[TS150] Clutch Troubles

[Agronski]

Hi all,

So I took TS150 out for a spin today (after leaving her sit for about 2 months...took me a few minutes to clean the buttery crud out of the carb that was blocking the main jet; think I might drill/install a drain plug for it soon.) Anyway - after warming up for a bit, I get her onto the main roads and the ride is fine - the gears are where they should be, the clutch isn't too heavy and the throttle responds nicely. But I get about 5 miles out on the 40mph roads, and the ride starts getting a bit hesitant, throttle stops pulling quite as smoothly as it did. I think maybe it's misfiring, but it doesn't sound like it. Then I come to a stop at a junction, and as I pulled in the clutch the engine died. Took me 5mins to get going again. Then it happens again a few minutes down the road. And again. AND AGAIN! Finally, I try and pull over to the side and I can't find neutral...had to almost bump-start the engine so it would turn the gears enough to slip into neutral. After a bit of time cooling off, I got into neutral just fine and the engine started again, but in gear there was no power and the engine would bog and die with any throttle at all...

Long story short, I had to push TS home up a half-mile-long hill because she would kickstart just fine, but the moment I got on and shifted into 1st gear, the revs would drop like a stone even when the clutch lever was against the bar and letting out the lever even a tiny bit would kill the engine dead, even if I tore the throttle wide open.

Technical details: unmodified 1976 TS150/2 engine; a (well tested, definitely non-faulty) transistorized 6V points-ignition; N.O.S. replacement clutch plates less than with 50 miles on them; original driven-plates (with some wear, but not much - see attached); new oil seals installed correctly with well-greased lips; gearbox filled with 0.5l fresh GL4 80W-90 _gear oil_; clutch worm adjusted to be 0.25 turns out from "tension" point on the clutch pressure-bolt. Definitely not burning gear oil, because the oil pours out from the check-screw hole just fine.

I have no idea what to check next. I'm pretty sure it's the clutch from the behaviour. When I changed the friction plates a few months ago, the springs still felt VERY stiff (hurt my hand getting the cups out!) and seemed about the right length (didn't put my calipers on them, however) so I wonder if it might be the springs losing tension because they're 30+ years old? Can anyone throw some light on this?

Thanks,

___

[arry_b]

I think you've got two problems:

Cutting out problem when warm, and won't run under the slightest load: Still running the original coil?
I've bought several MZs for next to no money because they were doing the same thing as yours is. A new coil returns the bike to normality. They show a nice fat spark when they're cold, so can lull you into a false sense of security.

The difficulty in finding neutral, I'd be looking at the gear oil.
Straight 80w gear oil is what's meant to be in there. Whenever I've used 80W90, I've found the change to get worse especially in colder weather. For the sake of half a litre of gear oil, that's the first thing I'd change. I'm assuming teh clutch basket wasn't worn when you changed the plates?

[Agronski]

I'm pretty sure the clutch basket and splined centre-unit are okay - the bike's got 15K miles on it (only about 50 are mine) but I doubt it got much exercise just before I bought it because it came from a garage that obviously didn't know how to service it. Didn't notice any bites/notches in the basket, the clutch centre didn't have obvious scoring/dents. I did have to file the new friction plate lugs so they fit smoothly between the basket fingers, but I don't think they're binding...

...besides, it's a TS150, which means only the friction plates actually put any force into the basket - and the friction plates are pure bonded-fibre stuff. Could these plates really deform/damage the clutch basket?

Yeah, the coil is original (or at least NOS). I'm surprised that it might be the coil, though, because I had it off the bike and rigged to a test circuit producing a nice fat spark, simulating 6000RPM for minutes at a time. Maybe I should take a blowtorch to the casing, see how it behaves when lightly toasted. The custom ignition driver doesn't use the condensor, so that's at least one weak point removed...

After my awful ride yesterday the plug looked like this: http://www.dansmc.com/Spark_Plugs/6.html - but it _is_ an older plug that I've cleaned out once before now. I wonder if it's not the coil but a partly fouled plug. I haven't done a proper plug-chop to check my mix and/or timing yet.

As for oil - you might be right, but finding neutral was fine when the bike was cold - how could warm oil (more runny) make neutral harder to find? Also, finding GL4 80W90 was hard enough. Know anywhere that sells straight 80W EP that _won't_ eat my gearbox?

___

[arry_b]

Oil - I've been using this:
http://www.aseriesspares.co.uk/workshop ... d_294.html
I buy at at my local parts factors, that last batch I bought was 5 litres for around £12.

I take your point about the 80W90 getting thinner as it gets hotter, but the plates will also expand slightly when they're hot, perhaps negating the viscosity drop?

I have seen worn clutch baskets on small TSs and ETZs where the fiber plated have eaten their way into the clutch basket fingers, but you'd have see that when you had it apart, it's not subtle.

Warming the coil on a test rig sounds exciting, but on the road I've always found a wayward coil gets hot enough when it's going into silly buggers mode to make itself known when an ungloved finger is held to it.

One other thing which I experienced last winter on my ES150, was very poor running when hot or with the lights on. That was cured by adding extra heavy duty 3mm earth wires between the headlight body, the engine and the main frame earth point next to the regulator. The difference was night and day.

[DAVID THOMPSON]

i use stranded 10 gage as the ground wire it is 5,26 mm
its a bit big but it works
nothing like a bad ground to screw up your day

this may be over kill but i ride some bikes that shops do not want to work on
try getting a bmw shop 1500 miles from Home .to help you fix your 1953 bmw r51/3 only a couple in the country
have a guy on staff thats ever seen one
and an mz ? the guys here think i put the yamaha engine in the traveller

riders here that have been riding 50 or 60 years have never heard of an MZ

dave