Chain Came Off and Cracked Left Crankcase

[MitchAustralia]

Hey guys,
Yesturday I was going for a ride when my engine just stopped dead and I knew something odd happened.
So I got off and sure enough the chain had came off.
I took a closer look and saw that it had made a little crack on the left crankcase.
I was pretty pissed cause I wasnt thinking straight and was convinced I would have to buy a new engine. LOL
Anyway, we got the chain back on and rode it up to the shed.
We tightened the chain a little because we believe it was too loose and thats what cause it to come off.
We then filed down the crack and chunk taken out of the crankcase and that was it.
I know it sounds like im overreacting cause this happens all the time but I just want your opinion on the crankcase damage.
Dad doesnt think its enough damage to have to get a new one but the crack will slowly make its way down and then we will have to buy a new one.
Here are some photos of the damage.
The crack is in the top right hand corner of the crankcase if you cant spot it.

Thanks, Mitch.

 

[Shing]

If the damage wont lead to any more damage (eg, let dirt etc get into the more important components etc, etc) then I wouldn't worry.

 

[SnItChY]

dont worrie mitch its only a side cover tho i would be replacing it there easy to pick up

NEW HD CUTAWAY IGNITION COVER CRF50 125CC 140CC 150CC - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 01-Aug-09 14:43:24 AEST)

 

[headsmess]

^^^^^^ditto, thats just a cover...you can get one for 30 bux.... or a clear plastic one...nothing to worry abot at alll...

 

[fat-magz]

just replace it?? its only a side cover an might be a good idea to tighten the chain abit more

 

[bulldog93]

ha not even that bad, replace it yeh but that cost money..so get the grinder out and cut a hole out so you don't have to take the side cover of to get to the sproket...do you get it??

 

[DvDRip]

I warned you about that KMC chain, they were specially designed to stretch and snap and crack your cases
Kracks Many Cases

throw it in the bin and get a Heavy Duty RK or D.I.D chain from a jap bike shop

 

[MitchAustralia]

Yeh thanks guys.
Is it real tricky to get the crankcase off and replace it with a new one?
Haha, Im liking the sound of the clear one, although thats plastic isnt it?
And my current one is metal, well at least it looks like it.
Thanks, Mitch.

 

[MitchAustralia]

throw it in the bin and get a Heavy Duty RK or D.I.D chain from a jap bike shop

Is it really worth the money?
Cause im pretty sure it was our fault for the chain being to loose and we have fixed that up.
The weird thing though, you might be able to answer this DvDRip, in the manual I got with the bike... it says that the chain should be about 2 inches between the middle of the swingarm or something..
That seemed way too loose for our liking and we had it set at 2 inches when it came off?
Thanks, Mitch.

 

[MitchAustralia]

ha not even that bad, replace it yeh but that cost money..so get the grinder out and cut a hole out so you don't have to take the side cover of to get to the sproket...do you get it??

Are you talking bout getting the chain back on?
If you are we already did that, was a piece of cake.
Just put it over the gears as well as we could then rolled it a bit and put itself back on.
Thanks, Mitch.

 

[MitchAustralia]

If the damage wont lead to any more damage (eg, let dirt etc get into the more important components etc, etc) then I wouldn't worry.

Yeh thats what I asked dad, but he showed me that the was stacks of room in there.
We stuck a philips head down there and there was about 10cm of room.
The flywheel is the only part which is near the surface under the crankcase and thats way off where the crack is.
Thanks, Mitch.

 

[pit_pro-250sx_rider-139]

Are you talking bout getting the chain back on?
If you are we already did that, was a piece of cake.
Just put it over the gears as well as we could then rolled it a bit and put itself back on.
Thanks, Mitch.

no his saying make it into a cut away cover i think theres a sticky on how to do it here somewhere

 

[DvDRip]

What you need to do is get the grinder out and cut the damaged part of the ignition cover so the damage doesn't spread, and if you cut it back till it looks like this picture it's less likely to do any damage if the chain comes off again

yea mate the real chains are worth it and cost about the same as a KMC one, KMC's just stretch like crazy and snap easily. real chains stretch a little bit at first then stay like that instead of going on forever.

THROW THE MANUAL FOR BIKE IN THE BIN!!! there's nothing even remotely usefull in there, if you need help come here and search just whatever you do don't go by what's in that sorry excuse for a manual

 

[headsmess]

the cutaway makes it easier to change the front sprocket, and to thread the chain over the sprocket...

as cactus mentioned somewhere, its best to use the biggest front(17) sprocket to minimise the chances of the chain binding up in the gap between the sprocket and case, which then smashes through the case, and breaks the pickup bracket off the stator plate.... plastic cases offer NO protection... but are good for things like checking timing/ finding tdc...

the cover is easy to remove/replace, its only two or three bolts holding it on...temoving the shifter first makes it even easier....

replacing the chain with RK, DID, or TSUBAKI is always the best option...NON o-ring some people disagree, but with a chain used near dirt? DONT oil them.... even wash a new chain in petrol so it wont catch grit... but, you can soak them in a pot of molten candle wax... it isnt sticky like oil is... they will last longer when they dont get full of grit

and...always put the clip for the master link on with the CLOSED end facing direction of travel...

1 inch of free play when sitting on the seat is the ideal tension...

i love my sexy "carbon fibre" cover

 

[MitchAustralia]

Yeh I understand now.
So basically cut if back and stop after where the crack is to prevent the crack from getting longer and causing damage.
Yeh I might consider getting one of those "real" chains.
Got any key named or brands for chains?
Yeh I agree, the manual isnt too helpfull and the pictures are horrible!
Thanks, Mitch.

 

[headsmess]

replacing the chain with RK, DID, or TSUBAKI is always the best option...

wtf? oh...the quote isnt counted in the "10 charcters" limit

 

[MitchAustralia]

ok, thanks alot headmess.
yeh I will try and remember to soak it in petrol.
yeh I think our chain has about 1.5 inch at the moment (with me sitting on it)
it seems about right.
Thanks, Mitch.

 

[MitchAustralia]

ok, thanks alot headmess.
yeh I will try and remember to soak it in petrol.
yeh I think our chain has about 1.5 inch at the moment (with me sitting on it)
it seems about right.
Thanks, Mitch.

 

[MitchAustralia]

alright, a shop in adelaide that sells pitties have DID chains for $65
does that sound about right?
how would I find the size of my chain because my manual is for the 150 not the XR 140.
Thanks, Mitch.

 

[rotn50]

Cutaway

I marked the case were i wanted to cut away and put the cover on the ground put my foot on it and used a jigsaw with a metal blade, the job is done in 5 mins mate, then just a quick file for any edges.

If you still have the chain take it to the shop and match it when you go to get the D.I.D, they will know what there looking at.