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Broken crankcase, can I fix it myself?

42K views 216 replies 7 participants last post by  Kubi07 
#1 · (Edited)
Broken crankcase, could I fix it myself?

Long story short, I blew my motor and now there’s a hole right where the balancer is supposed to be on the right crankcase. So, I would basically need to buy a new right side crankcase and transfer or replace everything to it and I wanna know if it's doable to do myself even though I don’t have much knowledge as to how I would do that. I have the service manual but want to know your guys’ opinion if it’s something that’s possible. Thank in advance.
 
#31 ·
Here's the plug I run.


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#34 ·
i don't know what I'm looking at
 
#35 · (Edited)
yep ,that's a broken case . that BTW is an expensive part
 
#36 ·
Yeah the crank case covers are a little over $300 Did you split it open yet and see what failed yet?

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#37 ·
i was thinking 500.
 
#38 ·
#40 ·
if in doubt , dont
 
#44 ·
The link in post #6 says it comes with a complete gasket kit, so I'd say yes.

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#43 ·
i don't remember
 
#49 ·
Also, it seems like there's a hairline crack on the other crankcase as well: Think i should replace it too?
Looks like more than a hairline crack! And the spark plug looks like the top end came apart as well as the bottom end. Your engine is toast, so no need to worry about taking it apart.

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#48 ·
maybe i missed it but why or what happened to brake the case ?
 
#50 ·
Is your jug cracked as well? The damage to plug looks like piston came apart. With all the damage you have, that ebay motor might be a better option. And the price has dropped on it. I just looked and seen it is in Wooster, Ohio $1750 and $150 freight.

Also wondering when this engine blew did it give any warnings like smoking, and we're you wot? I was wot when mine went. The piston cracked the jug, but my crank was fine, and plug looked good too.

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#109 · (Edited)
I guess you were mistaken on the jug being fine! I scrolled back through this thread today on cell phone, and all four of those pictures appeared fine. Idk where your ordering parts from, but partzilla.com is cheap, just don't be in a hurry. And best to call and dbl check they have the parts in stock. Also wondering what part of the world your located. There are lots of builder's on the west coast. And you can always ship motor to them. Or if your east side there's Ehs racing. On the honda atv forum there's a sponsor called.

Nflowmotorsports.com

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#55 ·
Tried taking out the camshaft today but had no luck since I can't turn the crank to be able to unscrew the cam sprocket. But, I did take out the flywheel, starter torque limiter and the idle gear. Any suggestions on getting the cam out though? Thanks.
 
#56 ·
Looking at your case it broke in the area of the counter balancer. I wonder if your counter balancer broke and that is also preventing you from being able to rotate the crank.

Have you removed the timing chain tensioner?

Remove the covers so you can get at the lower gear and try to pry it off down there. Otherwise you can cut it. I would replace the cam chain anyway since it's all apart.

Kind of like when you have to remove the timing belt to replace a water pump in a car. You almost always install a new timing belt. (unless it was recently replaced).
 
#57 ·
I’m thinking the counterbalancer broke as well. I really hope not since it’s an expensive part to replace as well. I’ve taken out the chain tensioner but it isn’t loose enough to get it off the sprocket. I’ll try to get at the lower gear and take it off from there, if not I’ll just cut it off then.
 
#58 ·
Checked out the oil pump and it looked good but I have a question about putting in back, for “oil pump B”, the one that’s on the inner part of the crankcase cover, aid the pinched out side supposed to be facing out toward the clutch side or in toward the outside. Hope you guys remember, the book doesn’t say anything about that for lump B so I’m guessing it’s supposed to be facing in toward the outside. Thanks.
 
#59 ·
i guess i find it odd that the balancer would brake . to me is more likely some thing had gotten between the balancer and the case wall . there is not much room between the two parts .
 
#60 ·
in the service manual 5-7 , does that pic help ?
 
#68 · (Edited)
So, here's what I've found:



Am I the only one that can't view these picture's? Okay I clicked on link with cell, and viewed from pb desktop would not view.. Is the 4th picture showing what's left of the piston? If so wow!

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#64 ·
i have a stock cylinder way better shape than that one
 
#66 ·
that would be the first time I've heard of it .
i do wonder if maybe the balancer may of gotten bent . and if so , could it be tweaked back to true
 
#69 ·
Really? So what are they talking about here? balancing a hot rods stroker crank.......... how necessary ?? - Honda TRX Forums: Honda TRX 450R Forum
I just don't wanna rebuild it and have it get destroyed. Have you done a stroker/ big bore without having it rebalanced? And if so, was there no vibrations?
And the balancer does seem to have gotten bent, I'll probably just buy a new one.
yes i did put in a +3 stroker with big bore . i was expecting vibration but it did not happen . in fact it was down right smooth

i also have a ltz400 with a +5 stroke turns out to 11000 rpm
 
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