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#1: 1996 xv750 Cracked Crankcase repair (SOLVED) Author: Viragohead,

Posted: Wed Aug 11, 2010 12:12 pm

A few months back I decided to replace my fork seals that costed me $120.00 and a crack crankcase along the seam between the two half. I can't see the crack but it looked like the gasket got cracked in one spot at the bottom when it got dropped. I had my wife sat at the back of the bike to hold the front up with center stand on and a 50 lbs of salt on the seat. She got off the bike, bam the front end hit the floor; the bottom of the engine hit the floor. Sh...........it. Long story short this will cost me anywhere 750 - 1000.00 if I take it to the dealer to repair the seal. They have to take the whole bike apart........
Should I do it myself since the whole cost is in the labor? I have a Yamaha factory manual but I didn't see any step by step for an xv750 taking an engine apart.

#2: Author: Matthew,

Posted: Wed Aug 11, 2010 1:00 pm

Its not a pressure situation, you can goop it from out side.

#3: Author: 48vintage,

Posted: Wed Aug 11, 2010 1:27 pm

If you cant see a crack, how do you know it's cracked - is it leaking oil?

#4: Author: Viragohead,

Posted: Wed Aug 11, 2010 1:38 pm

yes, it is a slow leak from along a line approx. 1" long at the bottom front where it started to go up. When I leave it park all day long at work, it drips to the ground and spread out to an area of about 4" diameter. Not a lot of leak but annoying and messy.

What kind of goop?

#5: Author: connormcmanus,

Posted: Wed Aug 11, 2010 1:47 pm

I would say a good clean up in the area and a nice thin coat of jb weld or the like, also, I'd rough up the area with a scotch pad or some such to give the jb weld some adhesion help.

#6: Author: 48vintage,

Posted: Wed Aug 11, 2010 2:12 pm

JB Weld or MSR Quick Aluminum/Steel should work.

Gary

#7: Author: Matthew,

Posted: Wed Aug 11, 2010 2:15 pm

you would want to drain all the oil, clean the area well and id used some 100% clear silicone and try to rub it into the crack some to fill it, it will last longer if the area expands n contracts as it heats n cools; also being clear it will be some what hidden, not stand out.

Though some ThreeBond 1194 would be the most ideal [gotta order it off the web], very similar to yahambond 4 [ no longer sold] that was used for the middle case gasket insted of a paper gasket as its a semi drying gasket goop that will expand n contract with heat.

#8: Author: Viragohead,

Posted: Wed Aug 11, 2010 2:58 pm

I tried some (stop leak) from NAPA that was supposed to be the best stuff for stopping leak, cost me $28.00. Pure into the oil and drove around for a few days. Didn't work. So I drained and put new oil in.
Can I re-use this fairly fresh oil if I drain it and patch the leak? It's only been about 20 miles since the oil change.

Will work on it this weekend.
I like to try some 100% silicone but it may not stick due to oil. JB Weld seems better.

#9: Author: grazingazer,

Posted: Wed Aug 11, 2010 3:55 pm

anything you add to the oil may damage your clutch...aircooled motorcycle engines are not the same as watercooled automotive engines

#10: Author: anaman51,

Posted: Wed Aug 11, 2010 7:50 pm

There are stories about JB Weld, like the one about the old farmer patching his engine block in the tractor after a rod went through it, and the next day going back to work. I don't know about that, but I do know that every time I've used it, it did the job and then some. If you prepare the surface by cleaning it good and then roughing it up, it'll do.

Dan

#11: Author: Viragohead,

Posted: Thu Aug 12, 2010 9:53 am

Thanks Dan. Looks like it will be a nice weekend to work on the bike.

#12: Author: Viragohead,

Posted: Mon Aug 16, 2010 11:25 am

Update:
Roughed the repair area by lightly grinding it up with a rotary tool and cleaned with mineral spirit. Patched with JB Weld mix. Seems to work so far after 10 miles ride. A cheap fix if it holds up.

#13: Author: backwatereddy,

Posted: Mon Aug 16, 2010 1:22 pm

Just a suggestion: change the oil you put the stop leak in. It may plug some holes that don't need plugging.

#14: Author: Viragohead,

Posted: Mon Aug 16, 2010 3:07 pm

I did that after I realized it did not work.

#15: Author: backwatereddy,

Posted: Mon Aug 16, 2010 3:52 pm

Excellent. It will likely save you an engine.

#16: Author: Sixties_Strat,

Posted: Mon Aug 16, 2010 5:23 pm

Mineral spirits is an oily solvent....hope it holds up. If not, try some lacquer thinner.
Mike

#17: Author: anaman51,

Posted: Mon Aug 16, 2010 7:05 pm

Glad to hear you're making progress! Good for you!

Dan

#18: Author: Viragohead,

Posted: Mon Aug 16, 2010 8:18 pm

Well, speaking too early. After I got home from work (16 highway miles there and back) and the bike has been sitting for 4 hrs, I ran my finger along the seam, I got oil on my finger. Dang.....It's either seeping thru the weld material or seeping between the weld material and the aluminum. Maybe I didn't rough or clean the area good enough. At least it's not dripping like it did before.
I will have to grind the weld off and redo it again.

Will update again with more rides and repair.........

#19: Author: connormcmanus,

Posted: Mon Aug 16, 2010 9:02 pm

If I might profer another opinion, using a plastic spatula like one for bondo, may help push the jb weld into the seam, also park the bike on an upward incline to move oil away from the affected area.

#20: Author: grazingazer,

Posted: Mon Aug 16, 2010 9:47 pm

jb weld will not hold...take matthews advice and if you clean with mineral spirits wash it off with water afterwards and dry the surface completely

#21: Author: Roger Ramjet,

Posted: Tue Aug 17, 2010 10:50 am

I can say fairly good things about JB Weld . Someone had put a longer bolt than needed in My AstroVans transmission Pan , When I noticed a leak I tightened all of the pan bolts ,When I tightened the one that was too long , right by where the shifter cable linkage bolts on it broke a three inch peice out of the transmission casting . At first my mechanic told me to look for a new transmission , it was on a Friday morning so they put it up on the hoist dropped the pan , cleaned the area really really well and applied JB Weld , They put the pan back in place and held it with a tranny jack and left it for the weekend to cure . That was five years ago and 200,000 kms ago still never leaked or cracked again . I and my mechanic we very impressed , we never expected it to work as well as it did .

But it is all in the preperation and we also felt that because it had the entire weekend to cure is probably the only reason it worked as well as it did .

we checked it at every oil change afterwards .

#22: Author: connormcmanus,

Posted: Tue Aug 17, 2010 11:09 am

Absolutely, it's all in prep. Just like any good paint job :). The cure time is a good point too though, and I'm sure over time the heat will help the JB.

#23: Author: grazingazer,

Posted: Tue Aug 17, 2010 12:17 pm

because the cases expand and contract with heating and cooling the rigid repair created by the jb weld will not hold...you need a pliable repair that flexes with the
movement of the cases

#24: Author: Roger Ramjet,

Posted: Tue Aug 17, 2010 12:24 pm

grazingazer wrote (View Post): ›
because the cases expand and contract with heating and cooling the rigid repair created by the jb weld will not hold...you need a pliable repair that flexes with the
movement of the cases

He's probably right about that , You could always put a harley Sticker on the tank and then the leak would be normal .

#25: Re: 1996 xv750 Cracked Crankcase repair Author: connormcmanus,

Posted: Tue Aug 17, 2010 12:30 pm

#26: Author: grazingazer,

Posted: Tue Aug 17, 2010 1:36 pm

or a vanity tag reading MARXITSPOT

#27: Author: Viragohead,

Posted: Tue Aug 17, 2010 1:46 pm

[/quote]He's probably right about that , You could always put a harley Sticker on the tank and then the leak would be normal .[/quote]

Mine is too pretty to be a harley. I wish I have a harley but I don't have $20K for a soft tail or willing to spend that much $ for a three months/yr ride.

I will use ThreeBond 1194 where I feel the leak. The top 1" line patched with JB weld seems to work but the other 1" section is leaking.

#28: Author: grazingazer,

Posted: Tue Aug 17, 2010 1:57 pm

the old timers fix for case bottom leaks was to split the cases...spread valve grinding compound on a level piece of steel or glass and rub the clean case on the flat surface until a .001" feeler gauge couldn't be inserted between the flat surface and the case half...both cases were treated this way and then butchers twine and indian head gasket cement was applied to one of the case halves before re-joining them...it worked

#29: Author: Roger Ramjet,

Posted: Tue Aug 17, 2010 2:04 pm

Or just do what I use to do when mine was leaking ... if someone mentioned it I'd say Nope that was from the guy parked there before me .

Either way sounds like a good off season project , why waste ride time for a minor leak just check the levels alot .

#30: Author: Viragohead,

Posted: Tue Aug 17, 2010 2:09 pm

Roger that.

#31: Author: Viragohead,

Posted: Wed Aug 25, 2010 4:57 pm

Update and will call this one closed or solved.
Last weekend I chiseled out the JB Weld. It came off almost like clay. It took me awhile grinding and sanding the channel with dremel tool. It was quite a surgical work upside down. Clean with Concentrated Purple Cleaner/Degreaser and lastly wipe off with brake cleaner (spraying on a cloth).
I went with YAMABOND 4 since the local cycle place has it. They also have the Threebond 1194 for a few bucks less.
So far so good after 24 miles ride.

#32: Author: anaman51,

Posted: Wed Aug 25, 2010 5:03 pm

Glad you got it licked. When I got mine, there was one tiny leak that took me forever to find, but I kept at it so I could say "Hell, no, it don't leak---it ain't no Hardly Ableson!" Besides, I spend too much time on the garage floor to be wallowing around in dripped oil.

Dan

#33: Author: Matthew,

Posted: Sat Aug 28, 2010 2:14 am

Yea YAMABOND 4 is the good stuff ThreeBond 1194 is the go to replacement as YAMABOND 5 isn't an upgrade, they done screwed it up like new coke.

ViragoTechForum.com » XV750 » 1996 xv750 Cracked Crankcase repair (SOLVED)

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