Cracked bolt...what to do?!

Hello guys. Got an 83-ish (lol) 250XC. It has the lighting coil and SEM ignition. I quit getting spark and figured something was going on with the ignition coil or stator or something to that effect. My brother and I pulled the side cover off to reveal that aluminum cover with the 24mm bolt in the middle and two holes on both sides of the nut. (not sure what the parts are called, more of a car person). I couldnt get it loose due to the engine wanting to turn over, so I left it go for a minute to check online to see if I could find some info. Meanwhile, he somehow cracked that center bolt off. I dont know HOW he could do it, but its definitely laying on the garage floor. I noticed now that the engine doesnt turn over-like it is seized up somehow. What can I do to fix this? How did the thing lock up when there is no bolt/nut assembly on the bike? Any responses are appreciated!!

Oh man! Thats horrible news! That sounds like a lot of work to put into the thing.

What if I cut off the flywheel and buttweld a bolt to whats left of the old bolt? Ive found a flywheel for a 250 on the internet for a decently cheap price

Is this a joke or are you serious? Guys on this forum will help you but if you are going to rigg it just go to the J model forums. Cut off flywheel then buttweld a bolt to it, come on get a grip. Later George

I appreciate the reply, ruwfo. Looks like this puppy is gonna sit for a while. That is a lot of money to put into something that only gets used for only a few times a year.

Up-tite, I was not kidding. I wasnt sure of how the assembly went together. Now that Ive gotten that flywheel off, Ive realized that it has the whole magnets and everything inside it.

I got a 72 250 WR 25 years ago as a parts bike, owner said he could not get it to run, I started to strip the bike down, pulled the engine covers, found a broken crankshaft with no threads. Now I know why he couldn't get it to run. So I got a bright idea ! Took that engine to work and clamped it on the table of a Bridgeport milling machine. Drilled and tapped a 1/4-28 LH thread right down the center of the crankshaft. Made a large washer to just fit inside the flywheel. Got a lot of strange looks and a few of the that wont work laughs, but after 25 years and still going strong I think it's a great cheap fix.

I'm a firm believer in 'poverty is the mother of invention' there's ways and means. If it can be made, it can be mended.

If you don't have the tools/skills for the above, take a look on ebay. I've just seen an engine sell for £35 GBP, so all is not lost!

Good luck

BobbyG,
Are you saying that the male-threaded end of the crankshaft came off? OR did the large nut split off the crank. It makes a HUGE difference to what you'll have to repair. IF the male threaded end of the crank came off... yup, gotta split that cases and rebuild the crank with a new crank half.

Most likely the motor is not turning over because you've jammed the flywheel down onto the stator underneath. There's not much clearance in there on purpose. You'll have to use the correct puller to remove that flywheel. Then you'll have to inspect the stator and flywheel to see if jamming then together has damaged them at all... a good possibility. Often the tapered portion of the aluminum flywheel will have gotten split by being overtightened. The crank taper acted like a log splitter/wedge.

Ya, that was an expensive oops. So sorry.

I wasn't being rude dude!!!

I'm advising him that he could do worse than look on ebay, he may find something local...

Hello Bobby
I just did the same thing with my 76 wr400 but I was even more stupid yet I was taping my crank out of the case with a rawhide hammer and the male threaded portion broke off I was told that I could chuck the crank in a lathe smooth out the rough end (where the threads used to be) drill the end of the crank with a 7/16 by #20 thread and thread in a grade 8 stud with red loc-tite get a thick cupped washer and nut and it doesn't have to be left handed thread if you dont have access to a lathe or the skills talk to a local machine shop and explain what you need done they might get you for 2 hours labor and if you do the case splitting yourself or get help from your brother and both do it you can do it for far less then $1000 Good Luck!

good job George

the next owner of this bike will thank you.

LOL I dont mind being eaten alive on the internet, I understand that ya'll wouldnt try and rig up your bike and thats cool. It's just that Im tight on money and neither buying an engine or crank assembly is an option.

BUT!...Check out what I did. I fitted my husky with General Motors HEI ignition! It works pretty decently, I am having trouble getting the timing correct to where it doesnt almost take my leg off while kickstarting (kickback is bad). Anyways after making the video I redid the wiring and moved all the electronics to the airbox under the seat and fitted the bike with a 12volt powersport battery to power the ignition. You would be surprised how long you can power ignition with a battery. (hint: its longer than it takes your crotch to get sore from riding). After fitting everything back to where the bike would look normal I rode her around the block!

Check out the video of the setup before I 'cleaned it up'

http://www.youtube.com/watch?v=OGsb1WiAOeQ

Jerry-rigged, yes...Awesome, yes as well. Talk about a powerful spark. I got bit by it a couple times during testing.

Heh...uh...sureee

No but really...I was looking at small-engine flywheels in my Prime-Line illustrated guide, but couldnt find one that would work. I would also have no real way to center it up on that bolt. Also I would have to find some other way to trigger the HEI pickup coil if I somehow fitted it with a flywheel. Not sure how I would do that. Anyways it runs, and runs fairly decently (good enough to be able to kill yourself on it ), just need to adjust the timing on it a tiny bit.

Question, a kickback on starting means timing is retarded (as opposed to advanced) correct?

Nope,

Excellent fix though bud, I'm impressed...

Interspan, eat your heart out.

LOL I was shocked too (in more ways than one haha). Drove her around the subdivision for about an hour, worked great. Like I say only thing I need to fix up is the timing.