Big bore ?'s, need some advice/opinions

[288sunny]

So i currently have a z400, it has hotcams, CDI, yosh exhaust, DRZ kit and timing chain upgrade, as well as a high compression piston, which causes me to run some octane boost from klotz, however bike does not run right, very tuff time getting it to ride a wheely, it is somewhat fast, but does not "POP" when letting out clutch and getting going, I say that with a grain of salt because i would have thought having all those parts would have made this z400 a beast, compariable to my buddys raptor 700 or even a 450.... also when the quad dies, its very tuff to start, have to crank for awhile and sometimes pull choke out.

I curious if i use some airplane fuel (think its 110 octane) if that would help it out, may or may not, but looking, not sure its worth a try????

Also im thinking about ordering a Cylinder Works big bore kit, to get to 434CC and go back to using 93 octane, as trying to get race gas is not possible where i live, I have to drive 50 miles to get it.

If i go with a big bore kit, do I have to have a FCR carb? Would it even make sense to get a big bore kit and leave stock carb on?
And if i have to have a FCR would the one from sparks racing for $500 be the best route to go, as i dont have alot of time to tune, and mess with jetting, etc... just looking for a nice reliable setup and a fast quad, trying to keep it simple, if thats possible??? thanks in advance...

[beaverclever02]

If you have the money to spend on a sparks, than sure, they sound easier to install but there is still tuning that needs to be done. My bike is a pain to start as well when it dies. I contribute some of that to my valves and there bad condition, but i have also learned that as a fiddle with my jetting that plays a big factor. Your bike is not a beast cause it still being fed like a child, get that FCR or bigger carb.., and you might adjust your valves or at least check the clearance.

[mmzuki]

What brand and compression is your piston? Octane boost does almost nothing. Untill recently my setup was similar to yours. You can't believe how much difference the FCR will make. What gearing do you have? Most of us that trail ride use 13/40. Gearing makes a big difference too. High compression and cams need more air/fuel in and out to be useful. Therefore bigger carb and a full exhaust. Is your Yoshi full or slip-on?

[biggiej42]

+1 on the fcr. You can make just about any fcr work, no need to spend $500 on it. Cylinder works makes a great bbk, I have their cylinder and a cp piston, and it runs like a champ. You'll want bigger cams with that 434.

[288sunny]

the piston is a weisco (SP) i had a local shop put in and do the tuning on. and the yosh exhaust is a full set up. I really tried to spare no expensense when i did this stuff however i just dont think it went the direction i thought it would, i thought it would be a beast. I will say from time to time it rips, but if it dies, then its pure hell to get started again... this part i hate.. curious if some race fuel or airplane fuel would help on any of this. I do also have hotcams in the bike, not sure how much bigger i could go. Other problem is i dont have a local shop that has the knowledge to make this bike an animal. wish i live close to a big race track at times..

I would love to do the FCR carb, however i would prefer to have it setup as i dont have tons of time to wrench and trouble shoot and i have been out of it for awhile. If i could find one that someone was selling that was on a Z400 that would be cool, but probably rare as everyone wants them. so i figured sparks would work better in my case, am i wrong.
is there other companys that sell these carbs too? thanks a million, keep the replys coming

[TuckerHardRide]

Originally Posted by 288sunny

I would love to do the FCR carb, however i would prefer to have it setup as i dont have tons of time to wrench and trouble shoot and i have been out of it for awhile. If i could find one that someone was selling that was on a Z400 that would be cool, but probably rare as everyone wants them.

That's what i said about 3 months ago before Biggie busted my balls to get a FCR, I didn't want one because i liked what i had and i didn't want to have to screw with jetting and all that and installing it. But I was patient and found a sick carb with tons of aftermarket stuff on it and with all the help here, installing was a pretty straight forward and easy. Now with the carb, it was probably one of the best upgrades, if not the best.

[z455]

What compression ratio are you running? Unless you are running higher than 13:1 comp ratio you do not need race gas. Check your valve clearances. It also wouldn't hurt to pull your carb apart and give it a good cleaning.

[biggiej42]

I did bust his balls about it . The fcr is a great addition, night and day difference. As far as cams, you've got tons of options bigger than nshc's. Those cams are way too small for a bored/stroked z.