Change the Oil in a Vintage Honda CB100

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About: Traveler

Intro: Change the Oil in a Vintage Honda CB100

I've had this bike for a while and have decided it's time for an oil change as I've not done that yet on this bike. so here we go.
first, it helps to have a service manual... for capacities and torque specs

Step 1: Drain the Oil

Step 2: Remove Kick Stand

to remove the clutch cover to access the centrifugal oil filter you'll need to remove the clutch side crankcase cover. This requires the removal of the kick starter, the foot pegs and the exhaust system. 

Step 3: Remove Exhaust

Step 4: Remove Kick Starter

Step 5: Loosen Screws on Clutch Cover

Make sure you use the correct screwdriver there are many types of "phillips" screws. they are NOT the same. These screws are easy to strip the phillips head. after some rummaging I was able to find the correct screwdriver and removed all the screws

Step 6: Whack It!

breaking loose the cover is easy with a couple taps of a rubber mallet

Step 7: Save the Gasket!

I didn't have a replacement gasket on hand so I tried to save as much of the gasket as possible and will be sealing it with gasket maker upon reassembly.

Step 8: Clean It!

clean out any sludge you see as well as anything you might find in the centrifugal filter

Step 9: Back Together!

I'm pretty sure that this is from my grandpas time and probably highly toxic but it works wonders!

Step 10: Remove Filter Screen Cover

Step 11: This Is What Comes Out...

clean the screen well and check for any metal filings.

Step 12: Shine It Up!

before putting the bike back together I decided to do some polishing... it's easier with the parts off... and why not?

Step 13: Test Ride!

After putting the bike back together and  filling the fluids of course!
after a short ride make sure everything is torqued correctly and there are no leaks! and you're done.

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    16 Discussions

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    st1sking

    3 years ago on Introduction

    Thanks for the info. I recovered my late father-in-law's '72 cb100
    from the woods where it has been laying for 27 years. I need to do a
    full restoration on it, down to the frame. Being a car guy, I have the
    skill, but have never touched a motorcycle before. It's nice to have a
    place to see step by step instructions for some of the tasks.

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    josh

    4 years ago

    My bike has 18" wheels front and back. And I'm running 18x3 tires on both. The tires are no-name ones I ordered through my local motorcycle shop. They're a modern street pattern so they don't have a vintage look but they were cheap!!. Sorry I can't help more!

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    Ladalske

    4 years ago on Introduction

    Josh,

    I have the same bike. What tires do you have on it? I am looking at different sizes and it looks like yours are balanced. I have 3.00 x17 on the rear and 2.5 x 18 on the front.

    Thanks

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    Dulaya

    5 years ago on Step 13

    I fully drained and changed oil (1 qt), removed foot stand and exhaust. I don't have the screw drive to remove the clutch cover. So I then put everything back together. Now the bike doesn't start. It was working fine right before the oil change.

    Could it be that I put too much oil? The manual recommends 1 liter, which is just over 1 qt. What about the muffler? I think I put it back correctly.

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    joshDulaya

    Reply 5 years ago on Step 13

    Dulaya, removing the kickstand and exhaust are usually not required if you are not planning on removing the clutch cover.
    As for your starting issue it is hard to determine what the actual cause of your bike not starting. First. Does the bike have ignition? Does it have fuel? Compression? Unfortunately I cannot say why your bike is not starting from the little info you've given. Some research on forums for your particular bike or a neighborhood mechanic should be able to help sort the problem.

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    7070x

    6 years ago on Introduction

    Broomm broomm !

    That's how us here rev, of course with aftermarket exhaust, when we meet with other CB 100 riders. Yours is a sweet retro classic style! Is that restored now?
    Mine below is going on some serious engine swap. Actually, I am replacing the cylinder head with Honda GL Pro Series, trying to get 156cc. Picked up the bike for Rp 2 million or US$220. still lots to invest on the project.

    100_3755.JPG
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    josh7070x

    Reply 5 years ago on Introduction

    Nice bike! I'm keeping this one all original no restoration. I've done some mods to the bike but they're all easily reversible. Wish we had a CB100 club here!

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    AaronMiller27

    5 years ago on Step 13

    Hey I've got the same bike. Was driving fine but when I did the oil change I took off the clutch cover as well and now when I go to put the bike in first gear it seems like its not engaging gears. Do you know what I might have messed up? I made sure that the little rotating part connected to the clutch lever was behind the metal part that is pushed out and sprung back. Not sure what else I could have messed up?

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    joshAaronMiller27

    Reply 5 years ago on Introduction

    It might be that when you put it back together that something got just a bit out of place. Also you might not have put the correct amount of oil in the case. It's a super simple engine/tranny if you get the service manual you might see quite quickly what's wrong

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    Beemer007

    6 years ago on Introduction

    I'm planning to get a 100cc bike soon. Thanks for the info.

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    josh2 stroke

    Reply 6 years ago on Introduction

    yes. It's a K&N, I swapped out the carb with a different one to test some things and it didn't fit with the stock aircleaner setup.

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    2 stroke josh

    Reply 6 years ago on Introduction

    i am getting a 2001 Kawasaki KE 100 2 stroke should do 75 mph after i put a smaller rear sproket how fast is your bike on wide open throttle

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    da winksta

    7 years ago on Step 13

    I have the same bike only with the red accents instead of blue. 1972 CB100.
    Thanks for the instructable, ive changed the oil a bunch of times but didnt know there was a filter in there!
    So why did you remove the clutch cover?

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    joshda winksta

    Reply 6 years ago on Introduction

    I removed the clutch cover to inspect the clutch and clean the centrifugal oil filter.

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    cokecola

    7 years ago on Introduction

    Nice bike, it looks like a 75 or 76.
    My Dad had a Honda CL100 that looked alot like the CB. He bought it in 1970 for $410 and sold in 3 years ago for 750.