Lessons learned on a 66cc Chinese Lady!

Okay so I am a newbie and I humbly admit it. However I have learned a few things so far and am trying new things regularly. I will post here as I learn whether they work or not.

Tip #1 and foremost is immediately take out that junk chinese spark plug and put in an NGK Iridium 4085 {also know as the NGK BPR6HIX}. They are hard to find and you might have to special order it in but go, go now and get one. They are a bit more expensive than normal plugs but oh so worth it. {anywhere from $6-00 to $15-00 depending where you get/order it from}. It made my engine way smoother, more powerful throughout, and added about 5 mph on to my top speed! Next I am going to put on a new plug wire and see what that does.

Tip #2 is the clutch cover. I have noticed that there is all sorts of sound dampening products out there to buy but I just took some left over silicone gasket caulking, cleaned the inside of the cover off and smeared the inside of the cover with the caulking. {I gently put it back a few times to get the right thickness so as not to smear it on too thick} I then let it dry overnight, then put it back on. Way way quieter, cheap and easy! {Before putting cover back on it is a good idea to put a bunch of good quality grease on the gears}

Tip #3 Now that we have a frame mount engine where the heck do I put my water bottle??? Find an old inner tube and a few hose clamps. Take your hose clamps and put them around your forks, wrap the fork where you are going to attach the cage with the inner tube and tighten the hose clamps!

I have done this to both front forks and now have a water bottle and a spare fuel bottle {use something like an MSR fuel bottle not a water bottle for the fuel}. I have further zip tied the top of the fuel bottle to the fork just to make it extra secure. I have gone both on street and off road and have had no problems with them getting lost or loosening. Mind you if you use a $2-00 H2O cage you get what you pay for.

Tip #4 Port your exhaust and intake. Even a small amount makes a difference.

Tip #5 This will not apply to all, but to who it applies to it makes a huge difference. The 66cc chinese lady I was given was several years old and had the stock muffler with no heat shield. I took the small nut off the bottom and took it apart. I then drilled 4 holes (about 1/4 inch) just before the catalytic converter. I probably tripled the power of my motor. I presume that my catalytic converter was badly clogged. I am a bit noisier now but not too bad, but wow talk about more power.

Tip #6 Tighten everything and then regularly check and tighten everything especially the head bolts! {Mind you be very careful not to over-tighten!!!} Thread lock compound can be your best friend! {http://www.loctiteproducts.com/threadlockers.shtml}

So far though with just what I have listed I have managed to get {on the flat and level with no wind} 52 km/h {32.3 mph}. I just took a 40 mile trip on it with no problems at all. On the highway though I usually cruise at 40 km/h {25 mph}. I am 200 lbs and this is a cheap old bike I have it installed on so your results might vary.

I have an expansion muffler and a smaller gear ordered and should be in within a few days. I will let you know more when I get them installed.

I also have a few more tips and tricks that I am going to try.

As I said though, I am a newbie. I am about to start my second build {a 4 stroke pusher}. I make no guarantees but what I will be posting here has worked for me {or if I try some lemons I will post them also.

If there is any real experts out there and I post anything too dumb please feel free to comment.

If anyone has any questions please post or pm me.

Tip #7 Don't use cheap 2 cycle oil!!! Use a good synthetic. Again, you get what you pay for. These are cheap engines and they need all the help they can get.

Tip #8 A small clean bottle with a few ounces of 2 cycle oil in it can be great in an emergency. I have a 37.5 ml trial size shampoo bottle filled with oil {then wound a few times with black tape to make sure it does not open on its own}. If you run out of gas dumping it in your gas tank and putting in 1/4 gallon {or 1 liter} of gas at a gas station can really take you a long way.

Tip #9 Get rid of the cheap fuel line and replace it. The chinese fuel line degrades quickly. Normal black fuel like is too thick to go on the carb but you can get good quality fuel line from most motorcycle dealers.

Tip #10 If your motor is older and your fuel continues to leak into the carb your fuel petcock gasket thingy might be worn or torn. Take out the 2 little screws and flip it over. Re-tighten the screws. This quick fix saved me tons of grief.

Tip #11 If you are stopped for more than 2 minutes turn off the fuel petcock valve. I have known people who did not do this then wondered why they would have to peddle for 2 blocks before their motor would start. It was because raw fuel continued to flow into your carb, then into your motor and badly floods the motor!

dragray said:

tip# 5...
TRIPLED the power of your motor?
This is not possible with a stock exhaust no matter what.
you wouldn't get triple the power if you bolted on a well tuned expansion chamber.

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Trust me, if your catalytic converter is that badly clogged it is possible. This is not an indication of how much power it got as much of a statement of how bad it was!

moonerdizzle said:

no way a plug could give you 5mph on your top end, it may make the motor idle better and rev a little smoother, but its not going to increase speed any. but every thing else you wrote is right on the ball. except i never had a problem with my carb leaking fuel while stopped, i forgot to turn off my petcock more than once and never had a problem.

Click to expand...

So you say but trust me, it is real. Most of this gain is not simply by putting in a quality plug I think as much it is of getting rid of a really cheap plug. Nonetheless it was the only change I made and it did make that much of a difference. Maybe the stars were aligned right that day also or something...

And as far as the carb thing, keep in mind my carb is several years old and probably is not seating very well, thus gas does leak on mine. From what I understand also, with all these china ladies, you get lucky with one, you get unlucky with the next.

Pilotgeek said:

For something a bit cheaper, a BPR6HS or BPR7HS also works well. $2 plug, same resistor, projected plug, just without the exotic material (which really is only for longevity). A good plug CAN make quite a difference if the old plug isn't making good enough spark to reliably ignite the fuel.

Click to expand...

Thanks pilotgeek. I was going to look it up and post those plugs but you beat me to it.

Good new and bad news on the new muffler.

Bad news first. It does not fit. It totally interferes with the pedal and crank. It is not a muffler at all. It does not provide any muffling and is really really loud.

Also while taking a short test drive I wiped out and smucked up hand, knee and elbow. I am almost impressed. I have not wiped out that bad on a bicycle in almost 25 years! {It's only a flesh wound!}

Good news is I seem to be able to modify it to fit and simply putting a hot dog muffler on the end seems to help tons with the noise.

So far though it does seem to help but I cannot really judge how much as I am having some electrical issues and I think I need to replace my spark wire so if the rain stops I will try to get that done tomorrow.

Also it was good timing in coming the day it did. My stock muffler fell apart somewhere {could not find the lost parts} the same day it came. Now this should be a lesson. As per above I should have taken my own advice and used locktite on my muffler nut!

More to come...

Okay so I put on the new pipe and then modified it and put on a hotdog muffler to quiet it down a bit and just put on a new plug boot and wire and it ran like an old tank. Checked out my plug and it was black and oily. I moved the clip on the carb needle up one position then took it for a spin, then moved it again to the top position and it runs great now.

Definitely more power throughout and I have to adjust my idle now as it is idling way faster. Hopefully later tonight or tomorrow I will put on the smaller rear sprocket and then give my final results.

Also if I figure out how to post a picture I will try to post a picture of my modified muffler.

I have now replaced my blown electronic parts and taken the bike out for a spin. WOW!!! It really made a huge difference putting on the expansion muffler and changing to a smaller gear. My bike now cruises nicely at 30MPH at about 30% throttle. It goes at 30 with minimal vibration. I could get it up to 30mph before but starting around 25 I would get a fair bit of vibration. I have not tried out the top speed yet {took it for a quick spin and was up to about 35 when a cop went by on the other side of the road so I slowed down}.

I would not get the same expansion muffler again as it was just too much hassle to put on but I would definitely get a different one.

One thing I am noticing is that it would be easier just to get a modded engine and not really all the much more expensive than doing it yourself especially if you could in time. Okay maybe you do save some money but unless you are fairly mechanical and have lots of time and tools you might think twice before doing it on your own, however doing the basics like putting in a decent spark plug etc anyone should be able to do.

On the lighter side, many people in my city have been asking me about my bike and I have given a lot of people info. Last week I saw someone who had taken my words of wisdom and bought a kit and hooked it up. He was however blowing a lot of smoke and dripping oil like crazy. It turns out he decided to follow some other advice he got and mix his oil at 50:1. The only problem was he seemed to think that meant half two stroke oil and half gas. I can't believe it even ran! I filled him in on what 50:1 really meant. Hopefully he is doing better now...

I think my next upgrade will be a ThatsDax rt High Performance Carburetor. It will probably be a month or so away though as I am currently working on a pusher bike.

Wow that sucks!!! Did you ever get it back? I had to adjust my needle but that seems about it. Yes I know you need to run more oil for break in, but honestly, I dont think this guy could add single digits to save his life. Yes mine looks like a banana. {Expansion pipe that is... lol}