My new Lifan 107 from Hooper

[kingsa7x]

Well,

For my xmas I got the new engine I asked for. It came from Hooper Imports promptly after ordered. Everything arrived in the box as specified. Would have been nice to get a little install info with it, but I guess there is a little on the the website.

The engine fit into the frame perfectly. The new carb did'nt quite line up with the air box boot with either the supplied intake manifold or the OEM one. It came close with the original though. A little duct tape is temporarly closing off the remaining 1/4 inch gap.

I pluged into the new coil and cdi with the Hooper simple wiring harness (additional purchase) . I hooked up everthing I had to take off to get to the engine in, and that was it. I kicked it over and it fired up on the second kick. I tuned up the carb and I was off.

As far as the electrics go, I'm totally lost. Nothing plugs into the original wiring harness, so no lights or ignition switch, but the bike runs.

At 107cc, I was hoping for a big boost in power and a modest increase in top speed. This is a 50% increase in displacement over the stock engine.

Unfortunately, I'm quite disappointed so far. Even with the new engine being a 4 spd, it gives me basically the performance as my old engine, except for the new engine shifter is alot harder to move, maybe that will get better as it get's broken in. 38 to 40 is top speed.

I have'nt called Hooper yet to get his thoughts , but can anyone think of what I might have down wrong or should check?
There are no air leaks and the engine is air intake is not blocked.

And please, No Chinese engines are garbage, I told you so, blah, blah, blah......

 

[Dan_Lorenze]

Hmm...

How's the bottom end power on the bike? Just an idea, since there are so many applications for these import motors it's possible that the counter shaft sprocket is a 13 or 14 which would give you some good bottom end performance but it would lack in the top end speed of the bike. These engines go in bikes with various sizes of wheels, and the internal gearing varies too. It's important to find the right power for the riding that you're doing. I've had good luck with 16 counter shaft sprockets with 35 rears with great success, especially since 1st gear is a "granny" grear,and yes both my bikes can handle the taller gearing, no problem.. So basically I think you should consider looking at the gearing of the bike, don't just assume that the internal gearing on a CT70 would be that same on an PRC knockoff. Also, what pipe are you using?

Dan

 

[MSZ]

If you want the bike to go faster, you'll have to regear appropriately, you'll have to get a better exhaust and bigger carb.

A stock 107 is good for 55-60mph easy if you gear it and set it up correctly.

 

[69ST]

I'd expect speeds in the high 50s from this engine. Even though an engine is easy enough to bolt into the frame, there are always setup issues to work through. As has been mentioned, you're probably undergeared for the new motor. Your stock exhaust is pretty restrictive for 107cc and the stock airbox is functionally akin to stuffing a rag down the carb venturi.

First order of business is figuring out the overall gearing (from crankshaft to rear wheel) and power curve of the engine. Start by gearing the bike so that engine rpm is at peak power around 55mph, then experiment from there to suit your preferences and the type of riding you do. If you can't get the gearing and powerband info, then trial & error testing is the only way to get your motor dialed-in.

Second step is to source an open-element air filter and improve exhaust flow. At the very least, remove the baffle from your stock CT70 pipe. That's not optimal, but it's better than nothing.

Lastly, new engines are tight. That means that they don't make full power and they also run very hot, right out of the box. Give the engine a break and take it easy for at least the first 100 miles...500 is better. Chinese motors don't have the slickest finish machining. That results in lots of friction, which initially causes the hot running, reduced power output, balky shifting and lots of metallic bits in the oil. All of these conditions will improve with mileage. Change the oil frequently for the first 500 miles or until the metalflake seen in the old oil diminshes, whichever comes last. Properly maintained, your motor will pull you along faster & run cooler as the mileage accumulates. That's pretty much the same with all engines. Just don't expect full break-in until at least 1000 miles. The only shortcoming you'll have to live with is shift quality. However, it should get better with mileage, as well.

 

[1moretoy]

break-in

I was thinking about following the break-in as well. (or really, not following it) This might be overkill, but I think "take it easy" is good advice. From Hooper's website:

The factory recommends these break-in steps to assure reliability and performance for the extended life of your engine. This procedure should be followed during the first 1000 kilometers of operation. Avoid full- throttle riding and heavy loads for the first 1000km.
(1) 0-150km
Use the maximum of ¼ (25%) throttle and vary the speed and be sure to shift gears often. Allow the engine to cool for 10 minutes after every hour or operation.
(2) 150-500km
Use the maximum of ½ (50%) throttle.
(3) 500-1000km
Use the maximum of ¾ (75%) throttle.
After your break-in period, be certain to conduct maintenance according to the Maintenance Schedule. By following these procedures you will extend the service life of your engine.

 

[kingsa7x]

Thanks guys,

Yeah I saw those break in recomendations....almost 700 miles untill you are supposed to go full throttle! I don't think I can wait that long, but I'll definately take it easy for awhile.

I went and checked out my sprockects. They have 15 and 35 teeth respectively. The bike definately feels like it's geared way to low. When you give or let off the gas, the ride is really jerky, and first gear is pretty much a joke. You could skip it completely.

Dan, you say you are running 16/35 sprockets on your bikes. That's almost what I have already. I have no idea what to try. What would you guys recomend?

My exhaust is a chinese repop I got off of ebay. I'm sure that it could hardly be considered "high performance". Can I take out the baffle from this, considering it is not an OEM part?

As far as the airfilter goes, Racer X I know you are right. I took a ride with the airfilter out and I got a definate increase in power. As far as a replacement, what do you guys like?

 

[kingsa7x]

And one more thing....

I have figured out that my throttle cable is too long, so obviously, I'm not getting full power, but.....
when I get it to full throttle (which I think is about 60 to 70%) and when I am at max cruise, the engine is not delivering smooth power. It feels like it is surging.

Does this sound like a engine defect or a tuning problem?....
i.e.....carb jets

 

[honda123]

What size carb are you running this engine with , bogging down is usualy a fuel air mixture problem. I imagine that if this carb came with the engine it is peobably a 22 or 24mm. First adjust your cable , then if the bogging is still there maybe carb adjustment is required or jetting.

 

[kingsa7x]

Well the bike isn't exactly bogging down, it surges. It accellerates normally, then when the throttle is full open (not really, cuz I haven't fixed the cable yet), it surges.

I'm not sure what the size of the carb is, Hooper's website says it comes with 19 mm. It's a Walbro. How can I tell what size it is?

 

[69ST]

Actually, short blips of full-throttle are okay (some say desireable) almost from the get-go. The issue is not running at WOT for more than a few seconds at a shot until the motor has enough break-in time to prevent overheating. 500-700 miles before attempting to cruise along at 50mph, or better, for miles at a time is not unreasonable. Occasional shots of 2-3 seconds, wide-open, followed by closed-throttle deceleration (compression braking) is supposed to help the rings seat properly. I'd still take things really easy, vary engine and bike speeds and change the oil frequently for the first few hundred miles. An oil dipstick thermometer will remove some of the guesswork, but not all of it. Cylinder temps can spike rapidly; a single hot spot in the cylinder wall can ruin your whole day.

Most 110-ish engines come with 18-20mm carburetors. Since your engine was sold as a package, your carb is probably sized & jetted pretty well for the application. It shouldn't be necessary to do more than idle & jet needle height adjustments.

K&N or UNI air filters are both excellent units. The former costs more and is supposedly better suited for road use. The UNI is easier to clean. Either should be fine for your application. You do get what you pay for.

Your exhaust is on the restrictive side for a motor this size. Removing the baffle should make a difference, but I've yet to see a Chinese CT70 muffler with a removable baffle.

 

[kingsa7x]

Thanks,

I have been putting around just about everyday trying to break this engine in. It has definately made the shifting a bit smoother.

I went down and picked up a uni filter from my local shop today. I wanted a k&n, but they didn't stock one for my engine. The new uni made a noticealble difference. The bike has more pep. The top sustained (average) speed increased to about 45. The surging seems to be gone. It seems that there just wasn't enough air.

Now the bike is almost performing my expectations.

Do you guys think that going from a 15 to 16 counter shaft would make a noticeable difference? There is enough low end power that I would like to trade some for a little more speed.

Thanks guys, I would'nt be having nearly as much fun if it wasn't for your help.

 

[kingsa7x]

A little update....

Now I have taken the bike on a few decent length rides. I'd have to say I'm pretty happy with the performance. While top speed increased only about 5 -7 mph over my stock engine, it gets up to top speed (about 45 sustained) alot quicker. One of the biggest improvements, and the one I was mainly looking for, is that the bike goes up hills ALOT BETTER. The engine starts good and runs smooth. It seems that my earlier problems where either from using the stock air filter or the engine being right out of the box without any break-in at all.

Now that I got a taste of the extra power, I realize how nice a 125 must be. It seems that they cost a bit more though. I would'nt pay an extra c note for it since the I got the 110 for only $300 bucks, but if was only say $40 or $50 more, I'd have to go for it.

Now, we will see how long this thing lasts.....

......And if I can figure out how to get the electrics wired right, even after see what dr. atv offers, I'm still pretty lost. Anyone have any advice?

 

[69ST]

Even a 1-tooth change of the countershaft sprocket will make a significant difference in overall gearing, but they're cheap. A good rule of thumb for determining ideal gearing on an unknown engine/trans combo is to do the rough tuning by swapping countershaft sprockets and the fine-tuning with the wheel sprocket. For a road bike, I'd start testing with a 16 & 17, then go a couple of teeth smaller on the rear wheel sprocket (if necessary) until a point is reached where the bike is obviously overgeared and feels weak in fourth gear. If you're thorough with trial & error testing, you'll find the best overall combo down to the exact number of teeth on the wheel sprocket. Believe it, or not, even a 1-tooth difference in wheel sprockets makes a noticeable difference once you get the gearing right to the edge of ideal.

If you're not concerned with top speed, per se, and hill-climbing ability is your goal, then you don't need to be concerned with getting the sprocket ratio dialed-in exactly. Just stay on the low side. From what you've described, I'd guess that your motor can probably pull 20% more gear than you now have.