how do i take the head off (lifan138cc)

[Divy]

can some one please tell me how to take a head off,
its not as easy as a 2stroke lol
im sure its that cog with the chain thats holding it on but i cant get to it

help me!!

 

[Hillz]

Divy you should'nt realy be trying to take it of if you don't know but....

first off take dress up covers off.

get some whiteout to mrk you cam wheel to the cam so you know where the timing has to be when it goes back together.

then undo the four head bolts

 

[CHINGArider]

Check out this thread mate. Its actually pretty easy.

http://www.miniriders.com.au/forum/showthread.php?t=9483&highlight=removing+head

 

[jamie__1221]

hey man see if this works good help http://www.danosbikeshop.com/Technical/docs/EngineTearDown_Instructions.doc

 

[Webbiespanels]

Head removal.....

On the side of the engine that ur kickstarter is on there is a ten mm bolt in the middle of the head, it goes right through the middle of the engine and holds the timing wheel cover on, unbolt this and u will see ur timing chain and timing wheel/sprocket it has three 9mm bolts holding it in place. Before you undo this take ur lh side cover off and there is two markings on the flywheel and one marking on ur case, make the case marking line up with the centre of the 2 on the flywheel ur piston shud be at the top of the cylinder if not turn the motor over one revolution and it shud be. There is witing on ur timing wheel it will be facing the front of ur engine. It has to go back in this position and the flywheel and case markings have to be in the same spot other wise ur timing will be out and it could damage ur engine if it is not correct. once you have taken note of all that undo the three nine mm bolts on the timing wheel, the four nuts at the top of the engine and the one on the left hand side and it will slide straight off. Hope this helps have tried to simplify it as much as I can

 

[Divy]

thanks webbie that got it off
ok now my 138cc barrel is 2mm shorter then the 140cc barrel so if i bolt it up how will it run??
if it wont run do i just need to buy a 140cc conrod an it will all bolt up an run perfect???

 

[Divy]

oh also what is the stroke of my lifan 138cc??

 

[tubes380]

55.5mm and the stroke of the 140 is 59mm i think so it prob wont work you best off just getting the barrel bored out to a bigger size and fitting a hc piston that will give you heaps more power while your at it you might as well port you head too. hope it goes all good for ya

 

[Webbiespanels]

head to head

The stroke difference is made up by different positioning of the piston pin in the piston the problem is that a 140 cc piston has a 15 mm piston pin and the 138cc/127cc piston has a 14mm piston pin, u cant have 1mm slop between the inner of ur piston and the piston pin a problem I am currently working on overcoming coz I dont really want to have to split the cases press the crankshaft apart and replace the conrod with one that has a 15 mm hole at the top. So far we have decided reeming the existing 14 mm hole is out of the question as there is not enuf metal at the top of the conrod to do it safely. An engine builder in my old mans car club says he has used a shims/spacers to fit renault pistons into a austin engine with a similar problem and has had no problems with doing this and they rev these engines over 7500 rpm so it would hold up easily in a pit bike. Im going down to the bearing wholsalers tomorrow to see if they have any shims off the shelf that fit before I go to the trouble of making them the only other alternative. I will get extras wether i make them or buy them and post sum to you if you would like.. oh just for additional info the 138cc top end bolts straight onto 125cc and 120cc lifans without any mods wich also means the 140cc will not..

 

[Divy]

how about the lifan 110cc will the 140 bolt straight on ??

 

[Webbiespanels]

140 wont bolt on to the 110 for the same reason the piston pin is smaller so im led to believe. I have got a bag full of spacers to step down your 15mm piston pin hole to a 14mm allowing you to put ur 140 kit onto a 110 120 125 138 cc lifan engine. The spacers still need to have the end machined off to make them 12mm long insted of 20 to wich you need a laith with a carbide tip as they are very hard . Ive put them in my engine and it is running great.The other problem I came accross was that the timing chain needed to be a link longer as the cylinder is longer. I would be happy to help you sort all this out and get ur bike running with the 140 but I dont no if u live ne where near me. Im in Mount Evelyn Vic 3796 or call my buisness between 830am and 430pm. 97364482 .