Leaking g/box

[johnbirchjar]

Hi guys,I'm safely back from the NOC rally in France,(The hot running engine on the Classic got no worse ,but the oil leak from the g/box definitely has .)Looking at the "exploded view" in the w/shop manual,it appears that the seal can be replaced "in-situe",is this the case?rgds,J.B.

[Richard Negus]

Hi John,Which seal? Where's the oil leaking from?R.

[johnbirchjar]

Hi Richard,I think it's the one behind the sprocket,what other ones can it be?The symptoms are,lots of extra oil in the rear chain gaiters,lots of oil blown on the R/H,side of the bike,but no extra oil in the primary chain case. The bike has had a bit of a leak for the last umpteen thousand miles,but has realy got bad over the last thousand or so,any ideas?J.B.(Tim Harrison has the same problem with his Commander)

[gripper]

Hi John, didn't see you down in France, you must have been keeping a low profile. You can replace the seal, it's a bit of a struggle fighting with the chain gaiters to get the chain out of the way to allow the sprocket to be removed. Once it's off you can carefully punch through the seal and prise it out. Get a new seal from a bearing stockist that has a good turnover in stock. I put one in from Norton Motors and it was hard. Had to do the job again five minuted later. "Oh dear me" I said.

[Richard Negus]

John,Wot 'e said, and please rivet the chain for your own safety.R.

[johnbirchjar]

Thanks guys,thinking more on the subject,is there anywhere else the oil can be comming from?It seems a bit odd that 95% of the bike is getting oil on the r/hand side, when (Iv'e been told)the oil from the box go's into the chain gaiter and leaks from there,Iv'e had a good look at the gaiter and I can't see where masses of oil is comming from .Is there another seal at the primary chain case end of the G/box?When I drained the oil from the rear chain when in France I got about 3/4 of a plastic cup(one of those awful things that caterers use )put a bit of fresh oil back in,then topped up the G/box.Returning to the UK(440miles) I drained of the rear chain,and not much,if any,more than I put in ,but still lots of oil on the R/hand side of the bike,I also had to top up the G/box again,any ideas?J.B.

[Richard Negus]

John,If there's no extra oil in the rear drive, and no extra oil in the primary, is there the correct amount of oil in the gearbox?If the answer to that is 'Yes', there it sounds very much like oil tank section of the frame is leaking. This happens occasionally when the paint is damaged and rest gets underneath and rots the steel.Have a look in the area of the rubber mud flap.Primary oil could be leaking through the starter motor, I suppose, but that usually results in the motor not performing properly.R.

[johnbirchjar]

Hi Richard,I toped up the G/box in France,it needed very little,egg cup full?if that, (the oil was just over the first "flange" as you look into the box) I put in no where near as much as I removed from the rear gaiter,so where did that oil come from? . After the run back to the UK,I checked the G/box,it needed a little,hardly worth bothering realy. That sugestion of yours about the leaking oil tank?,I'll have a look and report back,rgds,J.B.

[gripper]

The rubber mudflap that Richard is talking about forms a lip that fills with road dirt and then stays damp. It is possible to fit the flap on the front side of the mudguard edge and then the road dirt can get away. All IP2 Commander and Classic machines are affected. The other rot area is the top damper mounts. Pressure wash all the dirt out and spray with waxoil.

[Richard Negus]

I've seen several bikes with this fault, but only two rusted through and leaking oil (both Commanders). It's possible it started with mis-handling during original assembly when the part-built bike, without its suspension units, was lifted by the rear fork. The cross-tube of the fork contacts the sharp edge at the bottom of the oil tank section and punctures the paint, eventually allowing corrosion to creep under the coating and fester away unseen. It always seems to happen on the offside, opposite to the chain gaiters.Have a look at your cross-tube; if the paint on the back edge top surface is damaged (from just creased to badly rusted) have a close look at the frame. Here's a recent example where, fortunately, the frame paint was undamaged.

Fork damage.jpg

This one had a large area of rust on the top face but, again, nothing significant on the frame.

3184-31.jpg

It may be that rusting like this is limited to those frames that were nylon-coated; polyester powder coated ones may have a better bond coat to the steel.

[Interpol2471]

Hi Richard was this coating process random or did certain bikes get different coverings?I have checked my IP2 and Classic and both look fine and have good thick coverage just dirty but no rust.Thanks

[Richard Negus]

Hi Paul,I have no records to confirm when the changes occurred, but frames and rear forks would have been done batch by batch rather than by model.I've had IP2 and early Commander frames that couldn't be stripped by shot blasting yet the coating could be peeled off in large pieces. It seemed as though the metal had acquired a layer of surface rust prior to being coated.My current supplier does his treatment as a continuous process, shot blast, degrease, bond coat, powder coat, so there is no chance for rust to start.R.

[johnbirchjar]

Hi guys,I had a good old wipe round the underneath of the bike with rag (where I could reach) and have let it stand for the last 6 days to see if a drip developed(assuming that if the frame was leaking it would show,)Nothing. Then had a good look around the rear mudflap and the rear frame cross/section.No lifting paint or damaged/scratched paintwork that I could see in that area,in fact, that section of the frame is virtualy oil free ,what I did notice, while crawling about under there, was the r/hand side of the bike was much oilier than the left,I assume that there is an oil seal on the primary side of the g/box,could this be the culprite?J.B.

[Richard Negus]

Hi John,A mystery! But at least the frame is ok.There is an oil seal on the right side of the gearbox, but any leak from there goes into the primary drive compartment.If the bushes on the throttle spindles are worn, that allows small amounts of oil to leak onto the back of the engine, around the throttle levers, and could possibly be blown back onto the gearbox.How about photos of each side to show us where and how much oil?R.

[Interpol2471]

Thats got me interested now as I have had a very very slight leak from the right hand side I get a drip onto the rear right exhaust sometimes but too have never found the source but it is very minor so never really worried me!!!I thought it was from the join / seal between the gearbox and the primary as that can appear wet after long runs but after a wipe it never really shows up so this may be similar??

[Richard Negus]

The throttle spindle bushes have a ptfe-type of lining (actually Glacier DU bushes) and do wear after time and, as there aren't any seals, oil going in the fuel/air tends to weep out, covering the back of the engine and attracting road dust.Due to a cunning piece of design, fixing the leak requires the engine to be stripped, revealing other things that ought to be fixed.John; I assume it's not something simple like the primary drain screw leaking??

[johnbirchjar]

Take photgraphs ,me?(A) I havn't got a camara,and(B)I would have no idea how to post said photo's on the web-site anyway One of the first things I checked was all the allan key bolts for tightness,all were tight. I think that there is to much oil being blown about for it to be just "a weep",I will keep on looking,thanks for your ideas guys,ride safe,J.B.

[gripper]

You might check that the dashpot on the top of your carb is tight.

[Richard Negus]

John,Just a thought.Take off the r/h side panel and, with a torch, look underneath the casting that mounts the carburettor to the frame. Oil running down the frame there, onto the top of the gearbox, round and down the casting to drip off the bottom by the centre stand pivot? And the two screws that hold the casting on are very tight?Don't ask me how I just found that one. It'll be a new O-ring and extremely generous with the RTV this time.R.

[Interpol2471]

Well done Richard thats my leak BUT I have never used silicon on these rear castings and the bike has never appeared to have this also from new?I have fitted new 'o' rings to the Classic and they appear fine just the IP2 leaking.

[johnbirchjar]

Hi Richard,if the mounting bolts for the carbs were loose would that not make the running of the bike a bit off? And Gripper,I don't see how oil from the dash pots can dribble all the way down to the underneath of the bike without being blown away well beforehand,but thanks for the sugestion guys. I'll be out on the bike over the weekend and perhaps something will come to light . On a differant note,anbody else going to the gathering at Oxford on Monday?ride safe anyway,J.B.

[Richard Negus]

Hi Richard,if the mounting bolts for the carbs were loose would that not make the running of the bike a bit off?.

John, the point is that the bolts on mine were very tight, and still it leaked. I'll take that carb off tomorrow and find out why it was leaking. R.

[Richard Negus]

3120-17.jpg

Sure enough, my fault. When I put a bead of silicone over the O-ring, I left a small gap at the front lower corner allowing a very small dribble of oil to escape.

3120-18.jpg

No need to remove the carburettor, new O-ring + silicone and a new carb inlet gasket, 45 minutes work including coffee and cake, and the job's done.

[johnbirchjar]

Hi guys,Iv'e found,(and fixed) the leak,(this is most embarrassing )the problem was a knackered "0"ring on the clutch lift mechanism cover ,(silly me thinking that oil was being blown from UNDER the bike and back up and over the lower half of the p/chain case & r/hand exhaust silencer,when all the time it was dribbling down THEN being blownback up again and everywichway(is there such a word?) anyway,I put the new 'O' ring in last night,went for a bit of a spin,(about 20 miles)and yipee!! no sign of an oil leak ,so thats another one for the archives,ride safe,J.B.