X-Pro 150cc // Vader 150 // Lifan 150

ProDigit · Yesterday, 08:01 PM

Well, the project is still continuing.
The 30T rear sprocket arrived, and in combination with the 19T front sprocket, it makes this bike feel much more like a bigger bike.

It needs a bit more fine clutch control to start from a stop, but no complaints about acceleration.
1st gear accelerates fine, second and third a bit slow, so I usually try to hit 6-7k RPM in third gear. Fourth gear easily hits top speed at 8.4k RPM (roughly 64MPH indicated), meanwhile fifth gear does between 47 indicated (45GPS) with a slight headwind, to 60MPH on the way back.

So top speed definitely suffered, due to lack of engine power.

The rear does allow for a 29T should one so desire, however, I'm going to keep the 30T on there, and take out the amazon bought PZ27 carburetor, and swap out the OEM one.
Not because it's bad, but because the fuel bowl is cracked around the screws due to drilling them out, and it'd get more and more difficult to keep opening and closing it.

At roughly 10ft above sea level, and 90 degrees weather, the OEM carburetor came with a 40 pilot, and 95 main jet.
I upped this to a 108 main jet, but the exhaust is still running lean at 75-100%.
So I thought of opening up the PZ27, take out the pilot jet, use some solder flux on it generously, and add some solder in the jet, and just heat the whole thing up.
That way, a microscopic layer of solder lead will coat the jet, narrowing the opening hopefully by just enough to lower the idle fuel ratio, because it's running too rich.

With that setting I'd be able to richen up the main jet to 110, and get a little more power out of the engine, to match the 19/30T sprocket setup.

Unless someone has found a link to a smaller pilot jet for the PZ27?

The engine itself seems to gain some power around 6k and 8k rpm, and I'm wondering if this is valve float-related?
It's especially noticeable with taller gears, where the bike has trouble reaching 55MPH (<6K RPM) but then seems to accelerate faster from 6k to almost 7k RPM (55-63MPH) in 5th gear.
I'm not complaining. Bike hits well over 64MPH indicated on a short run in 4th gear (8.1k RPM) if I want to go faster.

5th gear now makes the bike want to stay below 5-5.5k RPM (45-50MPH), where it should get much better MPGs; except for with a tail wind or downhill.

I was thinking, when the main jet is upgraded, the bike runs cooler. That means if there was an easy way to increase compression ratio, you could increase performance, while consuming even less fuel.
I don't yet have sufficient knowledge on pushrod engines to make this happen.

On the other hand, I took an angle grinder, and ground down a bit of metal on the motor mount, to make the after market exhaust fit.
It significantly reduced the exhaust leak, to the point where I can't even hear it anymore.

Yesterday, 08:01 PM	#22
ProDigit Join Date: Aug 2013 Posts: 68	Well, the project is still continuing. The 30T rear sprocket arrived, and in combination with the 19T front sprocket, it makes this bike feel much more like a bigger bike. It needs a bit more fine clutch control to start from a stop, but no complaints about acceleration. 1st gear accelerates fine, second and third a bit slow, so I usually try to hit 6-7k RPM in third gear. Fourth gear easily hits top speed at 8.4k RPM (roughly 64MPH indicated), meanwhile fifth gear does between 47 indicated (45GPS) with a slight headwind, to 60MPH on the way back. So top speed definitely suffered, due to lack of engine power. The rear does allow for a 29T should one so desire, however, I'm going to keep the 30T on there, and take out the amazon bought PZ27 carburetor, and swap out the OEM one. Not because it's bad, but because the fuel bowl is cracked around the screws due to drilling them out, and it'd get more and more difficult to keep opening and closing it. At roughly 10ft above sea level, and 90 degrees weather, the OEM carburetor came with a 40 pilot, and 95 main jet. I upped this to a 108 main jet, but the exhaust is still running lean at 75-100%. So I thought of opening up the PZ27, take out the pilot jet, use some solder flux on it generously, and add some solder in the jet, and just heat the whole thing up. That way, a microscopic layer of solder lead will coat the jet, narrowing the opening hopefully by just enough to lower the idle fuel ratio, because it's running too rich. With that setting I'd be able to richen up the main jet to 110, and get a little more power out of the engine, to match the 19/30T sprocket setup. Unless someone has found a link to a smaller pilot jet for the PZ27? The engine itself seems to gain some power around 6k and 8k rpm, and I'm wondering if this is valve float-related? It's especially noticeable with taller gears, where the bike has trouble reaching 55MPH (<6K RPM) but then seems to accelerate faster from 6k to almost 7k RPM (55-63MPH) in 5th gear. I'm not complaining. Bike hits well over 64MPH indicated on a short run in 4th gear (8.1k RPM) if I want to go faster. 5th gear now makes the bike want to stay below 5-5.5k RPM (45-50MPH), where it should get much better MPGs; except for with a tail wind or downhill. I was thinking, when the main jet is upgraded, the bike runs cooler. That means if there was an easy way to increase compression ratio, you could increase performance, while consuming even less fuel. I don't yet have sufficient knowledge on pushrod engines to make this happen. On the other hand, I took an angle grinder, and ground down a bit of metal on the motor mount, to make the after market exhaust fit. It significantly reduced the exhaust leak, to the point where I can't even hear it anymore. __________________ Last edited by ProDigit; Yesterday at 10:30 PM.
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