Motorcycle Repair: 85 FXRS Low Glide, crank case, inner case

Question
Hi Mike

I live in Australia and I have an 85 FXRS which I purchased brand new. It has still only done about 40,000 kms (25,000 miles).

Many years ago, when only about nine years old the clutch, unbelievably, fell off. This resulted in significant damage to the outer primary drive case which I had welded and refinished. The inner case was less damaged and not removed at the time but repaired instead with Devcon.

Since then the inner primary cover was removed to replace the drive belt and pulleys. This revealed that half of the circular ring cast into the left hand side of the crank-case was missing. This cast ring locates the primary chaincase inner and helps it to retain oil. It had obviously happened some time previously as the bits were no longer there and the mechanic had obviously forgotten to tell me about it. I don’t know whether the clutch falling off had anything to do with the disintegrating ring or if it was just a weak casting. Since that revelation, the primary has been sealed to the crankcase using gobs of silicone with varying degrees of success.

More recently the Torrington needle-roller bearing on the Andrews EV.35 camshaft failed. This caused many teeth to chip off the cam pinion and one of those teeth to find its way into the oil pump where it wedged itself between the scavenge gears and stopped the pump dead. Surprisingly the engine still ran smoothly and the only indication of trouble was the oil-pressure warning lamp.

I am now stripping the engine and hope to resolve both the above issues.

•   Have you come across that particular crankcase issue before?
•   Do you think it can be repaired by welding and machining or is it too big a job? It would require a huge lathe for spinning the crankcase half, unless there’s a better way.
•   When the EV.35 was fitted, it came with its own pinion. I have since heard that it should have either had a matching crankshaft pinion or should have been installed with the old camshaft pinion. Is this correct and could it have caused the bearing to thrash out?
•   When I replace the cam, should I make sure it has matching crank and cam pinions?
•   I was happy with the characteristics of that cam, but is there a better one these days for street use?
•   I noted that the rear head was far more choked with carbon in the combustion chamber and exhaust port than the front. The valve guides seals and piston rings etc all look pretty good and are in the same condition as the front head. What could cause this? Sometimes the motor did use to cough and hesitate badly and nobody was able to resolve that issue. I suspect the carbon in the rear head is from the same cause. I am running an S&S Super E which was perfect for many years.

I would greatly appreciate any advice you could give me.

Kind regards,

Keith Lockitt


Answer
I have seen this break in the case before, but its rare. You would have to find a machine shop that can do this type of work for you or you can look around for a 1/2 a case that is not damaged.
When installing a new cam the pinion gear  should be measured to fit the cam gear. If to tight it will cause whinning, to loose it will cause a rattle, but it wount cause a bearing to fail.
I would go with a Andrews EV 27 cam. Works quit well with your motor.
On the carbon issue, this happens and there is really nothing you can do. Usually has to do with the length of the exhaust.
Good luck and happy riding
Mike