First ground up build

[2000chevy]

I am attempting to do my first ground up build and I have a few questions.
1. What is a good carb to go with for a close-to-stock build? I've often heard the stock is too small to start with and I want to do away with the tors system completely. It will have a mild port job (mainly just casting flaws removed and transfers touched up and exhaust port matched to the flange opening) it will also have some sort of aftermarket exhaust haven't decided yet open air box oil injection delete and shaved head.
2. What all mods need to be done for a z400 rear shock swap? I have one laying around collecting dust I figure it will ride better.
3. Gearing suggestions for 18 inch rear tires? I'm wanting to top out around 60-65 and get there quickly
Thanks for the help in advance

 

[2000chevy]

Also I was wondering about the bore size the piston that came with it says 150 on it but that's all it has on it

 

[dirtysquared]

I'd say keep the stock carb on for the work your planning on doing. Buy a tors eliminator kit, and jet it correctly.

The stock 26mm mikuni is a good reliable carb, and its fairly easy to tune.

The z400/shock will work with KOR bushings. All you kill have to do is drill the bottom shock holes to 12mm.

Sounds like a good build. Let's see some pics!!

 

[2000chevy]

No pictures yet its just a slew of parts right now I bought it came with enough to almost build 2 bikes

 

[Herpderplol]

stock carb with a stockish build
carb selection mostly relies on the pipe. i have a big carb for my LRD. i wouldnt have LRD with positive affects without porting. its a circle

kor bushings for the shock

no way you get to 60-65 with 18" tires.
i had 18" tires 14/40 gearing. aggressive porting and pipe and never got over 55

with my current blaster i think i could hit low 60s with 20" tires and 14/40 gearing on a good day

 

[Larry's Shee]

X-3 on stock carb. Use the $$ for other things first. Dual stage reeds, good air filter.
I suggest having bore and piston measured to determine clearance.
Most likely the 150 on piston means 1.5mm over size.

Kudos for home porting. You tube vids to help on that, also info from Gorden Jennings and H. Grahm Bell.
Exhaust port can be widened a bit, 1mm per side. IF you raise it, do not go more than 1mm. Be sure to use a nice radius from top to sides and be sure to champher well.

BTW, quick acceleration and high top speed won't happen with most Blasters, just not enough powwa

 

[2000chevy]

I had a blaster a few years back that seemed to top out around 60 or so but I have no idea what was done to it motor wise and that one was my first sporty style four wheeler I had just rode utilities so it probably seemed that fast at the time lol

 

[bummer981]

http://www.celicatech.com/luni/gearingcalculator.html

Gearing calculator for the Blaster 14/40 with 20 inch rear tires will get you to 60 mph, but you will loose the quick take off.

I run 13/40 with 20 inch rears and it suits me well. We run a lot of tight trails and rarely see fifth or sixth gear.

 

[2000chevy]

Well guys here's how my port job turned our Ive decided I'm gonna get it bored out also

 

[speedyslyder]

did you raise the exhaust port/or just polish it?

 

[2000chevy]

Think I accidently raised it a hair lol there were some nasty pits behind the sleeve that needed attention

 

[speedyslyder]

i raised mine 1mm

 

[2000chevy]

i raised mine 1mm

Maybe you can tell better from this picture how raised it is

 

[speedyslyder]

yeah i was just wondering if you raised it for more power,cant tell from pic really unless measureing it 1mm is almost like the lip that is on it when first starting grinding ruff estimate
id show you a pic of mine but i been going from computer to computer to computer 3 of em my wife keeps breaking them or should say neglecting them,so i get to fix lol dont got it tonight

 

[2000chevy]

I'm hoping one of the pros can chime in on this lol

 

[speedyslyder]

if there is a lip on it then it has not been raised 1mm on cylinder sleeve. it should have been measured then re measured but im not even sure if that was your goal or not i was just curious lol

 

[2000chevy]

Okay I definitely raised it 1mn then because there is no lip on the top or the sides anymore. How is that gonna make this thing run?

 

[speedyslyder]

you will feel it when you ride it lol
vitos piston have the exhaust side of piston filed down to act like raising the exhaust port.they claim 5 hp more i believe ive half to look or you can look at there superstock piston...but raising it on the cylinder itself is better then the piston option or at least i think it is lol

 

[Blaaster]

You say you are going to get it bored out, question is does it need boring , is it damaged.

Just boring it out is not going to give you any more power than a Gnats fart.

Raising the exhaust port will give some more power, but attacking the intake windows and drilling Boysen ports will compliment and increase the power even more.

Here is a pic of a KOR port job.

 

[jus_me]

Raising exhaust port is good as long as you keep it even and not go to high. 1mm is ok. Doing that you will lower compression though a little keep that in mind. Also if you look at the exhaust port pic to the left a little you can see a little hump on the bottom left edge of the exhaust port close to the sleeve. Try and take that hump out but don't get aggressive and make a dip just try to make it blend in with the rest. Also if you do get a bore make sure they chamfer the ports. If your cylinder is in good condition and piston and ring spec are good there is no reason to "bore out" a waste of a good cyl and $ in my opinion to go bigger just because. Like Blaaster said "Just boring it out is not going to give you any more power than a Gnats fart".