The Chinese Tracker/Scrambler thing...

This came together really well,
i just returned from a trip in south america and i heard
that some of those chinese models really hold there own!
 
catsy said:
This came together really well,
i just returned from a trip in south america and i heard
that some of those chinese models really hold there own!

Yes they sure do! This bike is 10 years old, when I received it it had nearly 42000 KM (26250 mi) about a year ago. It's impressive how tough this little engines are, even they are Chinese copies!

One thing I want to make clear is that every part bought for this build, was a Chinese one. This build was on a tight budget and fabing custom pieces or buying Japanese parts where out of the question. This objective has been accomplished as the only 3 machining jobs have been performed by me or for free. Tank paint job was also free, and frame will be.

On another subject. Talking about where I want to head the build from now on I have some thoughts I want suggestions on:

I'm wondering, should I lower the front fork a little bit? I think the fork is too long and having it lowered will make the bike have a better overall look like a tracker. Also that mod should give the bike a little better handing, little snappy side to side. What do you guys think?

Second question guys, should I paint the rims all black? There's a possibility that I can make a design with black and white with the rims, something simple like white spokes, and black outer rim or viceversa (have Powder coating at hand, only black or white)

Third questions, regarding the front fender, I want to run one as here when ir pours it really does (tropical monsoons) so was wonder if I should run it high on the fork or lower next to the tire?

I'm also looking for some skinnier fork boots as this ones have a big body and somehow clash with the visual "sturdiness" of the fork. Also having those big of a boots will make the front tire to look skinnier too.

DH900sl
 
This is what you call getting it done, with what you've got available on hand.

Have you guys ever seen 1970s 1980s Sang Yangs? They are essentially Hondas made in Taiwan. Honda and SYM were partners in the 60s before SYM started making their own engines etc. Then Honda said, ya bye. But that wasn't until after SYM imported BSAs for the first time to asia and created a huge influence on Honda's and SYMs design feel moving forward.

In short, they are neat little bikes, wonder if you can get them where you are.

Awesome, no excuses, build. Solid work.
 
I'm a sucker for black wheels, so that's got my vote. I also favor high fenders on this kind of bike, as long as it's tasteful and not a giant plastic motocross monstrosity. And yes, I'd say lowering the fork a little will improve the handling and the visuals a bit. Sometimes the little things make a huge impact in the overall aesthetic of the bike. Your on the right track(er)! Ha!
 
Thanks buds! I really appreciate that you like what you see, I've been struggling tu get the build going. I decided to begin to cut the frame (stay without a bike for 2-3 weeks) just 2 days before all the protests here in vzla exploded. Even though that was happening I just kept on going every bit of time I had, what you see is what's been done now.

Wheels will be black, just saw a bike on the street with the exact same rims all black

I think I'll mold a fender right from the tire profile, here I can't find anything that's not a replacement part. Here we don't have aftermarket parts, so I have to mod one or fab my own.

DH900sl
 
I also have access to a grey really close to match the color of the seat, what do you guys think it would look with powder coated gray on the rims?

DH900sl
 
Ha! That is some janky shit! Ya killed it given what it looks like you're working with though. Props for makin it count!
 
Hello fellas, I'm back at it again. Update for you people following this build.

Today was a good day, I had the chance to mill for free my fork leg, in order to be able to install the new wheel/tire up front.

y8uqy7ap.jpg


etenypyt.jpg


ujebyhap.jpg


ynumegu4.jpg


All of this was made with the bike in site. I rode to the university, presented an exam, then went to the machining lab, disassembled the fork, milled it, and installed it back on. This bike is my DD and it's easier to do this than bring the fork leg by car.

You may wonder how did I went back home. These little friends helped me out.

aqune8yr.jpg


6eqy7y9e.jpg


As of now, I'm going down to the parking lot, on my quest to install the new wheel, pics coming out tonight.

DH900sl
 
More updates! I've installed the new rim on the front, after milling the fork leg, it was just a breeze to successfully install the caliper and new rim/tire combo

Here I'm setting up my "work bench"

va2yqure.jpg


New rim installed

ra9u9are.jpg


e7y9yhud.jpg


Then I played with the fork height as in planning to lower the for some certain amount (not yet decided on how much).

I've taken some pics of the bike "lowered" in various positions

Stock height, new rims

6e5e4a4y.jpg


Lowered 1"

ybuvygu3.jpg


Lowered 1.5"

2yveby4u.jpg


Lowered 2"

6enupu7a.jpg


Lowered 2.5"

aveguta6.jpg


I'm settling between 1.5 and 2, just don't know what to pick, best choice I have is to go 1.5 and if I don't like it, go with 2.

What do you guys think? How much do you suggest I lower it?

And last but not least, here's a pic of the beauty on her first ride with the new front rubber.

e8aqajab.jpg


See you guys soon!


DH900sl
 
New little update guys

Just rattle caned the rims black to see which color I'm picking, I'm choosing black, because of the way they make the entire wheels look

Here are some pics:



Workbench set (hahaha)

adequdev.jpg




Masking job

4u3aby2y.jpg




Painting

y4abyvu2.jpg


yzuvasyt.jpg




Final Product

9a3avuba.jpg


2ytamebe.jpg


utebusep.jpg



After doing this I'm sure I'll be picking black when sending the frame, swingarm and bits to the powder coaters.

What do you guys think? Still have to lower the front? I think 2" down will still make a lot of difference in the bike.

DH900sl
 
Hello again, have some new little updates.

First, I've found a pod filter here in my country (somehow difficult) and installed it as the bike was lacking a filter at all.

I have also bought a 150cc conversion kit for my engine, so engine size would increase a whopping 25cc haha hahaha. The fact is that this bike has approximately 35k miles (55k km) so this little 125 is tired by now. I really struggle to get over hills and loose all speed and momentum when commuting on the city, so time for a fresh new cylinder, piston, and rings.

Here's what's in the mail, should be here today.

myjyhaqy.jpg


ybe9a3ys.jpg


apy7e8u7.jpg


juva4a3u.jpg


So this is it for now, keep you guys posted.



DH900sl
 
I'm going to try to Straighten the line of the tank with the seat, I think that will complete the look of the bike even more.

DH900sl
 
Hi there guys, 150cc conversion is a fact. So I've been receiving some parts slowly. Here's what's on my possession.

62mm cylinder, 62mm piston and ring kit
tyvenu6u.jpg


Full gasket kit
amusanyd.jpg


Skinnier fork boots (skinnier than what's installed right now)
a4u6yra2.jpg


And this little fella I'll be installing and using to run my cell phone charger
5e5a8ada.jpg


aru9u5yn.jpg


agy4evez.jpg


I'm still waiting for:

* Indicators, front and rear.
* Taillight.
* Grips.
* New throttle tube.
* 150cc carb kit.
* Universal fuse box.

I'm still left to do:

* Electrics box.
* Wiring.
* Taillight bracket/base/fixture.
* Fabricate rear peg mounts on frame (had to cut right side one to fit the rear master cylinder.)
* License plate holder. (behind rear fender.)
* Battery clamp (something to prevent it from falling from the swing arm. Now held by cable ties.)
* Powder coat black: rims, frame and assorted bike bits.)
* Paint fork lowers black.

Regarding the carb kit subject. My bike has originally bolted to the engine an authentic Walbro PZ26 carb, and I have no idea which number jets are installed. Also I have a spare Chinese copy of a Walbro PZ27. I think my current jets will get to small for the new displacement. True? Not true? I don't know yet.

As a I can notice on the streets of my city, every CG150 engine equipped bike, use a PZ27 carb, what would be best to do? Keep the 26mm carb and jet it to compensate for the new displacement or use the 27mm one with its stock jets? My intuition would suggest that using the 26mm with bigger jets, would make a faster stream of air through the carb than with the 27mm, leading to better gas dispersion. I don't think a 1mm restriction will cause too much of a restriction really.

As I'm no carb expert can someone shed some light on this subject? Help would be much appreciated, thanks!

DH900sl
 
A 25cc increase doesn't sound like much, but it's a 20% increase in displacement, over and above the lost power from many miles on a little Chinese clone engine. I imagine you'll love the improvement, and 150cc is a great size for a city commuter, especially when you're on a budget (you won't spend all your money on fuel = more money for other upgrades!)

I like the look so far, and think lowering the front a little, and adding a fender, will improve the look even more.

The smaller wheels with big tires look great, too, makes the bike look less like it will break at the first pothole (hole in the road.)

That seat upholstery job looks great, was that expensive?

Scott in Penfield NY
 
80sDweeb said:
A 25cc increase doesn't sound like much, but it's a 20% increase in displacement, over and above the lost power from many miles on a little Chinese clone engine. I imagine you'll love the improvement, and 150cc is a great size for a city commuter, especially when you're on a budget (you won't spend all your money on fuel = more money for other upgrades!)

I like the look so far, and think lowering the front a little, and adding a fender, will improve the look even more.

The smaller wheels with big tires look great, too, makes the bike look less like it will break at the first pothole (hole in the road.)

That seat upholstery job looks great, was that expensive?

Scott in Penfield NY

Hi there Scott, thanks for interesting in my build! Greetings from Venezuela!

It really does not sound like much, but comparing my actual engine performance vs the CG150 equipped bikes, it's substantial the amount of extra response those little bike have over mine.

I mainly do city commuting, sometimes through the speedway, sometimes through avenues and Streets. Either way, due to the topography of Caracas, you'll always have to go up some steep hills, and in those situations, the bikes I'm talking about, have just an extra bit of response that is what I'm lacking. I too blame those thousands of miles the engine already has in it, and I'm tired of not being able to upshift one more. That's the reason behind the upgrade, also the fact that this mod is practically bolt on and won't compromise the engine structurally makes it so no brainer.

Lowering the front and fabricating a front fender are two jobs I'll be tackling soon, those are key for the entire look of the bike.

About the upholstery job, it was really economic, even for me (by this I mean that it seemed a right quote for the price). If I had to say an amount in dollars, it would be so insignificant that it would be funny for you guys.

Making numbers, I'll say the seat job was about 10$ (told ya hahaha), but this numbers come from the fact that currently venezuela's currency has almost no value against the us dollar, but that's not the subject of interest here, I came to share my experience in building bikes, not complaining about economics, and life problems.
I'll look for the pics of the seat, after taking it from the upholstery so you can have a detail look on it. I erased all the pics from the phone for after backup and cleaning, just have to get them from Dropbox.

Sadly this week is going to be a "no-progress" week, I have midterms coming next week so I'll have to study instead of building, but somehow I'll manage to make something on the bike, as little as it may be even if it means only turning a tiny screw.

Cheers guys, see you soon


DH900sl
 
Hi there people! Important question arising.

I've been doing some research about my engine specs before doing the 150cc conversion and have some interesting doubts I want to share with you. And try to solve as well.

The stock compression ratio of the CG125 engine is 9.0:1. Having a 56.5mm piston and 49.5mm stroke, with these numbers I have a 124cc displacement (exactly 124,105771cc). Making calculations the combustion chamber should be the displacement divided by the CR, giving a exact13.7895301cc volume for the combustion chamber.

Now the new piston is 62mm, the stroke remains the same, so the displacement with the new piston will be 149cc (149.443992cc exactly) keeping the stock combustion chamber (cylinder head) the volume of the chamber remains unchanged also (13.7895301cc) calculating the new CR dividing the new displacement by the stock chamber volume, results in a CR of 10.8:1

Now the thing is, will this new CR be too high for the engine to handle? I've been doing some research and it is a high CR but not the highest I could find, but still this is the first time I rebuild an engine, I now the info but never had to apply it.

I found information about the specifications of both CG125 and CG150 clones on the net. Both engines have the same stroke (49.5mm) and the same stock compression ratio (9.0:1) this means the CG150 has a bigger combustion chamber in order to maintain the same CR while there's a difference between displacements.

Although it seems I'm on a dead end, a way to overcome this problem would be to get a CG150 head to install, in order to keep the CR at 9.0:1, BUT, I'd rather rebuild the engine with the high CR to gain in power (the absolute objective of this mod), but prefer not to if doing so will compromise the integrity of the engine. If I have to spend the moneys for safety reasons, I will, there's no doubt about it.

What I'm going to do is:

1st) Get the head out and measure the real volume of the combustion chamber.
2nd) Use that number to make the CR calculations again
3rd) Having the real numbers of the stock and future CR's decide if I really need the new bigger head or not.
4th) Proceed with the rebuild.

That's what's bothering me now. Weigh in, I'll appreciate it. Thanks

DH900sl
 
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