00 BMW 1973 R75/5 “Grover’s” First Engine Start

NOTE: The bike is named Grover, after the Muppet character that is blue like the bike. My R1150-RS is named Cookie Monster, who is the other blue Muppet and my wife’s F650-GS is Elmo, because it’s Red.

Okay, enough about the Muppets, on to the work to be done.

At this point in the project, the paint work still needs to be done, but I’m ready for the first engine start.  The bike was off the road for six years in a barn before I started work on the rebuild. I’ve spent just a bit over a year on the project, so it has been a bit more than seven years since the engine was last running.

Install the Center Stand

It’s time to get the bike off the lift and let it stand on its “own two legs”. I ordered stainless steel center stand bolts and washers (07 46 R kit 002 SS) from Hucky as one of the original bolts had bunged threads.

I put it on the side stand after lowering the lift carefully.

Off the Lift Standing on One Leg

Off the Lift Standing on One Leg

The side stand wants to snap up as soon as the weight is off the stand, and I’ll fix that after I get the center stand installed.

Here are the center stand parts.

Center Stand Parts

Center Stand Parts

A metal bushing goes in the hole at the top of each center stand leg.

Bushing in Pivot Hole

Bushing in Center Stand Pivot Hole

The frame has a bracket with a taped hole for the pivot bolt. Here is the orientation of the center stand mounting hardware.

Bolt, Wave Washer and Bushing

Bolt, Wave Washer and Bushing

I put a bit of Locktite on the beginning threads of the bolt where they go into the taped hole of the frame bracket. I put wheel bearing grease on the outside of the bushings.

Grease For Center Stand Bushing and Locktite for the Bolt

Grease For Center Stand Bushing and Locktite for the Bolt

I put the center stand under the bike and position it so I can install the bolt, washer and bushing. There is a bit more clearance between the engine bracket and exhaust on the left side and I install that side first. I finger tighten the left side bolt and then install the right side bolt. I tighten up the bolts using a crescent wrench and a firm final grunt. Of course I got grease on the header pipe, but I’ll clean that up as one of the last steps before the engine start so the pipes don’t cook any finger prints or grease onto them.

Tightening Pivot Bolt

Tightening Pivot Bolt

I put the bike on the center stand. In this position, the center stand springs are at minimum length so it’s easy to install them. There is a small hole in the shackle on the front engine mount on the right side and on the top of the side stand shackle on the left side.

Installing Centerstand Spring on Right Engine Mount Shackle

Installing Centerstand Spring on Right Engine Mount Shackle

I put the shaft of a Phillips head screw driver in the hook of the spring so I can pull it over the pin in the center stand and easily slip the end of the spring off the shaft onto the groove. It only takes five or six times 🙂

Center Stand Spring on Center Stand Pin

Center Stand Spring on Center Stand Pin

The center stand is installed.

Preventing Side Stand From Retracting

The side stand automatically retracts when the weight comes off it and that is a trap waiting to dump the bike on the ground in my humble opinion. There is a simple adjustment to the side stand shackle on the left engine mount that prevents it from automatically retracting. It is just enough to keep the side stand extended but if it strikes the the street while moving forward, the stand retracts.

I loosen the nut on the left forward engine mount so the side stand shackle can rotate when I put the side stand down.

Side Stand Shackle

Side Stand Shackle

When I push the side stand all the way down, the pivot pin of the stand stops the side stand when it is fully extended and the side stand spring pressure rotates the shackle clockwise. Then  I tighten the forward engine mounting nut to 55 FOOT/pounds. Bingo, the side stand no longer retracts on its own 🙂

Adjusted Side Stand to Prevent Automatic Retraction

Adjusted Side Stand to Prevent Automatic Retraction

Here’s the bike standing on it’s own two legs 🙂

Standing on Her Own Two Feet :-)

Standing on Her Own Two Feet 🙂

Check Out Prior to First Start

I’ve done a lot of work on the bike and changed a lot of things. I’m pretty sure I screwed something up along the way, but what?

I made a list of items to check in preparation for the first engine start.

  • Battery and Wiring Harness Smoke Test
  • Horn Test
  • Add All Fluids (Engine, Transmission, Drive Shaft, Rear Drive, Forks)
  • Starter Motor & Valve Operation Test
  • Oil Pump and Lubrication Check
  • Head Torque and Valve Clearance Check
  • Coils, Points, Plugs Check
  • Static Timing
  • Install Gas Tank & Petcocks, Check Carburetors
  • Clean and Degrease Exhaust System

Once I complete the check list, and correct any mistakes, I am ready to push the ignition key down into the headlight shell and thumb the starter button in an attempt to bring the engine back to life.

Battery and Wiring Harness Smoke Test

I did this test when I installed the wiring harness.

But, I check this again. First, I pull the front engine cover off. Since the battery is disconnected, I don’t have to remove the battery ground to avoid shorting out the diode board. I connect the battery cables to the battery and the ground cable to the speedometer cable breather bolt being careful not to over tighten that bolt. I push the ignition key in to ensure all the indicator lights light and nothing is shorting out.  I smell and see no smoke.

Horn Test

Yeap, when I hit the button the dog barked :-).

Add All Fluids

I use new washers on all the fill and drain plugs. I tighten all the drain plugs and then I add all the fluids to the bike working from front to back.

  • Forks – 250 cc, each leg, 7.5wt BMW Fork Oil
  • Engine  – 2.4 Qts 10w/40 Valvoline oil (full on the dip stick)
  • Transmission – 800 cc 80w/90 GL5 Transmission Lube
  • Shaft Drive – 100 cc 80w/90 GL5 Transmission Lube
  • Rear Drive – 250 cc 80w/90 GL5 Tranmission Lube

Starter Motor Test

I tested this back when I installed the wiring and engine electrics, but I want to make sure its still working and I haven’t screwed anything up with the other work that’s been done.

I make sure the bike is in neutral by manually rolling it forward and back and then put it back on the center stand.  I have the coils and spark plugs installed for this test.

First, I use the kick starter to spin the motor and make sure the valves are opening and closing and there is no indication of any problems in the valve train. Then I engage the starter button and spin the motor for several seconds. There are no unusual noises and the valve gear is working on both sides.

Oil Pump & Lubrication Check

I disconnect the green wire to the coils and pull the spark plugs.  I put the valve covers under the rockers to catch the oil from the top end. Then I push the ignition switch in and use the starter motor to spin the engine and pump oil throughout the engine. I keep cranking until oil starts to come out of the rocker assembly on both sides.

Oil Pump is Working

Oil Pump is Working

This proves the oil pump is working and I’m getting lubrication all the way to the top end.

Head Torque and Valve Clearance Check

I recheck the head nut torque is still 27 FOOT/pounds and check the valve clearances. The left valves clearance are correct (0.06 inch intake, 0.10 inch exhaust), but the right are a bit loose so I set them. I install the valve covers being careful not to over tighten the 10 mm nuts on the sides and the 13 mm chrome center nut.

Coils, Points, Plugs Check

I connect the green wire to the terminal on the left coil and install the right spark plug and its plug cap in the engine. I use the left plug for testing and ground the electrode to the cylinder fin so I can check for a spark when I push the starter button. And, there is no spark. 🙁

I use the ohm meter and find I have power to the coils and the coils aren’t shorted. I move on to the points. I check for continuity when the points are closed but the ohm meter shows an open circuit (infinite ohms). That’s not right.

I pull the points out and find some cam grease has gotten in between the points. I clean them, and then test them with the ohm meter. Now I get 0 ohms when they are closed and infinite ohms when I open them with my finger. I install them and set the points gap to 0.016 inch using the feeler gauge in the bike tool kit.

Static Timing

I use the ohm meter to statically set the ignition timing. When the points open (infinite ohms) the magnetic field in the primary coil collapses across the secondary coil creating a larger voltage in the secondary and that’s what creates the spark between the electrodes in the spark plug. So, I want to see a transition from 0 ohms (points closed) to infinite ohms (points open) when the “S” mark on the flywheel is in the flywheel timing window.

I clip one lead of the ohm meter to a cylinder fin and the touch the probe lightly to the bottom of the movable arm of the points. I don’t want to push the movable arm closed so I touch it lightly at the bottom towards the pivot. As shown below, the points are closed and the meter shows 0 ohms (Note the probe is too high on the movable arm, but shooting with one hand makes it hard to hold the probe at the bottom).

Use Ohm Meter to Check Points - Closed and "0" Ohms

Use Ohm Meter to Check Points – Closed and “0” Ohms

I rotate the engine so the “S” mark is a bit high in the timing window.

Points Closed

Points Closed

I rotate the points plate so the points are closed (0 ohms) at this flywheel setting . Then I use the rear wheel with the transmission in 2nd to bump the flywheel so the “S” mark is centered.

Points Open

Points Open

Now, I adjust the points plate so the points just open (infinite ohms). I recheck to be sure the points are closed (0 ohms) with “S” a bit high and open (infinite ohms) with “S” in the middle.

Now, I ground the left plug electrode on the cylinder fins and hit the starter. I get a nice blue spark across the electrodes of the plug 🙂

Install Gas Tank and Petcocks & Check Carburetors

Here is the petcock and the washer.

Petcock Washer

Petcock Washer

The nut has reverse threads on the bottom and standard threads on the top.

Orientation of Petcock Nut

Orientation of Petcock Nut

I put the petcocks in the tank and tighten the nuts finger tight being careful not to cross thread it.

Finger Tightening Petcock Nut

Finger Tightening Petcock Nut

This pulls the petcock up into the nut as it threads up onto the bottom of the tank. When it is finger tight, I snug it with a crescent wrench. I carefully mount the tank so I don’t chip the new powder coated frame. I connect the fuel lines. I add a gallon of gas and rotate the petcocks to reserve. I wait for the float bowls to fill and check to be sure there are no signs of fuel around the carburetors indicating a hung float.

I turn the petcocks off and carefully remove the float bowls. I check for any crud in the bottom and confirm the fuel height in the bowls is equal.

Checking Carburetor Fuel Level

Checking Carburetor Fuel Level

I reattach the bowls and turn the petcocks to reserve again.

Clean the Exhaust

I use acetone to clean the headers, cross-over pipe and mufflers to remove oil, grease and finger prints so the exhaust won’t discolor when the pipes get hot.

Things I Fixed During Checkout

  • No Spark at Plugs – Point cam grease prevented them for making contact.
  • Right Valve Clearances Too Large – Right side intake and exhaust valve clearances are a little too large.

At this point, I’ve convinced myself that the engine has oil, the oil is pumping, the ignition and starter work, the coils and wiring work, the spark plugs and plug wires work, the point gap is set, the timing is in the ball park and fuel is available to the carburetors. So, the engine ought to have spark, fuel, air and lubrication.

Engine First Start

I want to seat the rings so if I get the engine running, I’ll hold it at 2500-3000 RPM for 30 seconds and then shut it off. The bore is very lightly oiled so the cross-hatch in the bore can cut small grooves in the rings at they are pushed against the cylinder wall by the combustion gas pressure. And, since this is the first start, I try to keep a close eye on the instrument cluster and ensure the oil light doesn’t come on or there are any unexpected sounds coming from the bike. It’s been just over a year of work to get this far, so, no pressure 😉

I take a deep breath, push the ignition switch down in the headlight, clear my throat and hit the starter …

10 thoughts on “00 BMW 1973 R75/5 “Grover’s” First Engine Start

  1. Pingback: 1973 BMW R75/5 Rebuild: Grover’s First Engine Start | Motorcycles & Other Musings

    • Hi Jim,

      Yeah, I admit I am kinda proud of this milestone. Still a good deal more work on the painting, but I hope to take Grover for his first steps in the early spring.

      Best.
      Brook.

  2. Brook,
    Great Job !
    Have been following for the past 3 month’s, very impressed.
    Motor sounds tight Quiet valve train..I plan to start my 73 R75/5 restoration in about a month after I get heat in my new shop.
    Would like to here another recording of her running.

    • Hi Pete,

      Thanks for following along and keeping up with this project. I hope some of what I’ve documented is helpful to you on your project.

      I will try and do a short video shoot of Grover’s first steps when he goes on the road for the first time.

      Best.
      Brook.

      • Brook , Your welcome .Yes this is a great tutorial and will be a major reference for my restoration.
        Please check out my post on the MOA forum page 8 of your thread . I posted a picture regarding your coil wire orientation. I believe the coils should be rotated 180 degrees. This places the green wire on top with the crossover wires on the bottom. Tucking in the green wire for better protection.

        • Hi Pete,

          Thanks for the advice on orientation of the coil wires. Your suggestions provides cleaner wire routing.

          Best.
          Brook.

  3. Pingback: 1973 BMW R75/5 Rebuild: Prepare Fenders and Tank for Painting | Motorcycles & Other Musings

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