Discoloured primary chaincase oil

[MrB]

Advice please. Whilst I had the engine out of my Commander engined IP2 (Commanderpol?) I stripped and rebuilt the clutch as the rubbers were shot and the plates were sligtly distorted causing it to slip on full power - it was like this when I bought it some 15K miles ago. It's had new bearings, new rubbers (installed intact with the help of a home made 5 foot 'spanner'), a set of new friction plates from NLM, a genuine set of NOS plain plates and a new sprag clutch. Whilst in bits everything was cleaned meticulously including every little crevice in the casings and the primary chain tensioner. Everything was oiled prior to assembly. The chaincase was filled with 10W30 to the right level. After 500 miles I noticed the gearchange was not as good as when the work was first completed. Having read the forum I thought I'd try changing the oil for SAE20. The oil I've drained is looking pretty dark compared to what went in. It has a lot of very fine metallic particulates in it. A magnet swilled in it comes out clean so it must be bronze off the new plates - was this common at the first service for a new clutch? Is this likely to explain the darkening of the oil or could the rubbers be suffering for some reason? Any advice would be welcome.Johnny.

[Dell Boy]

Hello Johnny, Can`t help with the discolouration. Re: deterioration of gear change. When everything is clean you will get a good change. This then deteriorates quite rapidly back to where you were before you did all that work. My belief is the lack of "lift" due to the diaphragm spring design is the problem. I have played with norton rotary clutches for over 20 years & I despair with them. Richard, could not a Japanese multi spring clutch be adapted to fit the shaft. Also the heat glues the back plates together. I use automatic transmission fluid & always have in commando`s Interpol`s & commanders. Derek.

[MrB]

Hi Derek,I've been messing about with mine for seven years. One of my quests is a perfect clutch (if Graham W reads this he'll laugh his socks off as he told me it wasn't possible at the beginning!)When I first got mine the clutch was diabolical, at least I thought so. A strip and clean up improved things. Problem was it slipped before and it still slipped under load. I noticed the plates had worn unevenly so I stripped again and put them on a surface plate. Most were distorted, some up to 15 thou. The sum of the distortion equalled more than the lift so I rebuilt with some second hand plates taking the best I could get and bending them back into shape. The result was excellent, silent chnages including selecting first, easy neutral but still the occasional slip. It stayed that way for about 3K or so, then as you say it started going downhill again.I managed to source a full set of brand new plates so I thought my troubles were at an end, but it seems not yet. No slip at all now though, so at least that's sorted. I've just refilled with SAE 20 and added some Lucas stabiliser to the EP 80 gear oil (just wondering whether a little more drag in the oil might improve the feel??). 50 miles on things are better. I plan to do a few more miles and change the primary oil again, then let things settle. I'll let you know how it goes.Johnny

[berry_jr]

It may not be the prescribed method, but my Interpol clutch slipped hot and dragged cold when I bought it. A light dressing to the steel plates with an angle griner and 20/50 or Rotella. I've done over 40,000 since and the cluth has never caused me any further worries. No drag, no slip and reliable gear changes.

[Dell Boy]

Hi berry jr. Do you mean you dressed off the high spots or the whole steel plate? Derek. P.S. None of my clutches ever slipped only dragged to different degrees. My current one is diabolical.

[berry_jr]

I just VERY gently roughened the surface which stopped slipping and hydraulic locking of the plates. Great care needs to be taken, I'm sure you could do some serious damage.

[MrB]

The slip was caused by the original distortion in the plates resulting in something less than full surface area contact between the plates (well, that was my conclusion anyway). Bending them straight certainly helped a lot but there was still detectable slip at high speed under full load, I guess again because the uneven wear had to result in what where now hollows and therefore less than full contact area. Replacing the plates has solved that. On the old plates I did notice some burring of the teeth edges. I used a needle file rather than an angle grinder as I had to dress both sides of eighteen odd plates x loads of teeth = erm, absolutely loads of teeth. Did it improve things? I don't know - I did too much in one go to tell! I haven't dressed the surfaces of the plates though, hoped the new ones would be the correct surface finish.There are some just-detectable notches in the drum and hub splines but reallllly slight. Could this make any significant difference?I'm actually more concerned right now about the oil discolouration.Johny

[johnbirchjar]

Hi guys, the clutch on my Classic has never sliped,(coming up to 40,000 miles now)it used to drag something shocking until about 20,000 miles ago when I took a tip from Del Boy and changed the oil to automatic transmision oil,a marked improvment therafter, and seeing as I had developed the knack of selecting nuetral just before the bike came to a stop, its about as good as i'ts likely to get. Just as a matter of interest,do any of you own or know of a genuine Classic that has covered more miles than mine? regards J.B.

[Interpol2471]

I do the same as you JB but I use 10w40 and all has been fine so far. I must admit I change the oil about every 1000 miles and tend to ignore what comes out as all appears fine... so far

[MrB]

Thanks to David for the back issues of The Epitrochoid which included some informative and entertaining reading. It seems oils are possibly the longest running debating point amongst Rotarians. How fortunate Norton owners are in that we have four oils to argue over - er, I mean discuss - compared to only two for the Suzuki chaps!Further back in this chain I mentioned I had oil appearing around the generator cover and blackening of the primary oil chaincase, which I had concluded was engine oil contamination as I changed the clutch rubbers recently. Since changing to Silkolene instead of Rotella both have markedly reduced. Silkolene does look a touch more sticky than Rotella, or is that my imagination? Anyway, I got to thinking a bit - more years ago than I care to remember I messed about with chainsaws and outboard motors. Typical manufacturers recommendations were for 25:1 with standard mineral oil or this could be reduced to 50:1 if Valvoline or a good new fangled synthetic oil was used. Can / should the oil pump setting on Norton engines be reduced if running on Silkolene? (I don't want to be the first to try though!).Second thought. My rear chiancase oil seal weeps resulting in oil on the back wheel and tyre. Not good. I noticed another post recommending using less oil for the rear chain. I tried adding a little Lucas Oil Stabiliser which has the effect of making the oil more sticky, comparable to EP gear oil over straight. No more leaking from the back seal Any reasons why this is not a good idea? Could a light EP gear oil be used instead of SAE30?Thoughts from the panel welcome as ever.Johnny.

[Interpol2471]

I have Interpol and Classic chain case oil seals brand new if you need one.PAul

[Malc]

Johnny, I wouldn't lean off the pump when switching to Comp 2, Silkolene certainly didn't recommend this when I changed all the Derbyshire bikes ocer from rotella. I know what you mean though about reducing the ratio when using synthetic oils. At the dealership where I worked , we were agents for Bel-Ray, remember them? Well the boss was doing very well in the east midlands centre trials championship and he sold a lot to fellow competitors with good results running at much weaker ratios than with mineral oils as you probably found with outboard motors.As for the final drive, if you have found something that works in reducing the oil weep, then great. Compared to what on open chain gets, I dont think it matters what oil the final drive chain runs in.Malc

[Interpol2471]

I am running on Comp 2 without adjusting the oil feed and I have found it works really well, my pump is set to align as per Richard's instructions which is about 1800rpm if I remember correctly.