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Lifan 150 RH crank cases are made of plastic? Seriously.....

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stoozo

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*insert lots of swearing here* So went to see the tech master to see if we could solve the gear box issues today. This was the result...... :thumbdown:

What the F is this.....

My 150 looks like this:




Craigs Parts motor looks like this:




Craigs other parts motor which we knew was busted but SAME SPOT....ALL 3 of them Damn they need to start using real metal over in China :(





Seriously need some help with this! If anyone is wrecking a 140yx or a 150 Lifan please do let me know. Looking at possibly getting it welded but the first guy didnt want to touch it cause of the 'plastic' they use to make them with....Well I guess at least we discovered the problem(s)
 

stoozo

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I think we have to find a way of strengthening that cut out portion behind the bearing what do you think Craig?? Maybe like a plate screwed in that will not impeded the clutch, like Rob was saying,pressing it from the other side somehow? That bearing is taking the load from the entire gearbox and it has nothing but that supporting it on either side....there is the problem, needs to be made stronger or it will just happen over and again! Can we somehow bolt or screw a chromo plate in there? Dunno racking my brain for answers...it really needs to be 're-made' some how to be strong enough to cope with the stress' placed on it in that spot!
 

zwebx

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Maybe get another case, then weld a small triangle over the section in question covering all sides in question welded then grinded to make it clear other parts...
 

my67xr

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Zac, my mate reckons it is too poor quality alloy to weld, and he has done a lot of miracle repair welding jobs for me
 

zwebx

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Zac, my mate reckons it is too poor quality alloy to weld, and he has done a lot of miracle repair welding jobs for me
Well epoxies are off the menu as because the expansion rates will differ etc..
Maybe two large holes precisley drilled and a cross bar holding the cases together .. may make it worse because depending on where the load is (needs to be identified) then that differs to where the brace needs to be and how its done..
 

my67xr

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Devcon will bond and hold fine, but it isn't strong enough.
just below the bearing where the cracks are, is below the gear/tooth level of the smallest gear, so no hope of fitting any bolts through the cases either
 

stoozo

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What about a really strong spacer in place of the larger bearing and then use a smaller bearing? Something inside where the bearing is now to kind of dissipate the impact before it transfers into the case? Like a bigger version of a wheel spacer kind of deal with a bearing in the middle? The real problem is the transfer of force through that bearing into the crankcase(which isnt strong enough to handle it)....Obviously it likes to crack in that exact spot, due to exactly what, I have no idea! Disipating the force through a spacer on the outside of a smaller bearing as far as I know from physics should help at least. It would still need to be fixed first.....ahhhhh :microwave:
 

zwebx

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What about a really strong spacer in place of the larger bearing and then use a smaller bearing? Something inside where the bearing is now to kind of dissipate the impact before it transfers into the case? Like a bigger version of a wheel spacer kind of deal with a bearing in the middle? The real problem is the transfer of force through that bearing into the crankcase(which isnt strong enough to handle it)....Obviously it likes to crack in that exact spot, due to exactly what, I have no idea! Disipating the force through a spacer on the outside of a smaller bearing as far as I know from physics should help at least. It would still need to be fixed first.....ahhhhh :microwave:
Yes machine a circle larger od than this bearing and make it of somw high tensile steel nice and thick to spread the load to the cases and not a tiny peice
 

my67xr

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the case is only 2mm thick on the side where it cracks

the Daytona case looks like it would be ok, but they are expensive
 

stoozo

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I was thinking more fix the crack, then put a big spacer in the original bearing hole,with a smaller bearing diameter on the outside,but same size on the inside! Basically fix the case as it is now,spacer in the bearing hole and bearing inside the spacer,just so the force has somewhere to go instead of straight into the 2mm case! Any luck finding another RH case on ebay?

Sorry smaller diameter bearing on the outside...blah blah
 
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