need advice on changing rh centre case on lifan 140

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slick 50

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hey guys ,
i must say that this would have to be one of the best sites for minibikes and stuff that i have ever come across ,
and that your tech talk is very informative ,,
ok my problem is that i bought a second hand lifan 140 and it would be lucky to have an hours use on the clock ,
it had a clunking noise in the kick start area , so i have pulled it apart and found out that it has 3 teeth missing from the starter cog and that it has cracked the rh side of the centre case , ,

is there a trick to removing the centre case ???
as in leaving all the gearing and stuff on a particular side of the case ,
my kids race rm85's and i know that the trick to those in splitting the cases is to leave the gears and shafts in the left hand case so it all stays together ,

any advice would be great , :)
 
well i got all the parts yesty at 10.30 am ,
and i had the 140 split by 11.am , and the whole thing put back together and running in the my sons bike by 3.30 pm ,
let me say that it was a lot easier that what i thought it would be ,
the thing runs like a dream now , :eek:
 
That's great to hear mate !!!!!!! Bet you ended up with a bargain 140 in the end .... just kick the thing over properly and you'll avoid a repeat scenario .... I think nobody answered you because you stated that you and your kids already know how to split 2 strokes (same banana) ........

Actually having a go is the best way to learn ....... The cases on those engines aren't weak at all ........ it's just that as soon as you feel anything wrong with how smooth the kicker works ....... it's a really good idea to stop kicking immediately and get the clutch cover off to inspect for broken teeth ....... with a tooth missing ..... if you persist in kicking , one gear tooth catches halfway on the broken tooth and tries to jump another . The cam like wedge force shoves the shafts away from each other , putting tons of load on the cases and can easily split them open like an egg shell . The force can be the equivalent of slugging a chisel between the gears with a sledge hammer ........

I did type out an answer for you but backed out of posting it . At the time I felt it was a bit "CORNY' since I typed it when I had a splitting headache ...... LOL .....

So I'll post it anyway for the benefit of others :

MR CASE SPLIT THREAD .........‏
From: Cactus Jack ([email protected])
Sent: Wednesday, 12 December 2007 7:53:08 AM
I'm surprised that nobody else has answered your question yet ! It's basically the same as separating the cases on the RM85's ...... you have to remove the slinger , primary drive gear , clutch basket , selector shaft , shift star etc ...... All that I can add is ........ DON'T use idiot screw drivers to wedge the cases apart if you haven't got a case separating tool ....... only use something with a smooth , wide , flat surface like flat non serrated butter knives (or even something else wedge shaped that can't damage aluminium) and gradually , gently and evenly coax the cases apart . You can tap gently on the end of the crank with a plastic or rawhide hammer to get the case separation started but I for one don't the idea since it can put the crank halves out of whack . They're only pressed together onto the crank pin . What I do is grab the cylinder studs and wriggle the front open slightly then put a smooth butter knife blade in so that the gap doesn't close up when I use something between the footpeg mounts to get the rear of the cases started . You could tap the clutch side peg mount to get the rear started .Then they can be gradually opened up evenly from front to rear , top to bottom without creating any damage to the gasket mating surfaces . The main thing holding them in place are tight fitting hollow dowell bushes . If you do it right , you won't leave even the slightest mark on anything . Anyway , I'm sure you get the message , don't go hammering bodgy screw drivers in between the cases to force them apart ....... :p

To undo the nut on the end of the crank and the clutch basket ...... I've used the old rag jammed between the primary and secondary drive gears trick very effectively for over 3 decades . Use the proper 4 pronged tool for the crank nut unless you're experienced at doing it properly with a screwdriver or centre punch . And inspect VERY carefully for any metal metal chips or fragments if you DO use the bodgy method...... LOL .....

I know you more than likely already know most of what I've written ...... but I've written it for the benefit of others who don't have a clue ......
 
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