Lifan 150cc big-bore kit: Installation

stroker crazy

crazy as a fox
Remove seat and petrol tank to allow clear access:



Remove carburettor and intake, spark plug, exhaust, horn and bracket:



Remove head steady bracket, the two bolts holding the front engine mounting bracket to downtube, top rear mounting bolt, and loosen bottom rear mounting bolt:



Remove tappet cover:



Remove rocker assembly; when lifting pushrods, make a note of which is intake and which exhaust:



Remove the four head bolts, not forgetting the cam locating bolt on LHS of motor:



Lift head clear, keeping a look out for the dowels between head and cylinder:



Undo cylinder location screws on LHS of motor:



Lift cylinder, taking care to stuff crankcase openings as soon as possible



Pry out circlip from one end of gudgeon pin and push pin through the piston from the opposite side. (do not re-use circlips!)



Install new piston noting marked inlet side (lightly oil gudgeon pin to install),
make sure circlip gaps are to top or bottom rotate rings so that the gaps are 60 degrees apart:



Swap cam followers from original cylinder (be careful not to lose the wave washer) to the new cylinder:



Dowels in place in head:



Install 8mm/6mm exhaust studs:



Smear a very light coat of silcon sealant on cylinder mating surface, if you are not using a base gasket:



After cleaning any gasket remains from crankcase and replacing dowels, lightly oil the cylinder and carefully slide into place over the piston (remove the stuffing when the rings are inside the cylinder):



Position head gasket and top dowels:



Bolt head in place (20–22lbf. or 28–30n/m) and replace cam locating bolt (13–16.5 lbf.). Be very careful when replacing the pushrods – angle them toward the outside corner and rock the cam using the kick-start lever to ensure contact. If not positioned correctly they will drop into the motor, necessitating the removal of the head and cylinder in order to retrieve them:



Replace rocker assembly:



Replace engine mounting bolts (8mm 22.5–27.5 n/m)

Adjust valve clearances – intake 0.1mm (0.004˝), exhaust 0.15mm (0.006˝). For correct TDC inlet valve should be closing as piston rises.

Replace tappet cover, refit head steady, carby, spark plug, horn, tank, etc.

Before starting, remove oil bleed screw from rocker cover. Start motor; when oil bleeds from from vent, replace screw.
 

mikeyw64

Been Around the Block
a nice concise write up Sir 8)

One question

Adjust valve clearances – intake 0.1mm (0.004˝), exhaust 0.15mm (0.006˝).

Were they the settings recommended with the kit as aren't the standard settings 0.005 inlet & exhaust?
 

WJPez

Been Around the Block
Did you need to use a piston ring compressor or does the bore slot over the piston easily? Dis you get the kit from OORacing?

Wayne
 

orrible-64

Coast to Coast
nice walk through..thanks for going to the effort..was going to photograph when i did mine but got carried away doing job and didn't take any.

it is not too hard a job ..even for the unexperienced. take your time and follow this excellent guide.
only advice that was given on an earlier entry in main page was to put a long screwdriver through gudgeon pin so you do not loose circlips(used to call them "jesus clips" cause that is what you yell out when it flies off to unknown part of shed).
 

orrible-64

Coast to Coast
don't forget to crack the oil bleed bolt on rocker cover and do up when oil bleeds out from hole...this will insure you get proper lube to rockers
 

HerbertD

Active Member
Thanks Crazy,

Excellent write up and looking to do the 150cc upgrade very shortly myself. At this rate, we will be running out of mods to improve things further!
 

mikeyw64

Been Around the Block
orrible-64 said:
nice walk through..thanks for going to the effort..was going to photograph when i did mine but got carried away doing job and didn't take any.

it is not too hard a job ..even for the unexperienced. take your time and follow this excellent guide.
only advice that was given on an earlier entry in main page was to put a long screwdriver through gudgeon pin so you do not loose circlips(used to call them "jesus clips" cause that is what you yell out when it flies off to unknown part of shed).

Crazy mentioned not to reuse the circlips from the gudgeon pin. Are new ones included in the kit?
 

ACEitup

Been Around the Block
Thxs Crazy,
great walk thru,
this will be a great help when i do mine later this Year,
Thou I am sure I will be sending u Questions then!
Looking forward to seeing how much performance you get out of her?
cheers ACEitup
 

ChrisBNE

The Growler
stroker crazy said:
Although much of this information will be redundant for some ‘Ace’ owners, I decided to document my installation of the Lifan 150cc big-bore kit in case owners new to motorcycles might find something useful.

Thank you Tom for putting this together - a massive contribution and support for those who may not have felt comfortable to complete this modification. We're all the richer for you sharing your experence!
 

sprocket2cog

Been Around the Block
cool write up crazy.
one question, how does the pin/bolt come out for the cam followers ?
is it just a screw in thread ?
 

sprocket2cog

Been Around the Block
stroker crazy said:
It's easiest to push it out from the inside - the slot is to tell when you have it vertical so you can insert the long bolt from the head.

Crazy

ok cool, i got it now,i didnt realise it was held in place by that bolt, i can see it all now, thanks mate
 

mikeyw64

Been Around the Block
stroker crazy said:
It's easiest to push it out from the inside - the slot is to tell when you have it vertical so you can insert the long bolt from the head.

Crazy

Bit like an Ikea kit ;o)
 

Alton

New Member
hello im new here im in the middle of doing the topend in a lifan cg200 now just waiting on my parts . i was wondering if anyone new how to tell the top ring from the second ring i have herd the second ring is thicker and a beval to catch the oil and bring it down is there writing on the top of these rings ?
 

Alton

New Member
ill post pictures of my rebuild as soon as i know for sure what ring is what ? but these cg 125 engines and cg 200 engine are almost the same just one is bigger that the other.
 

stroker crazy

crazy as a fox
Alton said:
what ring is what ?

My Lifan 150cc kit had the rings already installed when I received it, so I didn't take much notice of the rings.

Just checked the original 'Ace' 125 rings - they are the same thickness and without any bevel or markings.

Crazy
 

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