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Post by scootnwinn on Jun 8, 2013 8:16:49 GMT -5
Are you still running it on paint thinner with the choke on? If so I doubt that engine is performing correctly... Those shift all seem too soon
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Post by prodigit on Jun 8, 2013 23:41:16 GMT -5
Yeah, the shifts are too soon; but the engine really doesn't have that much power.
It's power curve is below ~3.5k RPM, above that, there's no real torque improvement, which makes the bike an excellent bike for upto 30MPH.
You want to shift to 5th gear in 30, but can't (doesn't have a 5th gear).
The bike definitely needs a larger front sprocket, however, with the shifting, it can barely keep up with the cars starting from a green light.
At top speed (60MPH on the speedo; for reference 40MPH on the speedo equals ~35MPH in real life), the engine is revving too high. It definitely can use a sprocket change. I'm gonna ask if Rebelgears can make a front sprocket with 'groove lines' on the axis, like the original sprocket.
If they do, the housing can host 1T up, from the stock 15T to 16T. That's all that would fit in the housing.
Also interesting to know, for the other guy who bought a MC-05-127, it seems that the chain is eating through the rubber. If you open the front sprocket housing (2 screws behind which the front sprocket is), after riding it a bit, you'll notice a lot of black debris. This is the protection rubber. Once that's gone, the chain will eat through the rear fork (which is really bad)!
So instead on getting lower on the rear sprocket, I'm going to up the front sprocket by 1T!
The fuel addition wasn't paint thinner, but Chemtool B12.
I fueled up with Shell Premium fuel, after the bike stalled when the tank had 20% gasoline in it.
Lucky it stalled right in front of a gas station!
Seemingly a fuel issue, the carb doesn't suck enough fuel. As soon as I filled her up, she fired up again (more fuel flow from the tank).
The jets are too lean. I still ride with the choke 25% open, as the bike seems to perform best at that point.
Perhaps I could drill out the main jet some, but then I'd need a bigger main jet needle, which I don't yet have.
I don't know the carburetor well enough to be drilling out, or replacing the jets.
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Post by prodigit on Jun 9, 2013 2:39:05 GMT -5
Alright guys, Got some bad news for those who want to buy this bike for nice riding around town. First of all I need to upjet the darn thing; it runs too lean, and constantly need to ride with choke 1/4th opened. Second, I haven't yet done my full inspection, but the rear wheel axle nut came loose while riding. Now I have mounted it with a pneumatic hammer, so it was super tight! That's why the chain was loose, and I heard some cracking (chain rubbing against rubber). Third, almost all bolts are starting to corrode after riding only 2 small trips in the rain! 4: The front fairing (plastic plates in the front) start to vibrate a lot and make noise; almost like my BMS, who after 2000 miles was rattling apart! True, I put heavier oil in, so this coming oil change I will put lighter, 5W30 oil in, and see if engine vibration gets reduced. Since I haven't done the oil change yet, I can't tell how it looks like, but the first oil change MUST be done before 50km's! The oil was pretty metallic, and black. On the bottom, there are 2 oil drains. You need to use the bigger one, which is on the right side, near the foot brake pedal. Don't use the left one, because there's a rod in there, tightened with a large spring. And when opening the small one, and the spring jumps out, trying to get that spring back in sucks! 5: The clip holding the gearshift pedal got lost, causing the gear pedal to slide off the motorcycle! Very dangerous, and very weak manufacturing! I had to temporarily fix the issue with a plastic zip tie, until I find a more permanent solution.  (sorry, Imageshack rotated the image) 6: The stock spark plug is wearing faster than any chinese spark plug I've seen before. At 150 km, it was already worn in, so I suspect to be able to get 1000-2000 miles out of it. I changed it to an irridium spark plug now. I wrote Rebelgears to see if they can make me a front sprocket. If so, the front sprocket will be the first mod I will do to this bike! |
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Post by domindart on Jun 9, 2013 2:43:01 GMT -5
 are you enjoying it ?
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Post by prodigit on Jun 9, 2013 2:49:00 GMT -5
It goes well, so far it has an estimated 140 km on about 1 gal of fuel, very roughly estimated ~85MPG. I have worked on it, so it wasn't using fuel only to ride. A lot of the fuel was during startups, idle running etc. while I was working on it..
My only gripe was about 140km, with still 20% of fuel the thing just cut out. Turns out there's not enough fuel supply without a pump, when the tank is getting empty.
On the fuel gauge the LEDS stay green (100%) to about where there's 75% of fuel left in the tank. Then rapidly they diminish to 25% (which happen to also correspond with ~25% of fuel left in the tank), where the bike died.
I do enjoy riding it, with some mods to it.
However the ratio of wrenching/riding is too high.
This bike takes about 5-10x more wrenching than my EVO150, which takes about 3x more wrenching than my ATM50.
The good about the bike is that I can use the choke to optimize the AF ratio while riding. In S-florida we don't really need the choke, as it starts up fine without. I'm keeping it fixed at 1/4, perhaps on a cold morning I need to open it up a bit more to 1/2 for the first 10 seconds or so.
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Post by prodigit on Jun 9, 2013 18:13:51 GMT -5
Ok, with the choke I can kind of get the fuel mixture working at peak all the time. If I could upjet the main jet, I'd go even faster, but just riding with the choke on at 1/4th, it accelerates pretty fast, and reaches top speed pretty fast. I confirmed, when I was going up a bridge, I went at 59MPH, and went downhill at 62-63MPH (on the speedo). This lead me to believe that the bike is rev-limited, (as the speed difference between up and downhill was so small) and has much needed power spare that can be converted to more top speed. The engine is running at the top of it's revs, but if you're not too heavy, you can at least go 3 tooth down on the rear sprocket, or 1 up at the front. I'm probably going to do both; increase the front sprocket from odd 15T to even 16T, and the rear sprocket from even 40T down to odd 37T. That would be a change of 5.5T, or 13%; hopefully results in 13% higher top speed (~68MPH on the speedo), and since most riding is done in the final gear, it should bring MPG up by 10%, roughly estimated brings it in the  's of MPG. The bike feels most comfortable ~30MPH, with sprocket change I expect it to be ~35MPH. If I can not change the front sprocket, I'll change the rear to 36T, which is only 10% difference from stock. Since first gear is jerky, and very fast (I can accelerate too fast in first gear, and hit the car in front of me if I'm not slowing down a bit), a sprocket change would make not only higher top speed, but would slow down first gear acceleration, while allowing me to stay in gears longer. This is good, because after the first 20MPH, I've already shifted to 4th gear (or 3 shifts). A 10-13% change will not mean a lot, but it's something. That way I can hit 2 birds with one stone! So currently |
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Post by averageguy on Jun 9, 2013 21:05:41 GMT -5
Glad to hear you are liking your bike prodigit. I'm pretty happy with mine too for the cost. I worked on it a bit today and finally got the wheels on. I am pretty sure they are correct. This bike really rides nice. It is very comparable to the Honda XRM that they have overseas. I rented on last time I was in the Philippines and always said I wish I could get one like it in the states. This china bike is pretty close mechanically. After riding up and down the street a few times I did have a bit of a problem. I think maybe one of the vacuum hoses came off. Suddenly the idle went high and I noticed a hose hanging down. Since I already had all the plastics on already I just put it away and will look into it another day coz I didn't feel like taking all the plastics off again. Attachments:
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Post by averageguy on Jun 9, 2013 21:15:57 GMT -5
I also noticed there was some gas leaking from the connector here with no hose on it. I'm not sure if something needs to be connected there or not but I guess it might because I am sure there should not be gas leaking out. Attachments:
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Post by prodigit on Jun 9, 2013 22:29:52 GMT -5
That's actually the overflow vacuum line.
Gasoline would flow out, when you overfill the tank. When you overfill the tank, also the bike will suck in liquid gasoline, and inject that in the air intake, which will make it burp (rich), or shut down.
It's actually meant to suck gasoline vapors via the vacuum lines straight into the carburetor, to have a better air fuel mixture, as the vapor enriches the mixture, and vapor is better than fuel sprayed in the air (drops).
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Post by domindart on Jun 9, 2013 22:40:34 GMT -5
That's actually the overflow vacuum line. Gasoline would flow out, when you overfill the tank. When you overfill the tank, also the bike will suck in liquid gasoline, and inject that in the air intake, which will make it burp (rich), or shut down. It's actually meant to suck gasoline vapors via the vacuum lines straight into the carburetor, to have a better air fuel mixture, as the vapor enriches the mixture, and vapor is better than fuel sprayed in the air (drops). interesting, the vapor is BETTER than the fuel droplets? |
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Post by prodigit on Jun 9, 2013 23:47:38 GMT -5
well, with it I mean to say, it's better to have vapor and air, than just air. The vapor helps combustion. if the vapor was thicker (more fuel per air), it would be better, but the fuel tank vapor is so light, it basically is almost the same as regular air.
What I was trying to say is in vapor there are droplets the size of molecules. With droplets there's droplets. It's always better to have a fine mist of fuel in the air, than having larger droplets.
IMHO, you can just plug that thing! at least it won't let you waste gasoline that way.
The hose gets enough from the tank, besides, the vacuum line is also connected to the gearbox, with a larger tube, so you won't cause any vacuum problems plugging it. It might even be better, not to have airflow going through it.
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Post by prodigit on Jun 11, 2013 12:39:02 GMT -5
Alright, seems like no website is selling a custom 16T front sprocket, most websites only do rear sprockets, and that specific sprocket seems only to be available at 15T.
I've done some recalculations, and wasn't happy with the minor improvements of a 36T on the rear. I've decided to do the purchase for a 34T, as I re-measured the clearance in the back after tightening the chain, and seemingly I can go down to 30T now.
I'm sure the motor won't pull 30T (which is 25% difference) on the final gear, but 34 T on the rear would give a 15% difference, or a +10MPH top speed, and should bring MPG's near to 100MPG in final gear.
It also raises comfortable cruising speed from 30-35MPH in 4th gear, more into the 35-40MPH range. Shifting to 4th gear would go from 20MPH to 25MPH.
Doing the math, the following rear sprockets should be possible (upgraded from a 40T (I figure, I do the math, save you some time)):
- 30T (very bad gear ratio of 1/2 causing increased chain wear, Too heavy engine load)
- 31T (excellent gear ratio for chain wear, but low acceleration)
- 32T (good gear ratio for chainwear, possibly low acceleration)
- 33T (Normal gear ratio of 2.2 (link touches tooth every 5 rotations), possibly low acceleration)
- 34T (Good gear ratio, Perhaps barely enough acceleration, good top speed hopefully)
- 35T (slightly bad gear ratio of 2.333, link touches tooth every 3 rotations)
- 36T (Normal gear ratio, probably the best compromise between acceleration, and top speed)
- 37T (Good gear ratio, minor speed improvement, probably not worth the cost of the upgrade)
- 38T (Excellent gear ratio, minute differences, not worth the cost of the upgrade)
- 39T (Not the best gear ratio, not worth the cost of the upgrade)
- 40T Stock.
> 40T results in faster acceleration, faster shifting through gears, but also lower top speed, and much higher RPMs.
40T is probably good enough if you're ~200LBS rider, riding on a mostly hilly terrain, or riding on a level terrain with 2.
36T is probably good for a ~200LBS rider riding on mostly flat terrains.
34T is probably good for a ~170LBS rider riding on flat terrains (no hills).
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Post by prodigit on Jun 11, 2013 12:44:15 GMT -5
I've ordered both the 34 and 36T.
Stock price for a sprocket is $47. I'm willing to sell one of the sprockets if you're interested at a discount.
I will most likely not even use the 36T, but if I do, it's just for a short testride.
If the 34T is good enough for me (I'm 160LBS, riding on mostly level terrain), I would be selling my 36T sprocket to anyone interested.
If the 34T does not pull my weight, or does not function the way I was expecting, I will be using the 36T.
I'm mostly an economy rider, riding careful on the throttle, enjoying the ride better, the less it will cost me, so I will try to go for the 34T.
The 36T should give somewhat an improvement over the 40T, but should still allow better acceleration for those riding a few hills than a 34T.
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Post by prodigit on Jun 11, 2013 12:47:09 GMT -5
Glad to hear you are liking your bike prodigit. I'm pretty happy with mine too for the cost. I worked on it a bit today and finally got the wheels on. I am pretty sure they are correct. This bike really rides nice. It is very comparable to the Honda XRM that they have overseas. I rented on last time I was in the Philippines and always said I wish I could get one like it in the states. This china bike is pretty close mechanically. After riding up and down the street a few times I did have a bit of a problem. I think maybe one of the vacuum hoses came off. Suddenly the idle went high and I noticed a hose hanging down. Since I already had all the plastics on already I just put it away and will look into it another day coz I didn't feel like taking all the plastics off again. I just saw the picture. That hose is your carb drain. Don't worry about it. There's a carb drain, and a vacuum hose that's just loosely connected. You basically have 2 drains. Idle goes up because the engine heats up. When the engine heats up, you have to change the AF screw, to set it to a right value. You can also change the level of the choke while riding. Especially when riding wot, there will be a specific choke setting where the bike will perform best. Leave it there, until you re-jet the carb. |
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Post by gitsum on Jun 11, 2013 18:39:12 GMT -5
Wow! This thing sounds like a total nightmare. You are so lucky nothing critical has fallen apart causing you to crash...
The rear axle nut and gearshift pedal falling off is a very scary thing that could have had disastrous consequences! I really hope you don't end up getting seriously hurt or worse...
Please be careful, it might be better to just give up on it, it's just not worth risking injury.
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's of MPG.
