Slippig clutch and valve liffter on a 350 scrambler.

[Jacks the Lad]

As acquired the clutch slipped badly, the previous owner had tried to adjust it on the cable ends, however having found instructions on this forum I was able to restore the clearances by using the screw in the centre of the clutch plate. Adjusting it properly improved it, but did not solved the problem, it is still difficult to get the engine over compression. The engine has "allegedly" been rebuilt , but some peoples idea of rebuilding isn't the same as you and I might think. Did they put the forty odd years springs back in, or even the right ones? I was given a box of springs marked Surflex SM57/6 what ever that means. also had he put the correct oil in? As it's wet clutch the wrong oil might not be doing it any good. Even so I am struggling to kick it over compression anyway.
Which brings me to my next question, it does not have a valve lifter fitted and I really think think it needs one. I see from the parts list that it fits on the front valve cover, does anyone have one, or know where I can get one from?

[themoudie]

Aye jacks the lad,

"I was given a box of springs marked Surflex SM57/6 what ever that means."

To see what that means, use this link to the Surflex website and their listing of clutch parts for the 350 Scrambler (2nd update) at the bottom of page 12. Link: Surflex_Ducati_veteran_clutch_parts_list

Surflex SM57/6 springs appear to be the correct springs, but whether the new set have been fitted (correctly), only you can tell. These springs are also used on the 750 twins, but not the 450 single or 860/900 twins.

Oil? Ordinary car oil may contain additives that make the fibre friction clutch plates ineffective, the oil is too viscous. This effect can also be acheived due to the clutch having been left standing in oil and the fibre friction clutch plates becoming saturated with oil. The only cure is to dismantle the clutch plates and to thoroughly scrub/wash all the components in brake cleaner and then allow them to dry. then lightly buff the fibre surfaces with a brass wire brush, rinse off the dust with brake cleaner, dry and then rebuild the clutch in the correct order. Use either a motorcycle SAE40 mineral oil or a 20W/50 SAE multigrade oil suitable for wet clutches, to break the motor in. I add 1:50 two stroke oil to the fuel by volume, warm the engine up between 2-4,000rpm and then take it for a road test of ~25 miles; then drop the oil whilst it is hot. Check the filter and sump for bits of steel with a magnet, wash the filter in brake cleaner. Then re-install and refill with more of the same oil and run the motor up to 500 miles, letting it rev freely, but not initially exceeding 5,000rpm. DO NOT use a semi-synthetic or synthetic oil during the first 500 miles, as the stock oil/additives prevent the proper bedding in of the wearing parts. After 500 miles I still use SAE40 monograde mineral oil with no additives. Others prefer a 20W/50 SAE multigrade suitable for wet clutches, or a semi-synthetic/synthetic 20/50 multigrade suitable for wet clutches.

As for your problem turning the motor over TDC, a 350 should be manageable, but if you are not accustomed to kicking these motors over, a high compression piston was fitted, or there is a fault in the engine assembly, you need to ask questions of the engine builder. Add some upper cylinder lubricant/Redex through the plug hole and gently turn the motor over to see if this helps ease the rotation, before replacing the spark plug, with a smear of copper slip applied to the threads to prevent seizure; or take the head off to make initial checks of the piston and assembly.

How long has this motor been standing idle and in what conditions since it was "rebuilt"? If it was in a damp garage, with no oil and no lubricant used in the assembly, the whole lot may have a coat of oxide on it, including areas of the bearings and piston rings!

I would want to make more checks of the engine and it's assembled clearances, even if these are divulged by the vendor/builder, before worrying about fitting a valve lifter.

Apologies for the curmugeonly view and I wish you well.

Good health, Bill

[Jacks the Lad]

Thank you Bill,
I was afraid someone would say I have to take it all apart and clean the plates, but if that's what it takes, then that's what it takes. As to kicking over high compression single cylinder engines I was brought up on large British singles but they of course all had de-compressors and I was a lot younger back then , so even with the clutch problem fixed I would still like to have one
Regards,

[ranton_rambler]

Not sure if yours is the same, but on my 175 I can get the clutch apart in about 30 minutes. Don’t even need to drain the oil if you lean the bike to the right a bit.
Ian

[themoudie]

Aye jacks the lad and Ian,

jacks the lad Fortunately, inspite of being pensionable and 13 stone I can still turn the 450, with a ~9.0:1 compression over, without the valve lifter if I have to. That is why I am wondering if someone has fitted a high compression piston to your 350 motor.

Do you have a Ducati, Clymer or Haynes manual, all three or none? If the answer is the latter, then I would advise a wee investment.

Ian I agree with your wheeze for cleaning the clutch plates, as for the time........ You just hope that the gasket on the outer case (if you use gaskets) doesn't tear!

All the best, Bill

[Jordan]

You can use a claw hammer to safely remove the clutch cover, after removing the elliptical clutch adjustment cover.

[themoudie]

Aye Jordon,

You can use a claw hammer to safely remove the clutch cover, after removing the elliptical clutch adjustment cover.

Sounds a bit brutal. Never found the resistance to cover removal so great as to require a lever. Get your fingers through the elliptical clutch adjustment hole and then lever, whilst gently hitting around the case outer edge with a black rubber mallet; not a nylon one as it may mark up your alloy. "Slowly slowly, catch the monkey!"

Oh! And "gently hitting", means the same as a 2lb hammer can be tool or a weapon.

Regards, Bill

[blethermaskite]

For goodness sake guys, make up or buy a primary case extractor tool
Cheers,
George

[Jacks the Lad]

Bill
No, I do not have a manual other that a downloaded copy of the riders handbook (in Italian), But someone in my local club says he has a Haynes one if he can find it. As to kicking it over, yes Incan do it, but with one artificial knee and osteoarthritis I just don't like doing it.

[Jordan]

Usually the fit between the bearing inner race (in the cover) and the crankshaft end is a little tight, which is probably a good thing.
It does sound alarming I guess, but my claw hammer is used ever so gently and cannot mark the outside of the cover.
It puts pressure in a good place from behind the cover, using the clutch assembly as the fulcrum point.
If it doesn't come off immediately, I use a rubber mallet to help, or use a slide hammer.

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