Hawk Rear Sprocket Failures - reason why.

[NickThrash]

So these would be the right ones for the stock sprocket?

http://www.2wheelpros.com/oem-parts/...-940-part.html

And do i need to replace my hub? the bushings in mine have been pretty roughed up after the bolts broke. and part of the bolt is stuck in some of them.

[Megadan]

Originally Posted by NickThrash

So these would be the right ones for the stock sprocket?

http://www.2wheelpros.com/oem-parts/...-940-part.html

And do i need to replace my hub? the bushings in mine have been pretty roughed up after the bolts broke. and part of the bolt is stuck in some of them.

Yes, those are correct. Literally the same reply to the same link 3 posts ago

As far as the hub, you shouldnt have to replace the whole hub. You can rellace the bushings in the hub. I will have to dig for the part number when I get home.

[NickThrash]

Originally Posted by Megadan

Yes, those are correct. Literally the same reply to the same link 3 posts ago

As far as the hub, you shouldnt have to replace the whole hub. You can rellace the bushings in the hub. I will have to dig for the part number when I get home.

Thanks id appreciate that. Do you just rip the bushings out and jam the new ones in? or is there a special process for getting those in and out?

[Megadan]

Originally Posted by NickThrash

Thanks id appreciate that. Do you just rip the bushings out and jam the new ones in? or is there a special process for getting those in and out?

There are a few ways to get them out. I haven't yet had the pleasure of replacing my bushings yet, although I do want to in the near future. You have to kind of treat them like a blind hole bearing. The easiest trick I know of is to use a tap to cut threads into the inner metal sleeve and them a long bolt of that thread type with the end rounded off to be smooth and just using the bolt like a puller to remove the bushings. Here is a demonstration of that process.

Another trick that may work is one I and many others have used to remove pilot bearings from crankshafts. It involves filling the hole with grease and then using a rod or dowel that just barely fits into the hole and striking it with a hammer to drive the grease down to try and hydralic the bearing out. This will only work if there is a little bit of open space behind the bearing though.

Another option is to carefully cut them out using a dremel tool and/or a chisel, but this runs a risk of damaging the aluminum of the hub. This would be more of a last resort IMHO

The Hawk wheel hubs are somewhat based on the CG125 hubs, so likely those bushings will work. That part number is 41241-222-000.

However, before you go off and order those I would suggest trying to pull at least one bushing out to measure the outer diameter and height of said bushings so I can make sure I give you the right part number. There are a few variations on this style of bushing with the 9.2mm inner diameter, ranging in height from 19mm to over 40. And some are 24mm diameter while others are 25mm.

If you can manage to get one bushing free and measure it, that would guarantee the fitment.

Otherwise you can get a new hub, which basically means ordering a whole wheel assembly to the tune of $135, with up to a 2 month wait (I just went through this with a front wheel)

The other option with this would be to order a TT250 rear wheel hub and lace it to your rim. It's $75 for the hub, or you get get the whole rear wheel assembly with bearings and all for $134. The TT250 differs from the Hawk in one area, and that is how the sprocket mounts. The TT250 sprocket actually bolts to the hub instead of using the Snap ring and studs like our bikes and the old CG125's. You also likely wont have to wait upwards of 2 months to get it, and never have to worry about this again.

The rear wheel will work btw. The TT250 uses the same axle, bearings, axle adjusters and swing arm as the Hawk(first hand experience). Worst case scenario i that you may need the left side axle spacer... which is $6 lol. Likely the spacer is the same, but just something to keep in mind if you go that route.

Hub: http://www.cscmotorcycles.com/TT250-...p/zt26-115.htm

Entire wheel assembly: http://www.cscmotorcycles.com/TT250-...p/zt26-100.htm

The bushings would be the cheapest route obviously,

[NickThrash]

Originally Posted by Megadan

There are a few ways to get them out. I haven't yet had the pleasure of replacing my bushings yet, although I do want to in the near future. You have to kind of treat them like a blind hole bearing. The easiest trick I know of is to use a tap to cut threads into the inner metal sleeve and them a long bolt of that thread type with the end rounded off to be smooth and just using the bolt like a puller to remove the bushings. Here is a demonstration of that process.

Another trick that may work is one I and many others have used to remove pilot bearings from crankshafts. It involves filling the hole with grease and then using a rod or dowel that just barely fits into the hole and striking it with a hammer to drive the grease down to try and hydralic the bearing out. This will only work if there is a little bit of open space behind the bearing though.

Another option is to carefully cut them out using a dremel tool and/or a chisel, but this runs a risk of damaging the aluminum of the hub. This would be more of a last resort IMHO

The Hawk wheel hubs are somewhat based on the CG125 hubs, so likely those bushings will work. That part number is 41241-222-000.

However, before you go off and order those I would suggest trying to pull at least one bushing out to measure the outer diameter and height of said bushings so I can make sure I give you the right part number. There are a few variations on this style of bushing with the 9.2mm inner diameter, ranging in height from 19mm to over 40. And some are 24mm diameter while others are 25mm.

If you can manage to get one bushing free and measure it, that would guarantee the fitment.

Otherwise you can get a new hub, which basically means ordering a whole wheel assembly to the tune of $135, with up to a 2 month wait (I just went through this with a front wheel)

The other option with this would be to order a TT250 rear wheel hub and lace it to your rim. It's $75 for the hub, or you get get the whole rear wheel assembly with bearings and all for $134. The TT250 differs from the Hawk in one area, and that is how the sprocket mounts. The TT250 sprocket actually bolts to the hub instead of using the Snap ring and studs like our bikes and the old CG125's. You also likely wont have to wait upwards of 2 months to get it, and never have to worry about this again.

The rear wheel will work btw. The TT250 uses the same axle, bearings, axle adjusters and swing arm as the Hawk(first hand experience). Worst case scenario i that you may need the left side axle spacer... which is $6 lol. Likely the spacer is the same, but just something to keep in mind if you go that route.

Hub: http://www.cscmotorcycles.com/TT250-...p/zt26-115.htm

Entire wheel assembly: http://www.cscmotorcycles.com/TT250-...p/zt26-100.htm

The bushings would be the cheapest route obviously,

hmm.. looks like i am going to have to go the route of getting a whole new assembly... I also had to get the front rim assembly a while ago and i dont recall it taking that long. i think it was about 2 weeks. I ordered from txpowersports and this is the rear wheel i'll probably order...

https://www.txpowersports.com/ricky_....100030.02.htm

but ill also have to wait on the sprocket retainers.... THAT damn HAWK!

[NickThrash]

BTW did anyone have a link to a replacement c-clip that would fit and work? i browsed through this thread and didnt notice if one was posted.

I think mine is fine but i would like to have a list of new parts just in case or if I decide to just replace everything with brand new hardware

Thanks

[Megadan]

Originally Posted by NickThrash

BTW did anyone have a link to a replacement c-clip that would fit and work? i browsed through this thread and didnt notice if one was posted.

I think mine is fine but i would like to have a list of new parts just in case or if I decide to just replace everything with brand new hardware

Thanks

I ordered my front wheel through Txpowerport as well back in October, and got it in December. I honestly think they forgot to ship it to me until I contacted them going "Um, where is my wheel?"


As far as the snap ring goes, the dimensions are 2-1/4" Shaft Diameter, 0.078" Thick. Finding them individually seems to be more of a challenge lol. https://www.grainger.com/product/ROT...ain-Ring-5CA81


With a bit more searching, digging, or even contact suppliers with your specifications, it will likely help locate one. I do know at one point there was somebody selling them on this site, but I do not remember whom.

[Thumper]

I am going to upgrade to a 520 o-ring chain soon. I got lots of mud on my OEM 428 and it caked up in the front sprocket housing bad! I think it got into the links while I was cleaning it too, and it is making some thunks periodical while I am riding, even though I thoroughly cleaned and lubed it. Maybe I damaged the front sprocket too.

I also want to drop the gearing for a slightly lower 1st ratio. I don't mind losing some speed on the road since I usually just use residential streets for the most part.

So I need to choose sprockets. I made a chart with some commonly available sizes (JT, at least). I made this for my Storm (428H 17/46 OEM) and included the sizes for 520 that I might move to. Then I realized that Hawks are much more ubiquitous so I made one for the Hawk. I hope this is useful for you.
the top line in each chart is presumably your stock sprockets. The additional lines compare the OEM ratio to the chosen front/rear replacements so you can see the raw difference and % change compared to stock.





I sorted these two charts ascending based on ratio, so 428 or 520 ratios go up as you go down the rows.

I haven't looked at the individual gear ratios for 1st -5th inside the engine, but this is just comparing final drive to new choices which works since you already know what you get while riding it. And no one is going to change those internal gears!

Hawk OEM ratio is quite low (0.300), so it isn't surprising that most people want to go higher.

Storm comes with a taller ratio for final drive (0.3696). I will go 12/35 or 12/33, which will drop my final drive ratio by 1.6 or 7.2, respectively. Less than a 2% change is really negligible for off road purposes (or on road, for that matter!), Next time I go riding, I need to really decide if I want to drop 7% before I take the plunge

[Thumper]

I used a similar method (megadan's grease hydraulic method) to remove the pilot bearing in my 1st Gen Toyota years ago. I used a 19mm bolt in this case...

Get a newspaper and shred it into 2 inch wide strips. Get a bowl of water. Wet the strips and stuff them into the recess through the center hole of the bushing. Keep doing it until it is full, and then use a snug fitting bolt, and hammer, to compress the wet newspaper. Add more wet newspaper as it comes out. Just like the grease, it pushes the thing out from the inside in a snap. Amazingly simple.

The newspaper is what makes this work. Yes, it is a hydraulic "press" that you are building, but the newspaper holds the water nicely. Thick cooked oatmeal may also work. In fact, if the recess behind the bushing is small, it may still work if the newspaper can get pushed into the recess, however small.

Oh... photobucket is ransoming my images, and I haven't subscribe yet to recover them. But the picture still shows up at Yotatech forums for some reason with the photobucket watermark since I haven't subscribed!

[csavvy]

Originally Posted by Megadan

Ok, so I am finishing up with my bike, going over the rear end right now and I do believe I have discovered why a few folks have had the kush drive bolts shear or the C-clip come out. I did not find this until I had the rear wheel off. With the chain putting tension on the sprocket, it did not move.



After installing my JT Sprocket....



For your own safety please check your bike, please please please!

After working with the stock Snap Ring, I do not believe these to be a weak point. Snap Rings are NOT intended to take lateral thrust loads, and if the sprocket has play like mine did, under power, it could be enough to eventually cause a failure.

Also, something I wish I would have noted in the video, make sure those kush drive stud flats - the ovalish shaped part that sits on the back side of the sprocket - are seated inside the channel on the back of the sprocket. If those are aligned wrong, one side will actually ride up on the outside of the channel and put a lateral load on the stud and it will not seat right to the hub.

I just got a new Hawk X. The videos have been deleted on youtube and I checked a few other sites but not there. Could you repost them or tell me where to find them? Thanks.