Starter Clutch ?

A fair %age of the time,when the 750 is warm and I try to restart,there is a loud grinding noise. New 4T 20/50 oil, 4 or 5 changes in the year I've owned the machine. Read all the "search" threads. Swapped starters and solenoid the other day,cleaned many electrical connections. No improvement.
Toyed with pulling the transmission clutch plates,TCI and oil then filling it with a few liters of kerosene. Probably not a good plan but easier than swapping engines.
Anyway,looked at the starter clutch schematics.Where is the grinding sound coming from? In a car I'd point to bad teeth on the flywheel.(I know,no flywheel.) Is the starter clutch plate jumping from a weak spring?It doesn't look like a friction plate on the diagram.
How much damage is being done with the grinding noise????
I do have a low mileage donor motor,but would rather ride until mid-autumn,unless I'm REALLY doing harm. Don't like to bump-start,can't be good for the transmission..
Thanks,guys for the input. The XJ community is a wonderful thing.

 

I hear chain noise during hot starting. I'm wondering if it's the primary chain, which under this condition will have the tension applied in the opposite direction as normal operation, resulting in transposed stress and slack on the chain, sprockets, and tensioner.

 

The starter "clutch" is what's known as a "sprag" clutch. It consists of three spring loaded rollers riding in channels, against a solid center piece.

When loaded by the starter, the three rollers "grab" the center piece and (are supposed to) bind up on it so that the whole thing goes around and spins the motor.

When the load is from the "driven" side, it causes the rollers to effectively open up and allow the pieces to rotate freely.

The "grinding" sound is the rollers trying to grab the center piece, and being unable to, they chatter and create the sound.

USUALLY, this is because the incorrect oil has been used and the little rollers can't grab.

OCCASIONALLY, it's because the "body" of the starter clutch has cracked at the channels the rollers ride in and they can no longer grip. Unfortunately, replacing the starter clutch requires splitting the cases; which is why we always recommend oil changes first.

 

Thanks for the info. Seems that I'll be swapping engines for now and
splitting the case this winter.

 

compare prices for springs and rollers vs a whole unit, you might want to just beat on those till winter. and you won't know if the housing is cracked till you get in there, it might be cracked now

 

I don't think changing the springs & rollers is a worthwhile enterprise, if the body isn't cracked it will be as worn as the rollers.

 

Preface-went out this afternoon to check out used book stores (new to town) and had to bump-start it a couple times,"urinating" me off BIG TIME.
When I got home,went to XJ4ever to get a feel for prices.(Thanks to BigFitz for the explanation.) Read Len's blurb,echoing what other threads have said.
Still feeling irked,started the "thought experiment thing" which can get me in BIG trouble, I know.... if the housing is worn AND splooged (augmenting the slippage) can I for a modest investment,not look like an idiot in front of the SWEETIE standing behind the book store.Primary motivator, those sweeties.
If the housing were cracked vs. worn (thanks Wizard) would it start when cold and sometimes when warm ??? Hmmmm...de-splooge time.
So,got a new filter,3 qts. of cheap 20/50,a can of brake cleaner.Swapped the transmission clutch plates for an old set,pulled the starter,sprayed the opening for the starter gear (oh,by the way,can one buy a longer piece of the tubing which comes taped to the brake cleaner can...almost lost it into the opening...that would have sucked),poured most of a can of Seafoam in with the oil. Started it a few times,and buttoned things up just before the rain started.
Tomorrow I'll start it a few more times,to splash the Seafoam/brake cleaner (most of both cans) around,then change the oil twice.Cheap auto,then 4T.
At worst,25 bucks wasted,but if it gets me to October looking less
foolish in front of the aforementioned fairer sex,money well spent.

 

I am having a bit of an issue with that as well. It is more prominent when I have to switch over to reserve when it runs low. Be sure to update if this improves your issue.

 

hot or cold, it's been too long to remember but don't put car oil in it, you might undo all you've done and hose the main clutch too.
diesel oil is ok, i use it in all my bikes, mobil delvac 1300

 

Thanks Polock.Delvac was 13 bucks/gallon @ wally world. Less than half the price of Valvoline or Castrol
Started it a few times,ran for 5-8 min,while on the center stand..Drained the oil/solvent. Filthy dirty. I mean black,opaque filthy. The oil was new last week. Put in approx. 2 liters of Delvac, ran for 10 min. Drained the oil,not clear,but much better. The filter (new last week) was black with fine grit.
Swapped back to the newer main clutch plates. While torqueing the bolts (7.2 ft/lbs) one snapped. Luckily it WAS an e-z out. Finished putting things back together. 600 cc's leftover Valvoline and 2 liters Delvac and off I went.
75-85 mph on 481 no slipping,shifting seems a little mushy in slow traffic.
With block warm to hot,in the store for 5 min.,a little grinding BUT started right up with the second turn of the key.
While the starter clutch is probably very worn (35 k miles,waddaya expect?) it is MUCH BETTER than yesterday. Thanks all,for the helpful input.