1985 350 K2 re-commissioning

[penman]

Hi everyone,

I am a newcomer to this forum and also to Morinis. I recently acquired a 350 K2 which has been sitting unused since the 1990s. I have done various bike restorations, but this is very different. There are only 2000 miles on the clock, so pretty well zero wear and tear, but plenty of age-related problems. It took me a couple of weeks to get rid of the varnish in the carbs. I don't have access to an ultrasonic cleaner, so I use thinners which is slow but harmless. I also changed the timing belt which looked brand new, but I didn't trust it. Now I can start the engine and it runs well. I'm pleasantly surprised by the performance and also the slow, even idling. Now to the first question. It took me a little while to realise that the pilot mixture screw controls the fuel, not the air, but for best running, the screw is almost 3 turns out, at a point where the spring is starting lose tension, same on both carbs At this setting though, it does run very well - great idling, snappy off-idle response and very good mid-range. But I suspect the pilot jet is a bit too small. The whole carburetter line-up is:

Float – 74502
Float jet - 200
Throttle needle – E24
Main jet – 108
Pilot jet – 44
Starter jet – 50
Emulsifier tube – 258BD

I contacted a very helpful guy at Dellorto and he gave me a completely different configuration for this bike. Has anyone else been down this path with the K2? I should mention that this bike is a US model and may have different jetting to comply with US emissions rules of the 1980s. Maybe the European jetting would suit me better?

Second question, the clutch. This works smoothly, but tends to drag just enough to make it hard to engage neutral. I think it also makes gear changes a bit clunky at times. I have taken off the clutch side cover and the clutch cover, spring pockets and sleeve nuts are pretty rusty. I'd like to strip it and clean everything, but I can't get any of the sleeve nuts off. I made a tool to undo them, but they seem to want more torque than I'm happy to apply. I'll give them a squirt of WD40, but any other suggestions would be most welcome!

Many thanks!

Joe.

[Samandkimberly]

Speaking to the clutch bolts - WD-40 isn't the best at freeing stuck fasteners. Try Liquid Wrench or, better, make up a mix of 50%acetone and 50%Automatic transmission fluid, or a similar light oil. Works vastly better than anything you can buy.

Sam

[penman]

An update.
After the WD40 did its stuff overnight, 4 of the clutch sleeve nuts came off quite easily. The fifth appeared to be coming out OK but in fact it was the stud unscrewing from the back of the inner drum. I had a moment's panic because these things are often peened at the back, but I couldn't see any damage and it went back OK with a spot of loctite (which the spell checker wants to change to "lactate", not the same thing at all!). There was no wear on anything, however there is plenty of oxidation and on one of the friction discs, corrosion has crept under the friction material which is lifting off. All the other plates look to be OK. I guess I'll be ordering a new set of clutch plates!

By the way, thanks to Sam for the acetone tip - I'll bear that one in mind.

Regards,

Joe.

[EVguru]

Take a look at my clutch rebuild series on YouTube.

https://www.youtube.com/playlist?list=P ... mMpvHxFJ38

[penman]

Paul, many thanks for the link. You have some very interesting and useful stuff on there!

Any comments on my carburetter jetting question?

I received a new set of clutch plates in the post today, I'll reassemble it tomorrow and hope to have a perfect clutch after that. Hopefully I will go for an MOT next week, then it's the tedious business of getting it registered in the UK. On the road 1st of May? We'll see!

Regards,
Joe.

[EVguru]

Idle jet is about right for modern fuel, I usually go with a 43 to cure the stumble coming off idle with the usual 50. It does depend a bit on the slide cut-away. Do you have a 50 or a 40?

There are two styles of mixture screw, one with a short taper, one with a long. Do you have O-rings along with the springs?

Check your ignition timing at full advance.

[penman]

Paul,
Many thanks for your reply. I don't know the cut away number - is it stamped on the slide? I'll have a look. The starting, idle and off-idle response are all really good, my only issue is the idle mixture screw being almost 3 turns out, where is is on the verge of feeling loose. I do have the new O-rings on both screws. Maybe I'm worrying over something I can safely ignore! Thank you for the video on carb rebuild, it's boosted me up the Amal to Dellorto conversion curve!

I do have a more pressing problem though, back to the clutch. I studied your YT videos and this morning I reassembled the clutch with new friction plates and everything clinically clean. It's made no difference at all, I still have pretty bad clutch drag. It makes it impossible to select neutral at rest and makes up-changes stiff and clunky. Both adjustments are correct, and I've tried severely maladjusting the free-play and it still drags. I'll take the cover off again later and I'll see if there is any unbalance in the 5 springs - maybe I've one or more weak springs so the clutch is lifting at an angle? I'm running out of ideas though, so any suggestions....!

By the way, searching through the forum, I have seen one or two posts saying that clutch drag is "normal". I play around with plenty of classic bikes and I would say that drag is a common fault, which is always fixable - do you see it as normal for the Morini? I hope not, but I don't want to waste time chasing my tail! Thanks!

Regards,
Joe

[EVguru]

They're not always the easiest bikes to find neutral on when stationary, even with the clutch set up right, but later bikes tend to be better.

I find drag is best assessed by having the bike on the centre stand and rotating the back wheel in gear. You can get drag if the thrust washer between the hub and basket doesn't have enough clearance. The clutch might have been 'shimmed' in the past to limit the end float to make the action more progressive, but it can be overdone and the nylon thrust bearings changes dimension with temperature and moisture absorption. The helical primary drive gears give the clutch a little self servo action because of the end float, but I find changing the assembly order to the late one is as good or better than shimming.

[penman]

Hi Paul,
Many thanks for that. I did spend some time on it this afternoon and I must say, I'm beginning to wonder if I'm chasing a problem which doesn't exist. With the engine stopped and the clutch cover off, I can spin the clutch inner drum freely by hand with the clutch lever pulled back - if anything there is less resistance than I'd expect. So, certainly no drag with the engine stopped.

The actual problem is first, you can't engage neutral when stationary, though it clicks in easily if you are rolling at walking pace. More of an issue is that the up-change from 1st to 2nd is very stiff and difficult. It's the coming out of 1st which it doesn't want to do. As the bike slows down, you reach a speed where it suddenly clicks over OK, presumably as the pressure comes off the dogs. This is the problem which makes me reluctant to ride it. Up-changes to higher gears are easier, though the same problem exists to some extent. Needless to say, with the engine stopped and the bike on the stand, I can flick through the gears no problem. Down changes are fine, probably because you blip the throttle and that gives the gears a chance to synchronise.

Now there may be a clue in this self-servo action you mention, I can visualise what you mean. Does this tend to push the clutch basket outwards? I couldn't detect any play there at all. There is one thin shim under the hub and the plastic washer is in good condition. I certainly couldn't detect any friction between the inner drum and the basket, but of course that is with the engine stopped.

Any suggestions? The neutral issue might be livable with, the gear change issue isn't and can't be right. I'll crack it in the end!

Regards,
Joe.

[penman]

After posting the last message, I took the clutch apart again to examine all the parts carefully, looking for a weak spring or something like that. In fact the free lengths of the springs are all within 0.5mm so I doubt if there is any issue there. I couldn't come up with a quick and easy method of checking the compression on the springs, but pressing them down by hand I can say there are no detectable differences. I also measured the movement of the clutch cover at various lever positions and I can say that it is rising perfectly straight - certainly within 0.3mm which is quite impressive, it can't be practical to get it better than that!

So, I don't think there is anything wrong with any of the clutch components, or with its operation and I have to look elsewhere to find what is causing it to drag. I'm intrigued by the idea of the primary gears loading the clutch basket one way or the other and I wish I could feel some float there - but I can't! As usual, any suggestions?

I think I might bite the bullet and book in for an MOT tomorrow (Monday) and face the ride over there. Perhaps this gear change issue will ease with a bit of use. (he said rather lamely!)

By the way guys, my side stand won't stay down, and on examination, it's not designed to. On level ground, the bike's on the verge of falling over, if there is the very slightest downhill slope it WILL fall over if you let it. I think you can only use it if the bike is facing slightly uphill, and even then I don't trust it. Is it meant to be like this?

Regards,
Joe

[EVguru]

You do of course have a late bike, so safety requirements like an automatically retracting side stand were required, at least in some markets.

It's so easy to put a Morini 350 onto the centre stand, that I almost never use the side stand. The exception being the annual club track day when the centre stand is wired up.

A I recall, the side stand pivot bolt is extended so that the spring contacts it, rather than going over centre. Fitting a shorter bolt should put it back to the original non 'suicide' configuration.

I was forgetting that a K2 will have a crossover gear linkage, rather than having the rear brake where nature intended it on the opposite side of the bike to the front. Check that the linkage is in good condition. I had a problem shifting from 3rd to 4th on hot days and that turned out to be a problem with the lever locknut on the Tarozzi rearsets causing the lever to bind.

[penman]

Paul, you are absolutely right about the side stand, I hadn't looked closely at it. A bit of a bodge, I have to say, probably to conform with US requirements. Making it into a more or less non-functioning stand doesn't seem like a good solution! As you say though, putting it on the centre stand is so easy, it's hardly a big issue. A shorter bolt will be on there within the hour!

I did have a good look at the gear linkage and although it's all external, it is pretty well made and seems to be in good nick. I greased the pivots and replaced one rather rusty bolt, but it made no difference.

I have also tried maladjusting the clutch operating arm to give more lift but although I can set it up to release when the lever has only gone through about a quarter of its travel, it makes no difference to the neutral or up-change problems. If I can get an MOT appointment tomorrow, I'll be riding it about 20 miles in total. We'll see if that makes any difference - I hope so, but if not, I'll have to decide what to do next. Hmm!

By the way, I have been taking photos as I've been working on this bike and I'll put them on the web in "blog" format when I get around to it, it might be of help to anyone else venturing down this path!

Joe.

[penman]

An update, but more questions!

The bike passed its MOT, no problem and I've now sent all the paperwork off to dvla to get the UK registration. That's the good news!

This "clutch drag" problem makes it pretty unpleasant to ride. It didn't improve at all, though I did start to get used to blipping the throttle on up-changes as well as down changes - I don't recommend this as an enjoyable riding style however! The clutch only drags when the engine is running. With the engine stopped, it releases cleanly and there is absolutely no drag at all. I am guessing that this has to be due to the helical primary gears loading the clutch basket outwards against the clutch inner drum or against the clutch plate stack. If anyone has any other ideas, or any suggestions please let me know, I'll be tearing my hair soon!

I must admit, I am a bit surprised - and a bit dubious about the helical gear issue making so much difference, especially as I couldn't detect any float in the basket, but I'm out of ideas!

Regards,

Joe.

[EVguru]

The helical gear issue only tends to make the clutch action more sudden. Many magazine articles talk about the inevitably grabby dry clutch.

I've always been able to get them silky smooth.

If you've got too little clearance on the nylon thrust washer, then although it may be free when cold, it's going to heat up fast with the engine running and expand.

[penman]

Thanks Paul.

The clutch is certainly smooth, though it is a bit on/off compared to say my 1978 Bonneville. I wouldn't exactly say "grabby", but "a bit sharp" maybe. Hmm, maybe I'll figure out a way to turn the engine with a long spanner and observe if and how the clutch basket moves when the primary comes under strain. I think this has to be related to those helical gears somehow!

I'll report progress, if any.

Joe.