Introduction: Chain Tension Adjustment on Vintage Honda Motorcycles

Picture of Chain Tension Adjustment on Vintage Honda Motorcycles

The chain on my motorcycle was super loose, and should probably be replaced. I ordered a new one, but then found out that I should also replace the sprockets at the same time, so today I'm just adjusting the chain tension on my 1975 Honda CB200.

I almost didn't make this tutorial, since I basically just followed the excellent instructions from a video I found on Old Bike Garage's channel. But hey, I can offer you my experience of performing this routine maintenance for the first time, and a riding montage at the end of the video. And if nothing else, hopefully this'll stir up some Google juice for the excellent video that taught me.

Step 1: Loosen Up

Picture of Loosen Up

I started with my bike in neutral on its center stand, with room to get to both sides of the rear axle. I didn't remove the chain guard because there was one screw in a hard-to-remove place.

Then I removed the axle nut's cotter pin and loosened the nut itself with a 22mm wrench.

Next up, I loosened the lock nuts on both sides' adjuster bolts.

Step 2: Make Adjustment

Picture of Make Adjustment

The adjustment happens when you tighten the adjuster bolts, which then press against the frame to move the axle backwards.

The single notch on the chain adjuster is its index mark, and both right and left index marks should align with consistent positions on the notched scale along the rear fork.

According to my manual, the chain's free play at the tightest point should about 20mm, or three quarters of an inch.

Step 3: Tighten Everything Up

Picture of Tighten Everything Up

Then what remains is the reverse order of before: tighten the lock nuts, tighten the axle bolt, and reinsert and bend the cotter pin.

This adjustment can throw off the play in the rear brake pedal, so it's important to check and adjust that after adjusting the chain tension. I also took this opportunity to lubricate my chain as well.

I was pleasantly surprised by how easy it was to adjust my chain tension, something I should have been doing way more often than I have been.

Thanks for reading my Instructable! Check out more of my motorcycle projects:

Comments

jack_auckland (author)2017-09-08

Hi - one thing I'd like to suggest. The chain is tightest when the centre of the sprockets and the swing arm pivot are in line.

When the bike is on the centre stand the rear wheel will drop a bit so the chain will be slacker than at the tightest point.

Just before you re-tighten the rear axle, pays to drop it off the stand an lean over the bike so as to put some weight on the seat. This will get the sprockets / swing arm pivot in line and the chain will be at its tightest. Thats when you should check the play.

deluges (author)2017-08-07

Nice tips, thanks for posting them. I'm leaving fora 2000 km trip on my CM400T next week and haven't had to tighten the chain for the past 800 km. I check it every 200 km or so but it apparently never slacks. My free play never exceeded 15 mm, go figure..

AlphaOmega1 (author)deluges2017-08-10

Chain quality/size, contaminants (grit), engine power, sprocket size, sprocket wear, sprocket alignment, axis of rear suspension/travel, how big a handful of revs you grab at the lights etc. will all effect chain wear.

Simply spraying "lube" on the chain as shown above is a bad idea!

bekathwia (author)AlphaOmega12017-08-11

How could I improve my chain lubrication technique? I followed the tips from the Old Bike Barn video linked in the intro. Lost my straw, though.

AlphaOmega1 (author)bekathwia2017-08-11

The problem with adding oil to a dirty chain, is that along with existing and newly picked up sand and dirt (English meaning of the word), you are making lapping paste! Grinding away your expensive chain and sprockets.

So the first thing to do is remove the dirt (In fact the first thing is to visit the manufacturers website for a full list of do's & dont's to maintain their chain!). It usually means removing the chain to do a good job (I usually had two on the go, one on the bike, one being cleaned). You need to remove the dirt from the sprockets too.

Don't use solvents unless advised, some of the better chains have O-ring (sealed chains) to keep the dirt out of the gap between the roller and the bushing that may perish. Mechanical cleaning with a soft brush works (tooth brush etc.)

When the dirt is gone you need to lubricate the parts in contact with each other using the correct lubricant. (I used to use a hot wax based product, but that is probably old-hat now). Certainly not WD40! That will drive out any thicker lubricants and dirt sticks to it too easily (only good for penetrating, despite what it says on the can!)

Then the important bit, you need to get rid of the excess oil that acts as a sticky sand collector.

A sealed chain does not need lubricating, but should be kept clean!

LOL, just had a gander and found this in seconds, so ignore my blurb above....

http://www.sprocketsunlimited.com/Chainmaintenance.html

lawagoneer (author)2017-08-10

IN the Honda service manual they tell how to make a quick check for proper alignment that is very helpful. I had a CB400 Type II that the alignment marks were not very accurate and if I just used them the bike had weird handling issues. Using the describe alignment gauge I had no problems. My bike had never been down or damaged and was just off from the factory. A quick alignment check is always a good idea.

bekathwia (author)lawagoneer2017-08-11

What's the method for the quick alignment check?

RandyPerson (author)2017-08-04

When you re-tighten the axle nut, be sure to push down and forward with the wrench (which you did in the video). You'll be working with the adjuster bolt, and the adjustment won't change. If you start with the wrench up and pull back, you can move the axle and tighten the tension even more, and also tilt the wheel as you pull the adjuster on that side away from it's seat. And when the friction isn't enough, you'll be really startled when the axle snaps back to re-seat the adjuster bolt.

In my experience, the stamped marks are usually pretty good, but it won't hurt to back up and squint along the wheels. Your eye can pick up a very slight misalignment that you might not catch from the marks. Some detail-oriented folks even like to stretch a string from front to back to make sure the wheels are perfectly aligned.

As to replacement, here are two quick checks. Once adjusted, you should not be able to pull the chain off the rear sprocket much at all. If you can grab it at the back, near the adjuster bolt, and pull it away from the sprocket, the chain needs replacing. New sprockets have symmetrical teeth. When your teeth start looking more like a circular saw blade, the sprocket is shot. You'll typically go through 2 or 3 chains before you need new sprockets. Regular lube and adjustment will prolong the life of both.

Barnbaby (author)RandyPerson2017-08-10

These comments are an excellent addition to this very fine tutorial.

bekathwia (author)Barnbaby2017-08-11

Agreed, I love it when that happens! Thanks everybody!

DaBlakus (author)2017-08-10

On my machine CB77 the tension varies from the on stand or when seated on it off stand, so I feel it's better to adjust the chain for that situation. It can be done solo by reaching down and feeling the chain slack but easier with a bit of help.

Gofish (author)2017-08-10

Randy has mentioned the string trick and I'd like to add for road use a safety R-clip instead of a split-pin.

burzurk (author)2017-08-10

..one more VERY IMPORTANT thing.. wheel alignment. I'm not sure if your Honda has the adjusters on both sides..but just make sure the wheel is straight after adjusting the chain tension.

...Great Instructable :)

AlphaOmega1 (author)2017-08-10

Honda CB's ;) Takes me back!

Nice clear instruction

Just a note for the UK viewers. The pin is a split pin holding the castellated nut from rotating. In the UK a cotter pin is a pin (bolt) with a tapered flat, as used on older bicycle cranks etc.

You should replace your split pin since they work harden very easily. They only cost pennies and could save your life.

LesH12 (author)2017-08-10

Good info. I cut my riding "teeth" on Brit bikes in the '60's, and I would add a couple of points. (1) always replace chain and sprockets as a set. If you replace only one part of the set, this will cause premature wear on the rest of the set. (2) to get the maximum life of the set, check the chain tension once a week, and every month we would flip the sprockets over to get more even wear, and prolong the life of the whole set. (some bikes do not have reversible sprockets, however)

Barnbaby (author)2017-08-10

Excellent job! Very good use of video and text; they go together well. I would only suggest that you use a new cotter pin instead of re-using the old one, and always carry a spare just in case.

bekathwia (author)Barnbaby2017-08-10

Thank you, and solid suggestion about the cotter pin!

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Bio: Becky Stern is a content creator at Instructables. She has authored hundreds of tutorials about everything from wearable electronics to knitting. Before joining Instructables, Becky ... More »
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