it done by the new year. We are really good friends with our honda dealer and get 18% off the prices off everything. Its amazing, so I figure I can get a 40mm fcr or any other parts I would need for at a steal of a deal price and the shop foreman can help me jet my suzuki lol [img]i/expressions/face-icon-small-happy.gif[/img] You like your dyna cdi or should I get the yoshi cdi? I gotta make sure my quad can keep up with my 2 mx/trail buddies...1 has a 03' z470 (duncan racing kit, titanium frame) and other 04' 450r (sent to curtis sparks for everything). They got just about everything you can think in them. From what I hear the webcams are better then hotcams so hopefully Ill have some edge by staying away from those. I believe the 450r is running the stock carb but he has money down on an 06' and is sending it to curtis sparks again for all the stuff [img]i/expressions/face-icon-small-mad.gif[/img] The guy on the z470 went to Doug Gust's riding school too haha hes taken 1st in 34 of 38 mx races here in alberta. I have to stop him lol. What you think mucky? or any1

 

I would have it ported and polished for the added power that your doing. it helps the motor breath
I love my dyna cdi it works great fo me. some people dont like them
I have heard webcams are really good. i've never tried them
it sounds like your buddies quads and pretty hopped up
and have lots of power. theres lots of people here thats have the yoshi kit and love the power

 

Your in a good position to try both here.

With a good port job a 40mm would be minimum. I would go with a 41. The polish job isn't that important and you will lose some cc's by doing so and effectively lose some compression. It can become a moot point if you simplyi ncrease compression via thinner gaskets or a domed piston. I would rather just unshroud the valves, have a good port job and be done with it.

If you dont get the port and polish then it will be a tough decision. I think the 39 may be the ticket.

Remember, going to big will result in a loss of air velocity at lower rpms and kill your bottom end and probably not help through the rest of the rpm band. You want to have everything matched real well in your combo, which it sounds like you are planning well for. Here is the beauty of your situation. With an 18% discount you can always buy the biggest one and if it doesn't work out then you can sell it and break even and buy the next smallest size. You can even back up everything with some dyno runs.

Good luck in your decision!