RMZ Sprocket bolts

You could be overtightening them causing the threads to stretch and not hold them tight. I would only think get a good well known sproket not sure what your running. Ex: rental or pro taper. Get the stock bolts and nuts and apply red loctite then torque the nuts not the Allen head. Sorry if you tried this. But sounds like your stretching the threads causing them to loosen up.

I have always used the stock bolts with blue loctite and never had a problem. I would try what mxryder231 suggests.

On older RM's I have used a little tapping compound in the counter sink part of the bolt and sprocket then with a power drive spin the bolt with out the nut to seat the bolt into the sprocket then use loctite and torque the bolts to 16/18 foot pounds.

Ive got an 06 RMZ450 that the sprocket bolts like to come loose. I just check them after every ride along with my spokes. Sometimes they are a little loose, most of the time they arent. This was with stock and aftermarket sprockets, its just always been that way! (for me anyhow) But its also not the only bike i have ever had do it either.

Holmes, I said I always used the stock bolts with no problem.

Yeah I would try the blue loctite thats what I use and never had any problems and the red loctite is a pain bought a bike and they put red loctite and the sprocket/rotor oh yeah good luck getting that out ended up having to use a torch to heat the bolts out so we could get em out

I have a CRF250 that I am replacing a hub on right now for a friend. It happens on other bikes.

If the sprocket gets loose one time it is about done. When the bolts hammer inside the hub they egg shape the holes and the sprocket will not stay tight after that.

I have a 2011 KTM 65 and my kid went riding with some friends for a couple of days and the bike didn't get checked. Bolts got loose, egg shaped the holes in the hub and they wouldn't stay tight. Four rides on a new bike and I bought a new hub.

Oh, my nephew races the A class on a RM-Z250 and 450, never have replaced a hub.

One thing you might want to do is pull your wheel and tire off and check for the trueness of the wheel. I most usually see this problem when a wheel has loose spokes and has become untrue. When this happens the force from the chain pull will not be distrubuted equally around the hub/sprocket causing different amounts of force on the bolts. This will cause them to loosen. Pull your wheel seals out and measure the depth of the bearings (from the top of the hub down to the surface of the bearing) in several spots around the circumference of the bearing to make sure they haven't cocked and are allowing the axle to run true through the wheel.

Also check with a steel rule that youre axle is even in the swingarm. Don't use the tick marks in the swingarm because they aren't that acurate - I have seen cases where the axle is supposedly aligned perfectly with the tick marks, but when measured with a steel rule it was off by 1/16." Doesn't seem like much, but when you figure in the distance the chain travels from sprocket center to center, it can amplify the geomtery to be off by 1/8 to 1/4"

Make sure you're using grade 8 hardware. Blue locktite is all that's needed. Make sure the bolt head is bottomed out in the countersink before your cinch the nut down. Torque to spec while making sure you are applying lots of inward pressure to ensure the bolt head isn't backing out of the countersink. If the bolt head is backing outing, you aren't getting a true torque pressure on both sides. The locknut will be the only part torqued right, but in that scenario it can already move around by the amount the bolt head has backed off. This is the start of how they become loose.

The last thing i usually do is safety wire the locknut on. Use 1 strand of wire after you've properly torqued the nuts down. Place the safety wire on the first visible thread after the locknut. Twist it down tight, cut the twist down to 1/4"" and then bend it over the thread. This can be a lifesaver because even if you still have a locknut loosen, it can only back off up to the safety wire which will prevent you from shearing bolts, sprockets, and hubs. You still need to check them freqeuntly though. I check mine every time I change the oil, which is a pretty good basis.

If you do all the above, you won't have this problem anymore.