Sportsman project coming up...questions
- Thread starter brett7777
- Start date
does anyone have ideas on expansion chambers that'll fit this bike? the guy who supplied my motor supplies these & says they make the 48cc go faster than the 66cc.
It looks like it might be very efficient but might not be in keeping with this bike?
Expansion Chamber to fit Cycle Pro/Motrax Mopeds | Trade Me
It looks like it might be very efficient but might not be in keeping with this bike?
Expansion Chamber to fit Cycle Pro/Motrax Mopeds | Trade Me
I've heard that expansion chambers make the engine smoother but not more powerful. If it made the engine more powerful everyone would be running one.
I find the best way to smooth out a china two stroke is to port match the intake and exhaust flanges. First thing I always noticed after port matching. Smoother. Give it a try.
Make sure the gasket matches the port and then use as a template to grind as much material from the flanges of the intake and exhaust flanges. Some people use a dremel tool. I use (used) a mounted point on a pneumatic rotary grinder. Anyway, smoothing out the air in and exhaust out helps.
When I was running the China Girl I noticed the intake gasket was much too big and protruding into the intake manifold partially blocking and disturbing the air flow. After I trimmed the gasket flush the motor ran much better. This works with any engine but is more noticeable in two strokes.
Here is a good read for you Brett7777 http://motorbicycling.com/f52/basics-port-polish-port-matching-16646.html
Thanks for the info guys.
As far as pipes go I think I will just go with the mild 'performance pipe' - the stock curved one that comes with some of the engine kits. Apparently it's a bit better than the one I have.
And Im gonna try several size jets - 65 to 70 sizes - acceleration is smoother with the needle clip on a leaner setting but I lost some top end power, apparently a smaller jet can cure this
As far as pipes go I think I will just go with the mild 'performance pipe' - the stock curved one that comes with some of the engine kits. Apparently it's a bit better than the one I have.
And Im gonna try several size jets - 65 to 70 sizes - acceleration is smoother with the needle clip on a leaner setting but I lost some top end power, apparently a smaller jet can cure this
Your plug determines if your lean or rich. Run the manufacturers suggested premix. If the plug looks good and the premix is correct look elsewhere if it's not running right. Also, don't expect to do wheelies and burnouts with a China two stroke. Accept it for what it is, and what it is, well, it's like 2 1/2 hp.......
Hear is spark plug color chart info.. http://motorbicycling.com/f30/spark-plug-color-chart-motorized-bicycles-24873.html
yep that's cool, when I get the new pipe & some spare time, I will do some more riding & check the plug readings
Developments:
It turns out the guy who sold me my motor has been into tuning the China 2 strokes & is getting 80km/h with a 48cc. (bout 50 mph). That is admittedly with a carbon frame, but still good. So Im working away at making changes to get the best outta the 48cc. It actually feels ok to me at full throttle; I have my motorcycle if I wanna go faster.
In the meantime someone has shown interest in buying my worksman frame.
So Im wanting to swap my frame out for the loop frame with engine mounts.
Pat usually needs the China motor to set up the mounts, due to the variation in the motors, so I think Im gonna need to come up with some clever way to make a template of the motor.
It turns out the guy who sold me my motor has been into tuning the China 2 strokes & is getting 80km/h with a 48cc. (bout 50 mph). That is admittedly with a carbon frame, but still good. So Im working away at making changes to get the best outta the 48cc. It actually feels ok to me at full throttle; I have my motorcycle if I wanna go faster.
In the meantime someone has shown interest in buying my worksman frame.
So Im wanting to swap my frame out for the loop frame with engine mounts.
Pat usually needs the China motor to set up the mounts, due to the variation in the motors, so I think Im gonna need to come up with some clever way to make a template of the motor.
UPDATE:
I just received the performance pipe. HECK ! What a difference ! The vibrations on acceleration are GONE !!! There is also heaps more power. This thing is just purring along now, Im amazed at what a difference the change of pipe made.
Im getting a bit of 4 stroking if I try & go full throttle straight away, but if I ease it up slower I can get quite a good top speed. I will try putting a .66 jet in when they arrive from SBP; the guys on the 2 stroke threads seem to think that'll boost my top end.
I will also need to start having a look at my plug readings.
My problem now is, I just feel like riding the thing all day!
I just received the performance pipe. HECK ! What a difference ! The vibrations on acceleration are GONE !!! There is also heaps more power. This thing is just purring along now, Im amazed at what a difference the change of pipe made.
Im getting a bit of 4 stroking if I try & go full throttle straight away, but if I ease it up slower I can get quite a good top speed. I will try putting a .66 jet in when they arrive from SBP; the guys on the 2 stroke threads seem to think that'll boost my top end.
I will also need to start having a look at my plug readings.
My problem now is, I just feel like riding the thing all day!
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Thinking about how to make a template for the China motor mounts on the loop frame:
I can do a tracing from the motor mounts of the bolthole spacings.
Im thinking maybe I can put together a jig that surrounds the motor, & meets the motor mounts, then trace off from that jig, onto some cardboard? I could maybe use plywood & hotglue to make the jig.
Then send the tracing to Pat?
Any other ideas welcome.
Im gonna have to pull everything off the frame soon, as there is a lotta interest here from people locally in purchasing the frame. I think worksman frames here in NZ are either rare or non existent.
I can do a tracing from the motor mounts of the bolthole spacings.
Im thinking maybe I can put together a jig that surrounds the motor, & meets the motor mounts, then trace off from that jig, onto some cardboard? I could maybe use plywood & hotglue to make the jig.
Then send the tracing to Pat?
Any other ideas welcome.
Im gonna have to pull everything off the frame soon, as there is a lotta interest here from people locally in purchasing the frame. I think worksman frames here in NZ are either rare or non existent.
Well as some of you may've seen, I found a velodrome in our local area, in good condition. I just need a way to transport the bike there (as it's not road legal). I realized I could put it on one of those bicycle racks that attach to the towbar of the car. My wife & I have been talking about buying a bigger car for a while, one that we would enjoy driving & that would have some reasonable power, so we are now negotiating a price on this. It's a Ford with the Boss modular 5.4 V8, the make & model & specs are: a 2005 Ford Falcon XR8, 4-valve DOHC, 349 hp (260 kW) and 369 lb·ft (500 N·m). Here in NZ they are generally known as the 'Boss 260' motor. I gather they are also used in some US vehicles. The transmission is a 6 speed manual. It has a racing lowered suspension, race throttle body, & big bore exhaust, which adds about 15kw more, so supposedly has 275kw of power.
Im quite excited about buying this car. I haven't owned a bigger car for some years so Im looking forward to it. It is a friend of the family who is selling it so it is very well priced.
I dunno if there are any Ford performance fans on this forum but i thought someone might be interested.
Im quite excited about buying this car. I haven't owned a bigger car for some years so Im looking forward to it. It is a friend of the family who is selling it so it is very well priced.
I dunno if there are any Ford performance fans on this forum but i thought someone might be interested.
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Have given the local engineer some pics of a loop frame, to see what he thinks about cutting the downtube out & putting in a loop & mounts.
OOOOH! I lust for your motor and transmission. Very nice new ride. Im a Fordie, My Dad worked at the Wixom assembly plant for 32 years building Lincolns and T Birds. I even worked their for one. If you ever see a 1979 Lincoln with a moonroof I put it their. I have an old Ranger Splash 4X4 ( yellow of course) and a 1999 Roush Cobra with the 4.6 L flavor of your motor.