What I know is there are zongers that come from the factory with a 54 x 54 setup, running wider stud spacing like the 52.4x55.5, using a 69mm tall cylinder with 14mm pins, 27/23 valves, and your standard chinese camshaft. Why do I know this? Well, I wanted one for a really long time is why and spoke with all the chaps in the UK about them.



About 5 months ago, you could buy the complete top end for one of these for about $90 on ebay. Head, gaskets, cam, cam chain, cylinder, piston, rings...and I figured I get a couple of sets at that price and mix and match until I cam across a base engine to play with.



Fast forward to today, and I still do not have one of these lower ends. However, that is not the end of the story. These engines use practically the same cases as the lifan 120 and zonger 120 except in the kickstart mechanisms. They are generally rear-mounted 4-plate clutches too.



You can buy them as we speak on ebay. Also, Tbolt carries the black chrome version of the zonger. They have been popular in the UK because they are cheap and generally reliable. Nige at the Pedshed has been using these for a a while with good results.



If I had to make a call on what I would run in this base, I'd do the following (and I will go this way if my current 143cc ever craps out) Everything should fit in...



Cases: Lifan 120cc or Zonger 120cc Lower end, minus the crankshaft and its attachments.

Transmission: Toughy. I'd use a complete TRX90, 4-up tranny and shafts. Not mods necessary to run the stock lifan clutch.

Case Studs: TRX90 Case Studs

Cylinder: 57mm, alloy

Crank: DRPUK 56mm Crankshaft

Clutch: Original Clutch basket, using Kitaco Ultra Clutch Cover. HD Clutch Springs and Alloy Spring Retainer from kitaco.

Head: Original 27/23 Head with all necessary porting and good cam

Choice of Ignition (outer rotor is my preference, daytona brand)



Modification: Do not start in gear. Why you ask? Well, power is wasted on turning the gear on the end of the kickshaft in the oil. So, I'd modify that out so that power is not used to turn that gear without getting anything in return.

 

Is a TRX90 transmission a complete drop in for the Lifan 120/Jialing 124, etc?



The only pics I could find online of the Lifan varients showed crank mounted clutches, I'm assuming those don't use the crank driven oil pumps like the Monster 120?

 

Here is where it gets tricky...The crank mounted lifan and zonger 120s at 54x54 will have crank driven oil pumps...and then some do not. Oye! For clarification, any wide-stud patterned engine, regardless of jailing, lifan, zonger are running the large oil pumps driven by a gear. At least that is what I have found to be the case.



I have here a 2005 jailing engine. It is 52.4x55.5 with a 79mm long cylinder and Honda Nice studs (honda nice is same as xr50). This one has the clutch mounted on the crank and a gear-driven oil pump.



I would think this engine would make the perfect base for the project I am talking about...probably an absolutely perfect honda nice 62mm crank swap. The gears are all hardened gears (i just installed them).



On the trx90 gearset, if you have a dremel, you can mod the tranny shaft in about 2 minutes to drop right in a lifan 120 base. It is missing a notch where the clutch washer goes. If you had a complete bottom trx, you can make a giant killer I'm sure and use the original trx90 basket as well

 

fatcaaat,

what is the difference between the zongshen 120 and the 124? i have a 124 which i believe to be almost a square bore and it's supposed to have the 27/23 head. i know my 124 has the dog shit crank driven clutch. my 124 also has the wide stud spacing. the square bore revs like a mug. i can't find any mods for this engine. valves, pistons, etc. not to jump on kurlon's thread, but can you shed some light. kurlon, i have a new 124 that i could pull apart and measure if need be. i bought it to build a good race motor. instead it has been a dust collector.

 

Here's some information

fatcaaat,

what is the difference between the zongshen 120 and the 124? i have a 124 which i believe to be almost a square bore and it's supposed to have the 27/23 head. i know my 124 has the dog shit crank driven clutch. my 124 also has the wide stud spacing. the square bore revs like a mug. i can't find any mods for this engine. valves, pistons, etc. not to jump on kurlon's thread, but can you shed some light. kurlon, i have a new 124 that i could pull apart and measure if need be. i bought it to build a good race motor. instead it has been a dust collector.

There are tons of mods you can do to this motor to make it scream like crazy...the question is whether or not it is actually worth it to do it as it may be cheaper to just do something else.



If you want to mod it out, you can replace the main tranny shaft with one from a trx90 and then purchase a kitaco ultra clutch kit and mount it on there and you have a rear-mount clutch. Pop and inner rotor on it. Then, port the crap out of the head and pop in a g2 cam. It is likely running a 14mm wrist pin piston, so you will have to order a high-compression big piston from overseas. Too bad I just sold my last one. You can go as large as 57mm bore on the cylinder. I have 2 brand new stock cylinders and pistons sitting here collecting dust if you need something to work with.



That should get it moving quite well. You can also send out the crank to powroll to stroke it out to 60mm, that would certainly add some grunt, but don't know the build quality of the motor, so it may not hold up.

 

On the trx90 gearset, if you have a dremel, you can mod the tranny shaft in about 2 minutes to drop right in a lifan 120 base. It is missing a notch where the clutch washer goes. If you had a complete bottom trx, you can make a giant killer I'm sure and use the original trx90 basket as well

I am confused the lifan shaft is longer and must be used right.

it uses a pinion gear behind the clutch for the kick starter.





For anyone interested in this mod here are the specs of the trx90

because the shaft is longer in the non trx motors.





......................................->| . |<--2.80mm ......................................

..... |< ------- 28.46mm.---->| . |......................................................

.__. ______________________| . |______________________.__| |_____

).. ||..................................| . | .......................................| | ..... (

(.. ||..................................| . | ...................................... | | ...... )

).. ||..................................| . | .......................................| | ...... (

.__||_____________________| . |_________________________| |______)

. . . 1 .. . . . . . . . . . . . . . . . 3 . . . . . . . . . . . . . . . . . . . . . 2 . . . . . .



..... |< --------------------------- 67mm ------------------- >| ...





The dimension at the bottom is the for the grooves that is currently on the Lifan shaft. 1 to 2.



Both the Lifan and the TRX shafts are identical from the left end to what i numbered as groove 1.



From the edge it is 28.46mm from 1 to 3.

The width is 2.8mm @ 3.

The dept of cut is 1.6mm.

The od of the shaft is 17mm and the od once modified is 13.80mm @3.

I hope this helps, sorry for the sorry diagram:smile:

 

i have 2 new 54mm bore top ends, and they have 79.46mm tall cylinders,wide stud spacing,big valves,screw on tappet covers,14mm pin,chinese cam,small cam sprocket