[KB8ANY]

At the beginning of this summer I finally wised up and took the sprag clutch out of the starting train.  I had had it out before, but never opened it up because I was afraid I would not be able to get all of those dogs back into place with them under spring pressure.

Six of the dogs were loose inside the clutch.  No wonder it would catch and make a cracking noise (not to mention stopping the moter instantly) when the motor kicked back.  Its a good thing that the design keeps the dogs captive when they break loose.

So I just took it out.  I left the gear train in place, and the starter in place (to plug the big hole.)

It is not my imagination - with the clutch out the engine runs better - meaning it does not stall at inoppertune times, like when the light turns green, or when it is still cold and I have just stopped for a stop sign.  I read a Popular Mechanics article many years ago about how a load at the crankshaft, even a very light load, really saps the output of any motor, and if the motor is not properly tuned, or prone to stall, a light load can tip the balance, so to speak, into stalling.  PM knew what they were talking about.

I plan to leave it out for now.  A friend gave me a contact who thinks he can fit me up with a sprag-type clutch that uses spring-loaded balls, like the old automobile freewheels, that has close to the dimensions of the clutch, and can take a lot more abuse than this motor can dish out.  Next spring I may get around to checking into it.  In the meantime, I have become quite the pro at starting this thing with the kickstarter.

Good luck.

Paul

[JerryG]

Thanks for posting Paul. Removing the sprag is a job I'm thinking of attempting (starter motor etc already gone and hole blanked off).

Can you describe what's involved/necessary tools etc?

Jerry

[KB8ANY]

Jerry:

This will sound like more work than it actually is.  My favorite whine is how there is no drain fixture for the primary drive oil - draining the oil is the biggest pain here.

Executive summary, without all the little details,  follows.  I give details in the places I was clotheslined the first time I worked on it.  I do not use the holding tools/wrenches shown in the workshop manual - I got a cheap-o 1/2" drive electric impact wrench and set of sockets at Harbor Freight - this works just fine even on things like the crankshaft without securing it.  I also use 3/8" drive hex sockets - they work like a charm.

1.) Remove primary drive outer cover.
2.) Remove primary drive chain adjuster.
3.) Loosen and remove crainkshaft nut.  Once it is off, the drive sprocket comes off easily - it is keyed to the shaft.  I have never had to tap it off - apparently the impact wrench jiggles it enough to loosen it.
4.) Open clutch.  Break each bolt free, then loosen them 1/2 turn a time until the spring tension is slack, then speed up the operation.  Take out the clutch plates, being darn sure you note which two are dished, and how.  The drive sprocket, chain, and cluch basket come out as a unit.  This would be a good time to check drive chain "stretch."
5.) Remove "chain case inner," as the spare parts catalogue (sic.) calls it.  There are two seals: a banjo-spring seal around the shift rod, and a rubberized ( ? ) paper seal between the case and the side of the motor.  If you are very careful, you may be able to reuse the banjo-type seal.  You will need a new paper seal- it is under considerable pressure from the holding bolts.
6.) With the chain case on the work bench, remove the cover - this is the cover the starter sticks into.  The first time I did this I buggered two of the holding bolts.  They are available at any hardware store.
7.) Lift the cover off.  Even after having done this several times, I am very careful to lift straight up, and to make sure that no washers fall out.  The first time I did this, I had a very hard time getting the cover off.  It is a close fit.  Get your eyeball down there, and make sure the shaft does not come out with the cover.  The tolerances are close enough that the oil acts as a seal and things want to come out with the cover.  Even if you intend to leave the clutch out, you may change your mind later and apparently the spacers are extremely critical to proper operation.
8.) Note how all the parts are in there and take out the clutch.  I can't remember which sprocket comes out first, but one does.  Or maybe I'm remembering it wrong.
9.) Reassemble in reverse order.

I make drawings as I work.  I also use brand new lockwashers and nuts every time - it may be overkill, but this is a high vibration unit, and they are cheap.

If you do not have the spare parts catalogue I strongly recommend you get it before you start work.  Of all of the sources I have it is absolutely the best one.  The pictures have saved me any number of times.  I hope I haven't forgotten anything.  Like I indicated  at the start, it is not as hard as all of this text would suggest.

Good luck.

Paul

[JerryG]

Many thanks for your excellent and detailed guide Paul. It's often the way when working on bikes (or anything mechnical): the telling is a lot more complex than the doing.

I keep an old digital camera in the workshop and photograph as I go. Sometimes you get disturbed and don't return to a job for a few days and it's amazing how quickly what you've learned disappears into the aether (or maybe that's just age...).

Thanks again.

Jerry

[KB8ANY]

You're welcome.

I think I made a mistake and forgot something.

The banjo seal is for the clutch.  Either way not a big deal because it is clearly visible when you get down that far.  The first time I took the seal out.  The second time I carefully lifted the case straight off and then back on.

Somewhere in the chain case inner there is a single screw that acts both like a holder and a locator dowell.    The first time I did this I started wondering how much force to use to pry off the case, then fortunatelly I used a bright light and found the screw.  I think it is back by the clutch.

Sorry to be so vague.  I did this kind of work three years ago then again this spring and was in a hurry to get on the road, and the only photos the wife took were to silence the poseur down the street.

Paul

[DavidMeermans]

...there is no drain fixture for the primary drive oil - draining the oil is the biggest pain here.

I found a solution to draining the primary without making a mess.  I took an empty, rather large vitamin or supplement bottle (plastic, about a quart) and drilled a couple holes in the top.  Inserted two short lengths of brass tube (from hobby store) and attached a couple of lengths of PVC tubing (from auto parts).  Stick one in the primary case through the fill hole and attach the other to a hand vacuum pump (from auto parts) and vacuum the oil out.  I have done this twice now and there is only about a tablespoon's-worth left in the case when I open it.

[tooseevee]

I found a solution to draining the primary without making a mess.  I took an empty, rather large vitamin or supplement bottle (plastic, about a quart) and drilled a couple holes in the top.  Inserted two short lengths of brass tube (from hobby store) and attached a couple of lengths of PVC tubing (from auto parts).  Stick one in the primary case through the fill hole and attach the other to a hand vacuum pump (from auto parts) and vacuum the oil out.  I have done this twice now and there is only about a tablespoon's-worth left in the case when I open it.

           That's a neat idea. I'll bet you could also use one of those little accordian hand siphon pumps - the one you use to borrow gas from the neighbors at night. Or maybe that's what you mean.

            I use a sheet cake pan. Works fine.