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Xr400 sprocket teeth breaking off

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So I put a nail through my rear tire and while taking it off to repair the tube I noticed 6 teeth are missing off my stock 45T sprocket in randam spots. I mean I know the 400 makes monster torque but come on! Is this common? I don't think that the allignment is off? Should I just buy a used rear sprocket to go with the used chain and counter sprocket or should I buy a whole new set? This is just really weird. Is their a way to test for alignment?

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My 600 ripped about 6 of them off one time, and it was every other one. But i def. needed a new sprocket anyway. So i switched to steel. I just think the torque is too much for those whimpy alum. sprokets.

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Steel rear sprocket ,and you wont have any more problems.In baja the stock rear sprocket, goes bad in less than 300 miles.

I'm confused (well not really), both of my XR400's came with steel sprockets. :smashpc: My Renthal aluminum sprockets have held up as good as the steel ones. 👍

Cheers

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Aluminum rears wear much faster than steel and accelerate chain and front sprocket wear as well....steel is the only way to go. Don't even talk about weight difference, it is inconsequential.

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All you guys with these SUPER TORQUE Honda XR bikes!!! HA!HA! Funny! Buy some quality aluminum sprockets or run steel! Weight always matters!!

Swiss

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All you guys with these SUPER TORQUE Honda XR bikes!!! HA!HA! Funny! Buy some quality aluminum sprockets or run steel! Weight always matters!!

Swiss

Dude, you got a 74 XL listed in your garage. Not sure why your taking jabs at everyone in here.

Anyway,,, yeah if it was an aluminum unit that was breaking teeth try a steel one. Make sure your not running the chain too tight also.

You can check alignment by measuring from the swing arm pivot to the center of the axle on both sides. Sometimes the snail adjusters can be a little off.

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Aluminum rears wear much faster than steel and accelerate chain and front sprocket wear as well....steel is the only way to go. Don't even talk about weight difference, it is inconsequential.

My 2 XR4's say different. My proof in is my shed! :smashpc:

Your milage will vary.

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All you guys with these SUPER TORQUE Honda XR bikes!!! HA!HA! Funny! Buy some quality aluminum sprockets or run steel! Weight always matters!!

Swiss

+1

I think "quality aluminum sprockets" is the key :smashpc:, not the cheapest one (dollar wise) you can find. 👍

cheers,

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Should I just buy a used rear sprocket

A new rear sprocket only costs $30. Just buy new.

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New chain and 2 new sprockets is the proper way. They do wear out. Once you get your new sprocket compare it to the old one and you'll see the wear (it's hard to notice because it wears slowly, I fell into this trap). I lost 9 teeth on my rear sprocket and then I realized how bad the sprocket was worn. As far as adjusting the chain, I used to put the bike on a stand and spin the rear wheel by hand while watching the chain track over the rear sprocket (you can see when it's off). Now, I measure both sides from the axle to the back of the swing arm. Both ways seem to work well, although the second way is probably more accurate.

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I've been riding XRs from 200s to 650s for 28 years.....the combo of steel front & steel rear makes the whole driveline last longer....trust me.

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:smashpc:🙂

Dude, you got a 74 XL listed in your garage. Not sure why your taking jabs at everyone in here.

Anyway,,, yeah if it was an aluminum unit that was breaking teeth try a steel one. Make sure your not running the chain too tight also.

.

Michigan400, this is essentially a "Tech" problem and not limited to the XR Honda or the OP... However his post stating, "I mean I know the 400 makes monster torque but come on! Is this common?" made me laugh. I read the XR400 posts because I am following the 40/42mm CV carb thread. Figured I would see what was being posted on the sprocket issue. If there are teeth breaking off then it is a "Tech" problem. Worn sprocket, worn chain, bad alignment or bad sprocket, as in low quality or poor heat treat etc...

Yes I have a '74 XL350 in the garage and it puts out way more Torque than the OP's XR400 does. I have also been running aluminum sprockets since '75 when I finished building the bike. If you want to run steel try one of the newer expensive Supersprox or the even newer Cush sprockets. Combination aluminum and steel, lighter weight than all steel but with the wearing qualities of steel teeth. Going to be DOUBLE+ the cost of the suggested $30 replacement sprocket!

There IS a difference in wearing qualities of cheaper aluminum sprockets and high quality 7075 T-6 sprockets. Supposed to be some newer alloys out there that are even better. Actually the same goes for steel sprockets. There are good steel sprockets and there are high quality steel sprockets. The steel alloy and the proper heat treat make the difference. Don't cheap out with something that takes as much abuse as the sprockets do!

For Barnacle, yes a quality steel will last longer than a quality aluminum. But a cheap steel will probably wear about as fast as a quality aluminum... that is with alignment/lube etc. being equal.

For creeky, weight difference is never inconsequential! It all adds up in the end. Don't quote that mud adds 10lbs. to the bike, it will be the same 10lbs on a light bike or a heavy one and the lighter bike will STILL be lighter when both bikes have that extra 10lbs. added on.. I will take the light bike thank you.

Swiss:ride:

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👍🙂

Michigan400, this is essentially a "Tech" problem and not limited to the XR Honda or the OP... However his post stating, "I mean I know the 400 makes monster torque but come on! Is this common?" made me laugh. I read the XR400 posts because I am following the 40/42mm CV carb thread. Figured I would see what was being posted on the sprocket issue. If there are teeth breaking off then it is a "Tech" problem. Worn sprocket, worn chain, bad alignment or bad sprocket, as in low quality or poor heat treat etc...

Yes I have a '74 XL350 in the garage and it puts out way more Torque than the OP's XR400 does. I have also been running aluminum sprockets since '75 when I finished building the bike. If you want to run steel try one of the newer expensive Supersprox or the even newer Cush sprockets. Combination aluminum and steel, lighter weight than all steel but with the wearing qualities of steel teeth. Going to be DOUBLE+ the cost of the suggested $30 replacement sprocket!

There IS a difference in wearing qualities of cheaper aluminum sprockets and high quality 7075 T-6 sprockets. Supposed to be some newer alloys out there that are even better. Actually the same goes for steel sprockets. There are good steel sprockets and there are high quality steel sprockets. The steel alloy and the proper heat treat make the difference. Don't cheap out with something that takes as much abuse as the sprockets do!

For Barnacle, yes a quality steel will last longer than a quality aluminum. But a cheap steel will probably wear about as fast as a quality aluminum... that is with alignment/lube etc. being equal.

For creeky, weight difference is never inconsequential! It all adds up in the end. Don't quote that mud adds 10lbs. to the bike, it will be the same 10lbs on a light bike or a heavy one and the lighter bike will STILL be lighter when both bikes have that extra 10lbs. added on.. I will take the light bike thank you.

Swiss:ride:

This is rather pointless but ........... I'll just repeat my original posting. I've found that my aluminum Renthal sprockets have lasted as long or longer than the OEM steel sprocket. :smashpc:

Cheers,

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Dude, you got a 74 XL listed in your garage. Not sure why your taking jabs at everyone in here.

.

I'd say that gives him the right to point out the silliness of considering any XR/XL to be some kind of "torque monster". :smashpc:

Too tight chain puts a LOT of stress on those teeth.

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:smashpc:🙂

Michigan400, this is essentially a "Tech" problem and not limited to the XR Honda or the OP... However his post stating, "I mean I know the 400 makes monster torque but come on! Is this common?" made me laugh. I read the XR400 posts because I am following the 40/42mm CV carb thread. Figured I would see what was being posted on the sprocket issue. If there are teeth breaking off then it is a "Tech" problem. Worn sprocket, worn chain, bad alignment or bad sprocket, as in low quality or poor heat treat etc...

Yes I have a '74 XL350 in the garage and it puts out way more Torque than the OP's XR400 does. I have also been running aluminum sprockets since '75 when I finished building the bike. If you want to run steel try one of the newer expensive Supersprox or the even newer Cush sprockets. Combination aluminum and steel, lighter weight than all steel but with the wearing qualities of steel teeth. Going to be DOUBLE+ the cost of the suggested $30 replacement sprocket!

There IS a difference in wearing qualities of cheaper aluminum sprockets and high quality 7075 T-6 sprockets. Supposed to be some newer alloys out there that are even better. Actually the same goes for steel sprockets. There are good steel sprockets and there are high quality steel sprockets. The steel alloy and the proper heat treat make the difference. Don't cheap out with something that takes as much abuse as the sprockets do!

For Barnacle, yes a quality steel will last longer than a quality aluminum. But a cheap steel will probably wear about as fast as a quality aluminum... that is with alignment/lube etc. being equal.

For creeky, weight difference is never inconsequential! It all adds up in the end. Don't quote that mud adds 10lbs. to the bike, it will be the same 10lbs on a light bike or a heavy one and the lighter bike will STILL be lighter when both bikes have that extra 10lbs. added on.. I will take the light bike thank you.

Swiss:ride:

Apologies, I was havin a bad hair day and that sounded harsher than it was meant to be when I posted it. It was the " all you guys with these super tourque XR's,,ha ha" comment that struck me as odd coming from someone who also rides a XR/XL line of bike.

Nice lookin bike BTW, Swiss. I wasn't making fun of it just read your post and thought you were taking shots at all XR400 owners and when I looked in your garage saw an XL, I was suprised. I guess I figured I'd see a big bore 600 or 650 or something along those lines.

Edited by michigan400

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Guys, back in the '90s I built some pipes for some XR600/630s that made them close to Torque Monsters. The guys complained that they pealed the knobs off on the long gravel uphill roads in Baja. One of the worn out high mileage Stock XR600s pulled dead even with a fully kitted XR630 to the top speed of the 630 and then walked away from it on the top end by more than 10mph. None of them complained about breaking sprockets.

Barnacle, your first posting was right on. The quality Renthal aluminum sprocket is probably as good as a stock steel sprocket for wear and longevity. It is the better quality that makes it that way.

My Retro XL350/490 is undergoing another rebuild right now. It started out with 6" front and rear travel in '74/'75 and got rebuilt every now and then up to 12.5" of travel with TT600 front end/disk and custom ATK style countershaft rear disk. Weight when first built was 219lbs. w/oil-no gas. Over the years it climbed to as high as 224lbs. with lights and dual mufflers back in the late '80s/early '90s. Now it is time to get rid of a few pounds. It is on a diet and since I am getting older, I will drop the suspension to 11" of travel front and 12" rear to lower the height for easier riding in tight trails (I am only 5'8" with a 32" inseam - lower will be better!). Adapting a 43mm tube KTM 85sx USD front fork, and many other changes! Will stick with an aluminum rear sprocket!

Buy some good quality aluminum sprockets or go with the two combo sprockets that I mentioned and keep riding.

Swiss:ride:

Note: compared with the newer CRF bikes, the XRs could probably be considered "Torque Monsters" In truth if you understand how torque and HP work, the new bikes make more torque, but at higher rpms, that is what generates the much higher HP readings. Sometimes a bike with a really strong HP rating will have good torque down low also but the strength of the power blows right through the bottom end and you find yourself in the strong top end rush to Max Power. The main thing that the newer bikes lack is flywheel weight, so they rev much quicker and feel "soft" in the bottom end.

Edited by Swiss
added text

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Mindblower, I am going to stick with my original opinion that the xr 400/600 are indeed torque monsters. xr's make the best bottom end torque of most any bikes. they put the power where you need it, not at 11000RPM like the newer bikes. not to mention relaibility:busted:

Also my chain wasn't tight, if anything I would say I keep it a tad loose. So I guess I should look for a full kit with the chain, couter sprocket, and rear sprocket. Any suggestions?

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Mindblower, I am going to stick with my original opinion that the xr 400/600 are indeed torque monsters. xr's make the best bottom end torque of most any bikes. they put the power where you need it, not at 11000RPM like the newer bikes. not to mention relaibility:busted:

Also my chain wasn't tight, if anything I would say I keep it a tad loose. So I guess I should look for a full kit with the chain, couter sprocket, and rear sprocket. Any suggestions?

Better loose than too tight. Make sure when you put them on to check wheel alignment also. Measure from swing arm pivot to rear axle on both sides (center to center).

I always get the JT or Primary drive steel sprockets and a decent O ring chain. They last quite a while and are cheap to buy. The packages are usually just offered in stock gearing so I just pick out what I want and buy individually. Check out Rocky Mountain for good selection and prices.

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