Author Topic: "One Man Caravan" bike update  (Read 6958 times)

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Offline Patrick

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"One Man Caravan" bike update
« on: 31 May 2005 at 02:01 »
Howdy ya’ll,
First: What is the valves lash dimension for this 1932 T6 Douglas?

Second: Alwyn asked me a few questions last fall (fall in the USA), to which I will now respond.

In review, I am the foster parent/mechanic/caretaker for this motorcycle, which was inherited by, my friend, Travis Fulton, a son of Robert Edison Fulton, Jr. I made those photos in my front yard.

On display somewhere? Not formally, but if you’re in the Rocky Mountains, contact me and I’ll facilitate your opportunity to check out this historical moto.
Adventure touring on a late model GS?  Bah. Fulton’s was the epic adventure tour!

Presently, there is no evidence of the under-engine, hidey hole where the revolver was stashed.

That air cleaner is Mikuni.

The speedo/odo is zero-timed, but no drive cable is attached. I opened up the canister and observed that all the monkey motion is clean and complete, but whatever assembly lube was last used is now gummy or turned to varnish.
Doug, your information and advice was most helpful to me for inspecting the clutch. This one has a caged bearing assy., so I did not get to experience the rollyball splooge all over my garage floor.
I’m still not satisfied with the preload that must be kept on the clutch cable to gain a reasonable disengagement. The throwout cam block has seen some kind of welded/brazed repair. I wonder if it was not clocked or indexed accurately when that repair was made. I suspect most of the cable preload, I am dialing in, is to torque that cam into contact with the bearing.

When we first took delivery of the bike, last year, it appeared to have not been sufficiently run-in and test-hopped following its 1990 restoration in Kingswood, Bristol. I found numerous, and significant, bits of hardware maladjusted and insufficiently torqued.
I cleared out the varmints, replenished the fluids, and double checked the mag timing and that worn out, (but chromed!), Amalgamated carburetor. All of that was determined to be satisfactory. The engine then started easily and ran well. I elected to not go further into the innards of the engine. I delivered it to Travis, in November, right before our major winter commenced.

Last week, Travis complained about “the Duggie’s” poor running and no power. I confirmed that it suffered from no compushion on the aft cylinder. Further investigation revealed a backed off jam nut on the intake valve follower. I am surprised that this “too loose” condition would result in a tightening valve. The forward cylinder also has an insecure jam nut on its exhaust valve.

Thusly, what is the accepted lash to be set on this model’s valves?

We’re trying to make it legal and operational for the 4th of July parade in Aspen. That is where one could witness it in operation…amongst the Rolex Riders…and all of their Harley/chopper crap. Oh, well. It is not what you ride. It is that you ride.

More photos forthcoming? Here are two from last year and one from today.
Regards, Patrick

"compushion" :!:  - I like that!  8)  
See original discussion re 'One Man Caravan' and Fulton's bike HERE
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Patrick's photos of Robert Edison Fulton Jnr's Douglas.

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Offline Doug

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"One Man Caravan" bike update
« Reply #1 on: 01 Jun 2005 at 03:37 »

Valve clearance for these models is given at 0.006" for both inlet and exhaust in the service manual.  Special note is made not to allow it to fall below this value (could lead to burned valve.)  It is not said if to set hot or cold, so assume cold.  

Douglas always stressed that there should be 1/16" play in the clutch cable.  The reason being is the clutch throw out bearing should be unloaded when the clutch is not in use else it will have short life.  So having no free play is of concern and ought to be gotten to the bottom of.  It is important to differentiate between tension from the clutch return spring and tension from the pressure plate springs in the clutch.  The latter is what counts as that is when the throw out bearing comes under load.  It is substantially more than the return spring, so it is easily felt when it comes into action.

The ring with the three posts that the clutch throw out cam rises and falls on can be rotated on the crankcase spigot.  There should be one or more notches in it at the 4 o’clock position, and a peg in the crankcase spigot that locates in one.  The ring has to be eased off the spigot slightly (it is a press fit), at which point the ring can be tapped gently around to a new position.  This ring is indexed so that when the clutch just starts to lift, the clutch cable and the arm on the throw out cam is horizontal and forms an approximate 90 degree angle, so maximizing the mechanical advantage and travel.  Note this horizontal is an imaginary radial line from the tip of the arm to the center of the cam ring, not the last straight bit of the cranked clutch cam arm.  If the linings are new it should be just above, and worn, just below; as the clutch wears the cable needs to be lengthened.  Once set by the factory it should not need to be re-positioned through the life of the clutch lining.  

There are several styles of clutch operating arm, and the clutches at about this time were going through a change from Raybestos linings to cork inserts after 1931 but by 1934 on certain models.  They seemed to have started out with a straight arm offset slightly above center, then curved slightly upwards in 1931, then I think they went to the cranked version (or curved down) shown below.