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Post by greggkinney on Jan 15, 2017 1:53:30 GMT -5
i can say if you need a performabce cdi over the stock if you do 90's pickup mod, i havnt tried that YET. but i have tried both the orange and blue cdi and noticed gains worthy of the $10-20 cost. i like the orange best, ive had two and the 1st one lasted a decent while then it stated loping at idle like a drag car. the second one is still going after 4 months. the blue ones are junk out of 4 i had 3 that lasted a few weeks each and 1 that thru an arc soon as i installed it. 90 has some charts and a video with the timing advances graphed. he would be the go to man on this topic
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Post by 90GTVert on Jan 15, 2017 7:54:03 GMT -5
Do I need a different CDI to go with my 47mm BBK, or is the stock one good enough? Also, can someone recommend a stator that puts out more power than a stock one? This is for a 4t, AC system, All LED lights. Your stock CDI should work fine with a BBK. Depending on where your compression ends up, the engine may not like more timing anyway. As said above, you can try the pickup mod and see how that goes. Assuming you've already got the 8 coil stator, as most do, the only one I know of that puts out more is the 11 coil. |
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Post by dan50 on May 10, 2017 4:22:41 GMT -5
I started on the mods today.
Removed the rear plastics to paint them and get them out of the way for the 47mm BBK install.
Removed old exhaust, I have a performance exhaust with separate header and muffler.
Removed the stock airbox as I'm putting a high flow air filter on it.
Removed part of the front plastic because I have some wiring to do. Going ALL LED, so I need to install a LED flasher unit and change out the turn signal bulbs. Then it will be all LED! I also need to getapower wire to the light in my gauge cluster so I can see it at night (no power-wire in the harness). I'm going to tap into the small running light on the front of the scooter (my Dongfang is exactly like a Taotao ATM50-1. Same bodypanels, which I ordered a couple of the bottom side pieces. I will also be installing my LED 18w driving light to really light up the night.
More to come on this build.
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Post by dan50 on May 10, 2017 9:19:41 GMT -5
Dongfang update; I removed the rear inner fender so I can install a new gas shock (halfway done with the shock). I will also have to do a cutaway on the rear splash guard to fit the gas shock.
Remove engine shroud, carb and intake. Now it's time for the tear down and install the BBK.
I'm concentrating on the rear end and motor stuff before I tackle the front end wiring.
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Post by dan50 on May 11, 2017 15:40:10 GMT -5
I installed my new rear shock.
Painted the bracket that mounts the inner fender black so it looks nicer and not noticeable.
Installed the bracket that my performance muffler clamps to.
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Post by dan50 on May 15, 2017 22:50:00 GMT -5
Finished assembling the motor with the 47mm BBK. Engine shroud is in place. Performance muffler is mounted. Jet oil catch can mounted and hooked up (no longer using stock air filter box so I need crankcase breathing).
Mounting new 20mm carb now.
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Post by dan50 on May 15, 2017 23:36:52 GMT -5
Pics of Dongfang; Performance muffler and oil catch can;   The oil catch can. I cut circular air filter material from the stock air filter foam element, oiled them up and stuck them in the neck at the top of the can. I was worried about getting water in the oil because of the size of the opening, so I found a plastic bottle cap, punched a small hole in the center of it and clamped it to the opening on the catch can. This should keep water out of the oil (Bad, Bad to get water in the engine oil). As you can see the oil catch can ventilates the crankcase from the opening for the dipstick. Any excess oil will drain back into the crankcase.  |
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Post by dan50 on May 16, 2017 0:58:44 GMT -5
20mm Carb (#85 main jet & #35 pilot jet-for now, still have to tune carb) & free flow air filter installed. New intake manifold installed. Have to wait until tomorrow to fire it up and adjust carb.   |
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Post by dan50 on May 16, 2017 22:41:57 GMT -5
It RUNS!! I let it warm up at an idle (giving it a little throttle once in a while). I adjusted the 20mm carb so it idles smooth.
Now I'm letting it cool down so I can change the oil and re-set the valves. I set the valve lash to .004", but they are making a ticking sound, so I have to tighten them up.
I'll try to get a test ride in tomorrow.
Now I can post in the 47mm BBK thread!!!!
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Post by dan50 on May 17, 2017 3:13:48 GMT -5
After changing the oil and re-adjusting the valves (I tightened them up 1/8 turn, no ticking sound), I just had to go for a test ride.
This thing will get up and go from a standing stop at 1/3 throttle (I didn't want to go WOT yet. Break in the engine some first).
Even up a hill and into a 15mph wind it didn't slow down!
No stumbling or bogging from a standing stop, smooth acceleration (I tuned the CVT last summer), and real nice acceleration coming out of a corner.
The free-flow air filter has such a great sound! I love the sound of the scoot now. The performance muffler is a mild one, so it's not that loud. A noticeable amount louder that a stock muffler and sounds real good.
When it's broken in, I'll do some test runs on a calm day with the GPS. Though the top speed shouldn't change. After tuning the CVT my top speed is 42mph.
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Post by dan50 on May 17, 2017 22:35:44 GMT -5
I rode my Dongfang to work today. I took it easygoing to work, keeping under 35mph. On the way home I got on the throttle. WOT this BBK really likes to move (it's hard to keep this scoot at 25mph or 30mph. It just want's to go). I haven't re-tuned the CVT for the BBK yet. I did a lot of CVT tuning last Summer. My previous top speed was (yes WAS) 42mph. Below is a pic of my GPS showing that with no wind and flat road, I got up to 46mph!!!!  4mph gain just with the 47mm BBK. I am going to try 6gram rollers to see if I can any more speed. |
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Post by AtariGuy on May 17, 2017 22:59:15 GMT -5
Reading this gives me the urge to blow a huge wad of cash on 4t parts. I like your thorough approach earlier on making cvt adjustments, making sure its in tune, and working what you have to the best of the stock engine has. Curious if you plan on adding some more top end with a gear swap. And ultimately, what made you decide on 47 instead of 50? Also, are you a scrawny, short guy or a tall beefy fella? Curious how much power to rider size ratio the 47 has - seat of your pants dyno speaking...
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Post by dan50 on May 18, 2017 1:17:57 GMT -5
I'm 160 pounds and 5'9" tall. Add the 250 pounds the scoot weighs and carrying 20 to 30 pounds of tools and riding gear. That brings that to 440 pounds that the little motor has to get down the road.
The biggest gain in performance is tuning the CVT and carb. That really got my scoot to run well and at better speeds. The variator with the stock setup would fully open at 14mph to 15mph and the engine would bog to accelerate any faster. If there was any wind or a hill, my scoot would slow to a crawl.
The way I tuned my CVT was to not allow the variator to fully open until 25mph, which is what it does do. This keeps the engine in it's powerband and I could easily get to 30mph in a fairly strong wind. Also the scoot would not slow down as much going up hills.
To do this I ended up with 5 gram rollers and a 1K contra spring (stronger than stock). I get smooth acceleration all the way to 30+mph with the stock motor. I will try out 6gram rollers to see if it improves top end.
I went with a 47mm BBK as they are recommended for first time engine builds. The 47mm BBK is very reliable and gains 23 cc's over stock. A 50mm BBK will only add 11 cc's over the 47mm.
50mm BBK's require a new crank (the stock works well with the 47mm but not the 50mm). So a 50mm BBK is not only building the top of the engine, but also requires splitting the case and installing a quality crankshaft (go for the stroker crank, 44mm stroke instead of the stock 42mm).
The 47mm BBK also works well with the stock head, so no extra money there. The 50mm needs a bigger head.
The 47mm BBk is a powerful engine build. Stock is 2.5hp. I at least doubled that or more (I have no info on the actual horsepower for a 47mm kit). This scoot will really get it off the line and keep going with the CVT tuning that I did.
I spent just over $100 on the CVT tune and the 47mm BBK kit and new 20mm carb. Not expensive at all (a crankshaft for the 50mm BBK costs about $125 and up). I bought a Glixal BBK that cost about $35. Glixal 20mm carb for $24. Glixal A-9 cam for $13. $72 for the engine, that's all. The CVT cost me a 1k contra spring ($10 to $15), a few sets of rollers at about $9 each (I bought 3 sets, 5,6 & 7 gram sets) and a Mitsoboshi 681x17.7x30 belt for $12. A set of clutch springs for $3. Total $42 or so for tuning the CVT. Total $114.
I also added a free flow air filter (about $10). A free flow exhaust for $60. Including these, total costis around $200. Lot of bang for the buck at those prices.
I have no plans to swap gears on this scoot. But I might in the future, I don't know what ratio I'll try. The stock ratio is 10.125/1. That's a pretty tall gear for a stock motor, but that's what the scoot came with. Normally a 4t gears are 11/1 or so. (2t gears are 13/1 to 15/1 on a lot of stock scoots.
I did buy some body panels so I can change the color, as well as some dress-up items (mirrors,etc.). That part of the build is yet to come.
I hope this gives you some idea that you don't have to spend a fortune to build your motor an tune your CVT and carb (carb tuning is some main jets and pilot jets at $3 each. A stock carb is jetted too lean).
I hope this helps. More to come on this build.
Dan50
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Post by AtariGuy on May 18, 2017 14:42:38 GMT -5
This does help! I am familiar with crank replacement on a 2 stroke (see my 06 TNG Venice build thread) and literally a full teardown and rebuild so bolt-ons are easy enough. I have noticed that 4T engines are boatloads cheaper too. The engines are extremely common and aftermarket parts are always readily available. This will make rebuilding my wife's scooter a lot cheaper than mine was, but mine was trashed so i had a lot of stock parts i needed to find first lol thanks for your write-up!
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Post by dan50 on May 18, 2017 23:11:04 GMT -5
You are very welcome. Before I do anything mechanically on my scoot,I hit the Tech Section and read up on what I plan to do. All the knowledge I gained is due to this great scooter site and the Tech Section.
Installing the BBK was a lot easier than I thought it would be. I downloaded from the Manuals link and it has all the torque specs and really nice blowups of the engine. You will need Adobe Reader (free from Adobe.com).
Special thanks to 90GTYert and all who contributed to the Tech Section.
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