11 BMW 1983 R80ST Install Flywheel

I’ve removed the airbox, transmission and clutch to gain access to the flywheel. You can see how I did that work here.

I also show how to remove the flywheel here.

I’ve published documents on removing and installing the flywheel on other projects. You can see those documents here.

Since the 1983 R80ST engine is similar in many ways to the 1983 R100RS, I will link to the 1983 R100RS documents as appropriate in this document.

Parts

I replace the O-ring installed in the guide ring and the five flywheel bolts. I got these parts from Euro MotoElectrics. The “Gasket Ring”, aka, the O-ring, was included in the EME Gasket Kit, EME Part# GSK-EngineKit421.

Part # Description Qty
11 22 1 262 060  HEX BOLT – M11X1,5 5
11 22 1 337 093  GASKET RING – 59X3MM 1

Video

Here is a short YouTube video summarizing how I do this work.

VIDEO: 1983 BMW R80ST Install Flywheel

Preparing For Flywheel Installation

I show the preparation for flywheel installation in this 1983 R100RS document.

Polish The Guide Ring To Remove The Groove

Here are some pictures for the 1983 R80ST starting with what it looked like when I removed it.

Guide Ring Discoloration And Groove Worn By Lip Of Rear Main Seal

Guide Ring Discoloration And Groove Worn By Lip Of Rear Main Seal

Front Of Guide Ring Is Rusty

Front Of Guide Ring Is Rusty

Rear Of Guide Ring

Rear Of Guide Ring

Old O-ring Inside Guide Ring

Old O-ring Inside Guide Ring

Removing Old O-ring With Small Screwdriver

Removing Old O-ring With Small Screwdriver

Old O-ring Removed

Old O-ring Removed

Auto Sol Metal Polish

Auto Sol Metal Polish

Polishing Guide Ring

Polishing Guide Ring

Gunk Removed From Guide Ring

Gunk Removed From Guide Ring

Cleaned Up Guide Ring

Cleaned Up Guide Ring

Cleaned Up Guide Ring

Cleaned Up Guide Ring

Cleaned Up Guide Ring-Front Face

Cleaned Up Guide Ring-Front Face

Ready To Sand Out Edge Of Groove In Guide Ring

Ready To Sand Out Edge Of Groove In Guide Ring

Sanded And Polished Guide Ring Shows Slight Groove

Sanded And Polished Guide Ring Shows Slight Groove

Deburr Flywheel Teeth

There are some burrs on the flywheel teeth. I use a flat file to remove them.

Flywheel Teeth That Engage With Starter Motor

Flywheel Teeth That Engage With Starter Motor

Minor Damage To Flywheel Teeth

Minor Damage To Flywheel Teeth

Minor Damage To Flywheel Teeth

Minor Damage To Flywheel Teeth

Paint Timing Marks On Flywheel

I like to paint the timing marks on the flywheel so they are easier to see. I use Testor’s model paint; yellow for “OT”, white for “S” and red for “Z”.

Paint Applied To Flywheel Timing Marks

Paint Applied To Flywheel Timing Marks

Paint Applied To Flywheel Timing Marks

Paint Applied To Flywheel Timing Marks

Install Guide Ring O-ring

I install a new O-ring in the guide ring. This O-ring provides an oil seal around the crankshaft nose the guide ring fits on. I put a little oil on the O-ring so it will slide onto the crankshaft nose more easily.

New O-ring Installed In Guide Ring

New O-ring Installed In Guide Ring

Oil Guide Ring O-ring

Oil Guide Ring O-ring

Install Guide Ring and Flywheel On Crankshaft

This is how I do this work on the 1983 R100RS.

Here are some pictures for the R80ST. Since I have to torque the flywheel bolts to 90 Ft-Lbs, I use a wood clamp on the left side of the engine to clamp it to the benchtop so the engine won’t roll over when I torque the bolts. On the 1983 R100RS I screwed 2×4 pieces of wood to the bench top and used another 2×4 to brace the right side of the bell housing to keep the engine from rolling over. The wood clamp is easier and quicker and works just as well.

Using Wood Clamp To Keep Engine Block From Rolling Over When I Torque The Flywheel Bolts

Using Wood Clamp To Keep Engine Block From Rolling Over When I Torque The Flywheel Bolts

Clean Guide Ring and Rear Main Seal Teflon Seal Lip

Before I install the guide ring on the crankshaft nose, I clean the guide ring sealing surface and the Teflon lip of the rear main seal with alcohol wipes to get any dirt, debris and oil off them. You do not want to oil the Teflon lip of the rear main seal or it will not wear into the guide ring properly and it will leak.

Clean Guide Ring Seal Surface With Alcohol Wipe

Clean Guide Ring Seal Surface With Alcohol Wipe

Clean Teflon Seal Lip With Alcohol Wipe

Clean Teflon Seal Lip With Alcohol Wipe

Tighten New Flywheel Bolts To Pull Guide Ring Onto Crankshaft Nose

Tighten New Flywheel Bolts To Pull Guide Ring Onto Crankshaft Nose

I install the guide ring so the hole with the punch marks is aligned with the flywheel hole with the punch marks using new, clean and not oiled, flywheel bolts. I hand tighten the bolts to pull the guide ring all the way onto the crankshaft nose.

Center Flywheel On Flywheel Bolts

I loosen the bolts a bit and rotate the flywheel on the bolts using the edge of the starter motor casting to see how much the flywheel moves. It moves about a flywheel tooth. I move the flywheel so half the tooth is showing which centers the flywheel on the crankshaft bolt holes and gently tighten the flywheel bolts to hold the flywheel in place. This ensures the timing marks on the flywheel are accurate and the ignition timing will be accurate.

Flywheel Movement On Bolts

Flywheel Movement On Bolts

Flywheel Movement On Bolts-About One Tooth

Flywheel Movement On Bolts-About One Tooth

Centering Flywheel On Bolts-1/2 Tooth Movement Then Tighten Bolts

Centering Flywheel On Bolts-1/2 Tooth Movement Then Tighten Bolts

Torque Flywheel Bolts

I use a screwdriver to immobilize the flywheel and then torque the flywheel bolts to 90 Ft-Lbs in stages: 45 Ft-Lbs, 80 Ft-Lbs and then 90 Ft-Lbs.

Large Blade Screwdriver In Flywheel Teeth To Keep Engine From Rotating

Large Blade Screwdriver In Flywheel Teeth To Keep Engine From Rotating

Torque Flywheel Bolts to 90 Ft-Lbs In Two Stages

Torque Flywheel Bolts to 90 Ft-Lbs In Two Stages

With the flywheel installed I verify that the punch marks on the flywheel align with those on the case.

Flywheel Installed

Flywheel Installed

Verify Punch Marks Are Aligned

Verify Punch Marks Are Aligned

Revisions

2022-03-26  Added pictures of original condition of the guide ring when it was removed.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.