Clatter

Maestro, SEI-V
'It must be a .....'
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Joined: 12 Sep 2010 12:25

Re: Clatter

Post by 'It must be a .....' »

Hi, on a 500 engine I had a clatter/rattle with some vibration which got worse at high revs; looked at all the obvious stuff then suspected it was a loose ring nut on the crank primary drive gear causing the drive to chatter.
On inspection the ring nut was tight but the gearbox input bearing had some movement and needed replacing; the noise/vibration was caused by the large primary gear (plus input shaft and clutch) which were moving about on the worn input bearing.
Worth a look while you have it apart?
Good luck
pedro
Posts: 311
Joined: 04 Nov 2010 21:14

Re: Clatter

Post by pedro »

Interesting, the primary gear plus clutch basket has in and out movement, that's the only movement that I have found in the engine but I presumed that was normal, watching one of Paul's wonderful you tube clutch rebuilds, I though that I could detect movement on the film, am I wrong? There is no side to side movement, but there is in and out movement.
'It must be a .....'
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Re: Clatter

Post by 'It must be a .....' »

Hi, my problem was 'side to side movement'. I have just looked at the two 500 engines (5 speed and 6 speed) I have on the bench with their primary drive covers removed and the end float 'in and out' on the input shafts are only just felt and almost next to nothing.
EVguru
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Re: Clatter

Post by EVguru »

The clutch basket and primary gear have a lot of endfloat. This is limited when the clutch hub is fitted and the aim of shimming the clutch is to minimise this endfloat without causing drag between the clutch hub and its thrush washer. Because of the helical primary drive gears, you get a little 'self servo' action in the clutch that is supposed to be the cause of a grabby clutch. I've yet to resort to shimming a clutch, as I've always been able to get a smooth action anyway. The clutch on my own bike has quite a lot of endfloat.

Lets remember that this problem developed over a short period of time, so wear in the clutch bush is an unlikely cause.

Is the clutch basket securely tightened onto the primary gear? I had a low mileage early Sport through my workshop and the basket had been lose for some time. I had to ream the primary gear and basket and make oversize dowels.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
pedro
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Re: Clatter

Post by pedro »

Thanks Paul, yes the clutch basket is tight and always has been.

An update, I have got everything screwed back together and thought that I might as well put some oil in, start it up and try to track exactly where the noise is coming from. So I started it, and it was ticking over just fine, no noisier than usual, Tis a miracle, I thought, I've cured it, so I went for a ride, as soon as I put it under load, the noise was back, I didn't go 100 yards and came back, very hard to trace, on the stand at tickover, it sounds fine, load it and it's orrible. I'm beginning to wonder if it's a big end, although there was no appreciable play on the conrod, and the oil was clean. It was as Paul said, OK one minute, rattling the next.

I am going to be short of time for a few days, and I'm riding at Mallory next weekend, (the Bonanza) so I need to sort out another Morini to ride, this one is going to get shoved to the back of the garage for a while, any further thoughts would be most welcome though.
Papa Lazarou
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Re: Clatter

Post by Papa Lazarou »

pedro wrote:Nope, my first thoughts after loose exhaust, definitely engine and quite harsh but can't find where, I'm secretly hoping it will have gone away when I get it all back together but I don't think it will have. Then it will have to be off to someone with more knowledge than myself, NLM maybe unless I can find someone in the South East willing to take a look. Does anybody know of a South Eastern competent mechanic familiar with these beasties?
Pietro at http://www.dimarino.co.uk/ knows these things well.

Or Bolney garage, as a general classic bike shop. He's pretty good. http://www.themotorcycleworkshop.co.uk/
harrymuffin
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Re: Clatter

Post by harrymuffin »

If it is occurring only under load probability is either the drive side pinion is loose and the nut needs tightening up and not with an air hammer, but with a torque wrench to 36lb/ft or you have a big end on the way out. The nuts have nylon inserts fitted - nylocks and should be replace with a new every time the are removed, but you could simply use a drop of low bond Loctite. There is a holding tool that locates in the two holes found in the gear wheel that allows you to hold the crank whilst using the torque wrench, only tyre fitters use air spanners. Regarding grabbing clutch, then the person who is such an expert has obviously never ridden a motorcycle in the wet, in the evening rush hour, with it pouring with rain, in the Black Country between Great Bridge and Dudley, unable to filter and start stop progress on the 21st December in any year with the water trickling down your neck and the temperature just above zero. Having a digital clutch is not fun with frozen hands even if the expert rider has 50years experience of riding but then there are no rush hours in urban Bedfordshire.
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72degrees
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Re: Clatter

Post by 72degrees »

harrymuffin wrote: There is a holding tool that locates in the two holes found in the gear wheel that allows you to hold the crank whilst using the torque wrench, only tyre fitters use air spanners. Regarding grabbing clutch, then the person who is such an expert has obviously never ridden a motorcycle in the wet, in the evening rush hour, with it pouring with rain, in the Black Country between Great Bridge and Dudley, unable to filter and start stop progress on the 21st December in any year with the water trickling down your neck and the temperature just above zero. Having a digital clutch is not fun with frozen hands even if the expert rider has 50years experience of riding but then there are no rush hours in urban Bedfordshire.
I found it impossible to get the primary pinion off the project without using the holding tool (cunningly held in a wood working vice) and a breaker bar. Naturally I used a torque wrench with the special socket thingy for the new style nut. I'm sure the reference to a rattle gun is only to aid loosening a stubborn nut. I confess to resorting to one on things like Gilera GFR rear sprocket carriers and gearbox sprocket nuts - then in my experience with those, though a good rattle may help, it's usually been a long soak in Plusgas and breaker bar that have worked in the end.

I've found 'shimming' the clutch has always been worth doing and transformed the one on the 2C/375. It made the project one much less binary, but that's still slightly grabby despite all new plates. I suspect it may need wearing in a bit. A few rear wheel burnouts at hill climbs is improving it but it's still a bit 'sharp' compared with the other one. It does have the Wevee spring assist washers on the spring cups though which may be a factor - but thinking about it they didn't cause that when on the 375. I will double check the hub/basket end float when I find a tuit. I think, that for whatever reason, there may be more end float movement on the gearbox main shaft on the rebuilt project than other one. This is despite having all new bearings (though I couldn't source new gear bushes). I don't think I left a vital shim off the main shaft - but you never know.
harrymuffin
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Re: Clatter

Post by harrymuffin »

I still have a couple of copies of Benjamin Straw (aka WeeVee)technical information bulletins with drawings, on how to reduce the digital clutch action that Morinis are prone to have at times. If done correctly, then it is possible to have a clutch action as smooth as those on Velos or a babies bum. He, (BJ) I am sure, has forgotten more about Morinis than anyone posting on this forum has ever learnt or will learn. His successor, who past away some time ago, was also extremely erudite when dealing with Morinis.
Regarding the holding tool then it is the correct way to undo and do up the drive side nut and a similar tool for the flywheel nut + camshaft nut. If the person working on the engine cannot be bothered to make up these tools then the alternative is to put a bar through the little end and have the bar resting on pieces of wood resting on top of the crank case. If the correct torque is used on these two nuts you should not have to resort to heat, bashing or release agents, though the latter does help and no damage will occur to the little end. Anyone who resorts to impact spanners, air or electric should not be allowed near and engine, especially if they think it is alright to use one to do up the nuts. Only cowboy tyre fitters use them and if you should have a puncture you are fecked undoing the nuts with the correct spanner supplied.
EVguru
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Re: Clatter

Post by EVguru »

You know, I have told people many times that the Morini clutch should be smooth and I have had many happy customers who think that their clutch works very nicely after I've worked on it.

I actually pointed out the mechanism by which clutch endfloat could affect the action, but I made a simple statement; I've never found it necessary to shim a clutch.
I didn't cast aspersions on those that do, or claim that they were in error, I simply said that I haven't needed to do it. It's not where I would start.

Not everyone has access to a machine shop, or an easy source of the shims, or is even confident about how you'd go about shimming.

As to the use of rotary impact drivers, I happened to have a phone call with one of my old racing friends. He ran an automotive repair business for many years and just laughed at the idea that you shouldn't use power tools for taking engines apart. I know NLM do as I've spent some time in their workshop over the years.

I do use my air wrench do do up the flywheel nut, but it's MY air wrench and I know what torque I'll get with a given line pressure and with the torque control set to a particular setting.

If you have a torque wrench, is it a quality brand, do you always release the tension after use and when did you last have it calibrated? I read a trade journal a number of years ago and they'd done a survey and found that torque wrenches in profession automotive repair shops were on average more than 50% out.

Add in rust, damage, wear, or lubricant on the threads and who knows what kind of tension you've developed in the fastener. In many applications, it's the tension that's important, which is one of the reasons that yield bolts have become popular.

Spanners are different lengths for different sizes, so an appropriate amount of torque is applied. Old school mechanics developed the 'feel' for tightening a fastener and frowned somewhat on socket sets because the leverage was the same for every size fastener. If you watch some of the footage of engines being built at the old Triumph factory, you won't see torque wrenches, just hand tools with handles of the right length and workers who have had to develop the 'feel'. Torque wrenches were later introduced because it required less worker skill, but then you end up being reliant on the people that calibrate and set the wrenches. It wasn't always a gain.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
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72degrees
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Re: Clatter

Post by 72degrees »

I'll use a rattle gun as a weapon of last resort when dismantling an engine but I don't trust my air screwdriver and compressor enough to use to tighten anything. There are often cases where a good old fashioned impact screwdriver and a lump hammer are the best option on set screws. I have a small pistol grip electric screwdriver incorporating an LED which is wonderful for removing or replacing numerous socket head screws of the same size - like on fairings.

On anything below M8 I prefer to use 'mechanic's feel' - too many experiences of believing manuals like the Harglo blue one on rocker stud nuts. I even do wheel spindle nuts by 'grunt' as I know I'm very unlikely to have a torque wrench with me if a wheel needs to come out at the side of the road. I have a 3/8 drive decent quality 'clicker' torque wrench for most things (unwound when not in use) and 1/2 drive flexing pointer one for the really big stuff.

As to clutch shimming, NLM can supply a set of shims. It may not be the best place to start if just trying to improve a slightly on/off clutch but if doing a full clutch strip (say while doing the oil seals ) it seems sensible to check and correct the end float at the same time. It's a fairly straightforward procedure but requires patience to get a near perfect result. In comparison with shimming the valve clearances on a Yamaha DOHC 5 valve MX engine it's simple.

Now we can all agree that this digression isn't helping the original poster with their clatter problem. As I understand the story so far a loose drive pinion nut has been ruled out. Being worse under load does tend to point the finger at big ends, or possibly even a really bad main bearing, but you would expect the state of the oil to bear witness to either of those - though as it happened suddenly and not developed over time perhaps not.

I was first really alerted to the fact that all was not well with the bottom end of the Voxan when I found bronze coloured particles in the crankcase oil screen on doing an oil change (dry sump with three filters!). I'd noticed a bit of light rumbling under heavy load and perhaps a bit noisier at idle than it had been but 'clatter' would be overstating it. Using a 'screwdriver stethoscope' it certainly seemed to be originating from the crankcase not the top end though. I never found out whether it was the big end shells or mains (the engine uses shell main bearings).

By contrast, the 350 I rebuilt for the project had been running Ok and sounded not too bad at all at idle (though I never rode the bike it came out of). No obvious (to me anyway) play in the rods before removing them but the shells were toast and the journals scored (within regrind limits luckily). The conrod eyes had, however, gone oval!

There is also the possibility of a gearbox bearing breaking up I suppose. Our YZ450F made ominous noises that we dismissed as just 'racing engine' noise shortly before the primary shaft input bearing actually broke up so badly that a piece of the outer race ended up between the primary drive gears bringing things to an abrupt but thankfully not too painful stop while the lad was riding it up Loton Park. That sounded pretty nasty even at idle though to be fair.

Sounds like time to split the cases and have a good look inside to me, for peace of mind.
pedro
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Joined: 04 Nov 2010 21:14

Re: Clatter

Post by pedro »

Thanks for all your comments chaps, it's much appreciated.
I have managed to get a friend who is a mechanic, with a lot of experience of building Ducati single classic race engines, to agree to take a look at it with me. He has never worked on a Morini before, but as he says "an engine is an engine."
We will take a look at the drive side together in case I missed anything. If not, then it's engine out and I will deliver it to his workshop. I should get a chance to work on it with him which is good for my understanding of these lovely little things.
Meanwhile, it's Mallory next weekend for the Bonanza, then Bemsee Brands the weekend after to have a run around the long circuit in the lunchtime parade.
I have had bikes for over 50 years now, but have never had so much fun on bikes as I have since coming to Morini ownership.
pedro
Posts: 311
Joined: 04 Nov 2010 21:14

Re: Clatter

Post by pedro »

Well, got there in the end, being that it's a 501 in a 350 frame, it's not easy to get the barrels off in the frame, my pal confirmed that the drive side was all OK and we took the engine out of the frame. Barrels off and all became clear, a cam follower has broken up, all the followers were sloppy as hell, this in turn has done for the rear big end, the oil filter this time was full of metal despite only running for a couple of minutes. We then ran out of time and the rest of the stripdown will have to wait a couple of weeks.
In the meantime does anyone have any experience of NLM's big end shells,I believe sourced from a 1960's Fiat 600, also, bearing in mind that I do enjoy my on track ventures, I would like to find more speed while it's in bits, is there anything recommended to do or avoid doing, my pal is a good engineer so should be able to cope with most things, although he has no experience of Morini's.
MickeyMoto
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Re: Clatter

Post by MickeyMoto »

Will a bialbero corsacorta 1200 fit... ?

Still be a Lambertini twin...
norbert
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Re: Clatter

Post by norbert »

Hi Pedro,

could you please explain what is a cam follower? Don´t know this word :oops:

You can get the rear head (and even cilinder I guess) of a 501 out of a 350 frame by lowering down the engine. Therefore you have to take of the front plates for fixing the motor an take of the upper screw for fixing the motor behind. You only have to take of the exhaust and maybe carburators. Well, it seems that you have to open the heart anyhow :roll: . Sorry for that.

I also would be very intersted in altenative big en shells. Last time I was looking for them there were only available the original and the second "menosmedida" -0,2 (-0,1 I could not find anywhere :roll: )

(By the way: our PHBH 28 configuracion did not work with a W500 motor with 501 cilinders and heads that I tried with my new bike. Now I´ve put a lightly tuned 501 in and will try it again with the 268T "pulverizador")

suerte
norbert
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