Now I Can Tinker...

Last week I finally brought the kart home.  The winter weather had kept me from heading down to Dad and Ann's to work on it since November.   Finally, on my spring break I went down to do some chores for Ann, work on the kart and pack it up.  The temperature was about 35º, so even with my woolies on I got chilled quickly.  I tried to get the clutch working but to no avail, so I loaded up and headed home.

It has been wonderful to be able to tinker on the kart.  Especially, since I am on a time crunch. I have paid reservations for a test day at Grattan Raceway in Michigan on April 13.  About 25 karts will be there; most will be shifter karts, but will be a handful of 100cc Yamahas and then me... the total rookie with a vintage McCulloch. Call me "Milka."  Pam will be going... everyone else is invited.  SO EXITING.

Here is the kart where we have worked on for the last year or so.  Room to move around and leave tools.  

Dad purchased the Red Devil kart from Pete Evans in the early 1970s and many of the parts are in the original boxes.  I filled two blue RubberMaid tubs with the parts I might need.  Ann is letting some parts stay in the barn for now.

(one part I will need soon is the tire balancer.  I forgot to pack it.  It is the bent sheet metal piece behind the tire.  Ann!!  don't do anything with it. PLEASE!)

I was a bit afraid the kart would not fit in the bed of the truck, but had room to spare for the starter.   

Here is the set up at home in the garage.  Thankfully, the garage is long enough for the car to be in its normal place and still have room for the kart.  This photo makes it look spacious... it's not.  Just enough room to work.

One of my first tasks was to get the starter in working order.  When Pam and I tried to start it back in November the starter wires popped and cracked and smoked.  I found the insulation on the wire between the frame and the solenoid had melted.  So I removed the insulation and taped it up.  No more pops.  A new battery and box were also purchased.  It works very good now.

Then it was on to the brake tether.  This a recent mandatory safety feature implemented around 2009.  All karts must have a cable connecting the master cylinder arm to the brake pedal incase the brake rod malfunctions.  About $10 in parts and there is a bit more safety.

The cable is 1/16" galvanized steel with two cable locks on each end.  This is the pedal...

...and the master cylinder.

The biggest task was getting the clutch to work.  The pulley cup has the bolt that holds the whole thing together, BUT when it would be tightened the whole clutch would bind-up.  That is not what a clutch should do.  The large drum (and chain and tires) should move free of the pulley (and crank shaft) until the RPMs get high enough to engage the clutch, sending power to the tires.

This has been bothering me all winter.  I asked a couple vintage mentors back in December and they suggested two things: 1)  the half-moon key must be .02" below the shaft on the engine side.  NOPE: mine was sticking up above the shaft.  This probably kept the clutch from settling onto the cone;  2)  the   clutch may be too wide, so grind down the shoulder at the shaft hole.  

One of my mentors said he probably would be able to figure it out in a couple seconds if he had it in his hands.  That couldn't happen.  I had to visualize it.   So I measured and measured with a compass and drew up a reasonable representation of the Hartman Insta-slip clutch in Adobe Illustrator.  I understand it pretty well now.  Yea, its a bit nerdy, but its what I do. (the bar is 1" divided into 1/8th)

Here is the crank shaft coming out the engine

Here is the crank with the clutch drum on.  The half-moon key can be seen on the top of the cone.

Here the key has been ground down to allow the .02" 

Even after fixing the key, the clutch still bound up, so I moved onto testing the clutch hub. The clutch hub is attached to the crank and has the clutch shoes which swing out with centrifugal force to press against the drum  The drum is attached to the chain sprocket which turns the tires.

It seemed the binding was caused by the should hub being to thick. I did some testing by putting Sharpie marks on the cone then tightening the clutch together.   Ah Hah! the ink was not disturbed, thus the hub did not press or engage the cone securely.

The shoulder is the circle in the middle of the hub. It is only about 1/16" tall.  So I started filing it... still binding.  So off to the grinder... GRRRRRRRiiiiiiinnnndddddddddd.

Before Grinding

Before Grinding

Here is the shoulder after grinding.  It is basically flush with the hub.  The marks are where I tested to see if it touched the drum.  NOPE.  Put the whole clutch back together and it all worked!!  So now the hub presses onto the cone and the drum moves freely from the pulley/crank

This is the other side of the hub - it faces away from the engine.  The crank would protrude through the central hole and the pulley screws onto it. Even with the grinding the pulley would touch the clutch cover (third photo).  So I put a washer on the crank to move the pulley out. It worked. 

Now that the hub sits properly on the cone of the crank, I will "lap" the hub and crank with some grinding compound.  Another new piece of info from Rick Chapman.

The next job will be to put the clutch back together  and add the clutch oil to it.  Here is the 40+ year old Hartman Clutch Oil.  Should still be good.

I also brought home the second engine which probably last was ran by Pete Evans.  I would like to tear it down and get it running as a spare.

This is the little chest which contains a lot of the little things needed for karting.  Dad had this on the bench all these years.  Under it I found the homemade cover and lock (coat hanger) for traveling.  I love  finding stuff like that.

In the bigger boxes were many special finds...clutch parts, brakes, exhausts, sprockets.  And these:   Autolite spark plugs in their original packaging from ~1974.  The boxes are moist and falling apart but the plugs are perfect.  So the question is: are today's plugs better?

The last thing I did was test the carburetor for the pop-off setting.  I had not heard of this before about a month ago.  But it is very important for proper fuel pumping.  I looked all over for a gauge in Dad's tools, but found none.  I could purchase a new gauge at a kart shop for $40-65, but saw some homemade ones on the kart blogs.  So I spent about $30 on parts to create my own.  Yea, sort of like creating my own bench, shelves, and lightsaber(star wars reference).

Proper pressure should be 12-18psi, but Steve O'Hara says he uses 28psi on Macs. My carb popped at 25psi

Another piece completed was adding zip-ties to several areas where parts might vibrate out of place.  One of the most critical were the keys on the axle.  Originally, Dad only had electrical tape holding the keys.  Sometime I saw a kart online with zips on the keys, and thought it was a great idea.

The next step is to start the engine.  I am learning a huge amount about details.  :-)

Wheels 

I had to make a decision on what wheels to run.  A couple mentors suggested I put away the original cast aluminum wheels and get new, modern spun aluminum wheels.  That would add a lot of expense, so with a counter suggestion from another mentor, I will be using the original wheels. That means lots of time bolting the wheels together and the need for inner tubes.  I have decided to go with Hoosier tires.  Should call to order those on Friday.  After that will be the helmet in early April.

To-Do List

Brake safety tether (KISS)  3' 1/8" CABLE  / 2 CABLE CLAMPS /A LOC-TITE

3-5GAL GAS CAN

CONTACT HOOSIER TIRE FOR RECOMMENDATIONS - Fox Valley  (and tubes)

ADD FUEL FILTER TO FUEL LINE

Replace brake pin with bolt with locking nut/cotter pin

Buy gasoline (which grade?)  sunoco or shell premium (called Hi-test in past)

Mix gasoline and oil  (20:1 or 16:1) (10-12oz Burris castor:1gal gas//using Stihl chainsaw oil)  Shell & Stihl oil (add stabilizer for end of day flush)

Clutch oil --  old Hartman oil should work

Review first start procedure ( 1-2oz. fuel mix in carb and .5-1oz through plug hole to cylinder):  idle for 10 minutes until warmed up on horses/stand; repeat 3 times; re-torque head bolts)

Remove engine swing mount to fix rubber gasket

Place fixed swing mount

Place locking collar on Swing mount on axle (use punch to tighten then set screw)

Place engine on swing mount

Tighten engine mounting bolts to torque limit (loc-tite)  CHECK

Attach clutch to PTO side (half-moon key, clutch housing and ring, shoes, gasket, cover, tighten pulley         bolt, hex bolts with loc-tite, fill with oil) MORE WEIGHT= LESS SLIP

Align sprocket/oiler to drive sprocket (oiler not allowed.  put lube on sprocket)

Fill oiler at track(~70weight gear oil)(holds enough for one hour of racing)

Connect throttle cable to carb; attach to frame with zip-ties

Connect brake tubing to frame with zip-ties

Put on pipe (torque wrench)

Battery to starter and test (Check correct direction!!)

New belt?

Put on fuel line ( need a loop? PROBABLY)

Add gas/oil mix

Open the fuel valve

Set carb needles per manual before start

After start, set carb needles per manual

Buy new tires (Dunlop SL4) and tubes

SAND BLAST WHEELS???

Balance tires

Put on tires SWITCH FRONT TIMES SO COTTER PINS CAN WORK

Balance frame with a scale under each tire (what then?  tire pressure?   frame?)

Put temp gauge on spark plug (gauge is in helmet bag.  where is the plug end?)

Buy strong rod bolts (Bonbright)

Set clutch at high rpm

Inventory all kart parts and tools

New boxes for parts

catalog what tools are needed

table for pits

tent for pits (UMMM... BREAKING DESTRY TENT DID THAT)

Start wiki of info

EAR PLUGS



and much much more