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new member trying to learn modifications

1085 Views 8 Replies 4 Participants Last post by  EPR
Hi I thought I would introduce myself... My name is Shane and I have a zstar hco90 pocket bike... not sure if its a 49 cc or 47cc? the frame says 47 but I noticed gio frames are the same as well. the exhaust points straight down. the thing has been sitting in the garage forever. I cut the exhaust off just under the airfilter to try to let it breath better( seemed to work a little).

I installed new fuel lines and fuel filter, ngk spark plug, high flow airfilter, and purchased some slicks that seem gripier than the oem tires.

I tried to remove the old tires off the rims with 3 screwdrivers but no luck... I was only successful in pinching the tube haha. I snapped one of of the allen head bolts for the rotors in the rim and had to drill and tap it out. I was pushing so hard trying to break the bead that i didnt want to bend the rotors. Then the fuel tank basically crumbled into pieces while reinstalling it... guess the heat of sitting in the garage for years made it become brittle.

So my question is are these zstars even worth putting money into or is it just chinese quality i need to sort out with better hardware and parts. I would really like to pimp it out for my daughter so she can ride at the track with me.

How do you remove the tires off the rims? do I need a tire spoon kit?

I would like to put a stage 1 kit into it and I have started to paint it with a decal job to match my track bike

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Welcome aboard, tell me you did not cut the exhaust off, you need the exspansion chamber, to get max power. So, it runs, if its old its probably a 47cc ( 43cc ), the 49cc is ( 48.7cc ). I have 9 bikes now I believe, it keeps you busy. We have all broken bolts and so on, so don't feel bad. Takes alot work to keep these bikes running good. Its hard to get these tires off & on, I just got a small tire changing machine for 4 to 12" small rims, haven't used it yet. My X18 10" rim I took to the tire shop. You can get a new gas tank for $20, its Chinese plastic, not the best. Online at pocketbikeparts, in Florida, they have icons of bikes and engines and its easy for a new comer to find parts. Yours is either a MTA1 half fairing, or MTA2 full fairing Cagllari Daytona. They have alot of names but alot of the engine & other parts are the same.
I guess its a mta2 full fairing. thing runs great still fired up 3rd pull after sitting for years.

I have 3 full size bikes
01 rc51(street)
06 gsxr600(track)
08 crf450(dirt)

my daughter has
barbie escalade(power wheels)
dora quad(quad)
and this mta2

I cut the exhaust after the expansion chamber just under the airfilter. it kinda gives it a motogp look haha

Any brand stage 1 kit you guys recommend?

Im definately going to to bolt shop to get higher grade hardware! It shows where they cut corners to keep the cost down on these chinese bikes.
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I would get a 2 pc B/B 49cc Cylinder/Alloy Head Kit. Bigmotorsport online has them for around $40 or $50. The head will look like this.


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What are you running for carbs, reeds, clutch, and exhaust?

I like the idea of N/A motor... I can govern the throttle in increments... I dont think she can handle a NOS system.
there are a few carbs you can get for this... Ied just get a Walbro 603t pumper carb replica.

buy some stock clutches, they get eaten up quick.... you can drill holes into the shoes to lighten it.

Carbon fiber reeds + modified reed forks.

Forget about the boost bottle, you probably wont need it if this is for your daughter....

there are many exhausts available.... you can probably even chop the stock one up to make it better...
Also, big motor sports has a 1 piece BBK for 39 bucks. 48 shipped to my door.. I have one on my quad and it is just as good as the 2 piece billet head kit.

Lighten up your flywheel by cutting some fins out... make sure you cut an even amount and cut symmetric..
I just got a small tire changing machine for 4 to 12" small rims, haven't used it yet.
Of Subject sorry guys.. EPR, where did you get it? HOw much did it cost? Did you try it yet? lol

Interested!!! :rolleyes:

But on subject.. Be carefull with the cut off exhaust, it will spit oil and that can get on the tire, make it slic and slip.. just a warning...
That's a red Cag alloy head on a cut off piston port cylinder, highly modded. That's an old photo w/ the Walbro WT-813 pumper carb w/ accell pump. It's been on the engine stand and run, takes some muscle to start it,lol. Don't have anything to put it on, so it's boxed up. I did just put a Walbro HDA-223 19mm purge carb on a modded GS 40 billet purge manifold, haven't put boost fitting yet, haven't run it with that carb yet. Running free on the stand and pulling a bike and rider is a whole different story.
The alloy head is better than the one piece head cause you can change the compression pc to 17:1 if you want, and you can pull the head without pulling the cyld off. I can change the compression piece in 5 minutes. Plus it looks alot better, and cools better.
If your talking about the tire changer, it's was onsale at Northern Tools, in N. Carolina, $39.95 or something. The thing is pretty heavy and strong looking. The tire place had trouble w/ my front X18 tire and rim, ended up costing $40 labor and it still leaked, should have put a $11 tube in it. So, when I saw that $40 changer I got it. I figure with 9 bikes and 22 rims and tires, I will get my money back soon,lol.
Will lay it out and take photos, later.


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