What Did You Do With Your Commando Today?

Spending the day rebuilding the forks on my 74 Commando.
I had a leaking fork seal and I can't remember the last time I had them apart. The gators were dry rotted so it will be a good day to get this job done. Putting in the fork oil now. A friend built a tool to make putting the oil in a lot easier. He took an old fork tube and cut it off about 10" below the top of the tube. Then he cut off the head of a Commando fork bolt. People call then fork nuts, but they are bolts. Threaded the fork bolt into the old fork tube with about 1" sticking out. Now I can thread the tool into the top of the rebuilt fork tube and not baby sit it as the fork oil slowly drains down past the spring. I have tried to upload the pictures but I'm having issues with the "updates" that are supposed to make things easier and seldom do.

Went for a short ride as temps were conducive. Not many days like today left so making the most of them.

Stevo said:

Went for a short ride as temps were conducive. Not many days like today left so making the most of them.

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Yeah , me too . Primary takes a very long time to get warm , unlike the motor . The gearbox stays cool to cold . Seems the clutch must be pulled in to start every time now . MK 111 fun .

Colder every day . But still driving her . The trick seems to be pull in the clutch before hitting the magic button , plenty of tickled fuel before .
Got 3 compliments today . Beautiful bike X 2 , cars slowing down to say that . One pedestrian saying nice bike . That's just out front . Before even starting her up .

Fitted new rear isolastic rubbers, and also fitted a non-return valve to the crankcase breather. Valve is a Benelli 125 ebay item, which is an inline valve, rather than the more usual 90 degree versions available.
I tried fitting the valve at the oil tank top, but it was too crammed, and near the battery, so it ended up where there was more space.
Next job is make a new clutch lever bush.

On my Mk III I replaced the starter sprag (DC4127(3c)) with one from Aliexpress, that I learned of on this forum. Was getting the zing zing start about every other time. The old sprag fell apart when I pulled it out of the sprocket, the cage was broken in several places. Also checked the breakaway torque on the backfire device. It was at about 35 ft lb. Reset it to about 45-48 (close to 50). Works good now and starting is consistent, no more zing zing. While in there I checked the timing marker with a degree wheel on the rotor. It was off about 3 degrees, in the advanced direction. Removed the marker and slotted with my Dremel. Reset timing. Starts and runs great.
Cheers

Finally got a start on the tappet adjuster project today although still feeling somewhat delicate after a weekend of illness with some bastard bug I’d picked up from lord knows where; still, it gave me a focus. Cleared the garage of all 3 bikes to give me plenty room and installed a heater to keep me comfortable.

So on with the job. It was my hope that as someone here suggested I’d might get away without removing the rockers entirely and that’s how it worked out; inserting a barbecue skewer to prevent anything falling having first used a blow torch and extraction tool. This allowed enough lift of the rocker to lower the old mushroom adjuster and thread in the replacement after which I fashioned an alignment tool from doweling in readiness to reassemble. However there are signs of wear on the spindle, enough to convince myself replacement be prudent so ordered and awaiting delivery before I sign off part one of four.

Further hunting rewarded me with finding another tiny fragment of the deceased adjuster which as can be seen in the shot below was always going south at some point; it’ll be interesting to see the ends of the others.




Temporarily back together until new spindles arrive

What adjusters are you going to use, stock or the same that broke.

The second photo shows the installed replacement minus the lock nut of course, purchased from Britcycle.com in the US. These are what are now recommended by Matt. As you can see, the ‘mushroom’ is far more substantial and Matt reports zero failures so I’m happy to once again take his advice.

Naturally I tested the threads before removing the spindle just in case there was an issue.

Hoping to finish the job Thursday but been thinking. I reckon ‘key hole surgery’ may be tricky on the inlet side and it looks like the rockers won’t clear the cover stud. What thread is that exactly?; I’ll source a couple of nuts so I can remove it. Cheers

Café au Lait said:

What thread is that exactly?

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The outer end of the inlet cover stud is 5/16" x 26 Cycle (BSC/CEI) thread.

I unscrewed the stud using a Mole/vise grip on the plain section. It marked the stud a little but in an area that doesn't matter.

Just thought I’d update you guys.

All 4 adjusters and spindles fitted without a hitch using ‘keyhole method’ throughout although locating the thread on the right inlet was a bit tricky with the oil line, cover stud and throttle cable all around but managed not to drop it and didn’t let any of the Thackary washers fall either.

Tomorrow I’ll double check the clearances and use a syringe to squirt some oil down the pushrods to bathe the tappets and cam then take him for a test ride after which I’ll drop the oil and check the magnets. I did find another tiny fragment on top of one of the inlet springs so confident I’ve 90%+ of it out.

As you can see, all the adjusters were shot and ready to pop so I’m glad I spotted it when I did.


These in correct order. All 4 valve stems look perfect and no obvious scoring inside the rockers. All 4 spindles were similar one had a more pronounced score one felt almost perfect.

Overall, very satisfying to do so glad I didn’t farm it out. Here’s for some more trouble free riding until they cover out roads in salt.

Wow! Never seen that kind of pitting on tappet adjusters like that before. What Cam are you using? What were the tappets adjusted to?
All 4 like that.
Reviewing back to post #3129... there is something going on with that engine.

Café au Lait said:

Just thought I’d update you guys.

All 4 adjusters and spindles fitted without a hitch using ‘keyhole method’ throughout although locating the thread on the right inlet was a bit tricky with the oil line, cover stud and throttle cable all around but managed not to drop it and didn’t let any of the Thackary washers fall either.

Tomorrow I’ll double check the clearances and use a syringe to squirt some oil down the pushrods to bathe the tappets and cam then take him for a test ride after which I’ll drop the oil and check the magnets. I did find another tiny fragment on top of one of the inlet springs so confident I’ve 90%+ of it out.

As you can see, all the adjusters were shot and ready to pop so I’m glad I spotted it when I did.

View attachment 117568
These in correct order. All 4 valve stems look perfect and no obvious scoring inside the rockers. All 4 spindles were similar one had a more pronounced score one felt almost perfect.

Overall, very satisfying to do so glad I didn’t farm it out. Here’s for some more trouble free riding until they cover out roads in salt.

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Good catch !

Yikes!

CanukNortonNut said:

Wow! Never seen that kind of pitting on tappet adjusters like that before. What Cam are you using? What were the tappets adjusted to?
All 4 like that.
Reviewing back to post #3129... there is something going on with that engine.

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The cam is by Web. I know F all squared about such but I believe it’s a 312? They are adjusted to 006” - 006” as per Matt rather than 006” - 008” for the stock bike.

Matt said he had a few go like this many years back due to a hardening process issue so it seems I’ve fallen victim to those.

Obviously I’ll be keeping a close eye on things and will perform regular oil drops/changes and inspect the magnets!

Edit: the cam is a Web #12

Today, the temperature hit 50 degrees and I wanted to try new BPR7EIX plugs and new copper wires. Seemed to run great once it warmed up. There was a glazed look to the roadways everywhere that today's sun never hit so I rode around cautiously. My engine seems like it's gotten noisy at idle towards the end of the summer and I used a long screw driver like a stethoscope to try to locate the source. It seemed like it was less than I remembered so I'm just going to wait until next year to look. I'll get a new timing chain for it then and check into it further. Fun getting out in December, just to hear it run...

Yesterday I took advantage of the calm before the storm, it’s blowing a Gail right now, and did a 35 mile shake down ride after completing the tappet adjuster and spindle surgery.

I managed to perform the operation without the need to withdraw any rockers or the inlet cover stud, indeed it was a most straightforward job but rather satisfying nonetheless.

Happy to report all is well; bike running very strong with no leaks or unexpected noises. I’ll be keeping a close eye on the sump magnets over the next few rides before one last oil change a the year.