CB250 Two Fifty (and probably Nighthawk, and others) cush rubber replacement

For the past.. Uhh.. 20,000 miles or so, the rear sprocket on the CB250 has been flapping about, side to side, at one point so badly that the ends of the studs were once very nearly grazing the inside of the swingarm. This didn't stop it from passing MOTs of course, a locked solid rear wheel not being anywhere near as serious as a left handlebar grip that can eventually be worked off, but I knew in my heart of hearts that it was really bleedin' unsafe. I took a lot of play out by replacing the washer and circlip that hold the sprocket in place but this wasn't fixing the root cause of the issue - the root cause was that the pegs that the sprocket bolts to were being able to slap around inside the (poorly designed, very difficult to replace) cush rubbers. A quick search of the Internet shows there are quite a few CG125 owners facing a similar problem, but if other people can do it why can't I? So it begins..

Firstly, get the wheel out.

So far, so familiar. With the sprocket still held in place by the circlip, undo the nuts. Then "simply" remove the circlip (you have some circlip pliars to hand, right? And some flathead screwdrivers?), the washer, and pull the whole lot off. Say hello to the little things that are about to cause you a whole heap of trouble..

Those things there are what Honda laughably consider to be cush rubbers. In a time long past these were big wedge things that were really easy to replace.. But not now. Not at this moment. Right now we have to deal with a cost cutting exercise of easily pressed in cylinders of broken rubber and misery. You may not be able to tell from the image but the inside sleeve of all these are slightly oval, this is enough to allow the sprocket to float around. The pegs in the sprocket are also worn, allowing yet more slop.

Marvellous design. Couldn't be better. Glad it's not a bunch of wedges I could replace in 2 minutes.

At this point I was a bit stumped. I tried hammering the inner sleeve but this achieved nothing, the rubber simply absorbing the shock. A quick search of ebay showed a replacement wheel could be procured for £75, a quick search of Wemoto showed a set of replacement cush rubbers was £15 so I can spend money on a special tool and still come out ahead. But what could that tool be? Ooooohhh!! £33.50 was all it took to have a blind bearing puller set in my grubby mitts. As Delia Smith would say, LE'S BE 'AVIN' YOU.

I went straight for the rubber which I'd had the most success with, having managed to break the inner sleeve away from it's snug rubber home. Hnnnggg..

YESSSSS! Sadly the other three rubbers laughed off my attempts at freeing them from their confines, just giving me a lot of this:

And this..

This was quite annoying, so I moved on to my go-to weapon of destruction - the cheap Dremel knock off. It's a shame it came to this, but desperation had long since set in. With a little router type tool in the end I set about attacking the rubber.

Success came at a price, not only is that router bit covered in rubber but there is now rubber all over the drive, all over one of my work t shirts, it was all over my fingers and it's all over several tools. The rubber doesn't go back to how it was, it stays tacky and sticky, and smears all over everything. If you do this then lay a cloth down on the floor and wear overalls or something. Also make sure you're wearing long sleeves, the rubber splattered up my arm and I ended up with quite a few blisters from burn marks on the underside of my left arm. What a job!

A couple of days later I set to it again, cleaning the remnants of rubber from the inside of the outer sleeves.

Getting there! They have to be scrupulously clean though for the puller things to slide in. Grind grind grind with the Dremel.. Eventually this can happen:

The lip on the very bottom of the puller insert can get underneath the sleeve, and then you can use the slide hammer to knock/pull it straight out. This was pleasingly easy. The aftermath..

That's the hard bit out of the way!

Once your package has finally arrived from Wemoto you can get back to work. This bit is quite simple, just knock them in.

I initially tried using an old front sprocket to make sure they new rubbers were going in straight and I wasn't mashing an old outer too much..

But this was silly. I soon changed to just mashing the outer with the hammer, this was much easier. Soon enough, this happened!

Weyhey! If anyone cares (or if it makes finding these cush rubbers any easier) they are made by a company called Washi and the part number on the bag is W41241-KB4-003. I'm not quite convinced that these are exactly the same as the originals as the steel inner sleeve seems a little thinner, but they'll do - they're certainly better than what I've pulled out!

With the cush rubbers in place I decided to also replace the wheel bearings. I quite like that the wheel has a couple of faces in the hub to knock the bearings down on to, this saves knocking them on to the spacer tube too tight and you also know right when they are properly seated.

I ground down the outside of one of the old bearings until it was a loose fit in the wheel, and then hammered on that to drive the new bearings (6302RS SKF Explorers of course) and the seal (91257-230-003) in to place. Dead easy. Soon enough, with replacement sprocket stud peg things because the old ones have worn oval (4 x 90128-KK4-000), and a new circlip and washer because the old ones have worn thin due to everything flapping about (90664-216-000 and 41202-KB4-000) it was all done.

Easy as that.

**UPDATE**

I was about to go on a sizeable Euro-jolly so had the rear tyre replaced, at this point the new cush rubbers had been in for 1931 miles. While carrying the wheel and new tyre to the tyre man, I could hear the sprocket rattling away. I thought nothing of it until I got back home and went to put the wheel in, only then did I notice the new Washi cush rubbers were in a very poor state, rubber visibly being pushed out of the holes! I had no time to change which bike I was taking, so had to ignore it and set off anyway.

At Limoges in France, with something like 2400 miles on the rubbers, I had to use an angle grinder to remove the excess length of the new sprocket studs as the whole lot was wobbling around so much that the studs were starting to rub on the inside of the swinging arm!

At 5815 miles I arrived home, having been through Spain and France, and found this horror:

There was so little metal left on the lip of the wheel that the sprocket could have broken free at any time. And to show how little rubber was left..

Time to remove the sprocket.. In doing so the last slivers of metal broke off, the wheel now totally scrap. Thanks Washi!

The metal inners were no longer stuck to the rubber at all in most cases. Also the rubber had been squashed out of the way as if it were liquorice.

At this point I wholeheartedly recommend NOT fitting Washi cush rubbers to your CB250. I sent an email to Wemoto to point out that these are not fit for purpose and I was assured that they have notified Washi of my experience and that further testing would be carried out. I have no update on whether anything has been changed 5 months later.

Thankfully, there is hope -helpful commenter ThePerkinsFocus has pointed out that replacement rubbers can be purchased from Honda under the part number 41241-KB4-003. I absolutely recommend you buy these instead, I wish I'd known about them before buying a highly inferior aftermarket version. They're not even any more expensive! Lesson learned.