Chain Gaiter Seal

[Mick Taylor]

The rear wheel on my Classic seems to get oily / dirty fairly quickly; a couple of days back after a 130 mile round trip (running beautifully thank you Richard) it was obvious that there were flicks of oil on the wheel.After much cleaning I drained the chaincase, slightly less filthy black oil came out than I might have expected if it wasn't leaking.....and.....happy days, it didn't smell of gearbox oil. So far so good.The leak appears to be where the chain gaiter joins the sprocket casing even though the ties are in situ and look fine. Can I peel back the gaiters and having cleaned the area introduce some silicone sealant, or is there more to it than that?If so, any particular type of sealant other than bog standard black silicone guttering seal?While on the subject of the chain, I pondered how to get an accurate chain adjustment with those gaiters in situ..it must be like trying to build an Airfix kit wearing boxing gloves....is there a knack or technique to chain adjustment?Mick................kettle738

[Richard Negus]

'Morning Mick,Hmmm, seems I didn't stitch you for a pair of gaiters. Very remiss of me.If you're sure it's not the sprocket carrier oil seal, which are rarer than hen's teeth, you can snip the tie and peel it back. It helps to remove the l/h silencer and, with a hot air gun, warm the front bellows so you can push the straight bit of the gaiter forward, inverting the bellows and giving you room to work at the back. Put it in gear, push the gaiter forward and insert a small screwdriver through the chain to hold it out of the way while you clean off the old silicone.I use a high temperature silicone, Loctite 5368, but only because I use it in other rotary places. Be generous with it, you can always wipe off the excess.And while you can see the chain, check that it's riveted rather than connected with a detachable link.

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Checking chain tension with a stiff gaiter is difficult, but the principle is to be able to JUST, with thumb pressure alone, to push the top gaiter down to touch the rear fork whilst on the centre stand. The picture in the handbook shows how, but omits how difficult it is to push at that point.Unlike most IP2's, the Classic and Commander have a roller bearing either side of the gearbox sprocket to support the load of a tight chain.

[Mick Taylor]

Hi Richard, .....yes you could have happily stiffed me for a set of nice supple chain gaiters, but hey ho; thank you for the advice about warming the front bellows.......that's the sort of information that will hopefully make the job do-able. (is that a word?) I'm happy the old oil in the chain case was not gearbox oil......which is remarkably stinky stuff (why?) but I refilled it yesterday with 125ml of 20/50......before I read your note suggesting 100ml as sufficient.....which doesn't really matter as it's all coming back out again. I think I understand what you are saying about chain tension, but the pressure required presumably varies according to the age and flexibility of the gaiters.....and who's pushing it so it's almost a form of witchcraft.Best..................Mick.

[johnbirchjar]

Hi Mick,top chain gaiter, 1 and a 1/2" up and ditto down, has allways been my tension test,the "push the gaiter to the frame" as recomended in the manuel seemed to me to make the chain a tad slack,but hey,what do I know ,(and I,ve never been able to cure the "chain snatch" on the over-run )rgds J.B.

[Richard Negus]

I'm happy the old oil in the chain case was not gearbox oil......which is remarkably stinky stuff (why?) but I refilled it yesterday with 125ml of 20/50......before I read your note suggesting 100ml as sufficient.....which doesn't really matter as it's all coming back out again.

Just an after-thought before you get too involved in re-sealing. Are you sure where it's leaking from? Clean the gaiter very well and look closely around the rear bellow convolutions; that's one of the places it cracks with age and leaks, and occasionally it's the top one leaking, but dripping onto the bottom one.Until you can fix it, there's enough oil remaining in there to keep the chain lubricated.

[Mick Taylor]

Hi Richard, yes it could very easily be the top one leaking, I will get it on the bench, give it a forensic clean and see if I can spot it.How much pain is involved in replacing the gaiters?........I realise it's all childs play to you, but to the average plank with a decent toolkit.........can it be done without removing gearbox covers etc?I recall watching you remove the engine from my Classic, the special tools involved, the extreme force that had to be applied to certain fasteners, how weird it all seemed compared to my usual diet of sensible 1970s Jap bikes and how very happy I was that I wasn't attempting it.Can a typical dullwit do this without damaging anything?Mick.

[Richard Negus]

Mick,Not difficult, even riveting the chain can be done without the proper tools.First, let the dog see the rabbit: l/h silencer, l/h footrest plate, and l/h suspension unit off. Cut the gaiters off & clean the old silicone off too.Find the old rivet link (the pin riveting looks different to those that were machine riveted) and remove it (strong chain breaker required). Don't lose either end from the gearbox!Loosen the wheel spindle both sides and move the wheel as far forward as it will go.With the hot air gun, warm the front convolution until it's soft; apply silicone to the inside edge and al round the lower gearbox spout.With a long piece of wire (welding rod?) with a roller-sized hook, pull the gaiter over the lower chain run and lever it onto the spout (look at the rear end to check it's not the wrong way up) and fit the cable tie; put a screwdriver through the last link so you don't lose it up the gaiter.While the gaiter is still warm, invert the front bellows.Now do the same with the upper gaiter.Carefully thread the chain around the top of the rear sprocket and pull it out at the bottom; secure it with another screwdriver.Apply silicone to the upper spout and gaiter and pull the gaiter to the rear, wiggling it over the spout; fit cable tie. Massage the front bellows back into normal shape.Now, do the dance of the screwdrivers and move them along the chain so you've got at least one full link visible at each end to work on; a third screwdriver is invaluable for this.

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Fit NEW rivet link, stand back and admire riveting skill, and then fit gaiter to rear spout as above.Tension chain, fit other bits, add oil, job done.If it wasn't at least five hours each way on a good day, I'd say bring it here and I'll do it while you wait. Got the gaiters, clips, rivet links, oil and the tools

[Mick Taylor]

Thank you for an excellent explanation Richard, very much appreciated, I think even I can follow that.Next step......correctly identify the source of the leak.Best.................Mick.

[gripper]

I substituted carefully bent stainless steel jubilee clips for the front tywraps. if you bend it into a rectangle with some flatish sides it will give better pressure on the rubber than a tywrap. The back end is still tywraps though as they are a bit more accessible.

[gripper]

Going back to your original post, I thought that the chain was just flapping around inside two rubber tubes and wondered how accurate tension could be assessed. Once I had it all apart and realized that the gaiters form guides that closely fit the chain rollers, you can see that the slack in the gaiter is actually the slack in the chain-----ish.

[Mick Taylor]

Thank you for that, chain tension comment noted and appreciated; I'm still trying to accurately locate the leak before I jump into the job and work out if I need to order some new gaiters.As it happens I was looking at some of those stainless zip ties at an autojumble at the weekend....they look like a very good idea but I didn't bother buying any as I thought I didn't have a use for them....oh well, you live and learn.Mick.............kettle738