Local place to get flywheel key in a pinch

Jcary85

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Just like title says… sheared a flywheel key tonight and want to ride tomorrow. JM is fast as hell so I’m maybe good for the weekend, but where can I get a key locally that will work until then? Home Depot? Lowe’s? Harbor freight key set? Thanks in advance!

-Jordan
 

Jcary85

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Update: help section (dorman) at auto zone has a woodruff key assortment. There’s on in the kit with a width that is really close. Had to grind it down as it was too tall but it will definitely get me by for a few rides til I get an oem one back in there. Can’t miss riding days in the short PA season!
 
I once needed one in a similar pinch situation, got online and searched what other yamaha vehicles use the same key (I have a few around here) and found that my 1974 DT250 enduro bike uses the same part number key. Stole it off the bike and went riding.
 
You can run a flywheel without the key. You can mark the case with a paint pen, and the 12 o clock position of the flywheel. And the snout. The taper is what holds they flywheel in position. The key is purely for ease of installation.

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Snowmobiles regularly put 150+ hp through a clutch that is attached with nothing but a taper, so definitely it can be done, and if you forget to tighten your flywheel bolt the key will sheer very quickly (not that I've ever done that), so it is true the taper is what is really holding, the key is just to align it correctly when you install.

I'd be nervous trying to get that alignment perfect though.
 

Jcary85

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Ya I mean Ive heard of keys breaking and flywheels spinning many times. In fact, that’s what made me start this thread(flywheel spun). Don’t think it would be smart to not run a key.
 

be_lain

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I was able to find a woodruff key at Wilco farm store in a pinch, which I only ran for a short time until I got a new OEM one from JM.

I’ve had two OEM woodruff keys shear on me with the flywheel bolt torqued to spec from backfires. Also extremely difficult to accurately set up your timing without one. Would definitely discourage you from running no woodruff key.
 
Lol. I'm running a dasa 1100 with 230 psi with no woodruff key.

Again. The woodruff key is stircly for timing. It is a very, very soft material.

I've drilled 3 inch holes in 3 inch steel. With a Morse taper being the only thing holding it.

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Uhmm so why not run your Engine without the Flywheel Bolt after the Flywheel is seated if the Taper is the only thing holding it in place?
Because that bolt is pulling the flywheel into the taper of the crankshaft snout. The same reason a machine taper works. The same reason you tap the end of the puller with a hammer to shock the flywheel. You think a lathe can machine a chunk of steel with no keyway, but a 2 cycle crankshaft needs one? Think of the amount of surface area under friction. A clean lapped taper fit, is not going to budge. If it does, the bolt came loose. If it spins while it's clamped, it's going to gall itself right together and never come apart.

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Fwiw I'm not telling people to run their engines without a keyway. But if you degree your engines. You might, and probably will, have to. It's fairly common in the performance world. And if you bust a keyway and don't have one. It's fairly easy to deuce a way to get your engine to tdc and align the flywheel. And your back to riding until thag keyway shows up.

I'm not running a keyway because the previous owner had sheared 2 and damaged the flywheel snout. So I chose to degree the engine myself and opt out of a keyway to alleviate any future issues. Haven't had any for 25 gallons so far

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