The Chinese Motorcycle

[Mortblanc]

Enough of the morbid politics, time to get back to turning spanners, as you folk would say.

I am doing this work between cold snaps, and especially between wet snaps. We are in our winter weather pattern here where a low pressure system brings warm temps (15c) and rain, followed by high pressure cells that bring extreme cold (-0c).

When these two incidents overlap we call it "snow". We had some in November, the day my bike was delivered, but none since, which is unusual.

Anyway, I snatched the carburetor off the side of the little bike and installed a new jet. The old one was .88mm. Now compare this to the fuel jet of my 49cc moped, which uses a 75 stock jet and the tuning kit that comes with that mighty beast is a .85mm jet.

My 250 was running on the same fuel allotment of a 49 cc scooter in order to pass Euro 4 standards.

This operation required me to saw new screw head slots on the screws holding the float bowl, replace the main jet and add shims to the jet needle. The jet needle controls mid range throttle and the main jet controls wide open running.

I replaced the minuscule .88 jet with a 1.15 jet. I put about 15 miles on it and decided it was running rich. "Sputtering and gagging" as my neighbor stated. (said neighbor is in his mid 70s and rides a BMW 310, A Honda CB500x and a Harley Street Glide. His garage is a happy place.)

I returned to the machine and once again removed the offending carb, replacing the 1.15 jet with a 1.10 example. The bike smoothed out greatly. I have grunt in the low range and some scary torque in 3rd and fourth gears, with 5th being a brisk climb to cruise speed. One can basically bounce from standing start to 4th gear and ride it like a scooter up to 40 mph and back down to 10 mph without worrying about shifting.

I have increased the fuel flow by 20% with a corresponding increase in felt power. Yep, it wants to pull wheelies! Its performance up to 50 is now dramatically improved for the replacement of a jet and fiddling with the carb for an hour.

Now let us talk about "cruise speed". I am now faced with a wall called "gearing". This bike is geared low. By that I mean that the front sprocket is a 15 tooth and the rear 49. That is dirt bike/motocross gearing. It puts the bike to cranking huge rpm at 60mph. The little push rod engine sounds like it is trying to explode at 55 mph. Plus it is still running in, though I am out of the official mileage territory, which is 100 miles. 100 miles is not nearly enough to break in an engine and I know it will rev easier with some miles on it.

Still it is winding very high to achieve its goal. I must now replace the front sprocket with a 17 tooth model to give the bike some legs. It does not need much, perhaps a drop of 1k rpm at 55mph would make things pleasant.

One thing I have discovered while riding the back roads is that traffic wants to move along even on the narrow tracks and they do not mind pressing a biker, riding right on your tail. Here in the U.S. "country traffic" is mostly pickup trucks and SUV (full sized ones not your European midget counterparts) type vehicles and they appear as monsters in the rear view mirror on a bikes' handle bars. I did not notice this with the Enfield, it would zip right out of there and leave them in its wake.

I am also facing a bleak period of weather. We have had a mild winter so far, with many days above 15c, which is warm for this time of year. The approaching week is to bring another cold cycle with no let up probably through Feb and I expect it to be March before I see temps at 15c-17c again. It was -8 this morning when I rose and will not cross 0 today.

I have proper clothes for riding, that is not an issue. Thanks to the people at Sportsmans Guide, and the need to feed the chickens, I have plenty of gear intended for use on snow mobiles. What will slow me is not having adequate shelter to work in cold temps. No one wants to mess with a motorbike chain with ice on it!

Wet roads will bring me to a complete halt. I will admit that when it comes to slipping and sliding in ice and snow on a two wheel conveyance that I am too old for that s#%t !

Cost for the installation of the jet was $1 US, probably 75p in your money. $2 if you count the three stainless steel screws I used to replace the "sealed screws" I abused to open the unit.

Cost of the front sprocket I need will be $10 US. I intend for that to be my last expense on the "tune up" and have me set for the warmth of spring to return.