Vader 150 -> 250.

[ProDigit]

I went online to buy an engine upgrade for my Vader 150.
I found what I thought was a good deal on a CG250 (229cc) for $435 on the Walmart website. When I opened the cover, it looked like Arabic writings inside the engine. Didn't look Chinese, Indian or Indonesian, the countries you expect these engines to come from.

Engine: https://www.walmart.com/ip/Vertical-...roke/288560980

Turned out, walmart sent me an engine with step through gearbox. In other words, shifting from neutral into 1st is down, and any following gear is down as well.
Once you reach 5th you can shift down once more for neutral.

It's totally opposite of normal motorcycle gears, and I really have to pay attention that I don't accidentally shift into a lower gear when running already high rpms.

The nice thing is, coming to a stoplight, I only need to shift 1x down from 5th gear to be in neutral, and 1x down from neutral to go into 1st gear.

Bad part is possibly wrecking the bike, when accidentally shifting down twice from 5th gear into 1st gear; as well as when slowing down, but not coming to a full stop (like the light just turns green before you got there). You'll either have to shift 5th gear up to 3rd or 2nd, or whatever gear for the speed you need, or shift down into neutral, first, second, third... to whatever gear you need.
Gear shifts up are very clunky. But I noticed it can be done when not fully engaging the clutch, but keeping it at the friction zone instead. Also,only gear shifts when moving. Nearly impossible to shift when standing still.

I had a few false neutrals, between 4th and 5th.

This new gearing takes getting used to, but it's not entirely unusable.

I can't yet say a lot about the performance of the CG250, other than this version of it, is a rather weak engine.
My 150 was faster in top speed and speed overall, save for low rpm speed.
The 250 is like a tractor, pulling first to third gear as low as 2000rpm.
4th and 5th seem to like speeds above 3k rpm though.

I do realize that the engine is still breaking in (first 25 miles done), valve adjustment done (was too tight from the factory), and the engine by itself had less than 1oz of shipping oil in it.
I took the halfway used oil from the 150, and filled up the 250 with that. Oil will be dumped tomorrow anyway.

The 250 has the same gearing as the 150, comes from the factory with a 14t, but I installed the 19/29t gearing on it.
At the moment the 250 can't yet pull 5th gear past 50mph, but 4th gear it can up to 60.
The 150 could do 70, and 74 when conditions were right; but that engine was tuned to the max.

So far I've found that a 40 pilot is close to ideal, and a 125 main is a bit rich.
I'll look into a 115 and a 120 later. Despite me being at sea level, which requires bigger jets, I do have a silencer in my exhaust, which is why the 125 still was a bit too rich.

I also have to tune the needle jet height. It's set to 1 up from center, with a thin washer making the needle run 1.5 richer (up). I'm using the same PZ30 as my 150 engine had.

As far as installation went,
It was fairly easy.

Remove plastic side panels, remove carburetor, remove kick starter and gear pedal, disconnect wire harness, unplug sparkplug, disconnect sprocket and chain from transmission, unmount the 5 engine mount bolts holding the engine.

Do the valve adjustment on the new engine, install spark plug, transfer air intake manifold from 150 to the 250 (manifold was angled,causing the carburetor not to fit).
The old manifold is slightly smaller in diameter than the new one, but fits nonetheless. This manifold only fits PZ27 carburetors, however PZ30 also fit, albeit barely. The carburetor almost sticks out beyond the seal on top.


Pop in the new engine using a jack. Insert the main (big) 2 motormount bolts, but don't tighten, then insert the other (smaller) 3 motormount bolts.
Plug in the 6 pin cable (gear indicator) into the harness (under booth under seat). In my case, the other 5 (I believe) wires can be connected to one another, as they have a similar color code (pink, yellow, green, black, blue).
Plug in the sparkplug cable, connect the carburetor and fuel line, open the fuel petcock, turn on the bike with key, and turn on starter switch, and test with or without choke on.
Make sure you're in N, when starting from the side stand peg, otherwise you'll have no spark.

Mine started after a few tries, as I had no spark, due to side stand switch.

Set idle, adjust AF screw for fastest idle rpm.
If idle screw is all the way in or out, means you'll need to go smaller or bigger on the pilot jet.
I went from a 35/38 pilot on the 150, to a 40 on the 250 (229cc).
Still testing out the main jet, but it looks like I'll be going from the 112 main to a 115 main on the new engine.

On paper the CG250 should have 12hp, while the 150 should have 10.
While torque definitely is better on the 250 from 1-4k rpm, I probably will have to wait until the first 600 miles are over, before I can start noticing better higher rpm performance.

I read online the total install takes 4 hours. But for a first timer, and despite everything going well, it took roughly 12 hours.
This included rejetting the carburetor and testing.
Also, I don't have all tools, so sometimes I have to be inventive to get a job done, taking some extra time.

I'm expecting avg mpg to go from ~66 on the 150 (not including leisurely rides
between 30-45 MPH that net 84MPG), to go down to about 50-55, as the engine rpm in 5th is the same as on the 150.
Although it feels like first gear on the 250 is taller than on the 150.

I had a 20t front sprocket once, but it didn't fit the 150 engine.
I might check if it's still available, because it could potentially fit the 250, as it still has some room left to go. (Just ordered one on AliExpress.